TY - JOUR A1 - Zupanc, Günther K. H. A1 - Rössler, Wolfgang T1 - Government funding of research beyond biomedicine: challenges and opportunities for neuroethology JF - Journal of Comparative Physiology A N2 - Curiosity-driven research is fundamental for neuroethology and depends crucially on governmental funding. Here, we highlight similarities and differences in funding of curiosity-driven research across countries by comparing two major funding agencies—the National Science Foundation (NSF) in the United States and the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG). We interviewed representatives from each of the two agencies, focusing on general funding trends, levels of young investigator support, career-life balance, and international collaborations. While our analysis revealed a negative trend in NSF funding of biological research, including curiosity-driven research, German researchers in these areas have benefited from a robust positive trend in DFG funding. The main reason for the decrease in curiosity-driven research in the US is that the NSF has only partially been able to compensate for the funding gap resulting from the National Institutes of Health restricting their support to biomedical research using select model organisms. Notwithstanding some differences in funding programs, particularly those relevant for scientists in the postdoctoral phase, both the NSF and DFG clearly support curiosity-driven research. KW - German Research Foundation KW - Government research funding KW - National Science Foundation KW - Deutsche Forschungsgemeinschaft KW - neuroethology Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325113 VL - 208 IS - 3 ER - TY - JOUR A1 - Ziegler, Alice A1 - Meyer, Hanna A1 - Otte, Insa A1 - Peters, Marcell K. A1 - Appelhans, Tim A1 - Behler, Christina A1 - Böhning-Gaese, Katrin A1 - Classen, Alice A1 - Detsch, Florian A1 - Deckert, Jürgen A1 - Eardley, Connal D. A1 - Ferger, Stefan W. A1 - Fischer, Markus A1 - Gebert, Friederike A1 - Haas, Michael A1 - Helbig-Bonitz, Maria A1 - Hemp, Andreas A1 - Hemp, Claudia A1 - Kakengi, Victor A1 - Mayr, Antonia V. A1 - Ngereza, Christine A1 - Reudenbach, Christoph A1 - Röder, Juliane A1 - Rutten, Gemma A1 - Schellenberger Costa, David A1 - Schleuning, Matthias A1 - Ssymank, Axel A1 - Steffan-Dewenter, Ingolf A1 - Tardanico, Joseph A1 - Tschapka, Marco A1 - Vollstädt, Maximilian G. R. A1 - Wöllauer, Stephan A1 - Zhang, Jie A1 - Brandl, Roland A1 - Nauss, Thomas T1 - Potential of airborne LiDAR derived vegetation structure for the prediction of animal species richness at Mount Kilimanjaro JF - Remote Sensing N2 - The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-derived variables characterizing vegetation structure as predictors for animal species richness at the southern slopes of Mount Kilimanjaro. To disentangle the structural LiDAR information from co-factors related to elevational vegetation zones, LiDAR-based models were compared to the predictive power of elevation models. 17 taxa and 4 feeding guilds were modeled and the standardized study design allowed for a comparison across the assemblages. Results show that most taxa (14) and feeding guilds (3) can be predicted best by elevation with normalized RMSE values but only for three of those taxa and two of those feeding guilds the difference to other models is significant. Generally, modeling performances between different models vary only slightly for each assemblage. For the remaining, structural information at most showed little additional contribution to the performance. In summary, LiDAR observations can be used for animal species prediction. However, the effort and cost of aerial surveys are not always in proportion with the prediction quality, especially when the species distribution follows zonal patterns, and elevation information yields similar results. KW - biodiversity KW - species richness KW - LiDAR KW - elevation KW - partial least square regression KW - arthropods KW - birds KW - bats KW - predictive modeling Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262251 SN - 2072-4292 VL - 14 IS - 3 ER - TY - JOUR A1 - Wunder, Juliane A1 - Pemp, Daniela A1 - Cecil, Alexander A1 - Mahdiani, Maryam A1 - Hauptstein, René A1 - Schmalbach, Katja A1 - Geppert, Leo N. A1 - Ickstadt, Katja A1 - Esch, Harald L. A1 - Dankekar, Thomas A1 - Lehmann, Leane T1 - Influence of breast cancer risk factors on proliferation and DNA damage in human breast glandular tissues: role of intracellular estrogen levels, oxidative stress and estrogen biotransformation JF - Archives of Toxicology N2 - Breast cancer etiology is associated with both proliferation and DNA damage induced by estrogens. Breast cancer risk factors (BCRF) such as body mass index (BMI), smoking, and intake of estrogen-active drugs were recently shown to influence intratissue estrogen levels. Thus, the aim of the present study was to investigate the influence of BCRF on estrogen-induced proliferation and DNA damage in 41 well-characterized breast glandular tissues derived from women without breast cancer. Influence of intramammary estrogen levels and BCRF on estrogen receptor (ESR) activation, ESR-related proliferation (indicated by levels of marker transcripts), oxidative stress (indicated by levels of GCLC transcript and oxidative derivatives of cholesterol), and levels of transcripts encoding enzymes involved in estrogen biotransformation was identified by multiple linear regression models. Metabolic fluxes to adducts of estrogens with DNA (E-DNA) were assessed by a metabolic network model (MNM) which was validated by comparison of calculated fluxes with data on methoxylated and glucuronidated estrogens determined by GC- and UHPLC-MS/MS. Intratissue estrogen levels significantly influenced ESR activation and fluxes to E-DNA within the MNM. Likewise, all BCRF directly and/or indirectly influenced ESR activation, proliferation, and key flux constraints influencing E-DNA (i.e., levels of estrogens, CYP1B1, SULT1A1, SULT1A2, and GSTP1). However, no unambiguous total effect of BCRF on proliferation became apparent. Furthermore, BMI was the only BCRF to indeed influence fluxes to E-DNA (via congruent adverse influence on levels of estrogens, CYP1B1 and SULT1A2). KW - metabolic network model KW - estrogens KW - human breast KW - multiple linear regression Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265343 SN - 1432-0738 VL - 96 IS - 2 ER - TY - JOUR A1 - Widder, Anna A1 - Kelm, Matthias A1 - Reibetanz, Joachim A1 - Wiegering, Armin A1 - Matthes, Niels A1 - Germer, Christoph-Thomas A1 - Seyfried, Florian A1 - Flemming, Sven T1 - Robotic-assisted versus laparoscopic left hemicolectomy — postoperative inflammation status, short-term outcome and cost effectiveness JF - International Journal of Environmental Research and Public Health N2 - Robotic-assisted colon surgery may contain advantages over the laparoscopic approach, but clear evidence is sparse. This study aimed to analyze postoperative inflammation status, short-term outcome and cost-effectiveness of robotic-assisted versus laparoscopic left hemicolectomy. All consecutive patients who received minimal-invasive left hemicolectomy at the Department of Surgery I at the University Hospital of Wuerzburg in 2021 were prospectively included. Importantly, no patient selection for either procedure was carried out. The robotic-assisted versus laparoscopic approaches were compared head to head for postoperative short-term outcomes as well as cost-effectiveness. A total of 61 patients were included, with 26 patients having received a robotic-assisted approach. Baseline characteristics did not differ among the groups. Patients receiving a robotic-assisted approach had a significantly decreased length of hospital stay as well as lower rates of complications in comparison to patients who received laparoscopic surgery (n = 35). In addition, C-reactive protein as a marker of systemic stress response was significantly reduced postoperatively in patients who were operated on in a robotic-assisted manner. Consequently, robotic-assisted surgery could be performed in a cost-effective manner. Thus, robotic-assisted left hemicolectomy represents a safe and cost-effective procedure and might improve patient outcomes in comparison to laparoscopic surgery. KW - robotic surgery KW - colon resection KW - postoperative inflammation KW - cost-effectiveness KW - left hemicolectomy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286203 SN - 1660-4601 VL - 19 IS - 17 ER - TY - JOUR A1 - Wegener, Christian A1 - Chen, Jiangtian T1 - Allatostatin A signalling: progress and new challenges from a paradigmatic pleiotropic invertebrate neuropeptide family JF - Frontiers in Physiology N2 - Neuropeptides have gained broad attraction in insect neuroscience and physiology, as new genetic tools are increasingly uncovering their wide-ranging pleiotropic functions with high cellular resolution. Allatostatin A (AstA) peptides constitute one of the best studied insect neuropeptide families. In insects and other panarthropods, AstA peptides qualify as brain-gut peptides and have regained attention with the discovery of their role in regulating feeding, growth, activity/sleep and learning. AstA receptor homologs are found throughout the protostomia and group with vertebrate somatostatin/galanin/kisspeptin receptors. In this review, we summarise the current knowledge on the evolution and the pleiotropic and cell-specific non-allatostatic functions of AstA. We speculate about the core functions of AstA signalling, and derive open questions and challengesfor future research on AstA and invertebrate neuropeptides in general. KW - neuropeptide signalling KW - feeding KW - intestinal control KW - sleep/activity KW - kisspeptin/galanin/spexin signalling KW - metabolism and growth KW - learning KW - cardioactive factor Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-278749 SN - 1664-042X VL - 13 ER - TY - JOUR A1 - Wech, Tobias A1 - Ankenbrand, Markus Johannes A1 - Bley, Thorsten Alexander A1 - Heidenreich, Julius Frederik T1 - A data-driven semantic segmentation model for direct cardiac functional analysis based on undersampled radial MR cine series JF - Magnetic Resonance in Medicine N2 - Purpose Image acquisition and subsequent manual analysis of cardiac cine MRI is time-consuming. The purpose of this study was to train and evaluate a 3D artificial neural network for semantic segmentation of radially undersampled cardiac MRI to accelerate both scan time and postprocessing. Methods A database of Cartesian short-axis MR images of the heart (148,500 images, 484 examinations) was assembled from an openly accessible database and radial undersampling was simulated. A 3D U-Net architecture was pretrained for segmentation of undersampled spatiotemporal cine MRI. Transfer learning was then performed using samples from a second database, comprising 108 non-Cartesian radial cine series of the midventricular myocardium to optimize the performance for authentic data. The performance was evaluated for different levels of undersampling by the Dice similarity coefficient (DSC) with respect to reference labels, as well as by deriving ventricular volumes and myocardial masses. Results Without transfer learning, the pretrained model performed moderately on true radial data [maximum number of projections tested, P = 196; DSC = 0.87 (left ventricle), DSC = 0.76 (myocardium), and DSC =0.64 (right ventricle)]. After transfer learning with authentic data, the predictions achieved human level even for high undersampling rates (P = 33, DSC = 0.95, 0.87, and 0.93) without significant difference compared with segmentations derived from fully sampled data. Conclusion A 3D U-Net architecture can be used for semantic segmentation of radially undersampled cine acquisitions, achieving a performance comparable with human experts in fully sampled data. This approach can jointly accelerate time-consuming cine image acquisition and cumbersome manual image analysis. KW - undersampling KW - cardiovascular magnetic resonance (CMR) KW - deep learning KW - radial KW - semantic segmentation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257616 VL - 87 IS - 2 ER - TY - THES A1 - Wagner, Martin T1 - Zyto- und Gentoxizität von Zinkoxid-Nanopartikeln in humanen mesenchymalen Stammzellen nach repetitiver Exposition und im Langzeitversuch T1 - Time-Dependent Toxic and Genotoxic Effects of Zinc Oxide Nanoparticles after Long-Term and Repetitive Exposure to Human Mesenchymal Stem Cells N2 - Zinkoxid-Nanopartikel (ZnO-NP) finden in vielen Produkten des täglichen Verbrauchs Verwendung. Daten über die toxikologischen Eigenschaften von ZnO-NP werden kontrovers diskutiert. Die menschliche Haut ist in Bezug auf die ZnO-NP Exposition das wichtigste Kontakt-Organ. Intakte Haut stellt eine suffiziente Barriere gegenüber NP dar. Bei defekter Haut ist ein Kontakt zu den proliferierenden Stammzellen möglich, sodass diese als wichtiges toxikologische Ziel für NP darstellen. Das Ziel dieser Dissertation war die Bewertung der genotoxischen und zytotoxischen Effekte an humanen mesenchymalen Stammzellen (hMSC) durch niedrig dosierte ZnO-NP nach 24 stündiger Exposition, repetitiven Expositionen und im Langzeitversuch bis zu 6 Wochen. Zytotoxische Wirkungen von ZnO-NP wurden mit 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid-Test (MTT) gemessen. Darüber hinaus wurde die Genotoxizität durch den Comet-Assay bewertet. Zur Langzeitbeobachtung bis zu 6 Wochen wurde die Transmissionselektronenmikroskopie (TEM) verwendet. Zytotoxizität nach 24-stündiger ZnO-NP-Exposition war ab einer Konzentration von 50 µg/ml nachweisbar. Genotoxizität konnten bereits bei Konzentrationen von 1 und 10 µg/ml ZnO-NP beschrieben werden. Wiederholte Exposition verstärkte die Zyto-, aber nicht die Genotoxizität. Eine intrazelluläre NP-Akkumulation mit Penetration der Zellorganelle wurde bei einer Exposition bis zu 6 Wochen beobachtet. Die Ergebnisse deuten auf zytotoxische und genotoxisches Effekte von ZnO-NP hin. Bereits geringe Dosen von ZnO-NP können bei wiederholter Exposition toxische Wirkungen hervorrufen sowie eine langfristige Zellakkumulation. Diese Daten sollten bei der Verwendung von ZnO-NP an geschädigter Haut berücksichtigt werden. N2 - Zinc oxide nanoparticles (ZnO-NP) are widely used in many products of daily consumption. Data on the toxicological properties of the ZnO-NP used are discussed controversially. Human skin is the most important organ in terms of ZnO-NP exposure. Intact skin has been shown to provide an adequate barrier against NPs, while defective skin allows NP contact with proliferating cells. Among proliferating cells, stem cells are the main toxicological target for NPs. Therefore, the aim of this dissertation was to evaluate the genotoxic and cytotoxic effects of human mesenchymal stem cells (hMSC) by low-dose ZnO-NP after 24 hours of exposure, repetitive exposures and in long-term experiments up to 6 weeks. Cytotoxic effects of ZnO-NP were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT). In addition, genotoxicity was assessed by the comet assay. Transmission electron microscopy (TEM) was used for long-term observation after 6 exposure periods. The results of the study show that ZnO-NP has a cytotoxic effect starting at high concentrations of 50 µg/mL and could demonstrate genotoxic effects in hMSC exposed to 1 and 10 µg/ml ZnO-NP. Repeated exposure enhanced cytotoxicity but not genotoxicity. Intracellular NP accumulation with penetration of the cell organelles was observed at exposure up to 6 weeks. The results indicate the cytotoxic and genotoxic potential of ZnO-NP. Even small doses of ZnO-NP can cause toxic effects with repeated exposure and long-term cell accumulation. These data should be considered when using ZnO-NP on damaged skin. KW - nanoparticle KW - zinc oxid KW - stem cells KW - nanotoxicology KW - human skin KW - Nanopartikel KW - humane mesenchymale Stammzellen KW - Genotoxizität KW - Zytotoxizität KW - Repetitive Exposition KW - Elektronenmikroskopie Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-275726 ER - TY - JOUR A1 - Vollmuth, Nadine A1 - Schlicker, Lisa A1 - Guo, Yongxia A1 - Hovhannisyan, Pargev A1 - Janaki-Raman, Sudha A1 - Kurmasheva, Naziia A1 - Schmitz, Werner A1 - Schulze, Almut A1 - Stelzner, Kathrin A1 - Rajeeve, Karthika A1 - Rudel, Thomas T1 - c-Myc plays a key role in IFN-γ-induced persistence of Chlamydia trachomatis JF - eLife N2 - Chlamydia trachomatis (Ctr) can persist over extended times within their host cell and thereby establish chronic infections. One of the major inducers of chlamydial persistence is interferon-gamma (IFN-γ) released by immune cells as a mechanism of immune defence. IFN-γ activates the catabolic depletion of L-tryptophan (Trp) via indoleamine-2,3-dioxygenase (IDO), resulting in persistent Ctr. Here, we show that IFN-γ induces the downregulation of c-Myc, the key regulator of host cell metabolism, in a STAT1-dependent manner. Expression of c-Myc rescued Ctr from IFN-γ-induced persistence in cell lines and human fallopian tube organoids. Trp concentrations control c-Myc levels most likely via the PI3K-GSK3β axis. Unbiased metabolic analysis revealed that Ctr infection reprograms the host cell tricarboxylic acid (TCA) cycle to support pyrimidine biosynthesis. Addition of TCA cycle intermediates or pyrimidine/purine nucleosides to infected cells rescued Ctr from IFN-γ-induced persistence. Thus, our results challenge the longstanding hypothesis of Trp depletion through IDO as the major mechanism of IFN-γ-induced metabolic immune defence and significantly extends the understanding of the role of IFN-γ as a broad modulator of host cell metabolism. KW - Chlamydia trachomatis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301385 VL - 11 ER - TY - JOUR A1 - Volland, Julian Manuel A1 - Kaupp, Johannes A1 - Schmitz, Werner A1 - Wünsch, Anna Chiara A1 - Balint, Julia A1 - Möllmann, Marc A1 - El-Mesery, Mohamed A1 - Frackmann, Kyra A1 - Peter, Leslie A1 - Hartmann, Stefan A1 - Kübler, Alexander Christian A1 - Seher, Axel T1 - Mass spectrometric metabolic fingerprinting of 2-Deoxy-D-Glucose (2-DG)-induced inhibition of glycolysis and comparative analysis of methionine restriction versus glucose restriction under perfusion culture in the murine L929 model system JF - International Journal of Molecular Sciences N2 - All forms of restriction, from caloric to amino acid to glucose restriction, have been established in recent years as therapeutic options for various diseases, including cancer. However, usually there is no direct comparison between the different restriction forms. Additionally, many cell culture experiments take place under static conditions. In this work, we used a closed perfusion culture in murine L929 cells over a period of 7 days to compare methionine restriction (MetR) and glucose restriction (LowCarb) in the same system and analysed the metabolome by liquid chromatography mass spectrometry (LC-MS). In addition, we analysed the inhibition of glycolysis by 2-deoxy-D-glucose (2-DG) over a period of 72 h. 2-DG induced very fast a low-energy situation by a reduced glycolysis metabolite flow rate resulting in pyruvate, lactate, and ATP depletion. Under perfusion culture, both MetR and LowCarb were established on the metabolic level. Interestingly, over the period of 7 days, the metabolome of MetR and LowCarb showed more similarities than differences. This leads to the conclusion that the conditioned medium, in addition to the different restriction forms, substantially reprogramm the cells on the metabolic level. KW - amino acid restriction KW - glucose restriction KW - mass spectrometry KW - low carb KW - 2-deoxy-D-glucose KW - 2-DG KW - methionine KW - perfusion culture KW - energy restriction KW - caloric restriction Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286007 SN - 1422-0067 VL - 23 IS - 16 ER - TY - THES A1 - Vogel, Sebastian T1 - Determinants of saproxylic biodiversity and conclusions for conservation T1 - Einflussfaktoren auf xylobionte Artenvielfalt und Rückschlüsse für den Naturschutz N2 - Over the past centuries, anthropogenic utilization has fundamentally changed the appearance of European forest ecosystems. Constantly growing and changing demands have led to an enormous decline in ecological key elements and a structural homogenization of most forests. These changes have been accompanied by widespread declines of many forest-dwelling and especially saproxylic, i.e. species depending on deadwood. In order to counteract this development, various conservation strategies have been developed, but they primarily focus on a quantitative deadwood enrichment. However, the diversity of saproxylic species is furthermore driven by a variety of abiotic and biotic determinants as well as interactions between organisms. A detailed understanding of these processes has so far been largely lacking. The aim of the present thesis was therefore to improve the existing ecological knowledge of determinants influencing saproxylic species and species communities in order to provide the basis for evidence-based and adapted conservation measures. In chapter II of this thesis, I first investigated the impact of sun exposure, tree species, and their combination on saproxylic beetles, wood-inhabiting fungi, and spiders. Therefore, logs and branches of six tree species were set up under different sun exposures in an experimental approach. The impact of sun exposure and tree species strongly differed among single saproxylic taxa as well as diameters of deadwood. All investigated taxa were affected by sun exposure, whereby sun exposure resulted in a higher alpha-diversity of taxa recorded in logs and a lower alpha-diversity of saproxylic beetles reared from branches compared to shading by canopy. Saproxylic beetles and wood-inhabiting fungi as obligate saproxylic species were additionally affected by tree species. In logs, the respective impact of both determinants also resulted in divergent community compositions. Finally, a rarefaction/extrapolation method was used to evaluate the effectiveness of different combinations of tree species and sun exposure for the conservation of saproxylic species diversity. Based on this procedure, a combination of broadleaved and coniferous as well as hard- and softwood tree species was identified to support preferably high levels of saproxylic species diversity. The aim of chapter III was to evaluate the individual conservational importance of tree species for the protection of saproxylic beetles. For this, the list of tree species sampled for saproxylic beetles was increased to 42 different tree species. The considered tree species represented large parts of taxonomic and phylogenetic diversity native to Central Europe as well as the most important non-native tree species of silvicultural interest. Freshly cut branches were set up for one year and saproxylic beetles were reared afterwards for two subsequent years. The study revealed that some tree species, in particular Quercus sp., host a particular high diversity of saproxylic beetles, but tree species with a comparatively medium or low overall diversity were likewise important for red-listed saproxylic beetle species. Compared to native tree species, non-native tree species hosted a similar overall species diversity of saproxylic beetles but differed in community composition. In chapter IV, I finally analysed the interactions of host beetle diversity and the diversity of associated parasitoids by using experimentally manipulated communities of saproxylic beetles and parasitoid Hymenoptera as a model system. Classical approaches of species identification for saproxylic beetles were combined with DNA-barcoding for parasitoid Hymenoptera. The diversity of the host communities was inferred from their phylogenetic composition as well as differences in seven functional traits. Abundance, species richness, and Shannon-diversity of parasitoid Hymenoptera increased with increasing host abundance. However, the phylogenetic and functional dissimilarity of host communities showed no influence on the species communities of parasitoid Hymenoptera. The results clearly indicate an abundance-driven system in which the general availability, not necessarily the diversity of potential hosts, is decisive. In summary, the present thesis corroborates the general importance of deadwood heterogeneity for the diversity of saproxylic species by combining different experimental approaches. In order to increase their efficiency, conservation strategies for saproxylic species should generally promote deadwood from different tree species under different conditions of sun exposure on landscape-level in addition to the present enrichment of a certain deadwood amount. The most effective combinations of tree species should consider broadleaved and coniferous as well as hard- and softwood tree species. Furthermore, in addition to dominant tree species, special attention should be given to native, subdominant, silviculturally unimportant, and rare tree species. N2 - Während der letzten Jahrhunderte hat die anthropogene Nutzung das Erscheinungsbild der Waldökosysteme in Europa grundlegend verändert. Stetig wachsende und wandelnde Ansprüche führten zu einem enormen Rückgang ökologischer Schlüsselelemente und einer strukturellen Homogenisierung der meisten Wälder. In der Folge kam es zu Rückgängen vieler waldbewohnender und insbesondere xylobionter, d.h. von Totholz abhängigen, Arten. Um dieser Entwicklung entgegenzuwirken, wurden verschiedene Schutzstrategien entwickelt, welche jedoch vor allem auf eine quantitative Totholzanreicherung abzielen. Die Vielfalt xylobionter Arten wird aber weiterhin durch unterschiedliche abiotische und biotische Einflussfaktoren sowie durch Wechselwirkungen zwischen den Arten beeinflusst. Ein detailliertes Verständnis der genauen Vorgänge fehlt jedoch bislang größtenteils. Ziel der vorliegenden Promotionsarbeit war es deshalb, das diesbezüglich bestehende Wissen zu verbessern, um die Basis für evidenzbasierte und angepasste Naturschutzmaßnahmen zu schaffen. In Kapitel II dieser Arbeit habe ich zunächst den Einfluss der Besonnung und Baumart sowie deren Kombination im Vergleich auf xylobionte Käfer, holzbesiedelnde Pilze und Spinnen untersucht. Für die zugehörige Studie wurden dabei Stämme und Äste von sechs Baumarten bei unterschiedlicher Besonnung in einem experimentellen Ansatz ausgebracht. Der Einfluss der Besonnung und Baumart unterschied sich deutlich zwischen den einzelnen Artengruppen und Totholzdurchmessern. Alle Artengruppen wurden durch die Besonnung beeinflusst, wobei Besonnung im Vergleich zur Beschattung durch Baumkronen bei allen Artengruppen an Stämmen zu einer höheren alpha-Diversität führte und zu einer niedrigeren alpha-Diversität von xylobionten Käfern in Ästen. Xylobionte Käfer und holzbesiedelnde Pilze als obligat xylobionte Arten wurden weiterhin von der Baumart beeinflusst. Für die Artengruppen an Stämmen führten die jeweiligen Auswirkungen von Besonnung und Baumarten ebenfalls zu Unterschieden in der Zusammensetzung der Artgemeinschaften. Abschließend wurden Art-Akkumulationskurven genutzt, um die Effektivität unterschiedlicher Kombinationen aus Baumart und Besonnung für den Erhalt der xylobionten Diversität zu evaluieren. Um eine möglichst hohe Artenvielfalt zu fördern, wurde darauf basierend eine Kombination aus Laub- und Nadelholz einschließlich Weich- und Hartholzarten identifiziert. Ziel meiner Studie in Kapitel III war es den individuellen Beitrag einzelner Baumarten zum Schutz xylobionter Käfer zu identifizieren. Dafür wurde die Zahl untersuchter Baumarten auf 42 erhöht. Die untersuchten Baumarten umfassten dabei große Teile der taxonomischen und phylogenetischen Diversität, die in Mitteleuropa heimisch ist, sowie die wichtigsten, nicht-heimischen Baumarten von waldbaulichem Interesse. Frisch geschnittene Äste wurden für ein Jahr ausgebracht und xylobionte Käfer im Anschluss für zwei aufeinanderfolgende Jahre ausgezüchtet. Im Rahmen der Studie konnte gezeigt werden, dass einige Baumarten, insbesondere Quercus sp., eine besonders hohe Artenvielfalt aufweisen, aber auch Arten mit einer vergleichsweise geringen Gesamtartenzahl für Arten der Roten Liste von Bedeutung sind. Nicht-heimische Baumarten beherbergten insgesamt keine geringere Artenvielfalt von xylobionten Käfern, unterschieden sich aber in der Zusammensetzung ihrer Artgemeinschaften. Die Studie in Kapitel IV analysiert schließlich die Wechselwirkungen zwischen Wirtsdiversität und der Diversität assoziierter Parasitoide unter Verwendung experimentell manipulierter Gemeinschaften von xylobionten Käfern und parasitoiden Hymenopteren als Modellsystem. Klassische Ansätze zur Artidentifizierung für xylobionte Käfer wurden dabei mit DNA-Barcoding für die parasitoiden Hymenopteren kombiniert. Die Vielfalt der Wirtsgemeinschaften wurde aus ihrer phylogenetischen Zusammensetzung sowie Unterschieden in sieben funktionellen Merkmalen abgeleitet. Abundanz, Artenvielfalt und Shannon-Diversität nahmen mit zunehmender Abundanz der Wirte zu. Hingegen zeigten die phylogenetische und funktionelle Ähnlichkeit der Wirtsgemeinschaften insgesamt keinen Einfluss auf die Artgemeinschaften der parasitoiden Hymenopteren. Die Ergebnisse weisen damit klar auf ein abundanz-getriebenes System hin, in dem die generelle Verfügbarkeit und nicht unbedingt die Diversität potentieller Wirte entscheidend ist. Zusammenfassend betont die vorliegende Promotionsarbeit durch die Kombination verschiedener experimenteller Ansätze die generelle Bedeutung der Totholzheterogenität für die Vielfalt xylobionter Arten. Um ihre Effizienz zu steigern, sollten Schutzstrategien für xylobionte Arten neben einer bestimmten Totholzmenge daher generell Totholz verschiedener Baumarten bei unterschiedlicher Besonnung auf Landschaftsebene anreichern. Die effektivsten Baumarten-Kombinationen sollten dabei Laub- und Nadelholz sowie Weich- und Hartholzarten berücksichtigen. Neben den dominierenden Baumarten sollte zudem ein besonderes Augenmerk auf heimischen, subdominanten, wirtschaftlich irrelevanten und seltenen Baumarten liegen. KW - deadwood enrichment KW - saproxylic KW - beetles KW - spiders KW - woodinhabiting-fungi KW - tree species KW - forest conservation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-289266 ER - TY - THES A1 - Vogel, Cassandra Ezra T1 - The effects of land-use and agroecological practices on biodiversity and ecosystem services in tropical smallholder farms T1 - Die Effekte von Landnutzung und Agroökologie auf Biodiversität und Ökosystemdienstleistungen in der tropischen Subsistenzlandwirtschaft N2 - Biodiversity is in rapid decline worldwide. These declines are more pronounced in areas that are currently biodiversity rich, but economically poor – essentially describing many tropical regions in the Global South where landscapes are dominated by smallholder agriculture. Agriculture is an important driver of biodiversity decline, through habitat destruction and unsustainable practices. Ironically, agriculture itself is dependent on a range of ecosystem services, such as pollination and pest control, provided by biodiversity. Biodiversity on fields and the delivery of ecosystem services to crops is often closely tied to the composition of the surrounding landscape – complex landscapes with a higher proportion of (semi-)natural habitats tend to support a high abundances and biodiversity of pollinators and natural enemies that are beneficial to crop production. However, past landscape scale studies have focused primarily on industrialized agricultural landscapes in the Global North, and context dependent differences between regions and agricultural systems are understudied. Smallholder agriculture supports 2 billion people worldwide and contributes to over half the world’s food supply. Yet smallholders, particularly in sub-Saharan Africa, are underrepresented in research investigating the consequences of landscape change and agricultural practices. Where research in smallholder agriculture is conducted, the focus is often on commodity crops, such as cacao, and less on crops that are directly consumed by smallholder households, though the loss of services to these crops could potentially impact the most vulnerable farmers the hardest. Agroecology – a holistic and nature-based approach to agriculture, provides an alternative to unsustainable input-intensive agriculture. Agroecology has been found to benefit smallholders through improved agronomical and food-security outcomes. Co-benefits of agroecological practices with biodiversity and ecosystem services are assumed, but not often empirically tested. In addition, the local and landscape effects on biodiversity and ecosystem services are more commonly studied in isolation, but their potentially interactive effects are so far little explored. Our study region in northern Malawi exemplifies many challenges experienced by smallholder farmers throughout sub-Saharan Africa and more generally in the Global South. Malawi is located in a global biodiversity hotspot, but biodiversity is threatened by rapid habitat loss and a push for input-intensive agriculture by government and other stakeholders. In contrast, agroecology has been effectively promoted and implemented in the study region. We investigated how land-use differences and the agroecological practices affects biodiversity and ecosystem services of multiple taxa in a maize-bean intercropping system (Chapter 2), and pollination of pumpkin (Chapter 3) and pigeon pea (Chapter 4). Additionally, the effects of local and landscape scale shrub- to farmland habitat conversion was investigated on butterfly communities, as well as the potential for agroecology to mitigate these effects (Chapter 5). N2 - Die globale Biodiversität nimmt rapide ab. Dieser Biodiversitätsverlust ist in Regionen die reich an Biodiversität aber wirtschaftlich arm sind besonders stark ausgeprägt, insbesondere in vielen tropischen Regionen, die durch Subsistenzlandwirtschaft geprägt sind. Durch die Zerstörung natürlicher Lebensräume und nicht nachhaltige Land Nutzung ist Landwirtschaft eine der Hauptursachen dieses Biodiversitätsrückgangs. Dabei ist gerade landwirtschaftliche Produktion abhängig von Biodiversität, da Biodiversität Ökosystemdienstleistungen wie Bestäubung und natürliche Schädlingskontrolle bereitstellt. Biodiversität und Ökosystemdienstleistungen auf Feldern werden stark durch die umliegende Landschaft beeinflusst - komplexe Landschaften mit einen großen Anteil (halb-)natürlicher haben in der Regel höhere Abudanzen und eine größere Biodiversität von Bestäubern und natürlichen Feinden die vorteilhaft für die landwirtschaftliche Produktion sind. Forschung auf Landschaftebene hat bisher jedoch vorrangig auf die industrialisierte Landwirtschaft in z.B. Europa oder die USA fokussiert und kontextabhängige Unterschiede zwischen Regionen und landwirtschaftlichen Systemen sind nicht ausreichend studiert..Weltweit sind etwa 2 Milliarden Menschen von Subsistenzlandwirtschaft abhängig. Jedoch sind diese Kleinbauern, in der Forschung über die Konsequenzen von Landnutzung und landwirtschaftlichen Managements auf Biodiversität und Ökosystemdienstleistungen unterrepräsentiert, insbesondere Kleinbauern aus Subsahara-Afrika. Die wenigen verfügbaren Studien legend den Fokus oft auf wirtschaftlich wichtige Kulturpflanzen, wie etwa Kakao, und selten auf Kulturpflanzen, die für Ernährungssicherheit der Kleinbauern wichtig sind, obwohl der Verlust der Ökosystemdienstleistungen diese möglicherweise am härtesten trifft. Agroökologie ist eine nachhaltigere Form des landwirtschaftlichen Managements als die konventionelle Landwirtschaft, und will den Einsatz von Agrochemie zu reduzieren und eine holistische Landwirtschaft fördern. Agroökologie steigert die Ernährungssicherheit von Kleinbauern, insbesondere wenn die Bauern viele verschiedene agroökologische Verfahren nutzen. Vorteile der Agroökologie für Biodiversität und Ökosystemdienstleistungen werden oft vermutet, wurden bislang jedoch selten empirisch getestet. Zusätzlich wurden Effekte auf Biodiversität und Ökosystemdienstleistungen vorrangig getrennt zwischen der lokalen und der Landschaftsebene betrachtet, was das Erkennen potentieller Interaktionen erschwert. Unsere Studienregion in Nord Malawi spiegelt die viele Herausforderungen der afrikanischen Zusammenfassung Subsistenzlandwirtschaft wider. Malawi liegt in einem Biodiversitäts-Hotspot, jedoch ist diese Biodiversität durch einen schnellen Rückgang natürlicher Lebensräume und durch die Intensivierung der Landwirtschaft stark gefährdet. Dem gegenüber stehen erfolgreicher Ausbau und Umsetzung von Agroökologie in der Region. Das gab mir die Möglichkeit, die Effekte von Landnutzung und Agroökologie auf Biodiversität und Ökosystemdienstleistungen in Malawi zu untersuchen. Dafür habe ich in Mais und Bohnen in Einzel- und Mischkultur 7 taxonomische Gruppen die verschiedene Ökosystemdienstleistungen erbringen erfasst (Kapitel 2) sowie Bestäuber und Bestäubung auf Kürbis (Kapitel 3) und Straucherbsen studiert (Kapitel 4). Zusätzlich habe ich an Schmetterlingen die Effekte von Lebensraumverlust auf der lokalen und auf Landschaftsebene studiert, und untersucht, ob Agroökologie potenziell negative Effekte mindern kann (Kapitel 5). KW - biodiversity KW - ecosystem services KW - landscape ecology KW - smallholder agriculture KW - pollination KW - pest control KW - agroecology KW - tropical ecology Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290661 ER - TY - JOUR A1 - Viljur, Mari‐Liis A1 - Abella, Scott R. A1 - Adámek, Martin A1 - Alencar, Janderson Batista Rodrigues A1 - Barber, Nicholas A. A1 - Beudert, Burkhard A1 - Burkle, Laura A. A1 - Cagnolo, Luciano A1 - Campos, Brent R. A1 - Chao, Anne A1 - Chergui, Brahim A1 - Choi, Chang‐Yong A1 - Cleary, Daniel F. R. A1 - Davis, Thomas Seth A1 - Dechnik‐Vázquez, Yanus A. A1 - Downing, William M. A1 - Fuentes‐Ramirez, Andrés A1 - Gandhi, Kamal J. K. A1 - Gehring, Catherine A1 - Georgiev, Kostadin B. A1 - Gimbutas, Mark A1 - Gongalsky, Konstantin B. A1 - Gorbunova, Anastasiya Y. A1 - Greenberg, Cathryn H. A1 - Hylander, Kristoffer A1 - Jules, Erik S. A1 - Korobushkin, Daniil I. A1 - Köster, Kajar A1 - Kurth, Valerie A1 - Lanham, Joseph Drew A1 - Lazarina, Maria A1 - Leverkus, Alexandro B. A1 - Lindenmayer, David A1 - Marra, Daniel Magnabosco A1 - Martín‐Pinto, Pablo A1 - Meave, Jorge A. A1 - Moretti, Marco A1 - Nam, Hyun‐Young A1 - Obrist, Martin K. A1 - Petanidou, Theodora A1 - Pons, Pere A1 - Potts, Simon G. A1 - Rapoport, Irina B. A1 - Rhoades, Paul R. A1 - Richter, Clark A1 - Saifutdinov, Ruslan A. A1 - Sanders, Nathan J. A1 - Santos, Xavier A1 - Steel, Zachary A1 - Tavella, Julia A1 - Wendenburg, Clara A1 - Wermelinger, Beat A1 - Zaitsev, Andrey S. A1 - Thorn, Simon T1 - The effect of natural disturbances on forest biodiversity: an ecological synthesis JF - Biological Reviews N2 - Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human‐induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land‐use change. Conversely, the suppression of natural disturbances threatens disturbance‐dependent biota. Using a meta‐analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α‐diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground‐dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α‐diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta‐analysis by applying a unified diversity concept based on Hill numbers to estimate α‐diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity–disturbance relationships are shaped by species relative abundances. Our synthesis of α‐diversity was extended by a synthesis of disturbance‐induced change in species assemblages, and revealed that disturbance changes the β‐diversity of multiple taxonomic groups, including some groups that were not affected at the α‐diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α‐diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes. KW - natural disturbance KW - diversity–disturbance relationship KW - disturbance severity KW - disturbance extent KW - intermediate disturbance hypothesis KW - forest communities KW - α‐diversity KW - β‐diversity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287168 VL - 97 IS - 5 SP - 1930 EP - 1947 ER - TY - JOUR A1 - Venjakob, C. A1 - Ruedenauer, F. A. A1 - Klein, A.‐M. A1 - Leonhardt, S. D. T1 - Variation in nectar quality across 34 grassland plant species JF - Plant Biology N2 - Floral nectar is considered the most important floral reward for attracting pollinators. It contains large amounts of carbohydrates besides variable concentrations of amino acids and thus represents an important food source for many pollinators. Its nutrient content and composition can, however, strongly vary within and between plant species. The factors driving this variation in nectar quality are still largely unclear. We investigated factors underlying interspecific variation in macronutrient composition of floral nectar in 34 different grassland plant species. Specifically, we tested for correlations between the phylogenetic relatedness and morphology of plants and the carbohydrate (C) and total amino acid (AA) composition and C:AA ratios of nectar. We found that compositions of carbohydrates and (essential) amino acids as well as C:AA ratios in nectar varied significantly within and between plant species. They showed no clear phylogenetic signal. Moreover, variation in carbohydrate composition was related to family‐specific structural characteristics and combinations of morphological traits. Plants with nectar‐exposing flowers, bowl‐ or parabolic‐shaped flowers, as often found in the Apiaceae and Asteraceae, had nectar with higher proportions of hexoses, indicating a selective pressure to decelerate evaporation by increasing nectar osmolality. Our study suggests that variation in nectar nutrient composition is, among others, affected by family‐specific combinations of morphological traits. However, even within species, variation in nectar quality is high. As nectar quality can strongly affect visitation patterns of pollinators and thus pollination success, this intra‐ and interspecific variation requires more studies to fully elucidate the underlying causes and the consequences for pollinator behaviour. KW - flower morphology KW - flowering grassland plants KW - Jena Experiment KW - nectar macronutrients KW - phylogeny Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262612 VL - 24 IS - 1 SP - 134 EP - 144 ER - TY - JOUR A1 - Vellmer, Tim A1 - Hartleb, Laura A1 - Fradera Sola, Albert A1 - Kramer, Susanne A1 - Meyer-Natus, Elisabeth A1 - Butter, Falk A1 - Janzen, Christian J. T1 - A novel SNF2 ATPase complex in Trypanosoma brucei with a role in H2A.Z-mediated chromatin remodelling JF - PLoS Pathogens N2 - A cascade of histone acetylation events with subsequent incorporation of a histone H2A variant plays an essential part in transcription regulation in various model organisms. A key player in this cascade is the chromatin remodelling complex SWR1, which replaces the canonical histone H2A with its variant H2A.Z. Transcriptional regulation of polycistronic transcription units in the unicellular parasite Trypanosoma brucei has been shown to be highly dependent on acetylation of H2A.Z, which is mediated by the histone-acetyltransferase HAT2. The chromatin remodelling complex which mediates H2A.Z incorporation is not known and an SWR1 orthologue in trypanosomes has not yet been reported. In this study, we identified and characterised an SWR1-like remodeller complex in T. brucei that is responsible for Pol II-dependent transcriptional regulation. Bioinformatic analysis of potential SNF2 DEAD/Box helicases, the key component of SWR1 complexes, identified a 1211 amino acids-long protein that exhibits key structural characteristics of the SWR1 subfamily. Systematic protein-protein interaction analysis revealed the existence of a novel complex exhibiting key features of an SWR1-like chromatin remodeller. RNAi-mediated depletion of the ATPase subunit of this complex resulted in a significant reduction of H2A.Z incorporation at transcription start sites and a subsequent decrease of steady-state mRNA levels. Furthermore, depletion of SWR1 and RNA-polymerase II (Pol II) caused massive chromatin condensation. The potential function of several proteins associated with the SWR1-like complex and with HAT2, the key factor of H2A.Z incorporation, is discussed. KW - Trypanosoma KW - chromatin KW - histones KW - RNA interference KW - Trypanosoma brucei gambiense KW - luciferase KW - transcriptional control KW - nucleosomes Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301372 VL - 18 IS - 6 ER - TY - THES A1 - Vellmer, Tim T1 - New insights into the histone variant H2A.Z incorporation pathway in \(Trypanosoma\) \(brucei\) T1 - Neue Erkenntnisse zum Einbau der Histonvariante H2A.Z in \(Trypanosoma\) \(brucei\) N2 - The histone variant H2A.Z is a key player in transcription regulation in eukaryotes. Histone acetylations by the NuA4/TIP60 complex are required to enable proper incorporation of the histone variant and to promote the recruitment of other complexes and proteins required for transcription initiation. The second key player in H2A.Z-mediated transcription is the chromatin remodelling complex SWR1, which replaces the canonical histone H2A with its variant. By the time this project started little was known about H2A.Z in the unicellular parasite Trypanosoma brucei. Like in other eukaryotes H2A.Z was exclusively found in the transcription start sites of the polycistronic transcription units where it keeps the chromatin in an open conformation to enable RNA-polymerase II-mediated transcription. Previous studies showed the variant colocalizing with an acetylation of lysine on histone H4 and a methylation of lysine 4 on histone H3. Data indicated that HAT2 is linked to H2A.Z since it is required for acetylation of lyinse 10 on histone H4. A SWR1-like complex and a complex homologous to the NuA4/TIP60 could not be identified yet. This study aimed at identifying a SWR1-like remodelling complex in T. brucei and at identifying a protein complex orthologous to NuA4/TIP60 as well as at answering the question whether HAT2 is part of this complex or not. To this end, I performed multiple mass spectrometry-coupled co-Immunoprecipitation assays with potential subunits of a SWR1 complex, HAT2 and a putative homolog of a NuA4/TIP60 subunit. In the course of these experiments, I was able to identify the TbSWR1 complex. Subsequent cell fractionation and chromatin immunoprecipitation-coupled sequencing analysis experiments confirmed, that this complex is responsible for the incorporation of the histone variant H2A.Z in T. brucei. In addition to this chromatin remodelling complex, I was also able to identify two histone acetyltransferase complexes assembled around HAT1 and HAT2. In the course of my study data were published by the research group of Nicolai Siegel that identified the histone acetyltransferase HAT2 as being responsible for histone H4 acetylation, in preparation to promote H2A.Z incorporation. The data also indicated that HAT1 is responsible for acetylation of H2A.Z. According to the literature, this acetylation is required for proper transcription initiation. Experimental data generated in this study indicated, that H2A.Z and therefore TbSWR1 is involved in the DNA double strand break response of T. brucei. The identification of the specific complex composition of all three complexes provided some hints about how they could interact with each other in the course of transcription regulation and the DNA double strand break response. A proximity labelling approach performed with one of the subunits of the TbSWR1 complex identified multiple transcription factors, PTM writers and proteins potentially involved in chromatin maintenance. Overall, this work will provide some interesting insights about the composition of the complexes involved in H2A.Z incorporation in T. brucei. Furthermore, it is providing valuable information to set up experiments that could shed some light on RNA-polymerase II-mediated transcription and chromatin remodelling in T. brucei in particular and Kinetoplastids in general. N2 - Die Histonvariante H2A.Z ist ein Schlüsselelement bei der Transkriptionsregulation in Eukaryoten. Histonacetylierungen die vom NuA4/Tip60 Komplex prozessiert werden, sind für den korrekten Einbau der Variante unerlässlich. Darüber hinaus erlauben diese posttranslationellen Modifikationen die Rekrutierung weiterer Proteine und Komplexe die für die Transkription notwendig sind. Ein weiteres Schlüsselelement der mittels H2A.Z regulierten Transkription ist der Komplex zur Umstrukturierung des Chromatins SWR1, welcher das kanonische Histon H2A gegen seine Variante austauscht. Zu Beginn dieses Projektes war der Wissenstand bezüglich der Histonvariante H2A.Z in dem einzelligen Parasiten Trypanosoma brucei limitiert. Wie in anderen eukaryotischen Organismen wurde die Variante ausschließlich an den Startpunkten der polyzistronischen Transkriptionseinheiten gefunden, an denen es für die Öffnung des Chromatins verantwortlich ist und so die Transkription mittels RNAPolymerase II ermöglicht. Vorangegangene Studien konnten zeigen, dass die Variante mit einer Acetylierung des Lysins 10 im Histon H4 und einer Methylierung des Lysins 4 im Histon H3 co-lokalisiert. Einige Daten lieferten den Hinwies, dass die Histon-Acetyltransferase HAT2 mit H2A.Z in Zusammenhang steht, da diese die Acetylierung des Lysins 10 im Hinston H4 prozessiert. Komplexe die in ihrer Funktion dem SWR1 oder dem NuA4/TIP60 Komplex entsprechen, konnten bisher noch nicht gefunden werden. Die vorliegende Arbeit zielt darauf ab Komplexe zu identifizieren, die in ihrer Funktion dem SWR1 sowie dem NuA4/TIP60 Komplex entsprechen. Zudem soll die Frage geklärt werden ob HAT2 Teil eines möglichen NuA4/TIP60 Komplexes ist. In diesem Zusammenhang habe ich mehrere Massenspektrometrie gekoppelte Co-Immunopräzipitationen mit potenziellen Untereinheiten eines SWR1 Komplexes sowie HAT2 und einem Protein welches otholog zu einer NuA4/TIP60 Untereinheit ist, durchgeführt. Im Verlauf dieser Experimente konnte der SWR1 Komplex in T. brucei (TbSWR1) identifiziert werden. Anschließende Zellfraktionierungen sowie Chromatin Immunopräzipitationen gekoppelte Sequenzanalysen konnten bestätigen, dass der identifizierte Komplex für den Einbau der Histonvariante H2A.Z zuständig ist. Darüber hinaus konnten neben diesem Komplex noch zwei weitere Komplexe identifiziert werden, die jeweils die Histonacetyltransferasen HAT1 und HAT2 als Kernkomponenten enthalten. Im Verlauf meiner Arbeit wurden von der Arbeitsgruppe von Nicolai Siegel Daten publiziert die zeigten, dass die Histonacetyltransferase HAT2, in Vorbereitung auf den Einbau von H2A.Z, für die Acetylierung des Histons H4 verantwortlich ist. Im Gegenzug ist HAT1 für die Acetylierung von H2A.Z notwendig, welche wiederum für die korrekte Initiation der Transkription benötigt wird. Damit entspricht die Funktion der Acetylierung von H2A.Z in T. brucei der in der Literatur beschriebenen Funktion. Experimentelle Daten die im Verlauf dieser Arbeit generiert wurden, lieferten einen Hinweis darauf, dass H2A.Z auch an der Reparatur von DNS Doppelstrangbrüchen beteiligt ist. Die Aufschlüsselung der spezifischen Zusammensetzung aller drei Komplexe gab einige Hinweise darauf, wie sie sowohl während der Transkriptionsregulation als auch der Reparatur von DNS Doppelstrangbrüchen miteinander interagieren. Im Zuge einer molekularen Umgebungskartierung, die mit einer der Untereinheiten des TbSWR1 Komplexes durchgeführt wurde, konnten mehrere Transkriptionsfaktoren und Enzyme zur Histonmodifizierung identifiziert werden. Dabei wurden auch einige Proteine identifiziert, welche möglicherweise mit der Umformung des Chromatins in Zusammenhang stehen. Abschließend ist festzuhalten, dass diese Arbeit einige äußerst interessante Einsichten über die Zusammensetzung der Komplexe, die am H2A.Z Einbau in T. brucei beteiligt sind, liefern konnte. Darüber hinaus stellt sie einige wertvolle Informationen zur Verfügung. Diese könnten zur gezielten Planung von Experimenten genutzt werden, um mehr über RNA-Polymerase II vermittelte Transkription und Chromatin Umstrukturierung in T. brucei im speziellen und in Kinetoplastiden im Allgemeinen zu erfahren. KW - Chromatinremodelling KW - Histone KW - Transkription KW - Chromatinremodeling KW - Histones KW - Variants KW - Complexes Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257960 ER - TY - JOUR A1 - Vansynghel, Justine A1 - Ocampo-Ariza, Carolina A1 - Maas, Bea A1 - Martin, Emily A. A1 - Thomas, Evert A1 - Hanf-Dressler, Tara A1 - Schumacher, Nils-Christian A1 - Ulloque-Samatelo, Carlos A1 - Tscharntke, Teja A1 - Steffan-Dewenter, Ingolf T1 - Cacao flower visitation: Low pollen deposition, low fruit set and dominance of herbivores JF - Ecological Solutions and Evidence N2 - 1. Pollination services of cacao are crucial for global chocolate production, yet remain critically understudied, particularly in regions of origin of the species. Notably, uncertainties remain concerning the identity of cacao pollinators, the influence of landscape (forest distance) and management (shade cover) on flower visitation and the role of pollen deposition in limiting fruit set. 2. Here, we aimed to improve understanding of cacao pollination by studying limiting factors of fruit set in Peru, part of the centre of origin of cacao. Flower visitors were sampled with sticky insect glue in 20 cacao agroforests in two biogeographically distinct regions of Peru, across gradients of shade cover and forest distance. Further, we assessed pollen quantities and compared fruit set between naturally and manually pollinated flowers. 3. The most abundant flower visitors were aphids, ants and thrips in the north and thrips, midges and parasitoid wasps in the south of Peru. We present some evidence of increasing visitation rates from medium to high shade (40%–95% canopy closure) in the dry north, and opposite patterns in the semi-humid south, during the wet season. 4. Natural pollination resulted in remarkably low fruit set rates (2%), and very low pollen deposition. After hand pollination, fruit set more than tripled (7%), but was still low. 5. The diversity and high relative abundances of herbivore flower visitors limit our ability to draw conclusions on the functional role of different flower visitors. The remarkably low fruit set of naturally and even hand pollinated flowers indicates that other unaddressed factors limit cacao fruit production. Such factors could be, amongst others, a lack of effective pollinators, genetic incompatibility or resource limitation. Revealing efficient pollinator species and other causes of low fruit set rates is therefore key to establish location-specific management strategies and develop high yielding native cacao agroforestry systems in regions of origin of cacao KW - agroforestry KW - cocoa KW - flower visitors KW - forest proximity KW - hand pollination KW - pollen KW - pollination services KW - shade cover Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312722 SN - 2688-8319 VL - 3 IS - 2 ER - TY - JOUR A1 - Uttinger, Konstantin L. A1 - Riedmeier, Maria A1 - Reibetanz, Joachim A1 - Meyer, Thomas A1 - Germer, Christoph Thomas A1 - Fassnacht, Martin A1 - Wiegering, Armin A1 - Wiegering, Verena T1 - Adrenalectomies in children and adolescents in Germany – a diagnose related groups based analysis from 2009-2017 JF - Frontiers in Endocrinology N2 - Background Adrenalectomies are rare procedures especially in childhood. So far, no large cohort study on this topic has been published with data on to age distribution, operative procedures, hospital volume and operative outcome. Methods This is a retrospective analysis of anonymized nationwide hospital billing data (DRG data, 2009-2017). All adrenal surgeries (defined by OPS codes) of patients between the age 0 and 21 years in Germany were included. Results A total of 523 patient records were identified. The mean age was 8.6 ± 7.7 years and 262 patients were female (50.1%). The majority of patients were between 0 and 5 years old (52% overall), while 11.1% were between 6 and 11 and 38.8% older than 12 years. The most common diagnoses were malignant neoplasms of the adrenal gland (56%, mostly neuroblastoma) with the majority being younger than 5 years. Benign neoplasms in the adrenal gland (D350) account for 29% of all cases with the majority of affected patients being 12 years or older. 15% were not defined regarding tumor behavior. Overall complication rate was 27% with a clear higher complication rate in resection for malignant neoplasia of the adrenal gland. Bleeding occurrence and transfusions are the main complications, followed by the necessary of relaparotomy. There was an uneven patient distribution between hospital tertiles (low volume, medium and high volume tertile). While 164 patients received surgery in 85 different “low volume” hospitals (0.2 cases per hospital per year), 205 patients received surgery in 8 different “high volume” hospitals (2.8 cases per hospital per year; p<0.001). Patients in high volume centers were significant younger, had more extended resections and more often malignant neoplasia. In multivariable analysis younger age, extended resections and open procedures were independent predictors for occurrence of postoperative complications. Conclusion Overall complication rate of adrenalectomies in the pediatric population in Germany is low, demonstrating good therapeutic quality. Our analysis revealed a very uneven distribution of patient volume among hospitals. KW - pediatric KW - neuroblastoma – diagnosis KW - therapy KW - adrenocortical adenocarcinoma KW - outcome KW - volume KW - adrenalectomia Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-282280 SN - 1664-2392 VL - 13 ER - TY - JOUR A1 - Uhler, Johannes A1 - Haase, Peter A1 - Hoffmann, Lara A1 - Hothorn, Torsten A1 - Schmidl, Jürgen A1 - Stoll, Stefan A1 - Welti, Ellen A. R. A1 - Buse, Jörn A1 - Müller, Jörg T1 - A comparison of different Malaise trap types JF - Insect Conservation and Diversity N2 - Recent reports on insect decline have highlighted the need for long‐term data on insect communities towards identifying their trends and drivers. With the launch of many new insect monitoring schemes to investigate insect communities over large spatial and temporal scales, Malaise traps have become one of the most important tools due to the broad spectrum of species collected and reduced capture bias through passive sampling of insects day and night. However, Malaise traps can vary in size, shape, and colour, and it is unknown how these differences affect biomass, species richness, and composition of trap catch, making it difficult to compare results between studies. We compared five Malaise trap types (three variations of the Townes and two variations of the Bartak Malaise trap) to determine their effects on biomass and species richness as identified by metabarcoding. Insect biomass varied by 20%–55%, not strictly following trap size but varying with trap type. Total species richness was 20%–38% higher in the three Townes trap models compared to the Bartak traps. Bartak traps captured lower richness of highly mobile taxa but increased richness of ground‐dwelling taxa. The white roofed Townes trap captured a higher richness of pollinators. We find that biomass, total richness, and taxa group specific richness are all sensitive to Malaise trap type. Trap type should be carefully considered and aligned to match monitoring and research questions. Additionally, our estimates of trap type effects can be used to adjust results to facilitate comparisons across studies. KW - Bartak KW - biodiversity KW - insect communities KW - insect monitoring KW - Malaise trap KW - Townes KW - trap selectivity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293694 VL - 15 IS - 6 SP - 666 EP - 672 ER - TY - JOUR A1 - Trifault, Barbara A1 - Mamontova, Victoria A1 - Burger, Kaspar T1 - In vivo proximity labeling of nuclear and nucleolar proteins by a stably expressed, DNA damage-responsive NONO-APEX2 fusion protein JF - Frontiers in Molecular Biosciences N2 - Cellular stress can induce DNA lesions that threaten the stability of genes. The DNA damage response (DDR) recognises and repairs broken DNA to maintain genome stability. Intriguingly, components of nuclear paraspeckles like the non-POU domain containing octamer-binding protein (NONO) participate in the repair of DNA double-strand breaks (DSBs). NONO is a multifunctional RNA-binding protein (RBP) that facilitates the retention and editing of messenger (m)RNA as well as pre-mRNA processing. However, the role of NONO in the DDR is poorly understood. Here, we establish a novel human U2OS cell line that expresses NONO fused to the engineered ascorbate peroxidase 2 (U2OS:NONO-APEX2-HA). We show that NONO-APEX2-HA accumulates in the nucleolus in response to DNA damage. Combining viability assays, subcellular localisation studies, coimmunoprecipitation experiments and in vivo proximity labeling, we demonstrate that NONO-APEX2-HA is a stably expressed fusion protein that mimics endogenous NONO in terms of expression, localisation and bona fide interactors. We propose that in vivo proximity labeling in U2OS:NONO-APEX2-HA cells is capable for the assessment of NONO interactomes by downstream assays. U2OS:NONO-APEX2-HA cells will likely be a valuable resource for the investigation of NONO interactome dynamics in response to DNA damage and other stimuli. KW - APEX2 KW - proximity labeling KW - NONO KW - paraspeckles KW - nucleolus KW - DNA damage Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276707 SN - 2296-889X VL - 9 ER - TY - JOUR A1 - Tamihardja, Jörg A1 - Zehner, Leonie A1 - Hartrampf, Philipp A1 - Lisowski, Dominik A1 - Kneitz, Susanne A1 - Cirsi, Sinan A1 - Razinskas, Gary A1 - Flentje, Michael A1 - Polat, Bülent T1 - Salvage nodal radiotherapy as metastasis-directed therapy for oligorecurrent prostate cancer detected by positron emission tomography shows favorable outcome in long-term follow-up JF - Cancers N2 - Simple Summary Patients, who suffer from oligorecurrent prostate cancer with limited nodal involvement, may be offered positron emission tomography (PET)-directed salvage nodal radiotherapy to delay disease progression. This current analysis aimed to access salvage radiotherapy for nodal oligorecurrent prostate cancer with simultaneous integrated boost to PET-involved lymph nodes as metastasis-directed therapy. A long-term oncological outcome was favorable after salvage nodal radiotherapy and severe toxicity rates were low. Androgen deprivation therapy plays a major role in recurrent prostate cancer management and demonstrates a positive influence on the rate of biochemical progression in patients receiving salvage nodal radiotherapy. The present long-term analysis may help clinicians identify patients who would benefit from salvage nodal radiotherapy and androgen deprivation therapy, as a multimodal treatment strategy for oligorecurrent prostate cancer. Abstract Background: The study aimed to access the long-term outcome of salvage nodal radiotherapy (SNRT) in oligorecurrent prostate cancer. Methods: A total of 95 consecutive patients received SNRT for pelvic and/or extrapelvic nodal recurrence after prostate-specific membrane antigen (PSMA) or choline PET from 2010 to 2021. SNRT was applied as external beam radiotherapy with simultaneous integrated boost up to a median total dose of 62.9 Gy (EQD2\(_{1.5Gy}\)) to the recurrent lymph node metastases. The outcome was analyzed by cumulative incidence functions with death as the competing risk. Fine–Gray regression analyses were performed to estimate the relative hazards of the outcome parameters. Genitourinary (GU)/gastrointestinal (GI) toxicity evaluation utilized Common Toxicity Criteria for Adverse Events (v5.0). The results are as follows: the median follow-up was 47.1 months. The five-year biochemical progression rate (95% CI) was 50.1% (35.7–62.9%). Concomitant androgen deprivation therapy (ADT) was adminstered in 60.0% of the patients. The five-year biochemical progression rate was 75.0% (42.0–90.9%) without ADT versus 35.3% (19.6–51.4%) with ADT (p = 0.003). The cumulative five-year late grade 3 GU toxicity rate was 2.1%. No late grade 3 GI toxicity occured. Conclusions: Metastasis-directed therapy through SNRT for PET-staged oligorecurrent prostate cancer demonstrated a favorable long-term oncologic outcome. Omittance of ADT led to an increased biochemical progression. KW - metastasis-directed therapy KW - long-term outcome KW - oligorecurrence KW - prostate cancer KW - salvage radiotherapy KW - PSMA Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286064 SN - 2072-6694 VL - 14 IS - 15 ER - TY - JOUR A1 - Storms, Mona A1 - Jakhar, Aryan A1 - Mitesser, Oliver A1 - Jechow, Andreas A1 - Hölker, Franz A1 - Degen, Tobias A1 - Hovestadt, Thomas A1 - Degen, Jacqueline T1 - The rising moon promotes mate finding in moths JF - Communications Biology N2 - To counteract insect decline, it is essential to understand the underlying causes, especially for key pollinators such as nocturnal moths whose ability to orientate can easily be influenced by ambient light conditions. These comprise natural light sources as well as artificial light, but their specific relevance for moth orientation is still unknown. We investigated the influence of moonlight on the reproductive behavior of privet hawkmoths (Sphinx ligustri) at a relatively dark site where the Milky Way was visible while the horizon was illuminated by distant light sources and skyglow. We show that male moths use the moon for orientation and reach females significantly faster with increasing moon elevation. Furthermore, the choice of flight direction depended on the cardinal position of the moon but not on the illumination of the horizon caused by artificial light, indicating that the moon plays a key role in the orientation of male moths. KW - animal behaviour KW - biodiversity KW - conservation biology KW - entomology KW - urban ecology Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301365 VL - 5 ER - TY - JOUR A1 - Sponsler, Douglas A1 - Kallnik, Katharina A1 - Requier, Fabrice A1 - Classen, Alice A1 - Maihoff, A. Fabienne A1 - Sieger, Johanna A1 - Steffan-Dewenter, Ingolf T1 - Floral preferences of mountain bumble bees are constrained by functional traits but flexible through elevation and season JF - Oikos N2 - Patterns of resource use by animals can clarify how ecological communities have assembled in the past, how they currently function and how they are likely to respond to future perturbations. Bumble bees (Hymentoptera: Bombus spp.) and their floral hosts provide a diverse yet tractable system in which to explore resource selection in the context of plant–pollinator networks. Under conditions of resource limitation, the ability of bumble bees species to coexist should depend on dietary niche overlap. In this study, we report patterns and dynamics of floral morphotype preferences in a mountain bumble bee community based on ~13 000 observations of bumble bee floral visits recorded along a 1400 m elevation gradient. We found that bumble bees are highly selective generalists, rarely visiting floral morphotypes at the rates predicted by their relative abundances. Preferences also differed markedly across bumble bee species, and these differences were well-explained by variation in bumble bee tongue length, generating patterns of preference similarity that should be expected to predict competition under conditions of resource limitation. Within species, though, morphotype preferences varied by elevation and season, possibly representing adaptive flexibility in response to the high elevational and seasonal turnover of mountain floral communities. Patterns of resource partitioning among bumble bee communities may determine which species can coexist under the altered distributions of bumble bees and their floral hosts caused by climate and land use change. KW - resource selection KW - coexistence KW - competition KW - foraging KW - niche KW - pollinator Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259653 VL - 2022 IS - 3 ER - TY - JOUR A1 - Sponsler, Douglas B. A1 - Requier, Fabrice A1 - Kallnik, Katharina A1 - Classen, Alice A1 - Maihoff, Fabienne A1 - Sieger, Johanna A1 - Steffan‐Dewenter, Ingolf T1 - Contrasting patterns of richness, abundance, and turnover in mountain bumble bees and their floral hosts JF - Ecology N2 - Environmental gradients generate and maintain biodiversity on Earth. Mountain slopes are among the most pronounced terrestrial environmental gradients, and the elevational structure of species and their interactions can provide unique insight into the processes that govern community assembly and function in mountain ecosystems. We recorded bumble bee–flower interactions over 3 years along a 1400‐m elevational gradient in the German Alps. Using nonlinear modeling techniques, we analyzed elevational patterns at the levels of abundance, species richness, species β‐diversity, and interaction β‐diversity. Though floral richness exhibited a midelevation peak, bumble bee richness increased with elevation before leveling off at the highest sites, demonstrating the exceptional adaptation of these bees to cold temperatures and short growing seasons. In terms of abundance, though, bumble bees exhibited divergent species‐level responses to elevation, with a clear separation between species preferring low versus high elevations. Overall interaction β‐diversity was mainly caused by strong turnover in the floral community, which exhibited a well‐defined threshold of β‐diversity rate at the tree line ecotone. Interaction β‐diversity increased sharply at the upper extreme of the elevation gradient (1800–2000 m), an interval over which we also saw steep decline in floral richness and abundance. Turnover of bumble bees along the elevation gradient was modest, with the highest rate of β‐diversity occurring over the interval from low‐ to mid‐elevation sites. The contrast between the relative robustness bumble bee communities and sensitivity of plant communities to the elevational gradient in our study suggests that the strongest effects of climate change on mountain bumble bees may be indirect effects mediated by the responses of their floral hosts, though bumble bee species that specialize in high‐elevation habitats may also experience significant direct effects of warming. KW - alpine plants KW - climate KW - elevation gradient KW - mountain ecology KW - pollination network Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287199 VL - 103 IS - 7 ER - TY - THES A1 - Sisario, Dmitri Jonas T1 - Bildbasierte Analyse von Säugetierzellen unter dem Einfluss von osmotischem Stress, überkritischen elektrischen Feldern und ionisierender Strahlung T1 - Image-based analysis of mammalian cells subjected to osmotic stress, supracritical electric fields and ionizing radiation N2 - Im ersten Teil dieser Doktorarbeit wurde die kurz nach Elektroporation eintretende hämolytische Zellbewegung von humanen Erythrozyten erstmals quantitativ untersucht, um den zu Grunde liegenden Mechanismus aufzuklären. Die Ergebnisse legen nahe, dass die Bewegung aus dem Ausstoß von unter Druck stehendem Zytosol resultierte. Durch weitere Experimente wurde die Beteiligung des Nicht-Muskel-Myosins NMIIA am Aufbau des zytosolischen Überdrucks nachgewiesen. Ausgehend von diesen Ergebnissen wurde ein molekular-mechanischer bisher unbekannter NMII-basierter Mechanismus der rapiden Ghostbildung beschrieben. Diese Erkenntnis könnte biomedizinische Relevanz besitzen, da der Abbau von Erythrozyten in der Milz die Transformation zu Hb-armen Ghosts voraussetzt. Der zweite Teil dieser Arbeit befasste sich mit dem Hirntumor Glioblastoma multiforme (GBM), dessen Rezidiv hauptsächlich auf Strahlenresistenz und Zellinvasion zurückzuführen ist. Deshalb wurde mittels hochauflösender Fluoreszenzmikroskopie (dSTORM) die Nanostruktur des DSB-Markers Histon γH2AX und des DNA-Reparaturfaktors DNA-PKcs in bestrahlten GBM-Zellen analysiert. Anhand von dSTORM-Rekonstruktionen wurde erstmals gezeigt, dass die beiden Proteine kaum Kolokalisation im Nanometerbereich aufweisen. Zunehmend wird die anomale Expression von Membrantransportern aus der SLC-Familie mit der Migration von Krebszellen in Verbindung gebracht. Der finale Abschnitt befasste sich daher mit der subzellulären Lokalisierung der Transporterproteine SLC5A1 und SLC5A3 in GBM-Zellen, um ihre Beteiligung an der Zellmigration nachzuweisen. Dabei wurde erstmals gezeigt, dass der Leitsaum der untersuchten GBM-Zellen deutliches SLC5A1- und SLC5A3-Signal aufwies. Basierend auf diesen Befunden wurden den Transportern unterschiedliche Aufgaben bei der zellmigrativen lokalen Volumenregulation zugeschrieben. Somit ergänzen SLC5A1 und SLC5A3 das migrationsassoziierte Krebszell-Transportom. N2 - The unique properties of the highly specialized, enucleated mammalian erythrocytes allows them to withstand enormous mechanical stress. However, because their membrane area is limited, they display high osmotic fragility towards hypotonic shocks. In contrast, the much more complex tumor cells are not only capable of tolerating a wide range of osmotic stresses, but they frequently display considerable chemo- and even radioresistance. Because of these intriguing properties, both cell types have been the subject of intensive biophysical and biomedical research for decades. However, despite the long history of erythrocyte research, the apparently self-propelled motion of red blood cells that occurs in the course of hemolysis is a largely unknown phenomenon. In the first part of this doctoral thesis, the electroporation-triggered hemolytic cell motion of human erythrocytes was examined quantitatively for the first time in order to elucidate the underlying mechanism of this phenomenon. Using fluorescence and videomicroscopic analyses, the two main phases of electrohemolysis were identified. The first, prehemolytic phase was characterized by an efflux of low-molecular cytosolic solutes via electropores, accompanied by transient, osmotic cell shrinkage. Once the influx of extracellular solutes predominated, swelling to the critical cell volume started, apparent from the loss of discoid morphology. The second, hemolytic phase was characterized by a sudden cell acceleration to a peak velocity of ~35 µm/s, ~1 second of rapid and linear movement, gradual volume reduction and transformation to a hemoglobin-depleted, transparent ghost. The results of this work suggest that this rapid linear motion results from a cell contraction-driven expulsion of the pressurized hemoglobin (Hb)-rich cytosol through a single hemolytic hole. ... KW - Erythrozyt KW - Glioblastom KW - Zellmigration KW - DNS-Doppelstrangbruch KW - Hb-Jet Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246772 ER - TY - JOUR A1 - Schwarz, Jessica Denise A1 - Lukassen, Sören A1 - Bhandare, Pranjali A1 - Eing, Lorenz A1 - Snaebjörnsson, Marteinn Thor A1 - García, Yiliam Cruz A1 - Kisker, Jan Philipp A1 - Schulze, Almut A1 - Wolf, Elmar T1 - The glycolytic enzyme ALDOA and the exon junction complex protein RBM8A are regulators of ribosomal biogenesis JF - Frontiers in Cell and Developmental Biology N2 - Cellular growth is a fundamental process of life and must be precisely controlled in multicellular organisms. Growth is crucially controlled by the number of functional ribosomes available in cells. The production of new ribosomes depends critically on the activity of RNA polymerase (RNAP) II in addition to the activity of RNAP I and III, which produce ribosomal RNAs. Indeed, the expression of both, ribosomal proteins and proteins required for ribosome assembly (ribosomal biogenesis factors), is considered rate-limiting for ribosome synthesis. Here, we used genetic screening to identify novel transcriptional regulators of cell growth genes by fusing promoters from a ribosomal protein gene (Rpl18) and from a ribosomal biogenesis factor (Fbl) with fluorescent protein genes (RFP, GFP) as reporters. Subsequently, both reporters were stably integrated into immortalized mouse fibroblasts, which were then transduced with a genome-wide sgRNA-CRISPR knockout library. Subsequently, cells with altered reporter activity were isolated by FACS and the causative sgRNAs were identified. Interestingly, we identified two novel regulators of growth genes. Firstly, the exon junction complex protein RBM8A controls transcript levels of the intronless reporters used here. By acute depletion of RBM8A protein using the auxin degron system combined with the genome-wide analysis of nascent transcription, we showed that RBM8A is an important global regulator of ribosomal protein transcripts. Secondly, we unexpectedly observed that the glycolytic enzyme aldolase A (ALDOA) regulates the expression of ribosomal biogenesis factors. Consistent with published observations that a fraction of this protein is located in the nucleus, this may be a mechanism linking transcription of growth genes to metabolic processes and possibly to metabolite availability. KW - ribosome biogenesis KW - Ribosomal protein gene KW - genetic screen KW - genome-wide screen KW - RBM8A KW - Y14 KW - AldoA KW - aldolase A Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290875 SN - 2296-634X VL - 10 ER - TY - JOUR A1 - Schilcher, Felix A1 - Hilsmann, Lioba A1 - Ankenbrand, Markus J. A1 - Krischke, Markus A1 - Mueller, Martin J. A1 - Steffan-Dewenter, Ingolf A1 - Scheiner, Ricarda T1 - Honeybees are buffered against undernourishment during larval stages JF - Frontiers in Insect Science N2 - The negative impact of juvenile undernourishment on adult behavior has been well reported for vertebrates, but relatively little is known about invertebrates. In honeybees, nutrition has long been known to affect task performance and timing of behavioral transitions. Whether and how a dietary restriction during larval development affects the task performance of adult honeybees is largely unknown. We raised honeybees in-vitro, varying the amount of a standardized diet (150 µl, 160 µl, 180 µl in total). Emerging adults were marked and inserted into established colonies. Behavioral performance of nurse bees and foragers was investigated and physiological factors known to be involved in the regulation of social organization were quantified. Surprisingly, adult honeybees raised under different feeding regimes did not differ in any of the behaviors observed. No differences were observed in physiological parameters apart from weight. Honeybees were lighter when undernourished (150 µl), while they were heavier under the overfed treatment (180 µl) compared to the control group raised under a normal diet (160 µl). These data suggest that dietary restrictions during larval development do not affect task performance or physiology in this social insect despite producing clear effects on adult weight. We speculate that possible effects of larval undernourishment might be compensated during the early period of adult life. KW - nutrition KW - juvenile hormone KW - nurse bees KW - foragers KW - triglycerides KW - undernourishment KW - task allocation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-304646 SN - 2673-8600 VL - 2 ER - TY - JOUR A1 - Sarukhanyan, Edita A1 - Shanmugam, Tipack Ayothyapattanam A1 - Dandekar, Thomas T1 - In silico studies reveal Peramivir and Zanamivir as an optimal drug treatment even if H7N9 avian type influenza virus acquires further resistance JF - Molecules N2 - An epidemic of avian type H7N9 influenza virus, which took place in China in 2013, was enhanced by a naturally occurring R294K mutation resistant against Oseltamivir at the catalytic site of the neuraminidase. To cope with such drug-resistant neuraminidase mutations, we applied the molecular docking technique to evaluate the fitness of the available drugs such as Oseltamivir, Zanamivir, Peramivir, Laninamivir, L-Arginine and Benserazide hydrochloride concerning the N9 enzyme with single (R294K, R119K, R372K), double (R119_294K, R119_372K, R294_372K) and triple (R119_294_372K) mutations in the pocket. We found that the drugs Peramivir and Zanamivir score best amongst the studied compounds, demonstrating their high binding potential towards the pockets with the considered mutations. Despite the fact that mutations changed the shape of the pocket and reduced the binding strength for all drugs, Peramivir was the only drug that formed interactions with the key residues at positions 119, 294 and 372 in the pocket of the triple N9 mutant, while Zanamivir demonstrated the lowest RMSD value (0.7 Å) with respect to the reference structure. KW - H7N9 influenza virus KW - neuraminidase KW - mutation KW - binding pocket KW - molecular docking Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288240 SN - 1420-3049 VL - 27 IS - 18 ER - TY - THES A1 - Sagwe, Rose Nyakemiso T1 - Pollinator diversity, pollination deficits, and pollination efficiency in avocado (\(Persea\) \(americana\)) production across different landscapes in Murang’a county, Kenya T1 - Bestäuberdiversität, Bestäubungsdefizite und Bestäubungseffizienz in der Avocado (\(Persea\) \(americana\))-Produktion in verschiedenen Landschaften im Landkreis Murang’a, Kenia N2 - Avocado (Persea americana Mill.) is a major horticultural crop that relies on insect mediated pollination. In avocado production, a knowledge gap exists as to the importance of insect pollination, especially in East African smallholder farms. Although it is evident that pollination improves the yield of avocado fruits, it is still unclear if pollination has benefits on fruit quality and the nutritional profile, particularly oils. Prior studies have shown that honey bees increase avocado’s fruit set and yield. However, an avocado flower is being visited by various insect species. Therefore, determining pollination efficiency will allow a comparison of the relative importance of the different insect species to optimize crop pollination for increased fruit set and crop yield and pollinator conservation. This study was conducted in a leading smallholder avocado production region in Kenya, first I assessed the dependence of avocado fruit set on insect pollination and whether current smallholder production systems suffer from a deficit in pollination services. Furthermore, I assessed if supplementation with colonies of the Western honey bee (Apis mellifera L.) to farms mitigated potential pollination deficits. The results revealed a very high reliance of avocado on insect pollinators, with a significantly lower fruit set observed for self- and wind-pollinated (17.4%) or self-pollinated flowers (6.4%) in comparison with insect-pollinated flowers (89.5%). I found a significant pollination deficit across farms, with hand-pollinated flowers on average producing 20.7% more fruits than non-treated open flowers prior to fruit abortion. This pollination deficit could be compensated by the supplementation of farms with A. mellifera colonies. These findings suggest that pollination is limiting fruit set in avocado and that A. mellifera supplementation on farms is a potential option to increase fruit yield. Secondly, I investigated the contribution of insect pollination to fruit and seed weight, oil, protein, carbohydrate, and phytochemicals contents (flavonoids and phenolics), and whether supplementation with pollinators (honey bee) could improve these fruit parameters was assessed. This was through pollinator-manipulative pollination treatments: hand, open, pollinator exclusion experiments. The results showed that avocado fruit weight was significantly higher in open and hand-pollinated than pollinator exclusion treatments, indicating that flower visitors/pollinators contribute to avocado yields and enhance marketability. Furthermore, insect pollination resulted in heavier seeds and higher oil contents, indicating that insect pollination is beneficial for the fruit’s high seed yield and quantity of oil. Honey bee supplementation also enhanced the avocado fruit weight by 18% more than in control farms and slightly increased the avocado oil content (3.6%). Contrarily, insect pollination did not influence other assayed fruit quality parameters (protein, carbohydrates, and phytochemicals). These results indicate that insect pollinators are essential for optimizing avocado yields, nutritional quality (oils), and thus marketability, underscoring the value of beehive supplementation to achieve high-quality avocado fruits and improved food security. Thirdly, pollinator efficiency based on pollen deposition after single visits by different pollinator species in avocado flowers was tested, and their frequency was recorded. The estimated pollination efficiency was highest in honey bees (Apis mellifera), followed by the hoverfly species (Phytomia incisa). These two species had the highest pollen deposition and more pollen grains on their bodies. In addition, honey bees were the most frequent avocado flower visitors, followed by flies. The findings from this study highlight the higher pollination efficiency of honey bees and Phytomia incisa. Hence, management practices supporting these species will promote increased avocado fruit yield. Additionally, these results imply that managed honey bees can be maintained to improve avocado pollination, particularly in areas lacking sufficient wild pollinators. N2 - Kapitel I - Allgemeine Einführung Der Rückgang der Bestäuberpopulationen stellt eine erhebliche Bedrohung für die Lebensmittel- und Ernährungssicherheit und die Erhaltung der biologischen Vielfalt dar. Die Interaktionsnetze zwischen Pflanzen und Bestäubern leisten einen wichtigen Beitrag zur globalen biologischen Vielfalt, zur Funktion des Ökosystems, zu den Ökosystemleistungen für Nutzpflanzen und schließlich zur menschlichen Ernährung. Darüber hinaus ist eine nachhaltige Landwirtschaft ohne angemessene Bewirtschaftungspraktiken nicht zu erreichen. Die enorme Nachfrage nach Nahrungsmitteln, insbesondere in den afrikanischen Ländern südlich der Sahara, hat zu einer nicht nachhaltigen Intensivierung der Pflanzenproduktion mit schädlichen Praktiken geführt, die sich negativ auf die Ökosystemleistungen auswirken. Daher ist es notwendig, die Auswirkungen der Bestäubung auf den Ertrag, die Qualität und die Marktfähigkeit von Nutzpflanzen zu verstehen und die Bestäubungsdefizite von Nutzpflanzen zu bewerten. Darüber hinaus ist es notwendig, die Bestäubungsleistung verschiedener Bestäuberarten bestimmter Kulturpflanzen zu untersuchen, um die besten Bewirtschaftungspraktiken zur Unterstützung der Ökosystemleistung zu ermitteln und die Bestäubung von Kulturpflanzen zu optimieren. In dieser Studie wurde die Avocado (Persea americana Mill.) als Modellpflanze verwendet, um die Bedeutung der Bestäubung durch Insekten zu bewerten. Die Studie wurde im Bezirk Murang'a in Kenia durchgeführt, der als ein Gebiet mit hohem Potenzial für die Avocado-Produktion gilt. In dieser Arbeit liegt der Schwerpunkt auf: 1.) Bestäubungsdefiziten in kleinbäuerlichen Avocadobetrieben und der Bewertung des Einsatzes von Honigbienen, um die Bestäubungsdefizite in Avocadoproduktionssystemen in Kenia zu verringern (Kapitel 2), 2.) den Auswirkungen der Insektenbestäubung auf das Fruchtgewicht, die Qualität und die Marktfähigkeit von Avocadofrüchten (Kapitel 3), 3.) der Charakterisierung der Bestäubungseffizienz von Avocadoblüten-Insektenbesuchern (Kapitel 4), und 4.) der allgemeinen Diskussion und Schlussfolgerung (Kapitel 5). Kapitel 2: Bestäuberergänzung mildert Bestäubungsdefizite in kleinbäuerlichen Avocado (Persea americana Mill.) Produktionssystemen in Kenia. Die Umstellung vom traditionellen Getreideanbau auf den Anbau von hochwertigen Nutzpflanzen wie Obst und Gemüse in Afrika südlich der Sahara bringt Herausforderungen mit sich, wenn es darum geht, hohe Erträge in Bezug auf Qualität und Quantität zu erhalten und zu verbessern. Zu diesen Herausforderungen gehört die unzureichende Bestäubungsleistung aufgrund des Rückgangs der Bestäuberpopulationen und -vielfalt, der auf den Verlust von Lebensräumen, Landnutzungsänderungen, Monokulturen und den wahllosen Einsatz von Agrarchemikalien zurückzuführen ist. Daher besteht ein Bedarf an angemessenen Bestäubungsleistungen, um eine nachhaltige Lebensmittel- und Ernährungssicherheit zu gewährleisten. Die Avocado ist eine der wichtigsten Exportfrüchte Kenias, die ein Fünftel der gesamten Gartenbauexporte des Landes ausmacht und somit zum Wirtschaftswachstum des Landes beiträgt. Es gibt jedoch nur wenige Informationen über die Bestäubung durch Insekten im Avocadoanbau, insbesondere in den afrikanischen Ländern südlich der Sahara. In dieser Studie wurde der normierte differenzierte Vegetationsindex (Normalized Difference Vegetation Index (NDVI)) verwendet, um Landschaften anhand der Vegetationsproduktivität in niedrig, mittel und hoch zu klassifizieren. Die Abhängigkeit des Fruchtansatzes der Avocado von der Insektenbestäubung und Bestäubungsdefiziten wurde durch manipulative Bestäubungsexperimente (Selbst- und Windbestäubung, Selbstbestäubung, Insektenbestäubung und Handbestäubung) untersucht. Die Wirkung einer zusätzlichen Bestäubung durch die Westliche Honigbiene (Apis mellifera L.) zur Behebung von Bestäubungsdefiziten wurde untersucht. Avocado war in hohem Maße von der Bestäubung durch Insekten abhängig (89,5 %), und als die kleinbäuerlichen Betriebe durch Honigbienen ergänzt wurden, wurde ein Anstieg des Fruchtansatzes um 20,7 % verzeichnet, was auf Bestäubungsdefizite hinweist. Die Beibehaltung der Früchte wurde zwei Monate nach dem Fruchtansatz überwacht, und der Fruchtabfall war in den Betrieben mit Honigbienen weniger ausgeprägt. Die Auswirkungen von Landschaftsvariablen (NDVI-Klasse, Landschaftsvielfalt, nahe gelegene landwirtschaftliche Lebensräume und Betriebsgröße) auf Bestäubungsdefizite (Fruchtansatz) und Fruchterhaltungsraten wurden ebenfalls untersucht. Die Landschaftsvariablen hatten keinen signifikanten Einfluss auf den Fruchtansatz. Mit Ausnahme der Anzahl der Avocadobäume pro Betrieb wirkte sich keine der Landschaftsvariablen auf die Fruchterhaltung aus. Die Anzahl der Avocadobäume ist negativ korreliert mit dem Prozentsatz der Fruchterhaltung. Die Ergebnisse zeigen, dass die Avocado für den Fruchtansatz in hohem Maße von Insektenbestäubern abhängig ist und dass die Ergänzung der Betriebe mit A. mellifera das Bestäubungsdefizit ausgleicht, was zu einer Steigerung des Avocado-Fruchtertrags führt. Kapitel 3: Insektenbestäubung steigert Fruchtgewicht, Qualität und Marktfähigkeit von Avocado (Persea americana) Der Beitrag von Insektenbestäubern zur landwirtschaftlichen Produktion ist weitgehend unbekannt, insbesondere im Hinblick auf die menschliche Ernährung, vor allem in Afrika südlich der Sahara. Die meisten Landwirte verbessern ihre Ernteerträge durch Düngung, künstliche Bewässerung und Pestizide sowie durch die Abholzung von Wäldern für die landwirtschaftliche Expansion, ohne den potenziellen Beitrag der Insektenbestäubung zur Verbesserung der Ernteerträge und -qualität zu erkennen. Die Avocadoproduktion hat in den letzten Jahren aufgrund der hohen Nachfrage und des Bewusstseins für die hohe Nährstoffdichte der Avocado, insbesondere für einfach ungesättigte Öle und andere Nährstoffe wie Proteine, Ballaststoffe, wichtige Antioxidantien, Vitamine und Mineralien, einen erheblichen Anstieg erfahren. Obwohl es offensichtlich ist, dass die Bestäubung den Ertrag von Avocadofrüchten verbessert, ist noch unklar, ob die Bestäubung Vorteile für die Fruchtqualität und das Nährstoffprofil, insbesondere für die Öle, hat. In dieser Studie wurde der Beitrag der Insektenbestäubung zum Frucht- und Samengewicht, zum Öl-, Protein- und Kohlenhydratgehalt sowie zum Gehalt an sekundären Pflanzenstoffen (Flavonoide und Phenole) quantifiziert, und es wurde untersucht, ob eine Ergänzung mit Bestäubern (Honigbienen) diese Fruchtparameter verbessern könnte. Dies geschah mit Hilfe von manipulativen Bestäuberexperimenten: Handbestäubung, offene Bestäubung, Bestäuberausschlussversuche. Die Ergebnisse zeigten, dass das Gewicht der Avocadofrüchte bei offener und manueller Bestäubung signifikant höher war als beim Ausschluss von Bestäubern, was darauf hindeutet, dass Blütenbesucher/Bestäuber zu den Avocadoerträgen beitragen und die Marktfähigkeit verbessern. Darüber hinaus führte die Bestäubung durch Insekten zu schwereren Samen und einem höheren Ölgehalt, was darauf hindeutet, dass die Bestäubung durch Insekten für den hohen Samenertrag und den Ölgehalt der Frucht von Vorteil ist. Der Einsatz von Honigbienen steigerte auch das Gewicht der Avocadofrüchte um 18% im Vergleich zu den Kontrollbetrieben und erhöhte den Ölgehalt der Avocados leicht (3,6%). Im Gegensatz dazu hatte die Insektenbestäubung keinen Einfluss auf andere untersuchte Qualitätsparameter der Früchte (Eiweiße, Kohlenhydrate und sekundäre Pflanzenstoffe). Diese Ergebnisse deuten darauf hin, dass Insektenbestäuber für die Optimierung der Avocadoerträge, der Nährstoffqualität (Öle) und damit der Marktfähigkeit von entscheidender Bedeutung sind, was den Wert der Ergänzung von Bienenstöcken zur Erzielung hochwertiger Avocadofrüchte und einer verbesserten Ernährungssicherheit unterstreicht. Kapitel 4: Charakterisierung der Bestäubungseffizienz von Blütenbesuchern der Avocado (Persea americana) durch Insekten Nicht alle Blütenbesucher sind echte Bestäuber, denn einige Besucher sind Räuber oder Diebe von Pollen oder Nektar und verlassen die Pflanze, ohne sie zu bestäuben. Frühere Studien haben gezeigt, dass Honigbienen den Fruchtansatz und den Ertrag von Avocados erhöhen. Eine Avocadoblüte wird jedoch von verschiedenen Insektenarten besucht. Die Bestimmung der Bestäubungseffizienz ermöglicht daher einen Vergleich der relativen Bedeutung der verschiedenen Insektenarten, um die Bestäubung der Pflanzen zu optimieren und so den Fruchtansatz und den Ernteertrag zu steigern und die Bestäuber zu schützen. Die Bestäubungseffizienz von Avocadoblütenbesuchern wurde bisher nur selten dokumentiert, und diese Studie ist eine der ersten, die über die Bestäubungseffizienz von Avocadoblütenbesuchern in Afrika südlich der Sahara berichtet. In der vorliegenden Studie wurde die Bestäubungseffizienz auf der Grundlage der Pollenübertragung nach einzelnen Besuchen verschiedener Bestäuberarten in Avocadoblüten getestet und deren Häufigkeit erfasst. Die geschätzte Bestäubungseffizienz war bei Honigbienen (Apis mellifera) am höchsten, gefolgt von einer Schwebfliegenart (Phytomia incisa). Diese beiden Arten hatten den höchsten Polleneintrag und mehr Pollenkörner auf ihren Körpern. Darüber hinaus waren Honigbienen die häufigsten Besucher der Avocadoblüten, gefolgt von Fliegen. Die Ergebnisse dieser Studie unterstreichen die höhere Bestäubungseffizienz von Honigbienen und Phytomia incisa. Daher werden Bewirtschaftungsmethoden, die diese Arten unterstützen, den Ertrag von Avocadofrüchten steigern. Darüber hinaus deuten diese Ergebnisse darauf hin, dass die Bewirtschaftung von Honigbienen zur Verbesserung der Avocadobestäubung beibehalten werden kann, insbesondere in Gebieten, in denen es nicht genügend Wildbestäuber gibt. Kapitel 5 - Allgemeine Diskussion In dieser Studie wurde die Bedeutung der Insektenbestäubung für die Steigerung des Ertrags und der Qualität von Avocadofrüchten untersucht und die Bestäubungseffizienz von Avocado-Insektenblütenbesuchern bewertet. Die Studie hat gezeigt, dass die Insektenbestäubung, die in den meisten Fällen unterschätzt wird, eine entscheidende und wirtschaftlich wichtige Determinante für den Ertrag, die Qualität und die Marktfähigkeit der Früchte ist. Die Erkenntnisse aus dieser Studie können genutzt werden, um die Avocado-Produktion in kleinbäuerlichen Betrieben durch die Einführung von Honigbienenvölkern zu steigern. Folglich sollten unsere umfassenden Erkenntnisse auf eine breite Palette von Kulturpflanzen übertragbar sein, um deren Erträge und die Fruchtqualität zu verbessern. Es ist bemerkenswert, dass die Landwirte von der Integration der Diversität an Wildinsektenarten mit Honigbienen profitieren werden. Dies könnte durch die Anpflanzung einer Vielzahl von Pflanzen in der Nähe der Avocadoplantagen erreicht werden, um einheimische Bestäubergemeinschaften zu unterstützen und die Abhängigkeit der Avocadobestäubung von Honigbienen allein zu verringern. Dies würde die Kosten für die Bewirtschaftung der Bienenvölker senken, insbesondere für die arme Landbevölkerung in Afrika südlich der Sahara, und die Widerstandsfähigkeit des Systems erhöhen. KW - Pollination services KW - pollination Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-269202 ER - TY - JOUR A1 - Römer, Daniela A1 - Aguilar, Gonzalo Pacheco A1 - Meyer, Annika A1 - Roces, Flavio T1 - Symbiont demand guides resource supply: leaf-cutting ants preferentially deliver their harvested fragments to undernourished fungus gardens JF - The Science of Nature N2 - Leaf-cutting ants are highly successful herbivores in the Neotropics. They forage large amounts of fresh plant material to nourish a symbiotic fungus that sustains the colony. It is unknown how workers organize the intra-nest distribution of resources, and whether they respond to increasing demands in some fungus gardens by adjusting the amount of delivered resources accordingly. In laboratory experiments, we analyzed the spatial distribution of collected leaf fragments among nest chambers in Acromyrmex ambiguus leaf-cutting ants, and how it changed when one of the fungus gardens experienced undernourishment. Plant fragments were evenly distributed among nest chambers when the fungal symbiont was well nourished. That pattern changed when one of the fungus gardens was undernourished and had a higher leaf demand, resulting in more leaf discs delivered to the undernourished fungus garden over at least 2 days after deprivation. Some ants bypassed nourished gardens to directly deliver their resource to the chamber with higher nutritional demand. We hypothesize that cues arising from that chamber might be used for orientation and/or that informed individuals, presumably stemming from the undernourished chamber, may preferentially orient to them. KW - insect-fungus symbiosis KW - nutrition KW - pheromone trail KW - local cues KW - decision-making KW - decentralized control Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325080 VL - 109 IS - 3 ER - TY - JOUR A1 - Rohmer, Carina A1 - Dobritz, Ronja A1 - Tuncbilek-Dere, Dilek A1 - Lehmann, Esther A1 - Gerlach, David A1 - George, Shilpa Elizabeth A1 - Bae, Taeok A1 - Nieselt, Kay A1 - Wolz, Christiane T1 - Influence of Staphylococcus aureus strain background on Sa3int phage life cycle switches JF - Viruses N2 - Staphylococcus aureus asymptomatically colonizes the nasal cavity of mammals, but it is also a leading cause of life-threatening infections. Most human nasal isolates carry Sa3 phages, which integrate into the bacterial hlb gene encoding a sphingomyelinase. The virulence factor-encoding genes carried by the Sa3-phages are highly human-specific, and most animal strains are Sa3 negative. Thus, both insertion and excision of the prophage could potentially confer a fitness advantage to S. aureus. Here, we analyzed the phage life cycle of two Sa3 phages, Φ13 and ΦN315, in different phage-cured S. aureus strains. Based on phage transfer experiments, strains could be classified into low (8325-4, SH1000, and USA300c) and high (MW2c and Newman-c) transfer strains. High-transfer strains promoted the replication of phages, whereas phage adsorption, integration, excision, or recA transcription was not significantly different between strains. RNASeq analyses of replication-deficient lysogens revealed no strain-specific differences in the CI/Mor regulatory switch. However, lytic genes were significantly upregulated in the high transfer strain MW2c Φ13 compared to strain 8325-4 Φ13. By transcriptional start site prediction, new promoter regions within the lytic modules were identified, which are likely targeted by specific host factors. Such host-phage interaction probably accounts for the strain-specific differences in phage replication and transfer frequency. Thus, the genetic makeup of the host strains may determine the rate of phage mobilization, a feature that might impact the speed at which certain strains can achieve host adaptation. KW - phage KW - virulence KW - induction KW - gene regulation KW - Staphylococcus KW - hemolysin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297209 SN - 1999-4915 VL - 14 IS - 11 ER - TY - JOUR A1 - Reinhard, Sebastian A1 - Helmerich, Dominic A. A1 - Boras, Dominik A1 - Sauer, Markus A1 - Kollmannsberger, Philip T1 - ReCSAI: recursive compressed sensing artificial intelligence for confocal lifetime localization microscopy JF - BMC Bioinformatics N2 - Background Localization-based super-resolution microscopy resolves macromolecular structures down to a few nanometers by computationally reconstructing fluorescent emitter coordinates from diffraction-limited spots. The most commonly used algorithms are based on fitting parametric models of the point spread function (PSF) to a measured photon distribution. These algorithms make assumptions about the symmetry of the PSF and thus, do not work well with irregular, non-linear PSFs that occur for example in confocal lifetime imaging, where a laser is scanned across the sample. An alternative method for reconstructing sparse emitter sets from noisy, diffraction-limited images is compressed sensing, but due to its high computational cost it has not yet been widely adopted. Deep neural network fitters have recently emerged as a new competitive method for localization microscopy. They can learn to fit arbitrary PSFs, but require extensive simulated training data and do not generalize well. A method to efficiently fit the irregular PSFs from confocal lifetime localization microscopy combining the advantages of deep learning and compressed sensing would greatly improve the acquisition speed and throughput of this method. Results Here we introduce ReCSAI, a compressed sensing neural network to reconstruct localizations for confocal dSTORM, together with a simulation tool to generate training data. We implemented and compared different artificial network architectures, aiming to combine the advantages of compressed sensing and deep learning. We found that a U-Net with a recursive structure inspired by iterative compressed sensing showed the best results on realistic simulated datasets with noise, as well as on real experimentally measured confocal lifetime scanning data. Adding a trainable wavelet denoising layer as prior step further improved the reconstruction quality. Conclusions Our deep learning approach can reach a similar reconstruction accuracy for confocal dSTORM as frame binning with traditional fitting without requiring the acquisition of multiple frames. In addition, our work offers generic insights on the reconstruction of sparse measurements from noisy experimental data by combining compressed sensing and deep learning. We provide the trained networks, the code for network training and inference as well as the simulation tool as python code and Jupyter notebooks for easy reproducibility. KW - compressed sensing KW - AI KW - SMLM KW - FLIMbee KW - dSTORM Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-299768 VL - 23 IS - 1 ER - TY - JOUR A1 - Reinhard, Nils A1 - Schubert, Frank K. A1 - Bertolini, Enrico A1 - Hagedorn, Nicolas A1 - Manoli, Giulia A1 - Sekiguchi, Manabu A1 - Yoshii, Taishi A1 - Rieger, Dirk A1 - Helfrich-Förster, Charlotte T1 - The neuronal circuit of the dorsal circadian clock neurons in Drosophila melanogaster JF - Frontiers in Physiology N2 - Drosophila’s dorsal clock neurons (DNs) consist of four clusters (DN1as, DN1ps, DN2s, and DN3s) that largely differ in size. While the DN1as and the DN2s encompass only two neurons, the DN1ps consist of ∼15 neurons, and the DN3s comprise ∼40 neurons per brain hemisphere. In comparison to the well-characterized lateral clock neurons (LNs), the neuroanatomy and function of the DNs are still not clear. Over the past decade, numerous studies have addressed their role in the fly’s circadian system, leading to several sometimes divergent results. Nonetheless, these studies agreed that the DNs are important to fine-tune activity under light and temperature cycles and play essential roles in linking the output from the LNs to downstream neurons that control sleep and metabolism. Here, we used the Flybow system, specific split-GAL4 lines, trans-Tango, and the recently published fly connectome (called hemibrain) to describe the morphology of the DNs in greater detail, including their synaptic connections to other clock and non-clock neurons. We show that some DN groups are largely heterogenous. While certain DNs are strongly connected with the LNs, others are mainly output neurons that signal to circuits downstream of the clock. Among the latter are mushroom body neurons, central complex neurons, tubercle bulb neurons, neurosecretory cells in the pars intercerebralis, and other still unidentified partners. This heterogeneity of the DNs may explain some of the conflicting results previously found about their functionality. Most importantly, we identify two putative novel communication centers of the clock network: one fiber bundle in the superior lateral protocerebrum running toward the anterior optic tubercle and one fiber hub in the posterior lateral protocerebrum. Both are invaded by several DNs and LNs and might play an instrumental role in the clock network. KW - circadian clock KW - dorsal clock neurons KW - trans-tango KW - flybow KW - neuroanatomy KW - hemibrain KW - clock network Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-272527 SN - 1664-042X VL - 13 ER - TY - JOUR A1 - Reinhard, Nils A1 - Bertolini, Enrico A1 - Saito, Aika A1 - Sekiguchi, Manabu A1 - Yoshii, Taishi A1 - Rieger, Dirk A1 - Helfrich‐Förster, Charlotte T1 - The lateral posterior clock neurons of Drosophila melanogaster express three neuropeptides and have multiple connections within the circadian clock network and beyond JF - Journal of Comparative Neurology N2 - Drosophila’s lateral posterior neurons (LPNs) belong to a small group of circadian clock neurons that is so far not characterized in detail. Thanks to a new highly specific split‐Gal4 line, here we describe LPNs’ morphology in fine detail, their synaptic connections, daily bimodal expression of neuropeptides, and propose a putative role of this cluster in controlling daily activity and sleep patterns. We found that the three LPNs are heterogeneous. Two of the neurons with similar morphology arborize in the superior medial and lateral protocerebrum and most likely promote sleep. One unique, possibly wakefulness‐promoting, neuron with wider arborizations extends from the superior lateral protocerebrum toward the anterior optic tubercle. Both LPN types exhibit manifold connections with the other circadian clock neurons, especially with those that control the flies’ morning and evening activity (M‐ and E‐neurons, respectively). In addition, they form synaptic connections with neurons of the mushroom bodies, the fan‐shaped body, and with many additional still unidentified neurons. We found that both LPN types rhythmically express three neuropeptides, Allostatin A, Allostatin C, and Diuretic Hormone 31 with maxima in the morning and the evening. The three LPN neuropeptides may, furthermore, signal to the insect hormonal center in the pars intercerebralis and contribute to rhythmic modulation of metabolism, feeding, and reproduction. We discuss our findings in the light of anatomical details gained by the recently published hemibrain of a single female fly on the electron microscopic level and of previous functional studies concerning the LPN. KW - activity KW - circadian clock neurons KW - insect brain KW - neuropeptides KW - sleep KW - trans‐Tango Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276456 VL - 530 IS - 9 SP - 1507 EP - 1529 ER - TY - JOUR A1 - Reibetanz, Joachim A1 - Kelm, Matthias A1 - Uttinger, Konstantin L. A1 - Reuter, Miriam A1 - Schlegel, Nicolas A1 - Hankir, Mohamed A1 - Wiegering, Verena A1 - Germer, Christoph-Thomas A1 - Fassnacht, Martin A1 - Lock, Johan Friso A1 - Wiegering, Armin T1 - Differences in morbidity and mortality between unilateral adrenalectomy for adrenal Cushing’s syndrome and bilateral adrenalectomy for therapy refractory extra-adrenal Cushing’s syndrome JF - Langenbeck’s Archives of Surgery N2 - Purpose In selected cases of severe Cushing’s syndrome due to uncontrolled ACTH secretion, bilateral adrenalectomy appears unavoidable. Compared with unilateral adrenalectomy (for adrenal Cushing’s syndrome), bilateral adrenalectomy has a perceived higher perioperative morbidity. The aim of the current study was to compare both interventions in endogenous Cushing’s syndrome regarding postoperative outcomes. Methods We report a single-center, retrospective cohort study comparing patients with hypercortisolism undergoing bilateral vs. unilateral adrenalectomy during 2008–2021. Patients with adrenal Cushing’s syndrome due to adenoma were compared with patients with ACTH-dependent Cushing’s syndrome (Cushing’s disease and ectopic ACTH production) focusing on postoperative morbidity and mortality as well as long-term survival. Results Of 83 patients with adrenalectomy for hypercortisolism (65.1% female, median age 53 years), the indication for adrenalectomy was due to adrenal Cushing’s syndrome in 60 patients (72.2%; 59 unilateral and one bilateral), and due to hypercortisolism caused by Cushing’s disease (n = 16) or non-pituitary uncontrolled ACTH secretion of unknown origin (n = 7) (27.7% of all adrenalectomies). Compared with unilateral adrenalectomy (n = 59), patients with bilateral adrenalectomy (n = 24) had a higher rate of severe complications (0% vs. 33%; p < 0.001) and delayed recovery (median: 10.2% vs. 79.2%; p < 0.001). Using the MTL30 marker, patients with bilateral adrenalectomy fared worse than patients after unilateral surgery (MTL30 positive: 7.2% vs. 25.0% p < 0.001). Postoperative mortality was increased in patients with bilateral adrenalectomy (0% vs. 8.3%; p = 0.081). Conclusion While unilateral adrenalectomy for adrenal Cushing’s syndrome represents a safe and definitive therapeutic option, bilateral adrenalectomy to control ACTH-dependent extra-adrenal Cushing’s syndrome or Cushing’s disease is a more complicated intervention with a mortality of nearly 10%. KW - Cushing KW - adrenal surgery KW - MTL30 KW - complication Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-323947 VL - 407 IS - 6 ER - TY - JOUR A1 - Redlich, Sarah A1 - Zhang, Jie A1 - Benjamin, Caryl A1 - Dhillon, Maninder Singh A1 - Englmeier, Jana A1 - Ewald, Jörg A1 - Fricke, Ute A1 - Ganuza, Cristina A1 - Haensel, Maria A1 - Hovestadt, Thomas A1 - Kollmann, Johannes A1 - Koellner, Thomas A1 - Kübert‐Flock, Carina A1 - Kunstmann, Harald A1 - Menzel, Annette A1 - Moning, Christoph A1 - Peters, Wibke A1 - Riebl, Rebekka A1 - Rummler, Thomas A1 - Rojas‐Botero, Sandra A1 - Tobisch, Cynthia A1 - Uhler, Johannes A1 - Uphus, Lars A1 - Müller, Jörg A1 - Steffan‐Dewenter, Ingolf T1 - Disentangling effects of climate and land use on biodiversity and ecosystem services—A multi‐scale experimental design JF - Methods in Ecology and Evolution N2 - Climate and land-use change are key drivers of environmental degradation in the Anthropocene, but too little is known about their interactive effects on biodiversity and ecosystem services. Long-term data on biodiversity trends are currently lacking. Furthermore, previous ecological studies have rarely considered climate and land use in a joint design, did not achieve variable independence or lost statistical power by not covering the full range of environmental gradients. Here, we introduce a multi-scale space-for-time study design to disentangle effects of climate and land use on biodiversity and ecosystem services. The site selection approach coupled extensive GIS-based exploration (i.e. using a Geographic information system) and correlation heatmaps with a crossed and nested design covering regional, landscape and local scales. Its implementation in Bavaria (Germany) resulted in a set of study plots that maximise the potential range and independence of environmental variables at different spatial scales. Stratifying the state of Bavaria into five climate zones (reference period 1981–2010) and three prevailing land-use types, that is, near-natural, agriculture and urban, resulted in 60 study regions (5.8 × 5.8 km quadrants) covering a mean annual temperature gradient of 5.6–9.8°C and a spatial extent of ~310 × 310 km. Within these regions, we nested 180 study plots located in contrasting local land-use types, that is, forests, grasslands, arable land or settlement (local climate gradient 4.5–10°C). This approach achieved low correlations between climate and land use (proportional cover) at the regional and landscape scale with |r ≤ 0.33| and |r ≤ 0.29| respectively. Furthermore, using correlation heatmaps for local plot selection reduced potentially confounding relationships between landscape composition and configuration for plots located in forests, arable land and settlements. The suggested design expands upon previous research in covering a significant range of environmental gradients and including a diversity of dominant land-use types at different scales within different climatic contexts. It allows independent assessment of the relative contribution of multi-scale climate and land use on biodiversity and ecosystem services. Understanding potential interdependencies among global change drivers is essential to develop effective restoration and mitigation strategies against biodiversity decline, especially in expectation of future climatic changes. Importantly, this study also provides a baseline for long-term ecological monitoring programs. KW - study design KW - biodiversity KW - climate change KW - ecosystem functioning KW - insect monitoring KW - land use KW - space-for-time approach KW - spatial scales Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258270 VL - 13 IS - 2 ER - TY - JOUR A1 - Rackevei, Antonia S. A1 - Borges, Alyssa A1 - Engstler, Markus A1 - Dandekar, Thomas A1 - Wolf, Matthias T1 - About the analysis of 18S rDNA sequence data from trypanosomes in barcoding and phylogenetics: tracing a continuation error occurring in the literature JF - Biology N2 - The variable regions (V1–V9) of the 18S rDNA are routinely used in barcoding and phylogenetics. In handling these data for trypanosomes, we have noticed a misunderstanding that has apparently taken a life of its own in the literature over the years. In particular, in recent years, when studying the phylogenetic relationship of trypanosomes, the use of V7/V8 was systematically established. However, considering the current numbering system for all other organisms (including other Euglenozoa), V7/V8 was never used. In Maia da Silva et al. [Parasitology 2004, 129, 549–561], V7/V8 was promoted for the first time for trypanosome phylogenetics, and since then, more than 70 publications have replicated this nomenclature and even discussed the benefits of the use of this region in comparison to V4. However, the primers used to amplify the variable region of trypanosomes have actually amplified V4 (concerning the current 18S rDNA numbering system). KW - RNA secondary structure KW - variable regions KW - V1–V9 KW - V4 KW - V7/V8 KW - Trypanosoma Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297562 SN - 2079-7737 VL - 11 IS - 11 ER - TY - JOUR A1 - Prieto-Garcia, Cristian A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Braun, Fabian A1 - Bozkurt, Süleyman A1 - Pahor, Nikolett A1 - Fuss, Carmina A1 - Schirbel, Andreas A1 - Schülein-Völk, Christina A1 - Buchberger, Alexander A1 - Calzado Canale, Marco A. A1 - Rosenfeldt, Mathias A1 - Dikic, Ivan A1 - Münch, Christian A1 - Diefenbacher, Markus E. T1 - USP28 enables oncogenic transformation of respiratory cells, and its inhibition potentiates molecular therapy targeting mutant EGFR, BRAF and PI3K JF - Molecular Oncology N2 - Oncogenic transformation of lung epithelial cells is a multistep process, frequently starting with the inactivation of tumour suppressors and subsequent development of activating mutations in proto-oncogenes, such as members of the PI3K or MAPK families. Cells undergoing transformation have to adjust to changes, including altered metabolic requirements. This is achieved, in part, by modulating the protein abundance of transcription factors. Here, we report that the ubiquitin carboxyl-terminal hydrolase 28 (USP28) enables oncogenic reprogramming by regulating the protein abundance of proto-oncogenes such as c-JUN, c-MYC, NOTCH and ∆NP63 at early stages of malignant transformation. USP28 levels are increased in cancer compared with in normal cells due to a feed-forward loop, driven by increased amounts of oncogenic transcription factors such as c-MYC and c-JUN. Irrespective of oncogenic driver, interference with USP28 abundance or activity suppresses growth and survival of transformed lung cells. Furthermore, inhibition of USP28 via a small-molecule inhibitor resets the proteome of transformed cells towards a ‘premalignant’ state, and its inhibition synergizes with clinically established compounds used to target EGFR\(^{L858R}\)-, BRAF\(^{V600E}\)- or PI3K\(^{H1047R}\)-driven tumour cells. Targeting USP28 protein abundance at an early stage via inhibition of its activity is therefore a feasible strategy for the treatment of early-stage lung tumours, and the observed synergism with current standard-of-care inhibitors holds the potential for improved targeting of established tumours. KW - buparlisib KW - c-MYC KW - gefitinib KW - lung cancer KW - USP28 KW - vemurafenib Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312777 VL - 16 IS - 17 ER - TY - THES A1 - Prieto García, Cristian T1 - USP28 regulates Squamous cell oncogenesis and DNA repair via ΔNp63 deubiquitination T1 - USP28 reguliert Plattenepithelzell-Onkogenese und DNA-Reparatur über ΔNp63-Deubiquitinierung N2 - ∆Np63 is a master regulator of squamous cell identity and regulates several signaling pathways that crucially contribute to the development of squamous cell carcinoma (SCC) tumors. Its contribution to coordinating the expression of genes involved in oncogenesis, epithelial identity, DNA repair, and genome stability has been extensively studied and characterized. For SCC, the expression of ∆Np63 is an essential requirement to maintain the malignant phenotype. Additionally, ∆Np63 functionally contributes to the development of cancer resistance toward therapies inducing DNA damage. SCC patients are currently treated with the same conventional Cisplatin therapy as they would have been treated 30 years ago. In contrast to patients with other tumor entities, the survival of SCC patients is limited, and the efficacy of the current therapies is rather low. Considering the rising incidences of these tumor entities, the development of novel SCC therapies is urgently required. Targeting ∆Np63, the transcription factor, is a potential alternative to improve the therapeutic response and clinical outcomes of SCC patients. However, ∆Np63 is considered “undruggable.” As is commonly observed in transcription factors, ∆Np63 does not provide any suitable domains for the binding of small molecule inhibitors. ∆Np63 regulates a plethora of different pathways and cellular processes, making it difficult to counteract its function by targeting downstream effectors. As ∆Np63 is strongly regulated by the ubiquitin–proteasome system (UPS), the development of deubiquitinating enzyme inhibitors has emerged as a promising therapeutic strategy to target ∆Np63 in SCC treatment. This work involved identifying the first deubiquitinating enzyme that regulates ∆Np63 protein stability. Stateof-the-art SCC models were used to prove that USP28 deubiquitinates ∆Np63, regulates its protein stability, and affects squamous transcriptional profiles in vivo and ex vivo. Accordingly, SCC depends on USP28 to maintain essential levels of ∆Np63 protein abundance in tumor formation and maintenance. For the first time, ∆Np63, the transcription factor, was targeted in vivo using a small molecule inhibitor targeting the activity of USP28. The pharmacological inhibition of USP28 was sufficient to hinder the growth of SCC tumors in preclinical mouse models. Finally, this work demonstrated that the combination of Cisplatin with USP28 inhibitors as a novel therapeutic alternative could expand the limited available portfolio of SCC therapeutics. Collectively, the data presented within this dissertation demonstrates that the inhibition of USP28 in SCC decreases ∆Np63 protein abundance, thus downregulating the Fanconi anemia (FA) pathway and recombinational DNA repair. Accordingly, USP28 inhibition reduces the DNA damage response, thereby sensitizing SCC tumors to DNA damage therapies, such as Cisplatin. N2 - ∆Np63 ist ein Hauptregulator der Plattenepithelzellidentität und reguliert mehrere Signalwege, die entscheidend zur Entstehung von Plattenepithelkarzinomen (SCC) beitragen. Sein Beitrag zur Koordination der Expression von Genen, die an der Onkogenese, der epithelialen Identität, der DNA-Reparatur und der Genomstabilität beteiligt sind, wurde umfassend untersucht und charakterisiert. Für SCC ist die Expression von ∆Np63 eine wesentliche Voraussetzung, um den malignen Phänotyp zu erhalten. Darüber hinaus trägt ∆Np63 funktionell zur Entwicklung einer Krebsresistenz gegenüber Therapien bei, die DNA-Schäden induzieren. SCC-Patienten werden derzeit mit der gleichen konventionellen Cisplatin-Therapie behandelt, wie sie vor 30 Jahren behandelt worden wären. Im Gegensatz zu Patienten mit anderen Tumorentitäten ist das Überleben von SCC-Patienten begrenzt und die Wirksamkeit der aktuellen Therapien eher gering. Angesichts der steigenden Inzidenz dieser Tumorentitäten ist die Entwicklung neuer Therapien für das Plattenepithelkarzinom dringend erforderlich. Das Targeting von ∆Np63, dem Transkriptionsfaktor, ist eine potenzielle Alternative zur Verbesserung des therapeutischen Ansprechens und der klinischen Ergebnisse von SCC-Patienten. ∆Np63 gilt jedoch als „nicht medikamentös“. Wie bei Transkriptionsfaktoren häufig beobachtet, bietet ∆Np63 keine geeigneten Domänen für die Bindung von niedermolekularen Inhibitoren. ∆Np63 reguliert eine Vielzahl von verschiedenen Signalwegen und zellulären Prozessen, was es schwierig macht, seiner Funktion entgegenzuwirken, indem es nachgeschaltete Effektoren angreift. Da ∆Np63 stark durch das Ubiquitin-Proteasom-System (UPS) reguliert wird, hat sich die Entwicklung von deubiquitinierenden Enzyminhibitoren als vielversprechende therapeutische Strategie erwiesen, um ∆Np63 bei der Behandlung von Plattenepithelkarzinomen zu bekämpfen. Diese Arbeit beinhaltete die Identifizierung des ersten deubiquitinierenden Enzyms, das die Stabilität des ∆Np63-Proteins reguliert. Hochmoderne SCC-Modelle wurden verwendet, um zu beweisen, dass USP28 ∆Np63 deubiquitiniert, seine Proteinstabilität reguliert und Plattenepithel-Transkriptionsprofile in vivo und ex vivo beeinflusst. Dementsprechend hängt SCC von USP28 ab, um wesentliche Mengen des Np63-Proteinüberflusses bei der Tumorbildung und -erhaltung aufrechtzuerhalten. Zum ersten Mal wurde ∆Np63, der Transkriptionsfaktor, in vivo mit einem niedermolekularen Inhibitor gezielt, der auf die Aktivität von USP28 abzielt. Die pharmakologische Hemmung von USP28 war ausreichend, um das Wachstum von SCC-Tumoren in präklinischen Mausmodellen zu verhindern. Schließlich zeigte diese Arbeit, dass die Kombination von Cisplatin mit USP28-Inhibitoren als neuartige therapeutische Alternative das begrenzt verfügbare Portfolio an SCC-Therapeutika erweitern könnte. Zusammengefasst zeigen die in dieser Dissertation präsentierten Daten, dass die Hemmung von USP28 in SCC die Np63-Proteinhäufigkeit verringert, wodurch der Fanconi-Anämie (FA)-Signalweg und die rekombinatorische DNA-Reparatur herunterreguliert werden. Dementsprechend reduziert die Hemmung von USP28 die Reaktion auf DNA-Schäden und sensibilisiert dadurch SCC- Tumoren für DNA-Schädigungstherapien wie Cisplatin. KW - USP28 KW - Squamous cell carcinoma KW - ΔNp63 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270332 ER - TY - JOUR A1 - Prada, Juan Pablo A1 - Maag, Luca Estelle A1 - Siegmund, Laura A1 - Bencurova, Elena A1 - Liang, Chunguang A1 - Koutsilieri, Eleni A1 - Dandekar, Thomas A1 - Scheller, Carsten T1 - Estimation of R0 for the spread of SARS-CoV-2 in Germany from excess mortality JF - Scientific Reports N2 - For SARS-CoV-2, R0 calculations in the range of 2–3 dominate the literature, but much higher estimates have also been published. Because capacity for RT-PCR testing increased greatly in the early phase of the Covid-19 pandemic, R0 determinations based on these incidence values are subject to strong bias. We propose to use Covid-19-induced excess mortality to determine R0 regardless of RT-PCR testing capacity. We used data from the Robert Koch Institute (RKI) on the incidence of Covid cases, Covid-related deaths, number of RT-PCR tests performed, and excess mortality calculated from data from the Federal Statistical Office in Germany. We determined R0 using exponential growth estimates with a serial interval of 4.7 days. We used only datasets that were not yet under the influence of policy measures (e.g., lockdowns or school closures). The uncorrected R0 value for the spread of SARS-CoV-2 based on RT-PCR incidence data was 2.56 (95% CI 2.52–2.60) for Covid-19 cases and 2.03 (95% CI 1.96–2.10) for Covid-19-related deaths. However, because the number of RT-PCR tests increased by a growth factor of 1.381 during the same period, these R0 values must be corrected accordingly (R0corrected = R0uncorrected/1.381), yielding 1.86 for Covid-19 cases and 1.47 for Covid-19 deaths. The R0 value based on excess deaths was calculated to be 1.34 (95% CI 1.32–1.37). A sine-function-based adjustment for seasonal effects of 40% corresponds to a maximum value of R0January = 1.68 and a minimum value of R0July = 1.01. Our calculations show an R0 that is much lower than previously thought. This relatively low range of R0 fits very well with the observed seasonal pattern of infection across Europe in 2020 and 2021, including the emergence of more contagious escape variants such as delta or omicron. In general, our study shows that excess mortality can be used as a reliable surrogate to determine the R0 in pandemic situations. KW - SARS-CoV-2 KW - R0 KW - mortality Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301415 VL - 12 IS - 1 ER - TY - JOUR A1 - Plieger, Tanja A1 - Wolf, Matthias T1 - 18S and ITS2 rDNA sequence-structure phylogeny of Prototheca (Chlorophyta, Trebouxiophyceae) JF - Biologia N2 - Protothecosis is an infectious disease caused by organisms currently classified within the green algal genus Prototheca. The disease can manifest as cutaneous lesions, olecranon bursitis or disseminated or systemic infections in both immunocompetent and immunosuppressed patients. Concerning diagnostics, taxonomic validity is important. Prototheca, closely related to the Chlorella species complex, is known to be polyphyletic, branching with Auxenochlorella and Helicosporidium. The phylogeny of Prototheca was discussed and revisited several times in the last decade; new species have been described. Phylogenetic analyses were performed using ribosomal DNA (rDNA) and partial mitochondrial cytochrome b (cytb) sequence data. In this work we use Internal Transcribed Spacer 2 (ITS2) as well as 18S rDNA data. However, for the first time, we reconstruct phylogenetic relationships of Prototheca using primary sequence and RNA secondary structure information simultaneously, a concept shown to increase robustness and accuracy of phylogenetic tree estimation. Using encoded sequence-structure data, Neighbor-Joining, Maximum-Parsimony and Maximum-Likelihood methods yielded well-supported trees in agreement with other trees calculated on rDNA; but differ in several aspects from trees using cytb as a phylogenetic marker. ITS2 secondary structures of Prototheca sequences are in agreement with the well-known common core structure of eukaryotes but show unusual differences in their helix lengths. An elongation of the fourth helix of some species seems to have occurred independently in the course of evolution. KW - secondary structure KW - 18S KW - ITS2 KW - phylogeny KW - prototheca Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-269897 SN - 1336-9563 VL - 77 IS - 2 ER - TY - JOUR A1 - Pietro-Garcia, Christian A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Fischer, Thomas A1 - Maier, Carina R. A1 - Rosenfeldt, Mathias A1 - Schülein-Völk, Christina A1 - Klann, Kevin A1 - Kalb, Reinhard A1 - Dikic, Ivan A1 - Münch, Christian A1 - Diefenbacher, Markus E. T1 - Inhibition of USP28 overcomes Cisplatin-resistance of squamous tumors by suppression of the Fanconi anemia pathway JF - Cell Death and Differentiation N2 - Squamous cell carcinomas (SCC) frequently have an exceptionally high mutational burden. As consequence, they rapidly develop resistance to platinum-based chemotherapy and overall survival is limited. Novel therapeutic strategies are therefore urgently required. SCC express ∆Np63, which regulates the Fanconi Anemia (FA) DNA-damage response in cancer cells, thereby contributing to chemotherapy-resistance. Here we report that the deubiquitylase USP28 is recruited to sites of DNA damage in cisplatin-treated cells. ATR phosphorylates USP28 and increases its enzymatic activity. This phosphorylation event is required to positively regulate the DNA damage repair in SCC by stabilizing ∆Np63. Knock-down or inhibition of USP28 by a specific inhibitor weakens the ability of SCC to cope with DNA damage during platin-based chemotherapy. Hence, our study presents a novel mechanism by which ∆Np63 expressing SCC can be targeted to overcome chemotherapy resistance. Limited treatment options and low response rates to chemotherapy are particularly common in patients with squamous cancer. The SCC specific transcription factor ∆Np63 enhances the expression of Fanconi Anemia genes, thereby contributing to recombinational DNA repair and Cisplatin resistance. Targeting the USP28-∆Np63 axis in SCC tones down this DNA damage response pathways, thereby sensitizing SCC cells to cisplatin treatment. KW - USP28 KW - Cisplatin KW - squamous tumors Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-273014 SN - 1476-5403 VL - 29 IS - 3 ER - TY - JOUR A1 - Peters, Birte A1 - Keller, Alexander A1 - Leonhardt, Sara Diana T1 - Diets maintained in a changing world: Does land-use intensification alter wild bee communities by selecting for flexible generalists? JF - Ecology and evolution N2 - Biodiversity loss, as often found in intensively managed agricultural landscapes, correlates with reduced ecosystem functioning, for example, pollination by insects, and with altered plant composition, diversity, and abundance. But how does this change in floral resource diversity and composition relate to occurrence and resource use patterns of trap-nesting solitary bees? To better understand the impact of land-use intensification on communities of trap-nesting solitary bees in managed grasslands, we investigated their pollen foraging, reproductive fitness, and the nutritional quality of larval food along a land-use intensity gradient in Germany. We found bee species diversity to decrease with increasing land-use intensity irrespective of region-specific community compositions and interaction networks. Land use also strongly affected the diversity and composition of pollen collected by bees. Lack of suitable pollen sources likely explains the absence of several bee species at sites of high land-use intensity. The only species present throughout, Osmia bicornis (red mason bee), foraged on largely different pollen sources across sites. In doing so, it maintained a relatively stable, albeit variable nutritional quality of larval diets (i.e., protein to lipid (P:L) ratio). The observed changes in bee–plant pollen interaction patterns indicate that only the flexible generalists, such as O. bicornis, may be able to compensate the strong alterations in floral resource landscapes and to obtain food of sufficient quality through readily shifting to alternative plant sources. In contrast, other, less flexible, bee species disappear. KW - bee decline KW - biodiversity exploratories KW - foraging KW - metabarcoding KW - pollen nutrients KW - solitary bees Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312786 SN - 2045-7758 VL - 12 IS - 5 ER - TY - JOUR A1 - Peindl, Matthias A1 - Göttlich, Claudia A1 - Crouch, Samantha A1 - Hoff, Niklas A1 - Lüttgens, Tamara A1 - Schmitt, Franziska A1 - Pereira, Jesús Guillermo Nieves A1 - May, Celina A1 - Schliermann, Anna A1 - Kronenthaler, Corinna A1 - Cheufou, Danjouma A1 - Reu-Hofer, Simone A1 - Rosenwald, Andreas A1 - Weigl, Elena A1 - Walles, Thorsten A1 - Schüler, Julia A1 - Dandekar, Thomas A1 - Nietzer, Sarah A1 - Dandekar, Gudrun T1 - EMT, stemness, and drug resistance in biological context: a 3D tumor tissue/in silico platform for analysis of combinatorial treatment in NSCLC with aggressive KRAS-biomarker signatures JF - Cancers N2 - Epithelial-to-mesenchymal transition (EMT) is discussed to be centrally involved in invasion, stemness, and drug resistance. Experimental models to evaluate this process in its biological complexity are limited. To shed light on EMT impact and test drug response more reliably, we use a lung tumor test system based on a decellularized intestinal matrix showing more in vivo-like proliferation levels and enhanced expression of clinical markers and carcinogenesis-related genes. In our models, we found evidence for a correlation of EMT with drug resistance in primary and secondary resistant cells harboring KRAS\(^{G12C}\) or EGFR mutations, which was simulated in silico based on an optimized signaling network topology. Notably, drug resistance did not correlate with EMT status in KRAS-mutated patient-derived xenograft (PDX) cell lines, and drug efficacy was not affected by EMT induction via TGF-β. To investigate further determinants of drug response, we tested several drugs in combination with a KRAS\(^{G12C}\) inhibitor in KRAS\(^{G12C}\) mutant HCC44 models, which, besides EMT, display mutations in P53, LKB1, KEAP1, and high c-MYC expression. We identified an aurora-kinase A (AURKA) inhibitor as the most promising candidate. In our network, AURKA is a centrally linked hub to EMT, proliferation, apoptosis, LKB1, and c-MYC. This exemplifies our systemic analysis approach for clinical translation of biomarker signatures. KW - EMT KW - drug resistance KW - invasion KW - stemness KW - 3D lung tumor tissue models KW - KRAS biomarker signatures KW - boolean in silico models KW - targeted combination therapy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270744 SN - 2072-6694 VL - 14 IS - 9 ER - TY - THES A1 - Panzer, Sabine T1 - Spotlight on Fungal Rhodopsins: A Microscopic and Electrophysiological Study T1 - Pilzliche Rhodopsine im Rampenlicht: eine Mikroskopische und Elektrophysiologische Studie N2 - Microbial rhodopsins are abundant membrane proteins often capable of ion transport and are found in all three domains of life. Thus, many fungi, especially phyto-associated or phyto-pathogenic ones, contain these green-light-sensing photoreceptors. Proteins that perceive other wavelengths are often well characterized in terms of their impact on fungal biology whereas little is known about the function of fungal rhodopsins. In this work, five fungal rhodopsins, UmOps1 and UmOps2 from the corn smut Ustilago maydis as well as ApOps1, ApOps2 and ApOps3 from the black yeast Aureobasidium pullulans, were characterized electrophysiologically using mammalian expression systems and the patch-clamp technique to explore their ion transport properties. The latter three were modified using a membrane trafficking cassette, termed “2.0” that consists of the lucy rho motif, two Kir2.1 Golgi apparatus trafficking signals and a Kir2.1 endoplasmic reticulum export signal, what resulted in better plasma membrane localization. Rhodopsin mutants were created to identify amino acid residues that are key players in the ion transport process. Current enhancement in the presence of weak organic acids, that was already described before for the fungal rhodopsin CarO from Fusarium fujikuroi (García-Martínez et al., 2015; Adam et al., 2018), was investigated for the U. maydis rhodopsins as well as for ApOps2 by supplementing acetate in the patch-clamp electrolyte solutions. All five rhodopsins were found to be proton pumps unidirectionally transporting protons out of the cytosol upon green-light exposure with every rhodopsin exhibiting special features or unique characteristics in terms of the photocurrents. To name just a few, UmOps1, for example, showed a striking pH-dependency with massive enhancement of pump currents in the presence of extracellular acidic pH. Moreover, especially ApOps2 and ApOps3 showed very high current densities, however, the ones of ApOps3 were impaired when exchanging intracellular sodium to cesium. Concerning the mutations, it was found, that the electron releasing group in UmOps1 seems to be involved in the striking pH effect and that the mutation of the proton donor site resulted in almost unfunctional proteins. Moreover, a conserved arginine inside ApOps2 was mutated to turn the proton pump into a channel. Regarding the effect of weak organic acids, acetate was able to induce enhanced pump currents in UmOps1 and ApOps2, but not in UmOps2. Due to the capability of current production upon light illumination, microbial rhodopsins are used in the research field of optogenetics that aims to control neuronal activity by light. ApOps2 was used to test its functionality in differentiated NG108-15 cells addressing the question whether it is a promising candidate that can be used as an optogenetic tool. Indeed, this rhodopsin could be functionally expressed in this experimental system. Furthermore, microscopic studies were done to elucidate the localization of selected rhodopsins in fungal cells. Therefore, conventional (confocal laser scanning or structured illumination microscopy) as well as novel super-resolution techniques (expansion or correlated light and electron microscopy) were used. This was done on U. maydis sporidia, the yeast-like form of this fungus, via eGFP-tagged UmOps1 or UmOps2 expressing strains. Moreover, CarO-eYFP expressing F. fujikuroi was imaged microscopically to confirm the plasma membrane and tonoplast localization (García-Martínez et al., 2015) with the help of counterstaining experiments. UmOps1 was found to reside in the plasma membrane, UmOps2 localized to the tonoplast and CarO was indeed found in both of these localizations. This work gains further insight into rhodopsin functions and paves the way for further research in terms of the biological role of rhodopsins in fungal life cycles. N2 - Mikrobielle Rhodopsine sind häufig vorkommende Membranproteine, welche oft fähig sind, Ionen zu transportieren. Sie kommen in allen drei Domänen vor. So weisen auch Pilze – vor allem pflanzenassoziierte oder pflanzenpathogene – diese Grünlichtrezeptoren auf. Proteine, die andere Wellenlängen empfangen können, sind bereits häufig gut in Bezug auf ihren Einfluss auf die Pilzbiologie untersucht, wohingegen nur wenig über die Funktion der pilzlichen Rhodopsine bekannt ist. Hier wurden fünf Rhodopsine, UmOps1 und UmOps2 des Maisbeulenbrandes Ustilago maydis, sowie ApOps1, ApOps2 und ApOps3 des schwarzen Hefepilzes Aureobasidium pullulans bezüglich ihrer Ionentransport-Eigenschaften mit Hilfe von Säugerzelllinien und der Patch-Clamp Technik untersucht. Die drei letzteren wurden mit der „2.0“-Modifikation ausgestattet, bestehend aus dem lucy rho Motif, zwei Kir2.1 Golgiapparat Transfer- und einem Kir2.1 Endoplasmatischen Retikulum-Export-Signal, was zu einer besseren Plasmamembran-Lokalisierung der Proteine führte. Es wurden weiterhin Rhodopsin-Mutanten hergestellt um Aminosäuren zu identifizieren, welche im Ionentransport Schlüsselfunktionen einnehmen. Des Weiteren wurde der Effekt von schwachen organischen Säuren auf den Ionentransport der U. maydis Rhodopsine und auf ApOps2 mittels Supplementation der Patch-Clamp-Elektrolyten mit Acetat untersucht. Dieser Effekt wurde bereits früher für CarO aus Fusarium fujikuroi nachgewiesen (García-Martínez et al., 2015; Adam et al., 2018) und bezeichnet eine Erhöhung der lichtinduzierten Ströme durch die extrazelluläre Anwesenheit schwacher organischer Säuren. Alle fünf untersuchten Rhodopsine wurden als Grünlicht getriebene Pump-Rhodopsine identifiziert, welche Protonen unidirektional aus dem Zytosol transportieren. Hierbei zeigten die lichtinduzierten Ströme jedes Rhodopsins spezielle Eigenschaften und Merkmale. Unter anderem zeigte UmOps1 eine unerwartete pH-Abhängigkeit indem die Pumpströme bei extrazellulärem sauren pH massiv erhöht wurden. Des Weiteren zeigten sowohl ApOps2 als auch ApOps3 sehr hohe Stromdichten, wobei jedoch die von ApOps3 rapide abnahm, sobald intrazelluläres Natrium durch Caesium ersetzt wurde. Bezüglich der Rhodopsin- Mutanten konnte gezeigt werden, dass die Proton-Releasing-Group von UmOps1 wahrscheinlich in die erstaunliche pH-Abhängigkeit involviert ist und dass die Mutation des Proton-Donors zu meist nicht funktionalen Proteinen führt. Ein konserviertes Arginin in ApOps2 wurde mutiert um das Pump-Rhodopsin in einen Kanal umzuwandeln. Der Schwache-Organische-Säure-Effekt konnte für UmOps1 und ApOps2, nicht aber für UmOps2 nachgewiesen werden. Wegen ihrer Ionentransport-Eigenschaften werden mikrobielle Rhodopsine in der Optogenetik eingesetzt um neuronale Zellen mittels Lichts zu steuern. Hier wurde ApOps2 benutzt um dessen Funktionalität in ausdifferenzierten NG108-15 Zellen zu testen und ob dieses Rhodopsin ein vielversprechender Kandidat für optogenetische Anwendungen wäre. In der Tat gelang es, ApOps2 funktional in diesem Testsystem zu exprimieren. Des Weiteren wurde die Lokalisation von UmOps1 und UmOps2 in Sporidien (hefeähnliche Form von U. maydis) mittels eGFP-Label untersucht, sowie die Plasmamembran- und Tonoplast-Lokalisierung von CarO-eYFP in F. fujikuroi (García- Martínez et al., 2015) mittels Gegenfärbungen bestätigt. Hierfür wurden konventionelle (konfokale Laserraster-, sowie strukturierte Beleuchtungsmikroskopie) und auch neuartige hochaufgelöste Mikroskopie-Methoden (Expansions- und korrelative Licht- und Elektronenmikroskopie) verwendet. Es konnten hier weitere Einblicke in die Funktionen pilzlicher Rhodopsine gewonnen werden, welche den Weg für weitere Forschung in Bezug auf den Einfluss dieser Proteine auf das Leben der Pilze ebnen. KW - Opsin KW - Microscopy KW - Patch-clamp KW - Ustilago maydis KW - Aureobasidium pullulans KW - Expansion Microscopy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-271859 ER - TY - JOUR A1 - Otto, Christoph A1 - Kastner, Carolin A1 - Schmidt, Stefanie A1 - Uttinger, Konstantin A1 - Baluapuri, Apoorva A1 - Denk, Sarah A1 - Rosenfeldt, Mathias T. A1 - Rosenwald, Andreas A1 - Roehrig, Florian A1 - Ade, Carsten P. A1 - Schuelein-Voelk, Christina A1 - Diefenbacher, Markus E. A1 - Germer, Christoph-Thomas A1 - Wolf, Elmar A1 - Eilers, Martin A1 - Wiegering, Armin T1 - RNA polymerase I inhibition induces terminal differentiation, growth arrest, and vulnerability to senolytics in colorectal cancer cells JF - Molecular Oncology N2 - Ribosomal biogenesis and protein synthesis are deregulated in most cancers, suggesting that interfering with translation machinery may hold significant therapeutic potential. Here, we show that loss of the tumor suppressor adenomatous polyposis coli (APC), which constitutes the initiating event in the adenoma carcinoma sequence for colorectal cancer (CRC), induces the expression of RNA polymerase I (RNAPOL1) transcription machinery, and subsequently upregulates ribosomal DNA (rDNA) transcription. Targeting RNAPOL1 with a specific inhibitor, CX5461, disrupts nucleolar integrity, and induces a disbalance of ribosomal proteins. Surprisingly, CX5461-induced growth arrest is irreversible and exhibits features of senescence and terminal differentiation. Mechanistically, CX5461 promotes differentiation in an MYC-interacting zinc-finger protein 1 (MIZ1)- and retinoblastoma protein (Rb)-dependent manner. In addition, the inhibition of RNAPOL1 renders CRC cells vulnerable towards senolytic agents. We validated this therapeutic effect of CX5461 in murine- and patient-derived organoids, and in a xenograft mouse model. These results show that targeting ribosomal biogenesis together with targeting the consecutive, senescent phenotype using approved drugs is a new therapeutic approach, which can rapidly be transferred from bench to bedside. KW - CRC KW - CX5461 KW - MIZ1 KW - MYC KW - ribosome KW - RNAPOL1 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312806 VL - 16 IS - 15 ER - TY - THES A1 - Niehörster, Thomas T1 - Spektral aufgelöste Fluoreszenzlebensdauer-Mikroskopie mit vielen Farben T1 - Spectrally resolved fluorescence lifetime imaging microscopy with many colours N2 - Die Fluoreszenzmikroskopie ist eine vielseitig einsetzbare Untersuchungsmethode für biologische Proben, bei der Biomoleküle selektiv mit Fluoreszenzfarbstoffen markiert werden, um sie dann mit sehr gutem Kontrast abzubilden. Dies ist auch mit mehreren verschiedenartigen Zielmolekülen gleichzeitig möglich, wobei üblicherweise verschiedene Farbstoffe eingesetzt werden, die über ihre Spektren unterschieden werden können. Um die Anzahl gleichzeitig verwendbarer Färbungen zu maximieren, wird in dieser Arbeit zusätzlich zur spektralen Information auch das zeitliche Abklingverhalten der Fluoreszenzfarbstoffe mittels spektral aufgelöster Fluoreszenzlebensdauer-Mikroskopie (spectrally resolved fluorescence lifetime imaging microscopy, sFLIM) vermessen. Dazu wird die Probe in einem Konfokalmikroskop von drei abwechselnd gepulsten Lasern mit Wellenlängen von 485 nm, 532nm und 640nm angeregt. Die Detektion des Fluoreszenzlichtes erfolgt mit einer hohen spektralen Auflösung von 32 Kanälen und gleichzeitig mit sehr hoher zeitlicher Auflösung von einigen Picosekunden. Damit wird zu jedem detektierten Fluoreszenzphoton der Anregungslaser, der spektrale Kanal und die Ankunftszeit registriert. Diese detaillierte multidimensionale Information wird von einem Pattern-Matching-Algorithmus ausgewertet, der das Fluoreszenzsignal mit zuvor erstellten Referenzpattern der einzelnen Farbstoffe vergleicht. Der Algorithmus bestimmt so für jedes Pixel die Beiträge der einzelnen Farbstoffe. Mit dieser Technik konnten pro Anregungslaser fünf verschiedene Färbungen gleichzeitig dargestellt werden, also theoretisch insgesamt 15 Färbungen. In der Praxis konnten mit allen drei Lasern zusammen insgesamt neun Färbungen abgebildet werden, wobei die Anzahl der Farben vor allem durch die anspruchsvolle Probenvorbereitung limitiert war. In anderen Versuchen konnte die sehr hohe Sensitivität des sFLIM-Systems genutzt werden, um verschiedene Zielmoleküle voneinander zu unterscheiden, obwohl sie alle mit demselben Farbstoff markiert waren. Dies war möglich, weil sich die Fluoreszenzeigenschaften eines Farbstoffmoleküls geringfügig in Abhängigkeit von seiner Umgebung ändern. Weiterhin konnte die sFLIM-Technik mit der hochauflösenden STED-Mikroskopie (STED: stimulated emission depletion) kombiniert werden, um so hochaufgelöste zweifarbige Bilder zu erzeugen, wobei nur ein einziger gemeinsamer STED-Laser benötigt wurde. Die gleichzeitige Erfassung von mehreren photophysikalischen Messgrößen sowie deren Auswertung durch den Pattern-Matching-Algorithmus ermöglichten somit die Entwicklung von neuen Methoden der Fluoreszenzmikroskopie für Mehrfachfärbungen. N2 - Fluorescence microscopy is an important and near-universal technique to examine biological samples. Typically, biomolecules are selectively labelled with fluorophores and then imaged with high contrast. This can be done for several target molecules simultaneously, using different fluorophores that are usually distinguished by their spectra. This thesis describes a method to maximize the number of simultaneous stainings. Not only the spectral information but also the temporal information of the fluorescence decay is exploited by means of spectrally resolved fluorescence lifetime imaging microscopy (sFLIM). Using a confocal laser scanning microscope, the sample is excited by three alternatingly pulsed lasers at 485 nm, 532 nm, and 640 nm. Fluorescence light is detected on 32 spectrally separated detection channels with high time resolution of a few picoseconds. Thus, in this setup, we record the excitation laser, the spectral channel, and the time of arrival for each fluorescence photon. This detailed multi-dimensional information is then processed by a pattern-matching algorithm that compares the fluorescence signal with reference patterns of the used fluorophores to determine the contribution of each fluorophore in each pixel. Using this technique we imaged five different stainings per excitation laser, implying that 15 simultaneous stainings should theoretically be achievable. Current constraints in the sample preparation procedure limited the number of simultaneous stainings to nine. In additional experiments, we exploited the sensitivity of the sFLIM system to image several different target molecules simultaneously with the same fluorophore, taking advantage of slight changes in the fluorescence behaviour of the fluorophore due to environmental changes. We also combined sFLIM with stimulated emission depletion (STED) to perform super-resolution multi-target imaging with two stainings that operated with one common STED laser. Thus, the simultaneous exploitation of several photophysical parameters, in combination with algorythmic evaluation, allowed us to devise novel modes of multi-target imaging in fluorescence microscopy. KW - Fluoreszenzmikroskopie KW - Fluoreszenzlebensdauer-Mikroskopie KW - Konfokale Mikroskopie KW - STED-Mikroskopie KW - Fluoreszenz KW - Mustervergleich KW - Pattern Matching KW - sFLIM KW - TCSPC KW - Mikroskopie KW - Microscopy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-296573 ER - TY - JOUR A1 - Nguyen, Tu Anh Thi A1 - Beetz, M. Jerome A1 - Merlin, Christine A1 - Pfeiffer, Keram A1 - el Jundi, Basil T1 - Weighting of celestial and terrestrial cues in the monarch butterfly central complex JF - Frontiers in Neural Circuits N2 - Monarch butterflies rely on external cues for orientation during their annual long-distance migration from Northern US and Canada to Central Mexico. These external cues can be celestial cues, such as the sun or polarized light, which are processed in a brain region termed the central complex (CX). Previous research typically focused on how individual simulated celestial cues are encoded in the butterfly's CX. However, in nature, the butterflies perceive several celestial cues at the same time and need to integrate them to effectively use the compound of all cues for orientation. In addition, a recent behavioral study revealed that monarch butterflies can rely on terrestrial cues, such as the panoramic skyline, for orientation and use them in combination with the sun to maintain a directed flight course. How the CX encodes a combination of celestial and terrestrial cues and how they are weighted in the butterfly's CX is still unknown. Here, we examined how input neurons of the CX, termed TL neurons, combine celestial and terrestrial information. While recording intracellularly from the neurons, we presented a sun stimulus and polarized light to the butterflies as well as a simulated sun and a panoramic scene simultaneously. Our results show that celestial cues are integrated linearly in these cells, while the combination of the sun and a panoramic skyline did not always follow a linear integration of action potential rates. Interestingly, while the sun and polarized light were invariantly weighted between individual neurons, the sun stimulus and panoramic skyline were dynamically weighted when both stimuli were simultaneously presented. Taken together, this dynamic weighting between celestial and terrestrial cues may allow the butterflies to flexibly set their cue preference during navigation. KW - insect KW - central complex KW - navigation KW - orientation KW - landmark KW - migration KW - panorama KW - lepidoptera Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-279445 SN - 1662-5110 VL - 16 ER - TY - JOUR A1 - Nazzal, Yousef A1 - Howari, Fares M. A1 - Yaslam, Aya A1 - Iqbal, Jibran A1 - Maloukh, Lina A1 - Ambika, Lakshmi Kesari A1 - Al-Taani, Ahmed A. A1 - Ali, Ijaz A1 - Othman, Eman M. A1 - Jamal, Arshad A1 - Naseem, Muhammad T1 - A methodological review of tools that assess dust microbiomes, metatranscriptomes and the particulate chemistry of indoor dust JF - Atmosphere N2 - Indoor house dust is a blend of organic and inorganic materials, upon which diverse microbial communities such as viruses, bacteria and fungi reside. Adequate moisture in the indoor environment helps microbial communities multiply fast. The outdoor air and materials that are brought into the buildings by airflow, sandstorms, animals pets and house occupants endow the indoor dust particles with extra features that impact human health. Assessment of the health effects of indoor dust particles, the type of indoor microbial inoculants and the secreted enzymes by indoor insects as allergens merit detailed investigation. Here, we discuss the applications of next generation sequencing (NGS) technology which is used to assess microbial diversity and abundance of the indoor dust environments. Likewise, the applications of NGS are discussed to monitor the gene expression profiles of indoor human occupants or their surrogate cellular models when exposed to aqueous solution of collected indoor dust samples. We also highlight the detection methods of dust allergens and analytical procedures that quantify the chemical nature of indoor particulate matter with a potential impact on human health. Our review is thus unique in advocating the applications of interdisciplinary approaches that comprehensively assess the health effects due to bad air quality in built environments. KW - indoor dust KW - allergens KW - metagenomics KW - particulate matter KW - microbiomes KW - transcriptomes KW - health effects Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285957 SN - 2073-4433 VL - 13 IS - 8 ER - TY - JOUR A1 - Nanda, Indrajit A1 - Schories, Susanne A1 - Simeonov, Ivan A1 - Adolfi, Mateus Contar A1 - Du, Kang A1 - Steinlein, Claus A1 - Alsheimer, Manfred A1 - Haaf, Thomas A1 - Schartl, Manfred T1 - Evolution of the degenerated Y-chromosome of the swamp guppy, Micropoecilia picta JF - Cells N2 - The conspicuous colour sexual dimorphism of guppies has made them paradigmatic study objects for sex-linked traits and sex chromosome evolution. Both the X- and Y-chromosomes of the common guppy (Poecilia reticulata) are genetically active and homomorphic, with a large homologous part and a small sex specific region. This feature is considered to emulate the initial stage of sex chromosome evolution. A similar situation has been documented in the related Endler’s and Oropuche guppies (P. wingei, P. obscura) indicating a common origin of the Y in this group. A recent molecular study in the swamp guppy (Micropoecilia. picta) reported a low SNP density on the Y, indicating Y-chromosome deterioration. We performed a series of cytological studies on M. picta to show that the Y-chromosome is quite small compared to the X and has accumulated a high content of heterochromatin. Furthermore, the Y-chromosome stands out in displaying CpG clusters around the centromeric region. These cytological findings evidently illustrate that the Y-chromosome in M. picta is indeed highly degenerated. Immunostaining for SYCP3 and MLH1 in pachytene meiocytes revealed that a substantial part of the Y remains associated with the X. A specific MLH1 hotspot site was persistently marked at the distal end of the associated XY structure. These results unveil a landmark of a recombining pseudoautosomal region on the otherwise strongly degenerated Y chromosome of M. picta. Hormone treatments of females revealed that, unexpectedly, no sexually antagonistic color gene is Y-linked in M. picta. All these differences to the Poecilia group of guppies indicate that the trajectories associated with the evolution of sex chromosomes are not in parallel. KW - sex chromosomes KW - heterochromatin KW - Y chromosome degeneration KW - meiosis KW - synaptonemal complex KW - recombination KW - 5-methylcytosine KW - testosterone KW - sexual antagonistic genes KW - sex linked pigmentation pattern Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267242 SN - 2073-4409 VL - 11 IS - 7 ER - TY - RPRT A1 - Müller, Jörg A1 - Scherer-Lorenzen, Michael A1 - Ammer, Christian A1 - Eisenhauer, Nico A1 - Seidel, Dominik A1 - Schuldt, Bernhard A1 - Biedermann, Peter A1 - Schmitt, Thomas A1 - Künzer, Claudia A1 - Wegmann, Martin A1 - Cesarz, Simone A1 - Peters, Marcell A1 - Feldhaar, Heike A1 - Steffan-Dewenter, Ingolf A1 - Claßen, Alice A1 - Bässler, Claus A1 - von Oheimb, Goddert A1 - Fichtner, Andreas A1 - Thorn, Simon A1 - Weisser, Wolfgang T1 - BETA-FOR: Erhöhung der strukturellen Diversität zwischen Waldbeständen zur Erhöhung der Multidiversität und Multifunktionalität in Produktionswäldern. Antragstext für die DFG Forschungsgruppe FOR 5375 T1 - BETA-FOR: Enhancing the structural diversity between patches for improving multidiversity and multifunctionality in production forests. Proposal for DFG Research Unit FOR 5375 BT - β\(_4\) : Proposal for the 1st phase (2022-2026) of the DFG Research Unit FOR 5375/1 (DFG Forschergruppe FOR 5375/1 – BETA-FOR), Fabrikschleichach, October 2021 N2 - Der in jüngster Zeit beobachtete kontinuierliche Verlust der β-Diversität in Ökosystemen deutet auf homogene Gemeinschaften auf Landschaftsebene hin, was hauptsächlich auf die steigende Landnutzungsintensität zurückgeführt wird. Biologische Vielfalt ist mit zahlreichen Funktionen und der Stabilität von Ökosystemen verknüpft. Es ist daher zu erwarten, dass eine abnehmende β-Diversität auch die Multifunktionalität verringert. Wir kombinieren hier Fachwissen aus der Forstwissenschaft, der Ökologie, der Fernerkundung, der chemischen Ökologie und der Statistik in einem gemeinschaftlichen und experimentellen β-Diversitätsdesign, um einerseits die Auswirkungen der Homogenisierung zu bewerten und andererseits Konzepte zu entwickeln, um negative Auswirkungen durch Homogenisierung in Wäldern rückgängig zu machen. Konkret werden wir uns mit der Frage beschäftigen, ob die Verbesserung der strukturellen β-Komplexität (ESBC) in Wäldern durch Waldbau oder natürliche Störungen die Biodiversität und Multifunktionalität in ehemals homogenen Produktionswäldern erhöhen kann. Unser Ansatz wird mögliche Mechanismen hinter den beobachteten Homogenisierungs-Diversitäts-Beziehungen identifizieren und zeigen, wie sich diese auf die Multifunktionalität auswirken. An elf Standorten in ganz Deutschland haben wir dazu zwei Waldbestände als zwei kleine "Waldlandschaften" ausgewählt. In einem dieser beiden Bestände haben wir ESBC (Enhancement of Structural Beta Complexity)-Behandlungen durchgeführt. Im zweiten, dem Kontrollbestand, werden wir die gleich Anzahl 50x50m Parzellen ohne ESBC einrichten. Auf allen Parzellen werden wir 18 taxonomische Artengruppen aller trophischer Ebenen und 21 Ökosystemfunktionen, einschließlich der wichtigsten Funktionen in Wäldern der gemäßigten Zonen, messen. Der statistische Rahmen wird eine umfassende Analyse der Biodiversität ermöglichen, indem verschiedenen Aspekte (taxonomische, funktionelle und phylogenetische Vielfalt) auf verschiedenen Skalenebenen (α-, β-, γ-Diversität) quantifiziert werden. Um die Gesamtdiversität zu kombinieren, werden wir das Konzept der Multidiversität auf die 18 Taxa anwenden. Wir werden neue Ansätze zur Quantifizierung und Aufteilung der Multifunktionalität auf α- und β-Skalen verwenden und entwickeln. Durch die experimentelle Beschreibung des Zusammenhangs zwischen β-Diversität und Multifunktionalität in einer Reallandschaft wird unsere Forschung einen neuen Weg einschlagen. Darüber hinaus werden wir dazu beitragen, verbesserte Leitlinien für waldbauliche Konzepte und für das Management natürlicher Störungen zu entwickeln, um Homogenisierungseffekte der Vergangenheit umzukehren. N2 - The recently observed consistent loss of β-diversity across ecosystems indicates increasingly homogeneous communities in patches of landscapes, mainly caused by increasing land-use intensity. Biodiversity is related to numerous ecosystem functions and stability. Therefore, decreasing β-diversity is also expected to reduce multifunctionality. To assess the impact of homogenization and to develop guidelines to reverse its potentially negative effects, we combine expertise from forest science, ecology, remote sensing, chemical ecology and statistics in a collaborative and experimental β-diversity approach. Specifically, we will address the question whether the Enhancement of Structural Beta Complexity (ESBC) in forests by silviculture or natural disturbances will increase biodiversity and multifunctionality in formerly homogeneously structured production forests. Our approach will identify potential mechanisms behind observed homogenization-diversity-relationships and show how these translate into effects on multifunctionality. At eleven forest sites throughout Germany, we selected two districts as two types of small ‘forest landscapes’. In one of these two districts, we established ESBC treatments (nine differently treated 50x50 m patches with a focus on canopy cover and deadwood features). In the second, the control district, we will establish nine patches without ESBC. By a comprehensive sampling, we will monitor 18 taxonomic groups and measure 21 ecosystem functions, including key functions in temperate forests, on all patches. The statistical framework will allow a comprehensive biodiversity assessment by quantifying the different aspects of multitrophic biodiversity (taxonomical, functional and phylogenetic diversity) on different levels of biodiversity (α-, β-, γ-diversity). To combine overall diversity, we will apply the concept of multidiversity across the 18 taxa. We will use and develop new approaches for quantification and partitioning of multifunctionality at α- and β- scales. Overall, our study will herald a new research avenue, namely by experimentally describing the link between β-diversity and multifunctionality. Furthermore, we will help to develop guidelines for improved silvicultural concepts and concepts for management of natural disturbances in temperate forests reversing past homogenization effects. KW - Waldökosystem KW - Biodiversität KW - BETA-Multifunktionalität KW - beta-multifunctionality KW - BETA-Diversität KW - beta diversity KW - Forschungsstation Fabrikschleichach Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290849 ER - TY - JOUR A1 - Martinez-Bengochea, A. L. A1 - Kneitz, S. A1 - Herpin, A. A1 - Nobrega, R. H. A1 - Adolfi, M. C. A1 - Schartl, M. T1 - Sexual development dysgenesis in interspecific hybrids of Medaka fish JF - Scientific Reports N2 - Fish are amongst vertebrates the group with the highest diversity of known sex-determining genes. Particularly, the genus Oryzias is a suitable taxon to understand how different sex determination genetic networks evolved in closely related species. Two closely related species, O. latipes and O. curvinotus, do not only share the same XX/XY sex chromosome system, but also the same male sex-determining gene, dmrt1bY. We performed whole mRNA transcriptomes and morphology analyses of the gonads of hybrids resulting from reciprocal crosses between O. latipes and O. curvinotus. XY male hybrids, presenting meiotic arrest and no production of sperm were sterile, and about 30% of the XY hybrids underwent male-to-female sex reversal. Both XX and XY hybrid females exhibited reduced fertility and developed ovotestis while aging. Transcriptome data showed that male-related genes are upregulated in the XX and XY female hybrids. The transcriptomes of both types of female and of the male gonads are characterized by upregulation of meiosis and germ cell differentiation genes. Differences in the parental species in the downstream pathways of sexual development could explain sex reversal, sterility, and the development of intersex gonads in the hybrids. We hypothesize that male-to-female sex reversal may be connected to a different development time between species at which dmrt1bY expression starts. Our results provide molecular clues for the proximate mechanisms of hybrid incompatibility and Haldane’s rule. KW - sexual development dysgenesis KW - Medaka fish KW - sex-determining genes. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300295 VL - 12 IS - 1 ER - TY - JOUR A1 - Mamontova, Victoria A1 - Trifault, Barbara A1 - Burger, Kaspar T1 - Compartment-specific proximity ligation expands the toolbox to assess the interactome of the long non-coding RNA NEAT1 JF - International Journal of Molecular Sciences N2 - The nuclear paraspeckle assembly transcript 1 (NEAT1) locus encodes two long non-coding (lnc)RNA isoforms that are upregulated in many tumours and dynamically expressed in response to stress. NEAT1 transcripts form ribonucleoprotein complexes with numerous RNA-binding proteins (RBPs) to assemble paraspeckles and modulate the localisation and activity of gene regulatory enzymes as well as a subset of messenger (m)RNA transcripts. The investigation of the dynamic composition of NEAT1-associated proteins and mRNAs is critical to understand the function of NEAT1. Interestingly, a growing number of biochemical and genetic tools to assess NEAT1 interactomes has been reported. Here, we discuss the Hybridisation Proximity (HyPro) labeling technique in the context of NEAT1. HyPro labeling is a recently developed method to detect spatially ordered interactions of RNA-containing nuclear compartments in cultured human cells. After introducing NEAT1 and paraspeckles, we describe the advantages of the HyPro technology in the context of other methods to study RNA interactomes, and review the key findings in mapping NEAT1-associated RNA transcripts and protein binding partners. We further discuss the limitations and potential improvements of HyPro labeling, and conclude by delineating its applicability in paraspeckles-related cancer research. KW - proximity ligation KW - paraspeckles KW - NEAT1 KW - long non-coding RNA KW - cancer Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284185 SN - 1422-0067 VL - 23 IS - 8 ER - TY - JOUR A1 - Mainz, Laura A1 - Sarhan, Mohamed A. F. E. A1 - Roth, Sabine A1 - Sauer, Ursula A1 - Maurus, Katja A1 - Hartmann, Elena M. A1 - Seibert, Helen-Desiree A1 - Rosenwald, Andreas A1 - Diefenbacher, Markus E. A1 - Rosenfeldt, Mathias T. T1 - Autophagy blockage reduces the incidence of pancreatic ductal adenocarcinoma in the context of mutant Trp53 JF - Frontiers in Cell and Developmental Biology N2 - Macroautophagy (hereafter referred to as autophagy) is a homeostatic process that preserves cellular integrity. In mice, autophagy regulates pancreatic ductal adenocarcinoma (PDAC) development in a manner dependent on the status of the tumor suppressor gene Trp53. Studies published so far have investigated the impact of autophagy blockage in tumors arising from Trp53-hemizygous or -homozygous tissue. In contrast, in human PDACs the tumor suppressor gene TP53 is mutated rather than allelically lost, and TP53 mutants retain pathobiological functions that differ from complete allelic loss. In order to better represent the patient situation, we have investigated PDAC development in a well-characterized genetically engineered mouse model (GEMM) of PDAC with mutant Trp53 (Trp53\(^{R172H}\)) and deletion of the essential autophagy gene Atg7. Autophagy blockage reduced PDAC incidence but had no impact on survival time in the subset of animals that formed a tumor. In the absence of Atg7, non-tumor-bearing mice reached a similar age as animals with malignant disease. However, the architecture of autophagy-deficient, tumor-free pancreata was effaced, normal acinar tissue was largely replaced with low-grade pancreatic intraepithelial neoplasias (PanINs) and insulin expressing islet β-cells were reduced. Our data add further complexity to the interplay between Atg7 inhibition and Trp53 status in tumorigenesis. KW - pancreatic cancer KW - autophagy KW - p53 KW - metastasis KW - ATG7 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266005 SN - 2296-634X VL - 10 ER - TY - JOUR A1 - Maihoff, Fabienne A1 - Bohlke, Kyte A1 - Brockmann, Axel A1 - Schmitt, Thomas T1 - Increased complexity of worker CHC profiles in Apis dorsata correlates with nesting ecology JF - PLoS ONE N2 - Cuticular hydrocarbons (CHC) are known to serve as discrimination cues and will trigger defence behaviour in a plethora of eusocial insects. However, little is known how about nestmate recognition ability selects for CHC diversification. In this study we investigate differences in CHC composition of four major honey bee species with respect to the differences in their nesting behavior. In contrast to A. mellifera, A. cerana and A. florea, the giant honey bee A. dorsata prefers to build their nests in aggregations with very small spatial distances between nests, which increases the probability of intrusions. Thus, A. dorsata exhibits a particularly challenging nesting behavior which we hypothesize should be accompanied with an improved nestmate recognition system. Comparative analyses of the worker CHC profiles indicate that A. dorsata workers exhibit a unique and more complex CHC profile than the other three honey bee species. This increased complexity is likely based on a developmental process that retains the capability to synthesize methyl-branched hydrocarbons as adults. Furthermore, two sets of behavioral experiments provide evidence that A. dorsata shows an improved nestmate discrimination ability compared to the phylogenetically ancestral A. florea, which is also open-nesting but does not form nest aggregations. The results of our study suggest that ecological traits like nesting in aggregation might be able to drive CHC profile diversification even in closely related insect species. KW - Apis dorsata KW - cuticular hydrocarbons KW - nesting Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301353 VL - 17 IS - 7 ER - TY - THES A1 - Liu, Ruiqi T1 - Dynamic regulation of the melanocortin 4 receptor system in body weight homeostasis and reproductive maturation in fish T1 - Dynamische Regulation des Melanocortin-4-Rezeptor Systems bei der Körpergewichtshomöostase und der Fortpflanzungsreifung bei Fischen N2 - Puberty is an important period of life with physiological changes to enable animals to reproduce. Xiphophorus fish exhibit polymorphism in body size, puberty timing, and reproductive tactics. These phenotypical polymorphisms are controlled by the Puberty (P) locus. In X. nigrensis and X. multilineatus, the P locus encodes the melanocortin 4 receptor (Mc4r) with high genetic polymorphisms. Mc4r is a member of the melanocortin receptors, belonging to class A G-protein coupled receptors. The Mc4r signaling system consists of Mc4r, the agonist Pomc (precursor of various MSH and of ACTH), the antagonist Agrp and accessory protein Mrap2. In humans, MC4R has a role in energy homeostasis. MC4R and MRAP2 mutations are linked to human obesity but not to puberty. Mc4rs in X. nigrensis and X. multilineatus are present in three allele classes, A, B1 and B2, of which the X-linked A alleles express functional receptors and the male-specific Y-linked B alleles encode defective receptors. Male body sizes are correlated with B allele type and B allele copy numbers. Late-maturing large males carry B alleles in high copy number while early-maturing small males carry B alleles in low copy number or only A alleles. Cell culture co-expression experiments indicated that B alleles may act as dominant negative receptor mutants on A alleles. In this study, the main aim was to biochemically characterize the mechanism of puberty regulation by Mc4r in X. nigrensis and X. multilineatus, whether it is by Mc4r dimerization and/or Mrap2 interaction with Mc4r or other mechanisms. Furthermore, Mc4r in X. hellerii (another swordtail species) and medaka (a model organism phylogenetically close to Xiphophorus) were investigated to understand if the investigated mechanisms are conserved in other species. In medaka, the Mc4r signaling system genes (mc4r, mrap2, pomc, agrp1) are expressed before hatching, with agrp1 being highly upregulated during hatching and first feeding. These genes are mainly expressed in adult brain, and the transcripts of mrap2 co-localize with mc4r indicating a function in modulating Mc4r signaling. Functional comparison between wild-type and mc4r knockout medaka showed that Mc4r knockout does not affect puberty timing but significantly delays hatching due to the retarded embryonic development of knockout medaka. Hence, the Mc4r system in medaka is involved in regulation of growth rather than puberty. In Xiphophorus, expression co-localization of mc4r and mrap2 in X. nigrensis and X. hellerii fish adult brains was characterized by in situ hybridization. In both species, large males exhibit strikingly high expression of mc4r while mrap2 shows similar expression level in the large and small male and female. Differently, X. hellerii has only A-type alleles indicating that the puberty regulation mechanisms evolved independently in Xiphophorus genus. Functional analysis of Mrap2 and Mc4r A/B1/B2 alleles of X. multilineatus showed that increased Mrap2 amounts induce higher cAMP response but EC50 values do not change much upon Mrap2 co-expression with Mc4r (expressing only A allele or A and B1 alleles). A and B1 alleles were expressed higher in large male brains, while B2 alleles were only barely expressed. Mc4r A-B1 cells have lower cAMP production than Mc4r A cells. Together, this indicates a role of Mc4r alleles, but not Mrap2, in puberty onset regulation signaling. Interaction studies by FRET approach evidenced that Mc4r A and B alleles can form heterodimers and homodimers in vitro, but only for a certain fraction of the expressed receptors. Single-molecule colocalization study using super-resolution microscope dSTORM confirmed that only few Mc4r A and B1 receptors co-localized on the membrane. Altogether, the species-specific puberty onset regulation in X. nigrensis and X. multilineatus is linked to the presence of Mc4r B alleles and to some extent to its interaction with A allele gene products. This is reasoned to result in certain levels of cAMP signaling which reaches the dynamic or static threshold to permit late puberty in large males. In summary, puberty onset regulation by dominant negative effect of Mc4r mutant alleles is a special mechanism that is found so far only in X. nigrensis and X. multilineatus. Other Xiphophorus species obviously evolved the same function of the pathway by diverse mechanisms. Mc4r in other fish (medaka) has a role in regulation of growth, reminiscent of its role in energy homeostasis in humans. The results of this study will contribute to better understand the biochemical and physiological functions of the Mc4r system in vertebrates including human. N2 - Die Pubertät ist ein wichtiger Lebensabschnitt mit physiologischen Veränderungen, die die Fortpflanzung von Tieren ermöglichen. Xiphophorus Fische weisen einen Polymorphismus in Bezug auf Körpergröße, Pubertätszeit und Fortpflanzungstaktik auf. Diese phänotypischen Polymorphismen werden durch den Pubertäts (P) Locus gesteuert. In X. nigrensis und X. multilineatus kodiert der P Locus den Melanocortin-4-Rezeptor (Mc4r) mit hohen genetischen Polymorphismen. Mc4r gehört zu den Melanocortin-Rezeptoren, die zur Klasse A der G-Protein-gekoppelten Rezeptoren gehören. Das Mc4r-Signalsystem besteht aus Mc4r, dem Agonisten Pomc (Prohormon der verschiedenen MSH und des ACTH), dem Antagonisten Agrp und dem akzessorischen Protein Mrap2. Beim Menschen spielt MC4R eine Rolle bei der Energiehomöostase. MC4R und MRAP2 Mutationen stehen im Zusammenhang mit menschlicher Fettleibigkeit, jedoch nicht mit der Pubertät. Mc4rs in X. nigrensis und X. multilineatus sind in drei Allelklassen vorhanden, A, B1 und B2, von denen die X-chromosomalen A Allele funktionelle Rezeptoren exprimieren und die spezifischen männlichen Y-chromosomalen B Allele für defekte Rezeptoren kodieren. Die männliche Körpergröße korreliert mit dem B Alleltyp und der Kopienzahl des B Allels. Spätreife große Männchen tragen B Allele in hoher Kopienzahl, während frühreife kleine Männchen B Allele in niedriger Kopienzahl oder nur A Allele tragen. Koexpressions-Experimente in Zellkultur zeigten, dass B Allele als dominant negative Mutanten-Rezeptor auf A Allele wirken können. In dieser Studie war das Hauptziel die biochemische Charakterisierung des Mechanismus der Pubertätsregulation durch Mc4r in X. nigrensis und X. multilineatus. Dabei wurde untersucht, ob die Regulation durch eine Mc4r Dimerisierung und/oder Mrap2 Interaktion mit Mc4r oder durch andere Mechanismen erfolgt. Des Weiteren wurde Mc4r in X. hellerii (einer anderen Schwertträger Art) und Medaka (ein phylogenetisch naheliegender Modellorganismus von Xiphophorus) untersucht, um zu verstehen, ob die untersuchten Mechanismen in anderen Arten konserviert sind. In Medaka werden die Gene des Mc4r Signalsystems (mc4r, mrap2, pomc, agrp1) vor dem Schlüpfen exprimiert, wobei agrp1 während des Schlüpfens und der ersten Fütterung stark hochreguliert wird. Im adulten Medaka werden diese Gene hauptsächlich im Gehirn exprimiert und die Transkripte von mrap2 und mc4r kolokalisieren, was auf eine Funktion bei der Modulation der Mc4r-Signaltransduktion hinweist. Ein funktionaler Vergleich zwischen Wildtyp- und mc4r-Knockout Medaka zeigte, dass der Mc4r-Knockout das Pubertäts-Timing nicht beeinflusst, das Schlüpfen jedoch aufgrund der verzögerten embryonalen Entwicklung von Knockout-Medaka signifikant verzögert. Daher ist das Mc4r System in Medaka eher an der Regulation des Wachstums als an der Pubertät beteiligt. Bei Xiphophorus wurde die Lokalisierung von mc4r und mrap2 in erwachsenen Gehirnen von X. nigrensis und X. hellerii durch in situ Hybridisierung charakterisiert. Bei beiden Spezies zeigen große Männchen eine auffallend hohe Expression von mc4r, während mrap2 bei großen und kleinen Männchen und Weibchen ein ähnliches Expressionsniveau zeigt. Im Gegensatz dazu weist X. hellerii nur Allele vom A-Typ auf, was darauf hinweist, dass sich die Pubertätsregulationsmechanismen in dem Genus Xiphophorus unabhängig voneinander entwickelt haben. Die funktionelle Analyse der Mrap2 und Mc4r A/B1/B2 Allele von X. multilineatus zeigte, dass erhöhte Mrap2-Mengen eine höhere cAMP-Antwort induzieren, die EC50-Werte sich jedoch bei der Mrap2-Coexpression mit Mc4r nicht wesentlich ändern (nur A Allel oder A und B1 Allele). A und B1 Allele wurden in großen männlichen Gehirnen höher exprimiert, während B2 Allele kaum exprimiert wurden. Mc4r A-B1 Zellen haben eine geringere cAMP-Produktion als Mc4r A Zellen. Zusammengenommen deutet dies auf eine Rolle von Mc4r-Allelen, jedoch nicht von Mrap2, bei der Signalgebung zur Regulation des Pubertätsbeginns hin. Interaktionsstudien mit den FRET-Methoden zeigten, dass Mc4r A und B Allele in vitro Heterodimere und Homodimere bilden können, jedoch nur für einen bestimmten Anteil der exprimierten Rezeptoren. Die Einzelmolekül-co-lokalisierungsstudie unter Verwendung von der hochauflösenden Mikroskopiemethode dSTORM bestätigte, dass nur wenige Mc4r A und B1 Rezeptoren auf der Membran co-lokalisiert sind. Insgesamt ist die artspezifische Regulation des Pubertätsbeginns bei X. nigrensis und X. multilineatus auf das Vorhandensein von Mc4r B Allelen und teilweise auf deren Interaktion mit Genprodukten des A Allels zurückzuführen. Dies wird dadurch begründet, dass ein bestimmtes cAMP Niveau (statische oder dynamische Schwelle) erreicht werden muss, um die Pubertät einzuleiten. In großen Männchen wird dieses cAMP Niveau später erreicht und so die Pubertät später eingeleitet. Zusammenfassend ist die Regulation des Pubertätsbeginns durch die dominante negative Wirkung von mutierten Mc4r Allelen ein spezieller Mechanismus, der bisher nur bei X. nigrensis und X. multilineatus zu finden ist. Andere Xiphophorus Arten haben offensichtlich durch andere Mechanismen die gleiche Funktion des Signalwegs entwickelt. In anderen Fischen (Medaka) spielt Mc4r eine Rolle bei der Regulation des Wachstums und erinnert an seine Rolle bei der Energie-Homöostase beim Menschen. Die Ergebnisse dieser Studie werden dazu beitragen, die biochemischen und physiologischen Funktionen des Mc4r-Systems bei Wirbeltieren, einschließlich Menschen, besser zu verstehen. KW - Japankärpfling KW - Mc4r KW - Schwertkärpfling KW - Pubertät KW - Molekularbiologie KW - GPCR KW - Mrap2 KW - Medaka KW - Xiphophorus KW - Puberty KW - Growth Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-206536 ER - TY - JOUR A1 - Lichter, Katharina A1 - Paul, Mila Marie A1 - Pauli, Martin A1 - Schoch, Susanne A1 - Kollmannsberger, Philip A1 - Stigloher, Christian A1 - Heckmann, Manfred A1 - Sirén, Anna-Leena T1 - Ultrastructural analysis of wild-type and RIM1α knockout active zones in a large cortical synapse JF - Cell Reports N2 - Rab3A-interacting molecule (RIM) is crucial for fast Ca\(^{2+}\)-triggered synaptic vesicle (SV) release in presynaptic active zones (AZs). We investigated hippocampal giant mossy fiber bouton (MFB) AZ architecture in 3D using electron tomography of rapid cryo-immobilized acute brain slices in RIM1α\(^{−/−}\) and wild-type mice. In RIM1α\(^{−/−}\), AZs are larger with increased synaptic cleft widths and a 3-fold reduced number of tightly docked SVs (0–2 nm). The distance of tightly docked SVs to the AZ center is increased from 110 to 195 nm, and the width of their electron-dense material between outer SV membrane and AZ membrane is reduced. Furthermore, the SV pool in RIM1α\(^{−/−}\) is more heterogeneous. Thus, RIM1α, besides its role in tight SV docking, is crucial for synaptic architecture and vesicle pool organization in MFBs. KW - active zone KW - acute brain slices KW - CA3 KW - electron tomography KW - high-pressure freezing KW - hippocampal mossy fiber bouton KW - RIM1α KW - SV pool KW - synaptic ultrastructure KW - presynaptic Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300913 VL - 40 IS - 12 ER - TY - THES A1 - Lasway, Julius Vincent T1 - Impact of human land use on bee diversity and plant-pollinator interactions in Tanzania savannah ecosystems T1 - Auswirkungen der Landnutzung durch den Menschen auf die Bienendiversität und die Wechselwirkungen zwischen Pflanze und Bestäuber in den Savannenökosystemen Tansanias N2 - One of the pronounced global challenges facing ecologists is how to feed the current growing human population while sustaining biodiversity and ecosystem services. To shed light on this, I investigated the impact of human land use on bee diversity and plant-pollinator interactions in Tanzania Savannah ecosystems. The thesis comprises the following chapters: Chapter I: General Introduction This chapter provides the background information including the study objectives and hypotheses. It highlights the ecological importance of bees and the main threats facing bee pollinators with a focus on two land-use practices namely livestock grazing and agriculture. It also highlights the diversity and global distribution of bees. It further introduces the tropical savannah ecosystem, its climate, and vegetation characteristics and explains spectacular megafauna species of the system that form centers of wildlife tourism and inadequacy knowledge on pollinators diversity of the system. Finally, this chapter describes the study methodology including, the description of the study area, study design, and data collection. Chapter II: Positive effects of low livestock grazing intensity on East African bee assemblages mediated by increases in floral resources The impact of livestock grazing intensity on bee assemblage has been subjected to research over decades. Moreover, most of these studies have been conducted in temperate Europe and America leaving the huge tropical savannah of East Africa less studied. Using sweep netting and pan traps, a total of 183 species (from 2,691 individuals) representing 55 genera and five families were collected from 24 study sites representing three levels of livestock grazing intensity in savannah ecosystem of northern Tanzania. Results have shown that moderate livestock grazing slightly increased bee species richness. However, high livestock grazing intensity led to a strong decline. Besides, results revealed a unimodal distribution pattern of bee species richness and mean annual temperature. It was also found that the effect of livestock grazing and environmental temperature on bee species richness was mediated by a positive effect of moderate grazing on floral resource richness. The study, therefore, reveals that bee communities of the African savannah zone may benefit from low levels of livestock grazing as this favors the growth of flowering plant species. A high level of livestock grazing intensity will cause significant species losses, an effect that may increase with climatic warming. Chapter III: Agricultural intensification with seasonal fallow land promotes high bee diversity in Afrotropical drylands This study investigated the impact of local agriculture intensification on bee diversity in the Afro tropical drylands of northern Tanzania. Using sweep netting and pan traps, a total of 219 species (from 3,428 individuals) representing 58 genera and six families were collected from 24 study sites (distributed from 702 to 1708 m. asl) representing three levels of agriculture intensity spanning an extensive gradient of mean annual temperature. Results showed that bee species richness increased with agricultural intensity and with increasing temperature. However, the effects of agriculture intensity and temperature on bee species richness were mediated by the positive effects of agriculture and temperature on floral resource richness used by bee pollinators. Moreover, results showed that variation of bee body sizes increases with agricultural intensification, “that effect”, however, diminished in environments with higher temperatures. This study reveals that bee assemblages in Afrotropical drylands benefit from agriculture intensification in the way it is currently practiced. Further intensification, including year-round irrigated crop monocultures and extensive use of agrochemicals, is likely to exert a negative impact on bee diversity and pollination services, as reported in temperate regions. Moreover, several bee species were restricted to natural savannah habitats. Therefore, to conserve bee communities in Afro tropical drylands and guarantee pollination services, a mixture of savannah and agriculture, with long periods of fallow land should be maintained. Chapter IV: Impact of land use intensification and local features on plants and pollinators in Sub-Saharan smallholder farms For the first time in the region, this study explores the impact of land-use intensification on plants and pollinators in Sub-Saharan smallholder farms. The study complemented field surveys of bees with a modern DNA metabarcoding approach to characterize the foraged plants and thus built networks describing plant-pollinator interactions at the individual insect level. This information was coupled with quantitative traits of landscape composition and floral availability surrounding each farm. The study found that pollinator richness decreased with increasing impervious and agricultural cover in the landscape, whereas the flower density at each farm correlated with pollinator richness. The intensification of agricultural land use and urbanization correlated with a higher foraging niche overlap among pollinators due to the convergence of individuals' flower-visiting strategies. Furthermore, within farms, the higher availability of floral resources drove lower niche overlap among individuals, greater abundance of flower visitors shaped higher generalization at the networks level (H2I), possibly due to increased competition. These mechanistic understandings leading to individuals’ foraging niche overlap and generalism at the network level, could imply stability of interactions and the pollination ecosystem service. The integrative survey proved that plant-pollinator systems are largely affected by land use intensification and by local factors in smallholder farms of Sub-Saharan Africa. Thus, policies promoting nature-based solutions, among which the introduction of more pollinator-friendly practices by smallholder farmers, could be effective in mitigating the intensification of both urban and rural landscapes in this region, as well as in similar Sub-Saharan contexts. Chapter V: A synopsis of the Bee occurrence data of northern Tanzania This study represents a synopsis of the bee occurrence data of northern Tanzania obtained from a survey in the Kilimanjaro, Arusha, and Manyara regions. Bees were sampled using two standardized methods, sweep netting and colored pan traps. The study summed up 953 species occurrences of 45 species belonging to 20 genera and four families (Halictidae, Apidae, Megachilidae, and andrenidae) A. This study serves as the baseline information in understanding the diversity and distribution of bees in the northern parts of the country. Understanding the richness and distribution of bees is a critical step in devising robust conservation and monitoring strategies for their populations since limited taxonomic information of the existing and unidentified bee species makes their conservation haphazard. Chapter VI: General discussion In general, findings obtained in these studies suggest that livestock grazing and agriculture intensification affects bee assemblages and floral resources used by bee pollinators. Results have shown that moderate livestock grazing intensity may be important in preserving bee diversity. However, high level of livestock grazing intensity may result in a strong decline in bee species richness and abundance. Moreover, findings indicate that agriculture intensification with seasonal fallow lands supports high floral resource richness promoting high bee diversity in Afrotropical drylands. Nonetheless, natural savannahs were found to contain unique bee species. Therefore, agriculture intensification with seasonal fallow should go in hand with conserving remnant savannah in the landscapes to increase bee diversity and ensure pollination services. Likewise, findings suggest that increasing urbanization and agriculture cover at the landscape level reduce plant and pollinator biodiversity with negative impacts on their complex interactions with plants. Conversely, local scale availability of floral resources has shown the positive effects in buffering pollinators decline and mitigating all detrimental effects induced by land-use intensification. Moreover, findings suggest that the impact of human land use (livestock grazing and agriculture) do not act in isolation but synergistically interacts with climatic factors such as mean annual temperature, MAT. The impact of MAT on bee species richness in grazing gradient showed to be more detrimental than in agriculture habitats. This could probably be explained by the remaining vegetation cover following anthropogenic disturbance. Meaning that the remaining vegetation cover in the agricultural gradient probably absorbs the solar radiations hence reducing detrimental effect of mean annual temperature on bee species richness. This one is not the case in grazing gradient since the impact of livestock grazing is severe, leaving the bare land with no vegetation cover. Finally, our findings conclude that understanding the interplay of multiple anthropogenic activities and their interaction with MAT as a consequence of ongoing climate change is necessary for mitigating their potential consequences on bee assemblages and the provision of ecosystem services. Morever, future increases in livestock grazing and agriculture intensification (including year-round crop irrigated monocultures and excessive use of agrochemicals) may lead to undesirable consequences such as species loss and impair provision of pollination services. N2 - Eine der größten globalen Herausforderungen für Ökologen ist die Beantwortung der Frage, wie die wachsende menschliche Bevölkerung ernährt und gleichzeitig die biologische Vielfalt und die Ökosystemleistungen erhalten werden können. Um dies zu beleuchten, habe ich die Auswirkungen der menschlichen Landnutzung auf die Bienenvielfalt und die Wechselwirkungen zwischen Pflanzen und Bestäubern in den Ökosystemen der Tansania-Savanne untersucht. Die Arbeit umfasst die folgenden Kapitel: Kapitel I: Allgemeine Einführung Dieses Kapitel enthält die Hintergrundinformationen, einschließlich der Studienziele und Hypothesen. Es hebt die ökologische Bedeutung von Bienen und die Hauptbedrohungen für Bienenbestäuber hervor, wobei der Schwerpunkt auf zwei Landnutzungspraktiken liegt, nämlich Viehbeweidung und Landwirtschaft. Außerdem werden die Vielfalt und die globale Verbreitung der Bienen herausgearbeitet. Des Weiteren werden das Ökosystem der tropischen Savanne, sein Klima und seine Vegetationscharakteristika vorgestellt und die spektakulären Megafauna-Arten des Systems erläutert, die Zentren des Wildtiertourismus bilden, sowie die unzureichenden Kenntnisse über die Vielfalt der Bestäuber in diesem System. Schließlich wird in diesem Kapitel die Methodik der Studie beschrieben, einschließlich der Beschreibung des Untersuchungsgebiets, des Studiendesigns und der Datenerhebung. Kapitel II: Positive Auswirkungen einer geringen Beweidungsintensität auf ostafrikanische Bienengemeinschaften, vermittelt durch eine Zunahme der floralen Ressourcen Die Auswirkungen der Weideintensität auf die Bienenbestände sind seit Jahrzehnten Gegenstand von empirischen Untersuchungen. Die meisten dieser Studien wurden jedoch in den gemäßigten Breiten Europas und Amerikas durchgeführt, während die riesigen tropischen Savannen Ostafrikas weniger untersucht wurden. Mit Hilfe von Wurfnetzen und Schwenkfallen wurden insgesamt 183 Arten (von 2.691 Individuen) aus 55 Gattungen und fünf Familien an 24 Untersuchungsstandorten, die drei Stufen der Viehweideintensität im Savannen-Ökosystem im Norden Tansanias repräsentieren, gesammelt. Die Ergebnisse zeigen, dass eine mäßige Beweidung mit Weidevieh den Artenreichtum der Bienen leicht erhöht. Eine hohe Beweidungsintensität führte jedoch zu einem starken Rückgang. Außerdem zeigten die Ergebnisse ein unimodales Verteilungsmuster des Bienenartenreichtums und der mittleren Jahrestemperatur. Es wurde auch festgestellt, dass die Auswirkungen von Viehbeweidung und Umwelttemperatur auf den Bienenartenreichtum durch eine positive Auswirkung von mäßiger Beweidung auf den Reichtum an floralen Ressourcen vermittelt wurden. Die Studie zeigt daher, dass Bienengemeinschaften in der afrikanischen Savanne von einer geringen Beweidung durch Vieh profitieren können, da dies das Wachstum blühender Pflanzenarten fördert. Eine hohe Beweidungsintensität führt zu erheblichen Artenverlusten, die sich infolge der Klimaerwärmung noch verstärken können. Kapitel III: Intensivierung der Landwirtschaft mit saisonalem Brachland fördert hohe Bienenvielfalt in afrotropischen Trockengebieten In dieser Studie wurden die Auswirkungen der Intensivierung der lokalen Landwirtschaft auf die Bienenvielfalt in den afrotropischen Trockengebieten im Norden Tansanias untersucht. An 24 Untersuchungsstandorten (zwischen 702 und 1.708 m ü.N.N.), die drei Intensitätsstufen der Landwirtschaft repräsentieren und einen weiten Gradienten der Jahresmitteltemperatur abdecken, wurden 219 Arten (von 3.428 Individuen) gesammelt, die 58 Gattungen und sechs Familien repräsentieren. Die Ergebnisse zeigten, dass der Artenreichtum der Bienen mit der Intensität der Landwirtschaft und mit steigender Temperatur zunahm. Die Auswirkungen der Intensität der Landwirtschaft und der Temperatur auf den Artenreichtum der Bienen wurden jedoch durch die positiven Auswirkungen der Landwirtschaft und der Temperatur auf den Reichtum der von den Bienenbestäubern genutzten Blütenressourcen vermittelt. Außerdem zeigten die Ergebnisse, dass die Variation der Körpergröße der Bienen mit der Intensivierung der Landwirtschaft zunimmt, diese jedoch in Umgebungen mit höheren Temperaturen abnimmt. Diese Studie zeigt, dass die Bienengemeinschaften in afrotropischen Trockengebieten von der Intensivierung der Landwirtschaft, wie sie derzeit praktiziert wird, profitieren. Eine weitere Intensivierung, einschließlich ganzjährig bewässerter Monokulturen und intensiver Einsatz von Agrochemikalien, wird sich wahrscheinlich negativ auf die Bienenvielfalt und die Bestäubungsleistung auswirken, wie dies auch in den gemäßigten Regionen beobachtet wurde. Außerdem war das Vorkommen einiger Bienenarten auf natürliche Savannenlebensräume beschränkt. Um die Bienengemeinschaften in afrotropischen Trockengebieten zu erhalten und die Bestäubungsleistungen zu gewährleisten, sollte daher eine Mischung aus Savanne und Landwirtschaft mit Langzeitig-Brachflächen beibehalten werden. Kapitel IV: Auswirkungen der Intensivierung der Landnutzung und lokaler Gegebenheiten auf Pflanzen und Bestäuber in kleinbäuerlichen Betrieben südlich der Sahara In dieser Studie werden zum ersten Mal in der Region die Auswirkungen der Intensivierung der Landnutzung auf Pflanzen und Bestäuber in kleinbäuerlichen Betrieben südlich der Sahara untersucht. Hierbei wurden Felduntersuchungen von Bienen um einen modernen DNA-Metabarcoding-Ansatz ergänzt, um die beflogenen Pflanzen zu charakterisieren und so Netzwerke aufzudecken, die die Interaktionen zwischen Pflanzen und Bestäubern auf der Ebene einzelner Insekten beschreiben. Diese Informationen wurden mit quantitativen Merkmalen der Landschaftszusammensetzung und der Blütenverfügbarkeit in der Umgebung der einzelnen landwirtschaftlichen Betriebe verknüpft. Die Studie ergab, dass der Reichtum an Bestäubern mit zunehmendem Landschaftsanteil an undurchlässiger und landwirtschaftlicher Fläche abnahm, während die Blütendichte mit dem Reichtum an Bestäubern korrelierte. Die Intensivierung der landwirtschaftlichen Nutzung und die Urbanisierung korrelierten mit einer stärkeren Überlappung der Nischen für die Nahrungssuche von Bestäubern, was auf die Konvergenz der Strategien der Individuen bei der Suche nach Blüten zurückzuführen ist. Darüber hinaus führte innerhalb der landwirtschaftlichen Betriebe die höhere Verfügbarkeit von Blütenressourcen zu einer geringeren Nischenüberschneidung zwischen den Individuen, während eine größere Anzahl von Blütenbesuchern zu einer stärkeren Generalisierung auf der Ebene der Netzwerke führte (H2I), was möglicherweise auf einen erhöhten Wettbewerb zurückzuführen ist. Diese mechanistischen Erkenntnisse, die zur Überlappung der Nischen der Individuen bei der Nahrungssuche und zum Generalismus auf der Netzwerkebene führen, könnten die Stabilität der Interaktionen und der Ökosystemdienstleistung Bestäubung implizieren. Die integrative Untersuchung hat gezeigt, dass die Bestäubersysteme in den kleinbäuerlichen Betrieben Afrikas südlich der Sahara weitgehend von der Intensivierung der Landnutzung und von lokalen Faktoren beeinflusst werden. Daher könnten politische Maßnahmen zur Förderung naturbasierter Lösungen, zu denen auch die Einführung bestäuberfreundlicher Praktiken durch Kleinbauern gehört, die Intensivierung sowohl städtischer als auch ländlicher Landschaften in dieser Region wie auch in ähnlichen Kontexten südlich der Sahara wirksam abmildern. Kapitel V: Ein Überblick über die Daten zum Bienenvorkommen im Norden Tansanias Diese Studie gibt einen Überblick über die Daten zum Bienenvorkommen im Norden Tansanias, die im Rahmen einer Erhebung in den Regionen Kilimanjaro, Arusha und Manyara gewonnen wurden. Die Bienen wurden mit zwei standardisierten Methoden erfasst: mit Keschern und Farbschalen. Im Rahmen der Studie wurden 953 Individuen aus 45 Arten aus 20 Gattungen und vier Familien (Halictidae, Apidae, Megachilidae und Andrenidae) nachgewiesen. Diese Studie dient als Grundlage für das Verständnis der Vielfalt und Verbreitung von Bienen in den nördlichen Teilen des Landes. Das Verständnis des Reichtums und der Verbreitung von Bienen ist ein entscheidender Schritt bei der Entwicklung robuster Erhaltungs- und Überwachungsstrategien für deren Populationen, da die begrenzten taxonomischen Informationen über die vorhandenen und nicht identifizierten Bienenarten deren Erhaltung ungewiss erscheinen lassen. Kapitel VI: Allgemeine Diskussion Im Allgemeinen deuten die Ergebnisse dieser Studien darauf hin, dass die Beweidung mit Vieh und die Intensivierung der Landwirtschaft Auswirkungen auf die Bienenbestände und die von Bienenbestäubern genutzten Blütenressourcen haben. Die Ergebnisse haben gezeigt, dass eine mäßige Beweidungsintensität für die Erhaltung der Bienenvielfalt von Bedeutung sein kann. Eine hohe Beweidungsintensität kann jedoch zu einem starken Rückgang des Artenreichtums und der Abundanz von Bienen führen. Außerdem deuten die Ergebnisse darauf hin, dass die Intensivierung der Landwirtschaft mit saisonalem Brachland einen hohen Reichtum an floralen Ressourcen aufweist, der eine hohe Bienenvielfalt in afrotropischen Trockengebieten fördert. Nichtsdestotrotz zeigte sich, dass natürliche Savannen eine einzigartige Artenzusammensetzung aufweisen. Daher sollte die Intensivierung der Landwirtschaft mit saisonalem Brachland mit der Erhaltung von Savannenresten in den Landschaften einhergehen, um die Bienenvielfalt zu erhöhen und die Bestäubungsleistung sicherzustellen. Ebenso deuten die Ergebnisse darauf hin, dass die zunehmende Urbanisierung und landwirtschaftliche Nutzung auf Landschaftsebene die biologische Vielfalt von Pflanzen und Bestäubern verringert, was sich negativ auf ihre komplexen Interaktionen mit Pflanzen auswirkt. Umgekehrt hat sich die Verfügbarkeit von Blütenressourcen auf lokaler Ebene als positiv erwiesen, da sie den Rückgang der Bestäuber abpuffert und alle durch die Intensivierung der Flächennutzung verursachten negativen Auswirkungen abmildert. Darüber hinaus deuten die Ergebnisse darauf hin, dass die Auswirkungen der menschlichen Landnutzung (Viehbeweidung und Landwirtschaft) nicht isoliert wirken, sondern synergetisch mit Klimafaktoren wie der mittleren Jahrestemperatur (MAT) zusammenwirken. Die Auswirkung von MAT auf den Artenreichtum der Bienen in Weidegebieten erwies sich als nachteiliger als in landwirtschaftlich genutzten Lebensräumen. Dies könnte wahrscheinlich durch die verbleibende Vegetationsdeckung nach einer anthropogenen Störung erklärt werden. Das bedeutet, dass die verbleibende Vegetationsdeckung im landwirtschaftlichen Gradienten wahrscheinlich die Sonneneinstrahlung absorbiert und damit die nachteiligen Auswirkungen der mittleren Jahrestemperatur auf den Artenreichtum der Bienen verringert. Dies ist im Weidegradienten nicht der Fall, da die Auswirkungen der Beweidung durch das Weidevieh schwerwiegend sind und kahles Land ohne nennenswerte Vegetationsbedeckung zurücklassen. Unsere Ergebnisse lassen den Schluss zu, dass ein Verständnis des Zusammenspiels verschiedener anthropogener Aktivitäten und ihrer Interaktion mit MAT als Folge des fortschreitenden Klimawandels notwendig ist, um die potenziellen Folgen für die Bienenbestände und die Bereitstellung von Ökosystemleistungen zu mildern. Darüber hinaus können die künftige Zunahme der Viehbeweidung und die Intensivierung der Landwirtschaft (einschließlich ganzjährig bewässerter Monokulturen und übermäßiger Einsatz von Agrochemikalien) zu unerwünschten Folgen wie dem Verlust von Arten und Bestäubungsleistungen führen. KW - Human land use KW - Plant-pollinator interactions KW - Tanzania KW - Savannah ecosystems KW - Livestock grazing KW - Agriculture intensification KW - Bee assemblages KW - Bee abundance KW - Bee species richness Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257726 ER - TY - JOUR A1 - Lasway, Julius V. A1 - Peters, Marcell K. A1 - Njovu, Henry K. A1 - Eardley, Connal A1 - Pauly, Alain A1 - Steffan‐Dewenter, Ingolf T1 - Agricultural intensification with seasonal fallow land promotes high bee diversity in Afrotropical drylands JF - Journal of Applied Ecology N2 - The exponential increase in the human population in tandem with increased food demand has caused agriculture to be the global‐dominant form of land use. Afrotropical drylands are currently facing the loss of natural savannah habitats and agricultural intensification with largely unknown consequences for bees. Here we investigate the effects of agricultural intensification on bee assemblages in the Afrotropical drylands of northern Tanzania. We disentangled the direct effects of agricultural intensification and temperature on bee richness from indirect effects mediated by changes in floral resources. We collected data from 24 study sites representing three levels of management intensity (natural savannah, moderate intensive and highly intensive agriculture) spanning an extensive gradient of mean annual temperature (MAT) in northern Tanzania. We used ordinary linear models and path analysis to test the effects of agricultural intensity and MAT on bee species richness, bee species composition and body‐size variation of bee communities. We found that bee species richness increased with agricultural intensity and with increasing temperature. The effects of agricultural intensity and temperature on bee species richness were mediated by the positive effects of agriculture and temperature on the richness of floral resources used by bees. During the off‐growing season, agricultural land was characterized by an extensive period of fallow land holding a very high density of flowering plants with unique bee species composition. The increase in bee diversity in agricultural habitats paralleled an increasing variation of bee body sizes with agricultural intensification that, however, diminished in environments with higher temperatures. Synthesis and applications. Our study reveals that bee assemblages in Afrotropical drylands benefit from agricultural intensification in the way it is currently practiced. However, further land‐use intensification, including year‐round irrigated crop monocultures and excessive use of agrochemicals, is likely to exert a negative impact on bee diversity and pollination services, as reported in temperate regions. Moreover, several bee species were restricted to natural savannah habitats. To conserve bee communities and guarantee pollination services in the region, a mixture of savannah and agriculture, with long periods of fallow land should be maintained. KW - bee abundance KW - bee body size KW - bee species richness KW - forage resources KW - inter‐tegular distance KW - mean annual temperature KW - northern Tanzania KW - species community composition Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-311877 VL - 59 IS - 12 SP - 3014 EP - 3026 ER - TY - THES A1 - Kühl, Julia T1 - FAAP100, der FA/BRCA-Signalweg für genomische Stabilität und das DNA-Reparatur-Netzwerk T1 - FAAP100, the FA/BRCA pathway for genomic stability and the DNA repair network N2 - Die Fanconi-Anämie (FA) ist eine seltene, heterogene Erbkrankheit. Sie weist ein sehr variables klinisches Erscheinungsbild auf, das sich aus angeborenen Fehlbildungen, hämatologischen Funktionsstörungen, einem erhöhten Risiko für Tumorentwicklung und endokrinen Pathologien zusammensetzt. Die Erkrankung zählt zu den genomischen Instabilitätssyndromen, welche durch eine fehlerhafte DNA-Schadensreparatur gekennzeichnet sind. Bei der FA zeigt sich dies vor allem in einer charakteristischen Hypersensitivität gegenüber DNA-quervernetzenden Substanzen (z. B. Mitomycin C, Cisplatin). Der zelluläre FA-Phänotyp zeichnet sich durch eine erhöhte Chromosomenbrüchigkeit und einen Zellzyklusarrest in der G2-Phase aus. Diese Charakteristika sind bereits spontan vorhanden und werden durch Induktion mit DNA-quervernetzenden Substanzen verstärkt. Der Gendefekt ist dabei in einem der 22 bekannten FA-Gene (FANCA, -B, -C, -D1, -D2, -E, -F, -G, -I, -J, -L, -M, -N, -O, -P, -Q, -R, -S, -T, -U, -V, -W) oder in noch unbekannten FA-Genen zu finden. Die FA-Gendefekte werden mit Ausnahme von FANCR (dominant-negative de novo Mutationen) und FANCB (X-chromosomal) autosomal rezessiv vererbt. Die FA-Genprodukte bilden zusammen mit weiteren Proteinen den FA/BRCA-Signalweg. Das Schlüsselereignis dieses Signalwegs stellt die Monoubiquitinierung von FANCD2 und FANCI (ID2-Komplex) dar. Ausgehend davon lässt sich zwischen upstream- und downstream-gelegenen FA-Proteinen unterscheiden. Letztere sind direkt an der DNA-Schadensreparatur beteiligt. Zu den upstream-gelegenen Proteinen zählt der FA-Kernkomplex, der sich aus bekannten FA-Proteinen und aus FA-assoziierten-Proteinen (FAAPs) zusammensetzt und für die Monoubiquitinierung des ID2-Komplexes verantwortlich ist. Für FAAPs wurden bisher keine pathogenen humanen Mutationen beschrieben. Zu diesen Proteinen gehört auch FAAP100, das mit FANCB und FANCL innerhalb des FA-Kernkomplexes den Subkomplex LBP100 bildet. Durch die vorliegende Arbeit wurde eine nähere Charakterisierung dieses Proteins erreicht. In einer Amnion-Zelllinie konnte eine homozygote Missense-Mutation identifiziert werden. Der Fetus zeigte einen typischen FA-Phänotyp und auch seine Zellen wiesen charakteristische FA-Merkmale auf. Der zelluläre Phänotyp ließ sich durch FAAP100WT komplementieren, sodass die Pathogenität der Mutation bewiesen war. Unterstützend dazu wurden mithilfe des CRISPR/Cas9-Systems weitere FAAP100-defiziente Zelllinien generiert. Diese zeigten ebenfalls einen typischen FA-Phänotyp, welcher sich durch FAAP100WT komplementieren ließ. Die in vitro-Modelle dienten als Grundlage dafür, die Funktion des FA-Kernkomplexes im Allgemeinen und die des Subkomplexes LBP100 im Besonderen besser zu verstehen. Dabei kann nur durch intaktes FAAP100 das LBP100-Modul gebildet und dieses an die DNA-Schadensstelle transportiert werden. Dort leistet FAAP100 einen essentiellen Beitrag für den FANCD2-Monoubiquitinierungsprozess und somit für die Aktivierung der FA-abhängigen DNA-Schadensreparatur. Um die Funktion von FAAP100 auch in vivo zu untersuchen, wurde ein Faap100-/--Mausmodell generiert, das einen mit anderen FA-Mausmodellen vergleichbaren, relativ schweren FA-Phänotyp aufwies. Aufgrund der Ergebnisse lässt sich FAAP100 als neues FA-Gen klassifizieren. Zudem wurde die Rolle des Subkomplexes LBP100 innerhalb des FA-Kernkomplexes weiter aufgeklärt. Beides trägt zu einem besseren Verständnis des FA/BRCA-Signalweges bei. Ein weiterer Teil der vorliegenden Arbeit beschäftigt sich mit der Charakterisierung von FAAP100138, einer bisher nicht validierten Isoform von FAAP100. Durch dieses Protein konnte der zelluläre FA-Phänotyp von FAAP100-defizienten Zelllinien nicht komplementiert werden, jedoch wurden Hinweise auf einen dominant-negativen Effekt von FAAP100138 auf den FA/BRCA-Signalweg gefunden. Dies könnte zu der Erklärung beitragen, warum und wie der Signalweg, beispielsweise in bestimmtem Gewebearten, herunterreguliert wird. Zudem wäre eine Verwendung in der Krebstherapie denkbar. N2 - Fanconi Anemia (FA) is a rare heterogeneous hereditary disease. It shows a highly variable clinical presentation including congenital malformations, bone marrow failure and increased risk for cancer and endocrine pathologies. The disease is classified as one of the genomic instability disorders that are characterized by failure of DNA damage repair processes. FA shows a typical hypersensitivity toward DNA crosslinking agents (e.g. Mitomycin C, cisplatin). There is an increased rate of chromosomal breakage and cell cycle arrest in the G2 phase. These characteristics are present spontaneously and after incubation with DNA crosslinking agents. The genetic defect can be found in one of the 22 reported FA genes (FANCA, -B, -C, -D1, -D2, -E, -F, -G, -I, -J, -L, -M, -N, -O, -P, -Q, -R, -S, -T, -U, -V, -W) or yet unknown FA genes. FA gene defects are inherited in an autosomal recessive way with the exceptions of FANCR (dominant negative de novo mutations) and FANCB (X-linked). Together with other proteins, the FA gene products establish the FA/BRCA pathway. The key event of this pathway is the monoubiquitination of FANCD2 and FANCI (ID2 complex). From this point it is possible to differentiate between upstream and downstream FA proteins. The latter are directly involved in FA-dependent DNA repair processes. The upstream positioned FA proteins form the FA core complex that includes FA and FA-associated proteins (FAAPs). The FA core complex is responsible for the monoubiquitination of FANCD2 and FANCI. To date no pathogenic human mutations of the FAAPs have been described. Among these proteins is FAAP100 which together with FANCB and FANCL forms the subcomplex LBP100 within the FA core complex. In the present thesis a closer characterization of this protein has been achieved. In an amniotic cell line a homozygous missense mutation could be identified. The affected fetus displayed a typical FA phenotype and the cells also showed characteristics of FA. The cellular phenotype was complemented by FAAP100WT, thus proving the pathogenicity of the mutation. Supporting this result, additional FAAP100-deficient cell lines have been generated using the CRISPR/Cas9 system. These also exhibited a typical FA cellular phenotype which could be complemented by FAAP100WT. In vitro models served as a basis for better understanding the function of the FA core complex in general and of the LBP100 subcomplex in particular. Only in the presence of an intact FAAP100 the LBP100 module can be formed and transported to sites of DNA interstrand crosslinks. There, FAAP100 significantly contributes to the FANCD2 monoubiquitination process and thus to the activation of FA-dependent DNA damage repair. In order to also examine the function of FAAP100 in vivo, an Faap100-/- mouse model has been generated which shows a relatively severe FA phenotype comparable to other FA mouse models. Because of these results FAAP100 can be categorized as a new FA gene. Moreover, the role of the LBP100 subcomplex within the FA core complex was further elucidated and a better understanding of the FA/BRCA pathway was achieved. Another part of this thesis deals with the characterization of FAAP100138, a hitherto not validated isoform of FAAP100. The cellular FA phenotype of FAAP100-deficient cell lines could not be complemented by this isoform. However, there are clues pointing to a dominant negative effect of FAAP100138 on the FA/BRCA pathway. This finding could serve as a potential explanation of how and why the FA signaling pathway is downregulated in certain tissues. A therapeutic application for cancer of FAAP100138 appears possible. KW - Fanconi-Anämie KW - DNA-Reparatur KW - FAAP100 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171669 ER - TY - JOUR A1 - König, Sebastian A1 - Krauss, Jochen A1 - Keller, Alexander A1 - Bofinger, Lukas A1 - Steffan‐Dewenter, Ingolf T1 - Phylogenetic relatedness of food plants reveals highest insect herbivore specialization at intermediate temperatures along a broad climatic gradient JF - Global Change Biology N2 - The composition and richness of herbivore and plant assemblages change along climatic gradients, but knowledge about associated shifts in specialization is scarce and lacks controlling for the abundance and phylogeny of interaction partners. Thus, we aimed to test whether the specialization of phytophagous insects in insect‐plant interaction networks decreases toward cold habitats as predicted by the ‘altitude niche‐breadth hypothesis’ to forecast possible consequences of interaction rewiring under climate change. We used a non‐invasive, standardized metabarcoding approach to reconstruct dietary relationships of Orthoptera species as a major insect herbivore taxon along a broad temperature gradient (~12°C) in Southern Germany. Based on Orthoptera surveys, feeding observations, collection of fecal pellets from >3,000 individuals of 54 species, and parallel vegetation surveys on 41 grassland sites, we quantified plant resource availability and its use by herbivores. Herbivore assemblages were richer in species and individuals at sites with high summer temperatures, while plant richness peaked at intermediate temperatures. Corresponding interaction networks were most specialized in warm habitats. Considering phylogenetic relationships of plant resources, however, the specialization pattern was not linear but peaked at intermediate temperatures, mediated by herbivores feeding on a narrow range of phylogenetically related resources. Our study provides empirical evidence of resource specialization of insect herbivores along a climatic gradient, demonstrating that resource phylogeny, availability, and temperature interactively shape the specialization of herbivore assemblages. Instead of low specialization levels only in cold, harsh habitats, our results suggest increased generalist feeding due to intraspecific changes and compositional differences at both ends of the microclimatic gradient. We conclude that this nonlinear change of phylogeny‐based resource specialization questions predictions derived from the ‘altitude‐niche breadth hypothesis’ and highlights the currently limited understanding of how plant‐herbivore interactions will change under future climatic conditions. KW - Alps KW - diet breadth KW - distance‐based specialization index KW - herbivores KW - interaction networks KW - metabarcoding KW - microclimate KW - Orthoptera KW - plant richness KW - temperature gradient Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276441 VL - 28 IS - 13 SP - 4027 EP - 4040 ER - TY - JOUR A1 - Köhler, Franziska A1 - Reese, Lena A1 - Kastner, Carolin A1 - Hendricks, Anne A1 - Müller, Sophie A1 - Lock, Johan F. A1 - Germer, Christoph-Thomas A1 - Wiegering, Armin T1 - Surgical site infection following single-port appendectomy: a systematic review of the literature and meta-analysis JF - Frontiers in Surgery N2 - Introduction Surgical site infections (SSIs) are one of the most common postoperative complications after appendectomy leading to recurrent surgery, prolonged hospital stay, and the use of antibiotics. Numerous studies and meta-analyses have been published on the effect of open versus conventional laparoscopic appendectomy (CLA) reporting faster postoperative recovery and less postoperative pain for CLA. A development from CLA has been the single-port appendectomy (SPA), associated with a better cosmesis but seemingly having a higher risk of wound infections. The aim of this systematic literature review and meta-analysis is to investigate whether reduced port or SPA alters the ratio of SSIs. Methods Pubmed, Embase, and Cochrane databases were screened for suitable articles. All articles published between January 1, 2002, and March 23, 2022, were included. Articles regarding children below the age of 18 were excluded as well as manuscripts that investigated solemnly open appendectomies. Articles were screened for inclusion criteria by two independent authors. Incidence of SSI was the primary outcome. Duration of operation and length of hospital stay were defined as secondary outcomes. Results A total of 25 studies were found through a database search describing 5484 patients. A total of 2749 patients received SPA and 2735 received CLA. There was no statistical difference in the rate of SSI (P = 0.98). A total of 22 studies including 4699 patients reported the duration of operation (2223 SPA and 2476 CLA). There was a significantly shorter operation time seen in CLA. The length of hospital stay was reported in 23 studies (4735 patients: 2235 SPA and 2500 CLA). A shorter hospital stay was seen in the SPA group (P < 0.00001). Separately performed analysis of randomized controlled trials could not confirm this effect (P = 0.29). Discussion SPA is an equally safe procedure considering SSI compared to CLA and does not lead to an increased risk of SSI. A longer operation time for SPA and a minor difference in the length of stay does lead to the use of SPA in selected patients only. KW - appendicitis KW - appendectomy KW - surgical site infection KW - single-port appendectomy KW - conventional laparoscopic appendectomy KW - wound infection KW - SSI Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276943 SN - 2296-875X VL - 9 ER - TY - JOUR A1 - Köhler, Franziska A1 - Reese, Lena A1 - Hendricks, Anne A1 - Kastner, Carolin A1 - Müller, Sophie A1 - Lock, Johan F. A1 - Germer, Christoph-Thomas A1 - Wiegering, Armin T1 - Low-grade mucinous neoplasms (LAMN) of the appendix in Germany between 2011 and 2018: a nationwide analysis based on data provided by the German Center for Cancer Registry Data (ZfKD) at the Robert Koch Institute (RKI) JF - Langenbeck’s Archives of Surgery N2 - Introduction Low-grade appendiceal mucinous neoplasms (LAMN) are semi-malignant tumors of the appendix which are incidentally found in up to 1% of appendectomy specimen. To this day, no valid descriptive analysis on LAMN is available for the German population. Methods Data of LAMN (ICD-10: D37.3) were collected from the population-based cancer registries in Germany, provided by the German Center for Cancer Registry Data (Zentrum für Krebsregisterdaten—ZfKD). Data was anonymized and included gender, age at diagnosis, tumor staging according to the TNM-classification, state of residence, information on the performed therapy, and survival data. Results A total of 612 cases were reported to the ZfKD between 2011 and 2018. A total of 63.07% were female and 36.93% were male. Great inhomogeneity in reporting cases was seen in the federal states of Germany including the fact that some federal states did not report any cases at all. Age distribution showed a mean age of 62.03 years (SD 16.15) at diagnosis. However, data on tumor stage was only available in 24.86% of cases (n = 152). A total of 49.34% of these patients presented with a T4-stage. Likewise, information regarding performed therapy was available in the minority of patients: 269 patients received surgery, 22 did not and for 312 cases no information was available. Twenty-four patients received chemotherapy, 188 did not, and for 400 cases, no information was available. Overall 5-year survival was estimated at 79.52%. Patients below the age of 55 years at time of diagnosis had a significantly higher 5-year survival rate compared to patients above the age of 55 years (85.77% vs. 73.27%). Discussion In this study, we observed an incidence of LAMN in 0.13% of all appendectomy specimen in 2018. It seems likely that not all cases were reported to the ZfKD; therefore, case numbers may be considered underestimated. Age and gender distribution goes in line with international studies with females being predominantly affected. Especially regarding tumor stage and therapy in depth information cannot be provided through the ZfKD-database. This data analysis emphasizes the need for further studies and the need for setting up a specialized registry for this unique tumor entity to develop guidelines for the appropriate treatment and follow-up. KW - LAMN KW - low-grade mucinous neoplasm KW - appendix KW - epidemiology KW - ZfKD KW - Germany Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-323919 VL - 407 IS - 8 ER - TY - THES A1 - Kuhlemann, Alexander T1 - Bioorthogonal labeling of neuronal proteins using super-resolution fluorescence microscopy T1 - Bioorthogonale Markierung von neuronalen Proteinen mittels hochauflösender Fluoreszenzmikroskopie N2 - The synaptic cleft is of central importance for synaptic transmission, neuronal plasticity and memory and thus well studied in neurobiology. To target proteins of interest with high specificity and strong signal to noise conventional immunohistochemistry relies on the use of fluorescently labeled antibodies. However, investigations on synaptic receptors remain challenging due to the defined size of the synaptic cleft of ~20 nm between opposing pre- and postsynaptic membranes. At this limited space, antibodies bear unwanted side effects such as crosslinking, accessibility issues and a considerable linkage error between fluorophore and target of ~10 nm. With recent single molecule localization microscopy (SMLM) methods enabling localization precisions of a few nanometers, the demand for labeling approaches with minimal linkage error and reliable recognition of the target molecules rises. Within the scope of this work, different labeling techniques for super-resolution fluorescence microscopy were utilized allowing site-specific labeling of a single amino acid in synaptic proteins like kainate receptors (KARs), transmembrane α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor regulatory proteins (TARPs), γ-aminobutyric acid type A receptors (GABA-ARs) and neuroligin 2 (NL2). The method exploits the incorporation of unnatural amino acids (uAAs) in the protein of interest using genetic code expansion (GCE) via amber suppression technology and subsequent labeling with tetrazine functionalized fluorophores. Implementing this technique, hard-to-target proteins such as KARs, TARPs and GABA-ARs could be labeled successfully, which could only be imaged insufficiently with conventional labeling approaches. Furthermore, functional studies involving electrophysiological characterization, as well as FRAP and FRET experiments validated that incorporation of uAAs maintains the native character of the targeted proteins. Next, the method was transferred into primary hippocampal neurons and in combination with super-resolution microscopy it was possible to resolve the nanoscale organization of γ2 and γ8 TARPs. Cluster analysis of dSTORM localization data verified synaptic accumulation of γ2, while γ8 was homogenously distributed along the neuron. Additionally, GCE and bioorthogonal labeling allowed visualization of clickable GABA-A receptors located at postsynaptic compartments in dissociated hippocampal neurons. Moreover, saturation experiments and FRET imaging of clickable multimeric receptors revealed successful binding of multiple tetrazine functionalized fluorophores to uAA-modified dimeric GABA-AR α2 subunits in close proximity (~5 nm). Further utilization of tetrazine-dyes via super-resolution microscopy methods such as dSTORM and click-ExM will provide insights to subunit arrangement in receptors in the future. This work investigated the nanoscale organization of synaptic proteins with minimal linkage error enabling new insights into receptor assembly, trafficking and recycling, as well as protein-protein interactions at synapses. Ultimately, bioorthogonal labeling can help to understand pathologies such as the limbic encephalitis associated with GABA-AR autoantibodies and is already in application for cancer therapies. N2 - Der synaptische Spalt ist von zentraler Bedeutung für die synaptische Reizweiterleitung, neuronale Plastizität und Gedächtnis und dadurch neurobiologisch sehr gut charakterisiert. Um Zielproteine mit hoher Spezifität und einem guten Signal-zu-Rauschen Verhältnis zu adressieren, wird konventionell auf Immunhistochemie mittels Fluoreszenzfarbstoff-markierter Antikörper zurückgegriffen. Untersuchungen synaptischer Rezeptoren bleiben dabei jedoch aufgrund der limitierten Zugänglichkeit des synaptischen Spalts mit einem Abstand von ~20 nm zwischen gegenüberliegenden pre- und postsynaptischen Membranen herausfordernd. Speziell in einem räumlich begrenzten Umfeld können bei der Verwendung von Antikörpern unerwünschte Artefakte auftreten, die durch Kreuzverlinkung, eine verminderte Zugänglichkeit und einen erheblichen Markierungsabstand zwischen Fluorophor und Probe von ~10 nm entstehen. Aktuelle Verfahren der Einzelmolekül-Lokalisations-Mikroskopie (SMLM), die eine Lokalisationsgenauigkeit von wenigen Nanometern ermöglichen, erhöhen die Nachfrage an Markierungsstrategien mit minimalem Markierungsabstand und zuverlässiger Erkennung der Zielstruktur. Im Rahmen dieser Arbeit wurden daher verschiedene Markierungsmethoden für die hochauflösende Fluoreszenz-Mikroskopie erprobt. Dies ermöglichte die ortsspezifische Markierung einer einzigen Aminosäure in synaptischen Proteinen wie Kainat-Rezeptoren (KARs), Transmembran-α-Amino-3-hydroxy-5-methyl-4-isoxazol-Propionsäure-Rezeptor regulierenden Proteinen (TARPs), γ-Aminobuttersäure-Typ-A-Rezeptoren (GABA-ARs) oder Neuroligin 2 (NL2). Die angewandte Methodik nutzt den Einbau von unnatürlichen Aminosäuren (uAAs) in das Zielprotein mittels Erweiterung des genetischen Codes (GCE) durch Unterdrückung des Amber-Stop-Codons. Durch Anwendung dieser Strategie gelang es, schwer adressierbare Proteine wie KARs, TARPs und GABA-ARs, welche zuvor mittels konventioneller Markierungsversuche nur unzureichend abgebildet werden konnten, erfolgreich zu markieren. Funktionelle Studien wie elektrophysiologische Charakterisierungen, aber auch FRAP und FRET Experimente zeigten, dass dabei der native Zustand der Zielproteine auch nach dem Einbau von uAAs erhalten bleibt. Schließlich wurde die Methode in primäre hippocampale Neuronen überführt und in Kombination mit hochauflösender Mikroskopie konnte die Organisation von γ2 und γ8 TARPs im Nanobereich aufgelöst werden. Eine Cluster-Analyse von dSTORM Lokalisationsdaten bestätigte die Anreicherung von γ2 in Synapsen, während γ8 homogen entlang des Neurons verteilt vorliegt. Die Erweiterung des genetischen Codes in Kombination mit bioorthogonaler Markierung erlaubte zusätzlich die Visualisierung von clickbaren GABA-A Rezeptoren in Postsynapsen von dissoziierten hippocampalen Neuronen. Außerdem zeigten Saturierungs-Experimente und FRET-Bildgebung die erfolgreiche Bindung von mehreren Tetrazin-gekoppelten Fluorophoren an uAA-modifizierten, dimerischen GABA-AR α2-Untereinheiten in geringem Abstand (~5 nm). Auf der Basis dieser Resultate werden zukünftig hochauflösende mikroskopische Verfahren, wie dSTORM und click-ExM, in Kombination mit Tetrazin-Farbstoffen die Visualisierung von multimerischen Rezeptoren ermöglichen. Im Rahmen dieser Arbeit konnte die Organisation von synaptischen Proteinen mit minimalem Markierungsabstand im Nanobereich untersucht werden und dadurch neue Einsichten in Rezeptor-Zusammenbau, -Bewegungen und -Wiederverwertung, aber auch Protein-Protein Interaktionen in Synapsen gewonnen werden. Die Weiterentwicklung bioorthogonaler Markierungsstrategien kann in Zukunft dazu beitragen Krankheiten, wie die Limbische Enzephalitis, welche mit GABA-AR Autoantikörpern in Verbindung steht, besser zu verstehen und findet zudem bereits heute Anwendung in Krebstherapien. KW - microscopy KW - bioorthogonal labeling KW - super-resolution fluorescence microscopy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-243731 ER - TY - THES A1 - Krones, David T1 - The Role of Acid Sphingomyelinase in \(Staphylococcus\) \(aureus\) Infection of Endothelial Cells T1 - Die Rolle der sauren Sphingomyelinase bei \(Staphylococcus\) \(aureus\) Infektionen von Endothelzellen N2 - Staphylococcus aureus is a human bacterial pathogen responsible for a variety of diseases including bacterial pneumonia and sepsis. Recent studies provided an explanation, how S. aureus and its exotoxins contribute to the degradation of endothelial junction proteins and damage lung tissue [4]. Previous findings were indicating an involvement of acid sphingomyelinase (ASM) activity in cell barrier degradation [5]. In the presented study the impact of singular virulence factors, such as staphylococcal α-toxin, on in vitro cell barrier integrity as well as their ability to elicit an activation of ASM were investigated. Experiments with bacterial supernatants performed on human endothelial cells demonstrated a rapid dissociation after treatment, whereas murine endothelial cells were rather resistant against cell barrier degradation. Furthermore, amongst all tested staphylococcal toxins it was found that only α-toxin had a significant impact on endothelial junction proteins and ASM activity. Ablation of this single toxin was sufficient to protect endothelial cells from cell barrier degradation and activation of ASM was absent. In this process it was verified, that α-toxin induces a recruitment of intracellular ASM, which is accompanied by rapid and oscillating changes in cytoplasmic Ca2+ concentration and an increased exposure of Lysosomal associated membrane protein 1 (LAMP1) on the cell surface. Recruitment of lysosomal ASM is associated, among other aspects, to plasma membrane repair and was previously described to be involved with distinct pathogens as well as other pore forming toxins (PFT). However, with these findings a novel feature for α-toxin has been revealed, indicating that the staphylococcal PFT is able to elicit a similar process to previously described plasma membrane repair mechanisms. Increased exposure and intake of surface membrane markers questioned the involvement of ASM activity in S. aureus internalization by non-professional phagocytes such as endothelial cells. By modifying ASM expression pattern as well as application of inhibitors it was possible to reduce the intracellular bacterial count. Thus, a direct connection between ASM activity and S. aureus infection mechanisms was observed, therefore this study exemplifies how S. aureus is able to exploit the host cell sphingolipid metabolism as well as benefit of it for invasion into non-professional phagocytic cells N2 - Staphylococcus aureus ist ein bakterieller Erreger, der für eine Vielzahl von Erkrankungen des Menschen verantwortlich ist, darunter bakterielle Lungenentzündung und Sepsis. Neuere Studien konnten einen Ansatz dafür liefern, wie S. aureus und seine Exotoxine zur Degradation von endothelialen Verbindungsproteinen beitragen und das Lungengewebe schädigen. Weitere Befunde weisen auf eine Beteiligung der sauren Sphingomyelinase (ASM) bei der Degradation der Zellbarriere hin. In der vorliegenden Studie soll der Einfluss einzelner Virulenzfaktoren, wie z. B. Staphylokokkus α-Toxin, auf die Integrität der Zellbarriere in vitro sowie deren Fähigkeit, eine Aktivierung der ASM hervorzurufen, untersucht werden.Experimente mit bakteriellen Überständen die an humanen Endothelzellen durchgeführt wurden, zeigten eine rasche Dissoziation nach Behandlung, während murine Endothelzellen vorwiegend resistent gegen eine Degradation der Zellbarriere waren. Darüber hinaus wurde unter allen getesteten Staphylokokken-Toxinen festgestellt, dass nur α-Toxin einen signifikanten Einfluss auf endotheliale Verbindungssproteine und ASM-Aktivität hat. Die genetische Ablation des Toxins alleine reichte aus, um Endothelzellen vor einer Degradation der Zellbarriere zu schützen, und die Aktivierung von ASM blieb aus. Dabei konnte nachgewiesen werden, dass α-Toxin eine Rekrutierung von intrazellulärem ASM induziert, die mit schnellen oszillierenden Veränderungen der zytoplasmatischen Ca2+-Konzentration und einer erhöhten Exposition von Lysosome associated membrane protein 1 (LAMP1) an der Zelloberfläche einhergeht. Die Rekrutierung lysosomaler ASM ist u.a. mit der Reparatur von Plasmamembran assoziiert und wurde bereits im Zusammenhang mit verschiedenen Pathogenen sowie anderer porenbildende Toxine (PFT) beschrieben. Mit diesen Befunden konnte jedoch eine neue Eigenschaft für α-Toxin beschrieben werden, die darauf hindeutet, dass das Staphylokokken-PFT einen ähnlichen Prozess auslösen kann wie zuvor beschriebene Plasmamembran-Reparaturmechanismen. Die vermehrte Exposition und Aufnahme von Oberflächenmembranmerkmalen stellte die Beteiligung der ASM-Aktivität an der Internalisierung von S. aureus durch nicht-professionelle Phagozyten wie Endothelzellen in Frage. Durch Modifikation des ASM-Expressionsmusters sowie Applikation von Inhibitoren war es möglich, die intrazelluläre Keimzahl zu reduzieren. Somit konnte ein direkter Zusammenhang zwischen ASM-Aktivität und den Infektionsmechanismen von S. aureus beobachtet werden. Diese Studie verdeutlicht somit, wie S. aureus den Sphingolipid-Stoffwechsel der Wirtszelle ausnutzen und für die Invasion in nicht-professionelle phagozytische Zellen nutzen kann KW - Staphylococcus aureus KW - Endothelzelle KW - Endothelial cells KW - Acid Sphingomyelinase KW - Plasma membrane repair Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290492 ER - TY - JOUR A1 - Krimmer, Elena A1 - Martin, Emily A. A1 - Holzschuh, Andrea A1 - Krauss, Jochen A1 - Steffan‐Dewenter, Ingolf T1 - Flower fields and pesticide use interactively shape pollen beetle infestation and parasitism in oilseed rape fields JF - Journal of Applied Ecology N2 - Pollen beetles (Brassicogethes spp.) are the main pests of oilseed rape (OSR, Brassica napus) in Europe and responsible for massive yield losses. Upcoming pesticide resistances highlight the need for other means of crop protection, such as natural pest control. Sown flower fields aim to counteract the decrease of insect biodiversity in agricultural landscapes by providing resources to ecosystem service providers. However, the optimal age and size of flower fields to increase natural pest control is still unclear. We conducted experiments on 31 OSR fields located along a gradient of landscape-scale semi-natural habitat (SNH). OSR fields were located adjacent to flower fields which differed in age, continuity and size, or adjacent to crop fields or calcareous grasslands. Pesticide-free areas were established to examine interactive effects of pesticide use and flower field characteristics. The abundance of pollen beetle adults and larvae, parasitism and superparasitism rates in OSR were recorded at increasing distances to the adjacent sites. Flower fields and calcareous grasslands increased pollen beetle parasitism when compared to OSR fields neighbouring crop fields. The threshold for effective natural pest control of 35% could be reached in the pesticide-free areas of OSR fields adjacent to calcareous grasslands and flower fields maintained continuously for at least 6 years. In pesticide-sprayed areas, pollen beetle parasitism and superparasitism declined with increasing distance to the adjacent field. Furthermore, flower fields larger than 1.5 ha were able to improve pollen beetle parasitism more than smaller fields. Synthesis and applications. To promote natural pest control in oilseed rape (OSR), large flower fields should be maintained for several years, to create stable habitats for natural enemies. The continuous maintenance of flower fields should be preferred, as ploughing and resowing after 5–6 years decreased the positive effects of the flower fields on natural pest control in adjacent OSR fields. However, pesticide use can abrogate positive effects of flower fields on pollen beetle parasitism. This study highlights that sown flower fields have the potential to increase natural pest control in OSR, but this potential is depending on its age, continuity and size and can be hindered by pesticide use. KW - agri-environment scheme KW - sown flower field age and size KW - oilseed rape KW - natural pest control KW - ecosystem services KW - distance-decay function KW - Brassicogethes spp. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258037 VL - 59 IS - 1 ER - TY - JOUR A1 - Koster, Stefanie A1 - Gurumurthy, Rajendra Kumar A1 - Kumar, Naveen A1 - Prakash, Pon Ganish A1 - Dhanraj, Jayabhuvaneshwari A1 - Bayer, Sofia A1 - Berger, Hilmar A1 - Kurian, Shilpa Mary A1 - Drabkina, Marina A1 - Mollenkopf, Hans-Joachim A1 - Goosmann, Christian A1 - Brinkmann, Volker A1 - Nagel, Zachary A1 - Mangler, Mandy A1 - Meyer, Thomas F. A1 - Chumduri, Cindrilla T1 - Modelling Chlamydia and HPV co-infection in patient-derived ectocervix organoids reveals distinct cellular reprogramming JF - Nature Communications N2 - Coinfections with pathogenic microbes continually confront cervical mucosa, yet their implications in pathogenesis remain unclear. Lack of in-vitro models recapitulating cervical epithelium has been a bottleneck to study coinfections. Using patient-derived ectocervical organoids, we systematically modeled individual and coinfection dynamics of Human papillomavirus (HPV)16 E6E7 and Chlamydia, associated with carcinogenesis. The ectocervical stem cells were genetically manipulated to introduce E6E7 oncogenes to mimic HPV16 integration. Organoids from these stem cells develop the characteristics of precancerous lesions while retaining the self-renewal capacity and organize into mature stratified epithelium similar to healthy organoids. HPV16 E6E7 interferes with Chlamydia development and induces persistence. Unique transcriptional and post-translational responses induced by Chlamydia and HPV lead to distinct reprogramming of host cell processes. Strikingly, Chlamydia impedes HPV-induced mechanisms that maintain cellular and genome integrity, including mismatch repair in the stem cells. Together, our study employing organoids demonstrates the hazard of multiple infections and the unique cellular microenvironment they create, potentially contributing to neoplastic progression. KW - Chlamydia KW - HPV KW - cellular reprogramming Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301349 VL - 13 IS - 1 ER - TY - JOUR A1 - Kortmann, Mareike A1 - Roth, Nicolas A1 - Buse, Jörn A1 - Hilszczański, Jacek A1 - Jaworski, Tomasz A1 - Morinière, Jérôme A1 - Seidl, Rupert A1 - Thorn, Simon A1 - Müller, Jörg C. T1 - Arthropod dark taxa provide new insights into diversity responses to bark beetle infestations JF - Ecological Applications N2 - Natural disturbances are increasing around the globe, also impacting protected areas. Although previous studies have indicated that natural disturbances result in mainly positive effects on biodiversity, these analyses mostly focused on a few well established taxonomic groups, and thus uncertainty remains regarding the comprehensive impact of natural disturbances on biodiversity. Using Malaise traps and meta‐barcoding, we studied a broad range of arthropod taxa, including dark and cryptic taxa, along a gradient of bark beetle disturbance severities in five European national parks. We identified order‐level community thresholds of disturbance severity and classified barcode index numbers (BINs; a cluster system for DNA sequences, where each cluster corresponds to a species) as negative or positive disturbance indicators. Negative indicator BINs decreased above thresholds of low to medium disturbance severity (20%–30% of trees killed), whereas positive indicator BINs benefited from high disturbance severity (76%–98%). BINs allocated to a species name contained nearly as many positive as negative disturbance indicators, but dark and cryptic taxa, particularly Diptera and Hymenoptera in our data, contained higher numbers of negative disturbance indicator BINs. Analyses of changes in the richness of BINs showed variable responses of arthropods to disturbance severity at lower taxonomic levels, whereas no significant signal was detected at the order level due to the compensatory responses of the underlying taxa. We conclude that the analyses of dark taxa can offer new insights into biodiversity responses to disturbances. Our results suggest considerable potential for forest management to foster arthropod diversity, for example by maintaining both closed‐canopy forests (>70% cover) and open forests (<30% cover) on the landscape. KW - arthropods KW - biodiversity KW - conservation KW - metabarcoding KW - national park KW - natural disturbance KW - threshold indicator taxa analysis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276392 VL - 32 IS - 2 ER - TY - JOUR A1 - Kortmann, Mareike A1 - Angelstam, Per A1 - Mayer, Marius A1 - Leibl, Franz A1 - Reichert, Jessica A1 - Thorn, Christine A1 - Thorn, Simon T1 - Disturbance severity and human–nature relationships: A new approach to analyze people’s well-being along a bark beetle infestation gradient JF - Forests N2 - Contact to nature and greenspace is important for emotional well-being and can promote human health. Forest landscapes provide such access to greenspace, especially in protected areas. However, forested protected areas are impacted by natural disturbances such as bark beetle infestations. On the one hand, such disturbances have positive impacts on ecological processes and biodiversity. On the other hand, they have allegedly negative impacts on the recreational value of a landscape. Limited knowledge about the public’s perception of forests subject to natural disturbances still hampers forest management to balance ecological functions and visitors’ recreational experience. Thus, our aim was to determine how attitudes towards nature influence the personal well-being in a naturally disturbed landscape. We investigated self-reported well-being and attitudes towards nature in a standardized questionnaire-based survey of 1008 German inhabitants in an experimentally adapted landscape visualization. Self-reported well-being was generally highest in landscapes with relatively few bark-beetle-killed trees. This was especially the case for people who felt included with nature and preferred an appreciative use or preservation of nature. Conversely, people who had previously visited a national park with visible bark beetle infestations rated their personal well-being highest in landscapes with larger proportions of beetle-killed trees. Our results indicate that it is necessary to analyze people’s knowledge about and relations to forest landscapes as well as concepts of nature conservation, natural landscapes, and biodiversity to gain a better understanding of people’s perceptions of natural disturbances. KW - bark beetle disturbance KW - major environmental values KW - well-being KW - inclusion of nature in one’s self KW - national park Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297429 SN - 1999-4907 VL - 13 IS - 11 ER - TY - THES A1 - Kortmann, Mareike T1 - Biodiversity and recreation – Optimizing tourism and forest management in forests affected by bark beetles T1 - Biodiversität und Erholungsfunktionen – Optimierung von Tourismus- und Waldmanagement in Borkenkäferwäldern N2 - Forests are multi-functional system, which have to fulfil different objectives at the same time. The main functions include the production of wood, storage of carbon, the promotion of biological diversity and the provision of recreational space. Yet, global forests are affected by large and intense natural disturbances, like bark beetle infestations. While natural disturbances threaten wood production and are perceived as ‘catastrophe’ diminishing recreational value, biodiversity can benefit from the disturbance-induced changes in forest structures. This trade-off poses a dilemma to managers of bark beetle affected stands, particularly in protected areas designated to both nature conservation and recreation. Forest landscapes need a sustainable management concept aligning these different objectives. In order to support this goal with scientific knowledge, the aim of this work is to analyse ecological and social effects along a gradient of different disturbance severities. In this context, I studied the effects of a disturbance severity gradient on the diversity of different taxonomic groups including vascular plants, mosses, lichens, fungi, arthropods and birds in five national parks in Central Europe. To analyse the recreational value of the landscape I conducted visitor surveys in the same study areas in which the biodiversity surveys were performed. To analyse possible psychological or demographic effects on preferences for certain disturbance intensities, an additional online survey was carried out. N2 - Wälder müssen unterschiedliche Zielsetzungen zur gleichen Zeit erfüllen. Zu den wichtigsten Zielsetzungen zählen Produktion von Holz, Speicherung von CO2, die Förderung der biologischen Vielfalt und die Bereitstellung von Erholungsgebieten. Wälder sind jedoch global von intensiven natürlichen Störungen wie Borkenkäferbefall betroffen. Während natürliche Störungen die Holzproduktion bedrohen und von der Bevölkerung als „Katastrophe“ wahrgenommen werden, die den Erholungswert verringert, kann die biologische Vielfalt von den störungsbedingten Veränderungen der Waldstrukturen profitieren. Dieser Kompromiss stellt die Manager der von Borkenkäfern betroffenen Bestände vor ein Dilemma, insbesondere in Schutzgebieten, die sowohl dem Naturschutz als auch der Erholung gewidmet sind, und fordert ein nachhaltiges Bewirtschaftungskonzept, das diese unterschiedlichen Ziele in Einklang bringt. Um diese Vorhaben durch wissenschaftliche Erkenntnisse zu unterstützen, ist das Ziel dieser Arbeit, ökologische und soziale Effekte entlang eines Gradienten verschiedener Störungsintensitätsgrade zu analysieren. In diesem Zusammenhang wurden die Auswirkungen verschiedener Störungsintensitäten auf die Biodiversität verschiedener taxonomischer Gruppen, einschließlich Gefäßpflanzen, Moosen, Flechten, Pilzen, Arthropoden und Vögeln untersucht. Außerdem Befragungen von Nationalpark Besuchern durchgeführt, um den Erholungswert der Landschaft zu analysieren. Um mögliche psychologische oder demografische Auswirkungen auf Präferenzen für bestimmte Störungsintensitäten zu analysieren, wurde zudem eine Online-Umfrage durchgeführt. KW - Borkenkäfer KW - Nationalpark KW - Biodiversität KW - natural disturbance KW - nature conservation KW - national park KW - biodiversity KW - recreation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240317 ER - TY - JOUR A1 - Kohl, Patrick L. A1 - Steffan‐Dewenter, Ingolf T1 - Nectar robbing rather than pollinator availability constrains reproduction of a bee‐flowered plant at high elevations JF - Ecosphere N2 - Abiotic factors are generally assumed to determine whether species can exist at the extreme ends of environmental gradients, for example, at high elevations, whereas the role of biotic interactions is less clear. On temperate mountains, insect‐pollinated plant species with bilaterally symmetrical flowers exhibit a parallel elevational decline in species richness and abundance with bees. This suggests that the lack of mutualistic interaction partners sets the elevational range limits of plants via a reduction in reproductive success. We used the bee‐pollinated mountain plant Clinopodium alpinum (Lamiaceae), which blooms along a continuous 1000‐m elevational gradient and has bilaterally symmetrical flowers, as a model to test the predicted parallel elevational decline in flower visitation and seed production. Although the community of flower visitors changed with elevation, the flower visitation rate by the most frequent visitors, bumble bees (33.8% of legitimate visits), and the overall rate of flower visitation by potential pollinators did not vary significantly with elevation. However, we discovered that nectar robbing by bumble bees and nectar theft by ants, two interactions with potentially negative effects on flowers, sharply increased with elevation. Seed set depended on pollinators across elevations and followed a weak hump‐shaped pattern, peaking at mid‐elevations and decreasing by about 20% toward both elevational range edges. Considering the mid‐ and high elevations, elevational variation in seed production could not be explained by legitimate bee visitation rates but was inversely correlated with the frequency of nectar robbing. Our observations challenge the hypothesis that a decrease in the availability of pollinators limits seed production of bee‐flowered plants at high elevations but suggest that an increase in negative interactions (nectar robbing and larceny) constrains reproductive success. KW - altitudinal gradients KW - bee pollination KW - chalcidoid wasps KW - climatic gradients KW - elevational diversity patterns KW - floral larceny KW - fly pollination KW - mountain ecosystems KW - plant–pollinator interactions KW - range limits KW - zygomorphy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287141 VL - 13 IS - 6 ER - TY - JOUR A1 - Kohl, Patrick L. A1 - Rutschmann, Benjamin A1 - Steffan-Dewenter, Ingolf T1 - Population demography of feral honeybee colonies in central European forests JF - Royal Society Open Science N2 - European honeybee populations are considered to consist only of managed colonies, but recent censuses have revealed that wild/feral colonies still occur in various countries. To gauge the ecological and evolutionary relevance of wild-living honeybees, information is needed on their population demography. We monitored feral honeybee colonies in German forests for up to 4 years through regular inspections of woodpecker cavity trees and microsatellite genotyping. Each summer, about 10% of the trees were occupied, corresponding to average densities of 0.23 feral colonies km\(^{−2}\) (an estimated 5% of the regional honeybee populations). Populations decreased moderately until autumn but dropped massively during winter, so that their densities were only about 0.02 colonies km\(^{−2}\) in early spring. During the reproductive (swarming) season, in May and June, populations recovered, with new swarms preferring nest sites that had been occupied in the previous year. The annual survival rate and the estimated lifespan of feral colonies (n = 112) were 10.6% and 0.6 years, respectively. We conclude that managed forests in Germany do not harbour self-sustaining feral honeybee populations, but they are recolonized every year by swarms escaping from apiaries. KW - pollinator decline KW - nest site selection KW - life-history traits KW - wild honeybees KW - beech forests KW - swarming Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301335 SN - 2054-5703 VL - 9 IS - 8 ER - TY - JOUR A1 - Koderer, Corinna A1 - Schmitz, Werner A1 - Wünsch, Anna Chiara A1 - Balint, Julia A1 - El-Mesery, Mohamed A1 - Volland, Julian Manuel A1 - Hartmann, Stefan A1 - Linz, Christian A1 - Kübler, Alexander Christian A1 - Seher, Axel T1 - Low energy status under methionine restriction is essentially independent of proliferation or cell contact inhibition JF - Cells N2 - Nonlimited proliferation is one of the most striking features of neoplastic cells. The basis of cell division is the sufficient presence of mass (amino acids) and energy (ATP and NADH). A sophisticated intracellular network permanently measures the mass and energy levels. Thus, in vivo restrictions in the form of amino acid, protein, or caloric restrictions strongly affect absolute lifespan and age-associated diseases such as cancer. The induction of permanent low energy metabolism (LEM) is essential in this process. The murine cell line L929 responds to methionine restriction (MetR) for a short time period with LEM at the metabolic level defined by a characteristic fingerprint consisting of the molecules acetoacetate, creatine, spermidine, GSSG, UDP-glucose, pantothenate, and ATP. Here, we used mass spectrometry (LC/MS) to investigate the influence of proliferation and contact inhibition on the energy status of cells. Interestingly, the energy status was essentially independent of proliferation or contact inhibition. LC/MS analyses showed that in full medium, the cells maintain active and energetic metabolism for optional proliferation. In contrast, MetR induced LEM independently of proliferation or contact inhibition. These results are important for cell behaviour under MetR and for the optional application of restrictions in cancer therapy. KW - methionine restriction KW - caloric restriction KW - mass spectrometry KW - LC/MS KW - liquid chromatography/mass spectrometry KW - metabolomics KW - L929 KW - amino acid KW - proliferation KW - contact inhibition Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262329 SN - 2073-4409 VL - 11 IS - 3 ER - TY - JOUR A1 - Kaya-Zeeb, Sinan A1 - Engelmayer, Lorenz A1 - Straßburger, Mara A1 - Bayer, Jasmin A1 - Bähre, Heike A1 - Seifert, Roland A1 - Scherf-Clavel, Oliver A1 - Thamm, Markus T1 - Octopamine drives honeybee thermogenesis JF - eLife N2 - In times of environmental change species have two options to survive: they either relocate to a new habitat or they adapt to the altered environment. Adaptation requires physiological plasticity and provides a selection benefit. In this regard, the Western honeybee (Apis mellifera) protrudes with its thermoregulatory capabilities, which enables a nearly worldwide distribution. Especially in the cold, shivering thermogenesis enables foraging as well as proper brood development and thus survival. In this study, we present octopamine signaling as a neurochemical prerequisite for honeybee thermogenesis: we were able to induce hypothermia by depleting octopamine in the flight muscles. Additionally, we could restore the ability to increase body temperature by administering octopamine. Thus, we conclude that octopamine signaling in the flight muscles is necessary for thermogenesis. Moreover, we show that these effects are mediated by β octopamine receptors. The significance of our results is highlighted by the fact the respective receptor genes underlie enormous selective pressure due to adaptation to cold climates. Finally, octopamine signaling in the service of thermogenesis might be a key strategy to survive in a changing environment. KW - honeybee KW - octopamine KW - thermogenesis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301327 VL - 11 ER - TY - JOUR A1 - Kaya-Zeeb, Sinan A1 - Delac, Saskia A1 - Wolf, Lena A1 - Marante, Ana Luiza A1 - Scherf-Clavel, Oliver A1 - Thamm, Markus T1 - Robustness of the honeybee neuro-muscular octopaminergic system in the face of cold stress JF - Frontiers in Physiology N2 - In recent decades, our planet has undergone dramatic environmental changes resulting in the loss of numerous species. This contrasts with species that can adapt quickly to rapidly changing ambient conditions, which require physiological plasticity and must occur rapidly. The Western honeybee (Apis mellifera) apparently meets this challenge with remarkable success, as this species is adapted to numerous climates, resulting in an almost worldwide distribution. Here, coordinated individual thermoregulatory activities ensure survival at the colony level and thus the transmission of genetic material. Recently, we showed that shivering thermogenesis, which is critical for honeybee thermoregulation, depends on octopamine signaling. In this study, we tested the hypothesis that the thoracic neuro-muscular octopaminergic system strives for a steady-state equilibrium under cold stress to maintain endogenous thermogenesis. We can show that this applies for both, octopamine provision by flight muscle innervating neurons and octopamine receptor expression in the flight muscles. Additionally, we discovered alternative splicing for AmOARβ2. At least the expression of one isoform is needed to survive cold stress conditions. We assume that the thoracic neuro-muscular octopaminergic system is finely tuned in order to contribute decisively to survival in a changing environment. KW - honeybees KW - thermogenesis KW - cold stress KW - octopamine KW - octopamine receptors KW - gene expression Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-288753 SN - 1664-042X VL - 13 ER - TY - JOUR A1 - Jones, Jeffrey J. A1 - Huang, Shouguang A1 - Hedrich, Rainer A1 - Geilfus, Christoph‐Martin A1 - Roelfsema, M. Rob G. T1 - The green light gap: a window of opportunity for optogenetic control of stomatal movement JF - New Phytologist N2 - Green plants are equipped with photoreceptors that are capable of sensing radiation in the ultraviolet‐to‐blue and the red‐to‐far‐red parts of the light spectrum. However, plant cells are not particularly sensitive to green light (GL), and light which lies within this part of the spectrum does not efficiently trigger the opening of stomatal pores. Here, we discuss the current knowledge of stomatal responses to light, which are either provoked via photosynthetically active radiation or by specific blue light (BL) signaling pathways. The limited impact of GL on stomatal movements provides a unique option to use this light quality to control optogenetic tools. Recently, several of these tools have been optimized for use in plant biological research, either to control gene expression, or to provoke ion fluxes. Initial studies with the BL‐activated potassium channel BLINK1 showed that this tool can speed up stomatal movements. Moreover, the GL‐sensitive anion channel GtACR1 can induce stomatal closure, even at conditions that provoke stomatal opening in wild‐type plants. Given that crop plants in controlled‐environment agriculture and horticulture are often cultivated with artificial light sources (i.e. a combination of blue and red light from light‐emitting diodes), GL signals can be used as a remote‐control signal that controls stomatal transpiration and water consumption. KW - anion channel KW - channelrhodopsin KW - Chl KW - guard cell KW - ion channel KW - light‐gated KW - membrane potential KW - phototropin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293724 VL - 236 IS - 4 SP - 1237 EP - 1244 ER - TY - JOUR A1 - Jeanclos, Elisabeth A1 - Schlötzer, Jan A1 - Hadamek, Kerstin A1 - Yuan-Chen, Natalia A1 - Alwahsh, Mohammad A1 - Hollmann, Robert A1 - Fratz, Stefanie A1 - Yesilyurt-Gerhards, Dilan A1 - Frankenbach, Tina A1 - Engelmann, Daria A1 - Keller, Angelika A1 - Kaestner, Alexandra A1 - Schmitz, Werner A1 - Neuenschwander, Martin A1 - Hergenröder, Roland A1 - Sotriffer, Christoph A1 - von Kries, Jens Peter A1 - Schindelin, Hermann A1 - Gohla, Antje T1 - Glycolytic flux control by drugging phosphoglycolate phosphatase JF - Nature Communications N2 - Targeting the intrinsic metabolism of immune or tumor cells is a therapeutic strategy in autoimmunity, chronic inflammation or cancer. Metabolite repair enzymes may represent an alternative target class for selective metabolic inhibition, but pharmacological tools to test this concept are needed. Here, we demonstrate that phosphoglycolate phosphatase (PGP), a prototypical metabolite repair enzyme in glycolysis, is a pharmacologically actionable target. Using a combination of small molecule screening, protein crystallography, molecular dynamics simulations and NMR metabolomics, we discover and analyze a compound (CP1) that inhibits PGP with high selectivity and submicromolar potency. CP1 locks the phosphatase in a catalytically inactive conformation, dampens glycolytic flux, and phenocopies effects of cellular PGP-deficiency. This study provides key insights into effective and precise PGP targeting, at the same time validating an allosteric approach to control glycolysis that could advance discoveries of innovative therapeutic candidates. KW - phosphoglycolate phosphatase KW - glycolytic flux control KW - intrinsic metabolism Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300928 VL - 13 IS - 1 ER - TY - JOUR A1 - Hutin, Stephanie A1 - Ling, Wai Li A1 - Tarbouriech, Nicolas A1 - Schoehn, Guy A1 - Grimm, Clemens A1 - Fischer, Utz A1 - Burmeister, Wim P. T1 - The vaccinia virus DNA helicase structure from combined single-particle cryo-electron microscopy and AlphaFold2 prediction JF - Viruses N2 - Poxviruses are large DNA viruses with a linear double-stranded DNA genome circularized at the extremities. The helicase-primase D5, composed of six identical 90 kDa subunits, is required for DNA replication. D5 consists of a primase fragment flexibly attached to the hexameric C-terminal polypeptide (res. 323–785) with confirmed nucleotide hydrolase and DNA-binding activity but an elusive helicase activity. We determined its structure by single-particle cryo-electron microscopy. It displays an AAA+ helicase core flanked by N- and C-terminal domains. Model building was greatly helped by the predicted structure of D5 using AlphaFold2. The 3.9 Å structure of the N-terminal domain forms a well-defined tight ring while the resolution decreases towards the C-terminus, still allowing the fit of the predicted structure. The N-terminal domain is partially present in papillomavirus E1 and polyomavirus LTA helicases, as well as in a bacteriophage NrS-1 helicase domain, which is also closely related to the AAA+ helicase domain of D5. Using the Pfam domain database, a D5_N domain followed by DUF5906 and Pox_D5 domains could be assigned to the cryo-EM structure, providing the first 3D structures for D5_N and Pox_D5 domains. The same domain organization has been identified in a family of putative helicases from large DNA viruses, bacteriophages, and selfish DNA elements. KW - DNA replication KW - helicase KW - Pfam domain KW - poxvirus KW - cryo-electron microscopy KW - structure prediction KW - SF3 helicase KW - orthopoxvirus KW - DNA helicase Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290523 SN - 1999-4915 VL - 14 IS - 10 ER - TY - JOUR A1 - Hornick, Thomas A1 - Richter, Anett A1 - Harpole, William Stanley A1 - Bastl, Maximilian A1 - Bohlmann, Stephanie A1 - Bonn, Aletta A1 - Bumberger, Jan A1 - Dietrich, Peter A1 - Gemeinholzer, Birgit A1 - Grote, Rüdiger A1 - Heinold, Bernd A1 - Keller, Alexander A1 - Luttkus, Marie L. A1 - Mäder, Patrick A1 - Motivans Švara, Elena A1 - Passonneau, Sarah A1 - Punyasena, Surangi W. A1 - Rakosy, Demetra A1 - Richter, Ronny A1 - Sickel, Wiebke A1 - Steffan‐Dewenter, Ingolf A1 - Theodorou, Panagiotis A1 - Treudler, Regina A1 - Werchan, Barbora A1 - Werchan, Matthias A1 - Wolke, Ralf A1 - Dunker, Susanne T1 - An integrative environmental pollen diversity assessment and its importance for the Sustainable Development Goals JF - Plants, People, Planet N2 - Societal Impact Statement Pollen relates to many aspects of human and environmental health, which protection and improvement are endorsed by the United Nations Sustainable Development Goals. By highlighting these connections in the frame of current challenges in monitoring and research, we discuss the need of more integrative and multidisciplinary pollen research related to societal needs, improving health of humans and our ecosystems for a sustainable future. Summary Pollen is at once intimately part of the reproductive cycle of seed plants and simultaneously highly relevant for the environment (pollinators, vector for nutrients, or organisms), people (food safety and health), and climate (cloud condensation nuclei and climate reconstruction). We provide an interdisciplinary perspective on the many and connected roles of pollen to foster a better integration of the currently disparate fields of pollen research, which would benefit from the sharing of general knowledge, technical advancements, or data processing solutions. We propose a more interdisciplinary and holistic research approach that encompasses total environmental pollen diversity (ePD) (wind and animal and occasionally water distributed pollen) at multiple levels of diversity (genotypic, phenotypic, physiological, chemical, and functional) across space and time. This interdisciplinary approach holds the potential to contribute to pressing human issues, including addressing United Nations Sustainable Development Goals, fostering social and political awareness of these tiny yet important and fascinating particles. KW - aerobiology KW - allergy KW - diversity KW - environmental monitoring KW - food safety KW - paleoecology KW - palynology KW - pollination Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276487 VL - 4 IS - 2 SP - 110 EP - 121 ER - TY - JOUR A1 - Heydarian, Motaharehsadat A1 - Rühl, Eva A1 - Rawal, Ravisha A1 - Kozjak-Pavlovic, Vera T1 - Tissue models for Neisseria gonorrhoeae research — from 2D to 3D JF - Frontiers in Cellular and Infection Microbiology N2 - Neisseria gonorrhoeae is a human-specific pathogen that causes gonorrhea, the second most common sexually transmitted infection worldwide. Disease progression, drug discovery, and basic host-pathogen interactions are studied using different approaches, which rely on models ranging from 2D cell culture to complex 3D tissues and animals. In this review, we discuss the models used in N. gonorrhoeae research. We address both in vivo (animal) and in vitro cell culture models, discussing the pros and cons of each and outlining the recent advancements in the field of three-dimensional tissue models. From simple 2D monoculture to complex advanced 3D tissue models, we provide an overview of the relevant methodology and its application. Finally, we discuss future directions in the exciting field of 3D tissue models and how they can be applied for studying the interaction of N. gonorrhoeae with host cells under conditions closely resembling those found at the native sites of infection. KW - ex vivo KW - biomimetic tissue models KW - Neisseria gonorrhoeae KW - in vivo KW - in vitro Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-263046 SN - 2235-2988 VL - 12 ER - TY - JOUR A1 - Herbert, Saskia-Laureen A1 - Fick, Andrea A1 - Heydarian, Motaharehsadat A1 - Metzger, Marco A1 - Wöckel, Achim A1 - Rudel, Thomas A1 - Kozjak-Pavlovic, Vera A1 - Wulff, Christine T1 - Establishment of the SIS scaffold-based 3D model of human peritoneum for studying the dissemination of ovarian cancer JF - Journal of Tissue Engineering N2 - Ovarian cancer is the second most common gynecological malignancy in women. More than 70% of the cases are diagnosed at the advanced stage, presenting as primary peritoneal metastasis, which results in a poor 5-year survival rate of around 40%. Mechanisms of peritoneal metastasis, including adhesion, migration, and invasion, are still not completely understood and therapeutic options are extremely limited. Therefore, there is a strong requirement for a 3D model mimicking the in vivo situation. In this study, we describe the establishment of a 3D tissue model of the human peritoneum based on decellularized porcine small intestinal submucosa (SIS) scaffold. The SIS scaffold was populated with human dermal fibroblasts, with LP-9 cells on the apical side representing the peritoneal mesothelium, while HUVEC cells on the basal side of the scaffold served to mimic the endothelial cell layer. Functional analyses of the transepithelial electrical resistance (TEER) and the FITC-dextran assay indicated the high barrier integrity of our model. The histological, immunohistochemical, and ultrastructural analyses showed the main characteristics of the site of adhesion. Initial experiments using the SKOV-3 cell line as representative for ovarian carcinoma demonstrated the usefulness of our models for studying tumor cell adhesion, as well as the effect of tumor cells on endothelial cell-to-cell contacts. Taken together, our data show that the novel peritoneal 3D tissue model is a promising tool for studying the peritoneal dissemination of ovarian cancer. KW - ovarian cancer KW - 3D tissue model KW - co-culture KW - peritoneal metastasis KW - cancer dissemination Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301311 SN - 2041-7314 VL - 13 ER - TY - JOUR A1 - Henriksson, Sofia A1 - Calderón-Montaño, José Manuel A1 - Solvie, Daniel A1 - Warpman Berglund, Ulrika A1 - Helleday, Thomas T1 - Overexpressed c-Myc sensitizes cells to TH1579, a mitotic arrest and oxidative DNA damage inducer JF - Biomolecules N2 - Previously, we reported that MTH1 inhibitors TH588 and TH1579 selectively induce oxidative damage and kill Ras-expressing or -transforming cancer cells, as compared to non-transforming immortalized or primary cells. While this explains the impressive anti-cancer properties of the compounds, the molecular mechanism remains elusive. Several oncogenes induce replication stress, resulting in under replicated DNA and replication continuing into mitosis, where TH588 and TH1579 treatment causes toxicity and incorporation of oxidative damage. Hence, we hypothesized that oncogene-induced replication stress explains the cancer selectivity. To test this, we overexpressed c-Myc in human epithelial kidney cells (HA1EB), resulting in increased proliferation, polyploidy and replication stress. TH588 and TH1579 selectively kill c-Myc overexpressing clones, enforcing the cancer cell selective killing of these compounds. Moreover, the toxicity of TH588 and TH1579 in c-Myc overexpressing cells is rescued by transcription, proteasome or CDK1 inhibitors, but not by nucleoside supplementation. We conclude that the molecular toxicological mechanisms of how TH588 and TH1579 kill c-Myc overexpressing cells have several components and involve MTH1-independent proteasomal degradation of c-Myc itself, c-Myc-driven transcription and CDK activation. KW - MTH1 KW - TH588 KW - TH1579 KW - c-Myc KW - replication stress KW - DNA damage KW - cell death KW - cancer Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297547 SN - 2218-273X VL - 12 IS - 12 ER - TY - INPR A1 - Hennig, Thomas A1 - Prusty, Archana B. A1 - Kaufer, Benedikt A1 - Whisnant, Adam W. A1 - Lodha, Manivel A1 - Enders, Antje A1 - Thomas, Julius A1 - Kasimir, Francesca A1 - Grothey, Arnhild A1 - Herb, Stefanie A1 - Jürges, Christopher A1 - Meister, Gunter A1 - Erhard, Florian A1 - Dölken, Lars A1 - Prusty, Bhupesh K. T1 - Selective inhibition of miRNA 1 processing by a herpesvirus encoded miRNA N2 - Herpesviruses have mastered host cell modulation and immune evasion to augment productive infection, life-long latency and reactivation thereof 1,2. A long appreciated, yet elusively defined relationship exists between the lytic-latent switch and viral non-coding RNAs 3,4. Here, we identify miRNA-mediated inhibition of miRNA processing as a thus far unknown cellular mechanism that human herpesvirus 6A (HHV-6A) exploits to disrupt mitochondrial architecture, evade intrinsic host defense and drive the lytic-latent switch. We demonstrate that virus-encoded miR-aU14 selectively inhibits the processing of multiple miR-30 family members by direct interaction with the respective pri-miRNA hairpin loops. Subsequent loss of miR-30 and activation of the miR-30/p53/Drp1 axis triggers a profound disruption of mitochondrial architecture. This impairs induction of type I interferons and is necessary for both productive infection and virus reactivation. Ectopic expression of miR-aU14 triggered virus reactivation from latency, identifying viral miR-aU14 as a readily drugable master regulator of the herpesvirus lytic-latent switch. Our results show that miRNA-mediated inhibition of miRNA processing represents a generalized cellular mechanism that can be exploited to selectively target individual members of miRNA families. We anticipate that targeting miR-aU14 provides exciting therapeutic options for preventing herpesvirus reactivations in HHV-6-associated disorders. KW - Herpesvirus KW - HHV-6A KW - miRNA processing KW - miR-30 KW - mitochondria KW - fusion and fission KW - type I interferon KW - latency KW - virus reactivation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267862 ET - accepted version ER - TY - BOOK A1 - Halder, Partho T1 - Identification and characterization of synaptic proteins of Drosophila melanogaster using monoclonal antibodies of the Wuerzburg Hybridoma Library T1 - Identifikation und Charakterisierung von synaptischen Proteinen von Drosophila melanogaster mit Hilfe von monoklonalen Antikörpern der Würzburger Hybridoma-Bibliothek N2 - For a large fraction of the proteins expressed in the human brain only the primary structure is known from the genome project. Proteins conserved in evolution can be studied in genetic models such as Drosophila. In this doctoral thesis monoclonal antibodies (mAbs) from the Wuerzburg Hybridoma library are produced and characterized with the aim to identify the target antigen. The mAb ab52 was found to be an IgM which recognized a cytosolic protein of Mr ~110 kDa on Western blots. The antigen was resolved by two-dimensional gel electrophoresis (2DE) as a single distinct spot. Mass spectrometric analysis of this spot revealed EPS-15 (epidermal growth factor receptor pathway substrate clone 15) to be a strong candidate. Another mAb from the library, aa2, was already found to recognize EPS-15, and comparison of the signal of both mAbs on Western blots of 1D and 2D electrophoretic separations revealed similar patterns, hence indicating that both antigens could represent the same protein. Finally absence of the wild-type signal in homozygous Eps15 mutants in a Western blot with ab52 confirmed the ab52 antigen to be EPS-15. Thus both the mAbs aa2 and ab52 recognize the Drosophila homologue of EPS-15. The mAb aa2, being an IgG, is more suitable for applications like immunoprecipitation (IP). It has already been submitted to the Developmental Studies Hybridoma Bank (DSHB) to be easily available for the entire research community. The mAb na21 was also found to be an IgM. It recognizes a membrane associated antigen of Mr ~10 kDa on Western blots. Due to the membrane associated nature of the protein, it was not possible to resolve it by 2DE and due to the IgM nature of the mAb it was not possible to enrich the antigen by IP. Preliminary attempts to biochemically purify the endogenously expressed protein from the tissue, gave 99 promising results but could not be completed due to lack of time. Thus biochemical purification of the protein seems possible in order to facilitate its identification by mass spectrometry. Several other mAbs were studied for their staining pattern on cryosections and whole mounts of Drosophila brains. However, many of these mAbs stained very few structures in the brain, which indicated that only a very limited amount of protein would be available as starting material. Because these antibodies did not produce signals on Western blots, which made it impossible to enrich the antigens by electrophoretic methods, we did not attempt their purification. However, the specific localization of these proteins makes them highly interesting and calls for their further characterization, as they may play a highly specialized role in the development and/or function of the neural circuits they are present in. The purification and identification of such low expression proteins would need novel methods of enrichment of the stained structures. N2 - Für einen Großteil der Proteine, die im menschlichen Gehirn exprimiert werden, ist lediglich die Primärstruktur aus dem Genomprojekt bekannt. Proteine, die in der Evolution konserviert wurden, können in genetischen Modellsystemen wie Drosophila untersucht werden. In dieser Doktorarbeit werden monoklonale Antikörper (mAk) aus der Würzburger Hybridoma Bibliothek produziert und charakterisiert, mit dem Ziel, die erkannten Proteine zu identifizieren. Der mAk ab52 wurde als IgM typisiert, das auf Western Blots ein zytosolisches Protein von Mr ~110 kDa erkennt. Das Antigen wurde durch zwei-dimensionale Gelelektrophorese (2DE) als einzelner Fleck aufgelöst. Massenspektrometrische Analyse dieses Flecks identifizierte dass EPS-15 (epidermal growth factor receptor pathway substrate clone 15) als viel versprechenden Kandidaten. Da für einen anderen mAk aus der Bibliothek, aa2, bereits bekannt war, dass er EPS-15 erkennt, wurden die Western-Blot-Signale der beiden Antikörper nach 1D und 2D Trennungen von Kopfhomogenat verglichen. Die Ähnlichkeit der beiden Muster deuteten darauf hin, dass beide Antigene dasselbe Protein erkennen. Das Fehlen des Wildtyp-Signals in homozygoten Eps15 Mutanten in einem Western Blot mit mAk ab52 bestätigten schließlich, dass EPS-15 das Antigen zu mAk ab52 darstellt. Demnach erkennen beide mAk, aa2 und ab52, das Drosophila Homolog zu EPS- 15. Da mAk aa2 ein IgG ist, dürfte er für Anwendungen wie Immunpräzipitation (IP) besser geeignet sein. Er wurde daher bereits bei der Developmental Studies Hybridoma Bank (DSHB) eingereicht, um ihn der ganzen Forschergemeinde leicht zugänglich zu machen. Der mAk na21 wurde ebenfalls als IgM typisiert. Er erkennt ein Membran assoziiertes Antigen von Mr ~10 kDa auf Western Blots. Aufgrund der Membranassoziierung des Proteins war es nicht möglich, es in 2DE aufzulösen und 101 da es sich um ein IgM handelt, war eine Anreicherung des Antigens mittels IP nicht erfolgreich. Vorversuche zur biochemischen Reinigung des endogenen Proteins aus Gewebe waren Erfolg versprechend, konnten aber aus Zeitmangel nicht abgeschlossen werden. Daher erscheint eine biochemische Reinigung des Proteins für eine Identifikation durch Massenspektrometrie möglich. Eine Reihe weiterer mAk wurden hinsichtlich ihrer Färbemuster auf Gefrierschnitten und in Ganzpräparaten von Drosophila Gehirnen untersucht. Allerdings färbten viele dieser mAk sehr wenige Strukturen im Gehirn, so dass nur eine sehr begrenzte Menge an Protein als Startmaterial verfügbar wäre. Da diese Antikörper keine Signale auf Western Blots produzierten und daher eine Anreicherung des Antigens durch elektrophoretische Methoden ausschlossen, wurde keine Reinigung versucht. Andererseits macht die spezifische Lokalisation dieser Proteine sie hoch interessant für eine weitere Charakterisierung, da sie eine besonders spezialisierte Rolle in der Entwicklung oder für die Funktion von neuralen Schaltkreisen, in denen sie vorkommen, spielen könnten. Die Reinigung und Identifikation solcher Proteine mit niedrigem Expressionsniveau würde neue Methoden der Anreicherung der gefärbten Strukturen erfordern. KW - synaptic proteins KW - Taufliege KW - Synapse KW - Proteine KW - Monoklonaler Antikörper KW - synaptische Proteine KW - monoklonale Antikörper KW - Drosophila melanogaster KW - monoclonal antibodies Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-270205 N1 - ursprüngliche Originalausgabe der Dissertation erschienen am 19.01.2012 unter: https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-67325 ER - TY - JOUR A1 - Gupta, Shishir K. A1 - Osmanoglu, Özge A1 - Minocha, Rashmi A1 - Bandi, Sourish Reddy A1 - Bencurova, Elena A1 - Srivastava, Mugdha A1 - Dandekar, Thomas T1 - Genome-wide scan for potential CD4+ T-cell vaccine candidates in Candida auris by exploiting reverse vaccinology and evolutionary information JF - Frontiers in Medicine N2 - Candida auris is a globally emerging fungal pathogen responsible for causing nosocomial outbreaks in healthcare associated settings. It is known to cause infection in all age groups and exhibits multi-drug resistance with high potential for horizontal transmission. Because of this reason combined with limited therapeutic choices available, C. auris infection has been acknowledged as a potential risk for causing a future pandemic, and thus seeking a promising strategy for its treatment is imperative. Here, we combined evolutionary information with reverse vaccinology approach to identify novel epitopes for vaccine design that could elicit CD4+ T-cell responses against C. auris. To this end, we extensively scanned the family of proteins encoded by C. auris genome. In addition, a pathogen may acquire substitutions in epitopes over a period of time which could cause its escape from the immune response thus rendering the vaccine ineffective. To lower this possibility in our design, we eliminated all rapidly evolving genes of C. auris with positive selection. We further employed highly conserved regions of multiple C. auris strains and identified two immunogenic and antigenic T-cell epitopes that could generate the most effective immune response against C. auris. The antigenicity scores of our predicted vaccine candidates were calculated as 0.85 and 1.88 where 0.5 is the threshold for prediction of fungal antigenic sequences. Based on our results, we conclude that our vaccine candidates have the potential to be successfully employed for the treatment of C. auris infection. However, in vivo experiments are imperative to further demonstrate the efficacy of our design. KW - T-cell epitope KW - epitope prediction KW - positive selection KW - evolution KW - immune-informatics Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293953 SN - 2296-858X VL - 9 ER - TY - JOUR A1 - Gupta, Shishir K. A1 - Minocha, Rashmi A1 - Thapa, Prithivi Jung A1 - Srivastava, Mugdha A1 - Dandekar, Thomas T1 - Role of the pangolin in origin of SARS-CoV-2: an evolutionary perspective JF - International Journal of Molecular Sciences N2 - After the recent emergence of SARS-CoV-2 infection, unanswered questions remain related to its evolutionary history, path of transmission or divergence and role of recombination. There is emerging evidence on amino acid substitutions occurring in key residues of the receptor-binding domain of the spike glycoprotein in coronavirus isolates from bat and pangolins. In this article, we summarize our current knowledge on the origin of SARS-CoV-2. We also analyze the host ACE2-interacting residues of the receptor-binding domain of spike glycoprotein in SARS-CoV-2 isolates from bats, and compare it to pangolin SARS-CoV-2 isolates collected from Guangdong province (GD Pangolin-CoV) and Guangxi autonomous regions (GX Pangolin-CoV) of South China. Based on our comparative analysis, we support the view that the Guangdong Pangolins are the intermediate hosts that adapted the SARS-CoV-2 and represented a significant evolutionary link in the path of transmission of SARS-CoV-2 virus. We also discuss the role of intermediate hosts in the origin of Omicron. KW - COVID-19 KW - SARS-CoV-2 KW - origin KW - evolution KW - intermediate host KW - pangolin KW - mutation KW - recombination KW - adaptation KW - transmission KW - comparative sequence analysis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285995 SN - 1422-0067 VL - 23 IS - 16 ER - TY - RPRT A1 - Groß, Lennart T1 - Advices derived from troubleshooting a sensor-based adaptive optics direct stochastic optical reconstruction microscope T1 - Hinweise aus der Fehleranalyse eines Mikroskops mit direkter stochastischer optischer Rekonstruktion und sensorgestützter adaptiver Optik N2 - One rarely finds practical guidelines for the implementation of complex optical setups. Here, we aim to provide technical details on the decision making of building and revising a custom sensor-based adaptive optics (AO) direct stochastic optical reconstruction microscope (dSTORM) to provide practical assistance in setting up or troubleshooting similar devices. The foundation of this report is an instrument constructed as part of a master's thesis in 2021, which was built for deep tissue imaging. The setup is presented in the following way: (1) An optical and mechanical overview of the system at the beginning of this internship is given. (2) The optical components are described in detail in the order at which the light passes through, highlighting their working principle and implementation in the system. The optical component include (2A) a focus on even sample illumination, (2B) restoring telecentricity when working with commercial microscope bodies, (2C) the AO elements, namely the deformable mirror (DM) and the wavefront sensor, and their integration, and (2D) the separation of wavefront and image capture using fluorescent beads and a dichroic mirror. After addressing the limitations of the existing setup, modification options are derived. The modifications include the implementation of adjustment only light paths to improve system stability and revise the degrees of freedom of the components and changes in lens choices to meet the specifications of the AO components. Last, the capabilities of the modified setup are presented and discussed: (1) First, we enable epifluorescence imaging of bead samples through 180 µm unstained murine hippocampal tissue with wavefront error correction of ~ 90 %. Point spread function, wavefront shape and Zernike decomposition of bead samples are presented. (2) Second, we move from epifluorescent to dSTORM imaging of tubulin stained primary mouse hippocampal cells, which are imaged through up to 180 µm of unstained murine hippocampal tissue. We show that full width at half maximum (FWHM) of prominent features can be reduced in size by nearly a magnitude from uncorrected epiflourescence images to dSTORM images corrected by the adaptive optics. We present dSTORM localization count and FWHM of prominent features as as a function of imaging depth. N2 - Praktische Leitlinien für die Implementierung komplexer optischer Systeme sind selten zu finden. Hier wollen wir technische Details zur Entscheidungsfindung beim Bau und der Überarbeitung eines maßgefertigten Mikroskops mit sensorgestützter adaptiver Optik (AO) und direkter stochastischer optischer Rekonstruktion (dSTORM) bereitstellen, um praktische Hilfestellung bei der Einrichtung oder Fehlerbehebung ähnlicher Geräte zu geben. Grundlage dieses Berichts ist ein Instrument, das im Rahmen einer Masterarbeit im Jahr 2021 für die Abbildung von tiefem Gewebe gebaut wurde. Der Aufbau wird wie folgt dargestellt: (1) Es wird ein optischer und mechanischer Überblick über das System zu Beginn dieses Praktikums gegeben. (2) Die optischen Komponenten werden in der Reihenfolge, in der das Licht sie durchläuft, detailliert beschrieben und ihre Funktionsweise und Umsetzung im System hervorgehoben. Zu den optischen Komponenten gehören (2A) ein Fokus auf gleichmäßige Probenausleuchtung, (2B) die Wiederherstellung der Telezentrizität bei der Arbeit mit handelsüblichen Mikroskopkörpern, (2C) die AO-Elemente, nämlich der deformierbare Spiegel (DM) und der Wellenfrontsensor, und deren Integration, sowie (2D) die Trennung von Wellenfront- und Bilderfassung mittels fluoreszierender Beads und einem dichroitischen Spiegel. Nachdem die Einschränkungen des bestehenden Aufbaus angesprochen wurden, werden Modifikationsmöglichkeiten abgeleitet. Die Modifikationen umfassen die Implementierung von Justage-Lichtpfaden, um die Systemstabilität zu verbessern und die Freiheitsgrade der Komponenten zu überarbeiten, sowie Änderungen bei der Auswahl der Linsen, um die Spezifikationen der AO-Komponenten zu erfüllen. Abschließend werden die Ergebnisse des modifizierten Aufbaus vorgestellt und diskutiert: (1) Zunächst ermöglichen wir die Epifluoreszenz-Abbildung von Bead-Proben durch 180 µm ungefärbtes Hippocampus-Gewebe der Maus mit einer Wellenfront-Fehlerkorrektur von ~ 90 %. Es werden Punktspreizungsfunktion, Wellenfrontform und Zernike-Zerlegung von Bead-Proben vorgestellt. (2) Zweitens gehen wir von der Epifluoreszenz zur dSTORM-Bildgebung von Tubulin-gefärbten primären Hippocampuszellen der Maus über, die durch bis zu 180 µm ungefärbtes Hippocampusgewebe der Maus abgebildet werden. Wir zeigen, dass die Halbwertsbreite (Full Width at Half Maximum, FWHM) auffälliger Merkmale von unkorrigierten Epifloureszenz-Bildern zu dSTORM-Bildern, die durch die adaptive Optik korrigiert wurden, um fast eine Größenordnung reduziert werden kann. Wir präsentieren die Anzahl der dSTORM-Lokalisierungen und die FWHM auffälliger Merkmale als Funktion der Abbildungstiefe. KW - Einzelmolekülmikroskopie KW - Adaptive Optik KW - Adaptive Optics KW - Single Molecule Localization Microscopy KW - dSTORM Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-289951 ER - TY - THES A1 - Grob, Robin T1 - The Function of Learning Walks of \({Cataglyphis Ants}\): Behavioral and Neuronal Analyses T1 - Die Funktion der Lernläufe in \(Cataglyphis\) Ameisen: eine Studie des Verhaltens und der neuronalen Auswirkungen N2 - Humans and animals alike use the sun, the moon, and the stars to guide their ways. However, the position of celestial cues changes depending on daytime, season, and place on earth. To use these celestial cues for reliable navigation, the rotation of the sky has to be compensated. While humans invented complicated mechanisms like the Antikythera mechanism to keep track of celestial movements, animals can only rely on their brains. The desert ant Cataglyphis is a prime example of an animal using celestial cues for navigation. Using the sun and the related skylight polarization pattern as a compass, and a step integrator for distance measurements, it can determine a vector always pointing homewards. This mechanism is called path integration. Since the sun’s position and, therefore, also the polarization pattern changes throughout the day, Cataglyphis have to correct this movement. If they did not compensate for time, the ants’ compass would direct them in different directions in the morning and the evening. Thus, the ants have to learn the solar ephemeris before their far-reaching foraging trips. To do so, Cataglyphis ants perform a well-structured learning-walk behavior during the transition phase from indoor worker to outdoor forager. While walking in small loops around the nest entrance, the ants repeatedly stop their forward movements to perform turns. These can be small walked circles (voltes) or tight turns about the ants’ body axes (pirouettes). During pirouettes, the ants gaze back to their nest entrance during stopping phases. These look backs provide a behavioral read-out for the state of the path integrator. The ants “tell” the observer where they think their nest is, by looking back to it. Pirouettes are only performed by Cataglyphis ants inhabiting an environment with a prominent visual panorama. This indicates, that pirouettes are performed to learn the visual panorama. Voltes, on the other hand, might be used for calibrating the celestial compass of the ants. In my doctoral thesis, I employed a wide range of state-of-the-art techniques from different disciplines in biology to gain a deeper understanding of how navigational information is acquired, memorized, used, and calibrated during the transition phase from interior worker to outdoor forager. I could show, that celestial orientation cues that provide the main compass during foraging, do not guide the ants during the look-backbehavior of initial learning walks. Instead Cataglyphis nodus relies on the earth’s magnetic field as a compass during this early learning phase. While not guiding the ants during their first walks outside of the nest, excluding the ants from perceiving the natural polarization pattern of the skylight has significant consequences on learning-related plasticity in the ants’ brain. Only if the ants are able to perform their learning-walk behavior under a skylight polarization pattern that changes throughout the day, plastic neuronal changes in high-order integration centers are induced. Especially the mushroom bogy collar, a center for learning and memory, and the central complex, a center for orientation and motor control, showed an increase in volume after learning walks. This underlines the importance of learning walks for calibrating the celestial compass. The magnetic compass might provide the necessary stable reference system for the ants to calibrate their celestial compass and learn the position of landmark information. In the ant brain, visual information from the polarization-sensitive ocelli converge in tight apposition with neuronal afferents of the mechanosensitive Johnston’s organ in the ant’s antennae. This makes the ants’ antennae an interesting candidate for studying the sensory bases of compass calibration in Cataglyphis ants. The brain of the desert navigators is well adapted to successfully accomplish their navigational needs. Females (gynes and workers) have voluminous mushroom bodies, and the synaptic complexity to store large amount of view-based navigational information, which they acquire during initial learning walks. The male Cataglyphis brain is better suited for innate behaviors that support finding a mate. The results of my thesis show that the well adapted brain of C. nodus ants undergoes massive structural changes during leaning walks, dependent on a changing celestial polarization pattern. This underlies the essential role of learning walks in the calibration of orientation systems in desert ants. N2 - Die Gestirne helfen nicht nur Menschen uns zurecht zu finden, sondern auch Tiere können Sonne, Mond und Sterne für Navigation nutzen. Dabei gilt es aber zu beachten, dass die Himmelskörper ihre Position abhängig von der Tageszeit, den Jahreszeiten und dem Standort auf der Erde verändern. Um anhand von Himmelseigenschaften erfolgreich navigieren zu können, ist es deshalb unerlässlich diese Himmelsrotation zu kennen und für sie zu kompensieren. Menschen haben dafür bereits in der Antike komplizierte Maschinen wie den Antikythera Mechanismus entwickelt, Tiere dagegen brauchen nur ihr Gehirn. Wüstenameisen der Galtung Cataglyphis sind kleine Meisternavigatoren. Sie benutzen einen Himmelskompass, basierend auf der Sonne und dem mit ihr assoziierten Polarisationsmuster des Himmels, und einen Schrittintegrator, um einen Vektor zu bestimmen, der immer genau zu ihrem Ausgangspunkt zurück zeigt. Dieser Orientierungsmechanismus heißt Wegintegration. Da sich allerdings die Position der Sonne am Himmel und damit auch das Polarisationsmuster des Himmels über den Tag verändern, muss Cataglyphis für diese Veränderung kompensieren. Würde sie das nicht tun, würde ihr Kompass morgens in eine ganz andere Richtung als abends zeigen. Deshalb müssen Ameisen den Sonnenverlauf erlernen bevor sie zu ihren weitläufigen Futtersuchläufen aufbrechen. Cataglyphis führt dazu ein strukturiertes Lernlaufverhalten durch während des Übergangs von Innendiensttier zu Sammlerinnen. Dabei laufen die Ameisen in kleinen Schlaufen um ihren Nesteingang und stoppen ihre Vorwärtsbewegung mehrmalig, um Drehungen durchzuführen. Diese Drehungen sind entweder kleine gelaufene Kreise (Volten) oder Drehungen um die eigene Achse (Pirouetten). Nur Cataglyphis, die Gegenden mit einem reichhaltigen visuellen Panorama bewohnen, führen Pirouetten aus bei denen sie zurück zu ihrem Nesteingang schauen. Dies legt nahe, dass während Pirouetten das Panorama gelernt wird. Während Volten wird wohl der Himmelskompass kalibriert. Die Rückdrehungen während ihrer Lernläufe geben die einmalige Möglichkeit, die Ameise zu „fragen“ wo sie denkt, dass ihr Nest sei und damit ihren Wegintegrator auszulesen. In meiner Doktorarbeit kombinierte ich viele biologischen Methoden unterschiedlicher Disziplinen um zu untersuchen wie die Ameisen ihre Navigationssysteme während der ersten Läufe außerhalb des Nestes erlernen, speichern, kalibrieren und später nutzen. Ich konnte zeigen, dass Himmelsinformationen, die bei Sammlerinnen als wichtigster 4 Kompass dienen, nicht für die Orientierung der Rückblicke während Lernläufen dienen. Stattdessen nutzten naive Cataglyphis nodus das Erdmagnetfeld als Kompass. Obwohl Himmelsinformationen nicht als Kompass während der Lernläufe genutzt werden, spielen sie eine essentielle Rolle für neuroplastische Veränderungen im Gehirn der Ameisen. Nur wenn Ameisen ihre Lernläufe unter einem Polaristaionsmuster, das sich über den Tag hinweg verändert, ausführen, kommt es zu plastischen Veränderungen in neuronalen Integrationszentren. Besonders die Pilzkörper, Zentren für Lernen und Gedächtnis, und der Zentralkomplex, Zentrum für Orientierung und Bewegungssteuerung, nehmen im Volumen nach Lernläufen zu. Lernläufe spielen also eine wichtige Rolle für die Kalibrierung der Navigationsinformationen. Das Erdmagnetfeld könnte das für die Kalibierung notwendige erdgebundene, stabile Referenzsystem bieten, an dem die Himmelsbewegung gelernt wird. Im Ameisengehirn laufen visuelle Informationen von den polarisatiossensitiven Ocelli mit Afferenzen des mechanosensitiven Johnstonschen Organ aus der Antenne zusammen. Die Antenne könnte daher eine wichtiges Organ für die Kalibrierung der Orientierungssysteme sein. Das kleine Gehirn der Ameisen ist bestens an ihre Anforderungen als große Navigatoren angepasst. Weibliche C. nodus (Arbeiterinnen und Königinnen) besitzen große Pilzkörper mit einer Anzahl an Synapsen, die es ihnen erlaubt eine Vielzahl von Umgebungsbildern zu speichern, die sie während ihrer initialen Lernläufe lernen müssen. Das männliche Cataglyphis-Gehirn ist besser auf angeborene Orientierungsstrategien angepasst, die ihm helfen einen Geschlechtspartner zu finden. Die Ergebnisse meiner Doktorarbeit zeigen, dass das an die navigatorischen Herausforderungen angepasste Gehirn von C. nodus signifikante neuronale Veränderungen in Abhängigkeit eines sich veränderten Polaristaionsmusters während der Lernläufe erfährt. Dies zeigt die essentielle Rolle der Lernläufe in der Kalibrierung der Navigationssysteme von Wüstenameisen. KW - Cataglyphis KW - Kompass KW - Navigation KW - Nahrungserwerb KW - Neuroethologie KW - Neuroethology KW - Polyethism KW - Learning Walk KW - Geomagnetic Field KW - Learning & Memory Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-290173 ER - TY - JOUR A1 - Grittner, Rebecca A1 - Baird, Emily A1 - Stöckl, Anna T1 - Spatial tuning of translational optic flow responses in hawkmoths of varying body size JF - Journal of Comparative Physiology A N2 - To safely navigate their environment, flying insects rely on visual cues, such as optic flow. Which cues insects can extract from their environment depends closely on the spatial and temporal response properties of their visual system. These in turn can vary between individuals that differ in body size. How optic flow-based flight control depends on the spatial structure of visual cues, and how this relationship scales with body size, has previously been investigated in insects with apposition compound eyes. Here, we characterised the visual flight control response limits and their relationship to body size in an insect with superposition compound eyes: the hummingbird hawkmoth Macroglossum stellatarum. We used the hawkmoths' centring response in a flight tunnel as a readout for their reception of translational optic flow stimuli of different spatial frequencies. We show that their responses cut off at different spatial frequencies when translational optic flow was presented on either one, or both tunnel walls. Combined with differences in flight speed, this suggests that their flight control was primarily limited by their temporal rather than spatial resolution. We also observed strong individual differences in flight performance, but no correlation between the spatial response cutoffs and body or eye size. KW - allometry KW - vision KW - optic flow KW - flight control KW - hawkmoth Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266565 SN - 1432-1351 VL - 208 IS - 2 ER - TY - JOUR A1 - Graf, Marlene A1 - Lettenmaier, Ludwig A1 - Müller, Jörg A1 - Hagge, Jonas T1 - Saproxylic beetles trace deadwood and differentiate between deadwood niches before their arrival on potential hosts JF - Insect Conservation and Diversity N2 - Deadwood provides a variety of habitats for saproxylic beetles. Whereas the understanding of the drivers promoting saproxylic beetle diversity has improved, the process of deadwood colonisation and beetle's potential to trace resources is poorly understood. However, the mechanisms facilitating deadwood detection by saproxylic beetles appears to be essential for survival, as deadwood is usually scattered in time and space. To investigate whether saproxylic beetles distinguish before their arrival on potential hosts between alive trees and deadwood (lying, stumps, standing), deadwood arrangement (aggregated, distributed) and different heights on standing resources (bottom = 0.5 m, middle = 4–5 m, top = 7.30–11.60 m), we sampled saproxylic beetles with sticky traps in a deadwood experiment. We found on average 67% higher abundance, 100% higher species numbers and 50–130% higher species diversity of colonising saproxylic beetles consistently for all deadwood types compared to alive trees with a distinct community composition on lying deadwood compared to the other resource types. Aggregated deadwood arrangement, which is associated with higher sun‐exposure, had a positive effect on species richness. The abundance, species number and diversity, was significantly higher for standing deadwood and alive trees at the bottom section of tree trunks. In contrast to living trees, however, the vertical position had an additional effect on the community composition on standing deadwood. Our results indicate that saproxylic beetles are attracted to potential deadwood habitats and actively select specific trunk sections before arriving on potential hosts. Furthermore, this study highlights the importance of sun‐exposed resources for species richness in saproxylic beetles. KW - deadwood KW - experiment KW - host discrimination KW - host selection KW - microclimate KW - saproxylic beetles KW - vertical stratification Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262507 VL - 15 IS - 1 SP - 48 EP - 60 ER - TY - JOUR A1 - Geiger, Nina A1 - Kersting, Louise A1 - Schlegel, Jan A1 - Stelz, Linda A1 - Fähr, Sofie A1 - Diesendorf, Viktoria A1 - Roll, Valeria A1 - Sostmann, Marie A1 - König, Eva-Maria A1 - Reinhard, Sebastian A1 - Brenner, Daniela A1 - Schneider-Schaulies, Sibylle A1 - Sauer, Markus A1 - Seibel, Jürgen A1 - Bodem, Jochen T1 - The acid ceramidase is a SARS-CoV-2 host factor JF - Cells N2 - SARS-CoV-2 variants such as the delta or omicron variants, with higher transmission rates, accelerated the global COVID-19 pandemic. Thus, novel therapeutic strategies need to be deployed. The inhibition of acid sphingomyelinase (ASM), interfering with viral entry by fluoxetine was reported. Here, we described the acid ceramidase as an additional target of fluoxetine. To discover these effects, we synthesized an ASM-independent fluoxetine derivative, AKS466. High-resolution SARS-CoV-2–RNA FISH and RTqPCR analyses demonstrate that AKS466 down-regulates viral gene expression. It is shown that SARS-CoV-2 deacidifies the lysosomal pH using the ORF3 protein. However, treatment with AKS488 or fluoxetine lowers the lysosomal pH. Our biochemical results show that AKS466 localizes to the endo-lysosomal replication compartments of infected cells, and demonstrate the enrichment of the viral genomic, minus-stranded RNA and mRNAs there. Both fluoxetine and AKS466 inhibit the acid ceramidase activity, cause endo-lysosomal ceramide elevation, and interfere with viral replication. Furthermore, Ceranib-2, a specific acid ceramidase inhibitor, reduces SARS-CoV-2 replication and, most importantly, the exogenous supplementation of C6-ceramide interferes with viral replication. These results support the hypotheses that the acid ceramidase is a SARS-CoV-2 host factor. KW - SARS-CoV-2 KW - ceramides KW - ceramidase KW - fluoxetine KW - acid sphingomyelinase Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286105 SN - 2073-4409 VL - 11 IS - 16 ER - TY - JOUR A1 - Gebert, Friederike A1 - Steffan‐Dewenter, Ingolf A1 - Kronbach, Patrick A1 - Peters, Marcell K. T1 - The role of diversity, body size and climate in dung removal: A correlative and experimental approach JF - Journal of Animal Ecology N2 - The mechanisms by which climatic changes influence ecosystem functions, that is, by a direct climatic control of ecosystem processes or by modifying richness and trait compositions of species communities, remain unresolved. This study is a contribution to this discourse by elucidating the linkages between climate, land use, biodiversity, body size and ecosystem functions. We disentangled direct climatic from biodiversity‐mediated effects by using dung removal by dung beetles as a model system and by combining correlative field data and exclosure experiments along an extensive elevational gradient on Mt. Kilimanjaro, Tanzania. Dung removal declined with increasing elevation, being associated with a strong reduction in the richness and body size traits of dung beetle communities. Climate influenced dung removal rates by modifying biodiversity rather than by direct effects. The biodiversity–ecosystem effect was driven by a change in the mean body size of dung beetles. Dung removal rates were strongly reduced when large dung beetles were experimentally excluded. This study underscores that climate influences ecosystem functions mainly by modifying biodiversity and underpins the important role of body size for dung removal. KW - altitudinal gradients KW - biodiversity–ecosystem functioning relationship KW - body size KW - diversity gradients KW - ecosystem services KW - land use KW - Scarabaeidae KW - temperature Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293907 VL - 91 IS - 11 SP - 2181 EP - 2191 ER - TY - THES A1 - Gebert, Friederike T1 - Mammals and dung beetles along elevational and land use gradients on Mount Kilimanjaro: diversity, traits and ecosystem services T1 - Säugetiere und Dungkäfer entlang von Höhen- und Landnutzungsgradienten am Kilimandscharo: Diversität, funktionelle Merkmale und Ökosystemdienstleistungen N2 - Despite belonging to the best described patterns in ecology, the mechanisms driving biodiversity along broad-scale climatic gradients, like the latitudinal gradient in diversity, remain poorly understood. Because of their high biodiversity, restricted spatial ranges, the continuous change in abiotic factors with altitude and their worldwide occurrence, mountains constitute ideal study systems to elucidate the predictors of global biodiversity patterns. However, mountain ecosystems are increasingly threatened by human land use and climate change. Since the consequences of such alterations on mountainous biodiversity and related ecosystem services are hardly known, research along elevational gradients is also of utmost importance from a conservation point of view. In addition to classical biodiversity research focusing on taxonomy, the significance of studying functional traits and their prominence in biodiversity ecosystem functioning (BEF) relationships is increasingly acknowledged. In this dissertation, I explore the patterns and drivers of mammal and dung beetle diversity along elevational and land use gradients on Mt. Kilimanjaro, Tanzania. Furthermore, I investigate the predictors of dung decomposition by dung beetles under different extinction scenarios. Mammals are not only charismatic, they also fulfil important roles in ecosystems. They provide important ecosystem services such as seed dispersal and nutrient cycling by turning over high amounts of biomass. In chapter II, I show that mammal diversity and community biomass both exhibited a unimodal distribution with elevation on Mt.Kilimanjaro and were mainly impacted by primary productivity, a measure of the total food abundance, and the protection status of study plots. Due to their large size and endothermy, mammals, in contrast to most arthopods, are theoretically predicted to be limited by food availability. My results are in concordance with this prediction. The significantly higher diversity and biomass in the Kilimanjaro National Park and in other conservation areas underscore the important role of habitat protection is vital for the conservation of large mammal biodiversity on tropical mountains. Dung beetles are dependent on mammals since they rely upon mammalian dung as a food and nesting resource. Dung beetles are also important ecosystem service providers: they play an important role in nutrient cycling, bioturbation, secondary seed dispersal and parasite suppression. In chapter III, I show that dung beetle diversity declined with elevation while dung beetle abundance followed a hump-shaped pattern along the elevational gradient. In contrast to mammals, dung beetle diversity was primarily predicted by temperature. Despite my attempt to accurately quantifiy mammalian dung resources by calculating mammalian defecation rates, I did not find an influence of dung resource availability on dung beetle richness. Instead, higher temperature translated into higher dung beetle diversity. Apart from being important ecosystem service providers, dung beetles are also model organisms for BEF studies since they rely on a resource which can be quantified easily. In chapter IV, I explore dung decomposition by dung beetles along the elevational gradient by means of an exclosure experiment in the presence of the whole dung beetle community, in the absence of large dung beetles and without any dung beetles. I show that dung decomposition was the highest when the dung could be decomposed by the whole dung beetle community, while dung decomposition was significantly reduced in the sole presence of small dung beetles and the lowest in the absence of dung beetles. Furthermore, I demonstrate that the drivers of dung decomposition were depend on the intactness of the dung beetle community. While body size was the most important driver in the presence of the whole dung beetle community, species richness gained in importance when large dung beetles were excluded. In the most perturbed state of the system with no dung beetles present, temperature was the sole driver of dung decomposition. In conclusion, abiotic drivers become more important predictors of ecosystem services the more the study system is disturbed. In this dissertation, I exemplify that the drivers of diversity along broad-scale climatic gradients on Mt. Kilimanjaro depend on the thermoregulatory strategy of organisms. While mammal diversity was mainly impacted by food/energy resources, dung beetle diversity was mainly limited by temperature. I also demonstrate the importance of protected areas for the preservation of large mammal biodiversity. Furthermore, I show that large dung beetles were disproportionately important for dung decomposition as dung decomposition significantly decreased when large dung beetles were excluded. As regards land use, I did not detect an overall effect on dung beetle and mammal diversity nor on dung beetle-mediated dung decomposition. However, for the most specialised mammal trophic guilds and dung beetle functional groups, negative land use effects were already visible. Even though the current moderate levels of land use on Mt. Kilimanjaro can sustain high levels of biodiversity, the pressure of the human population on Mt. Kilimanjaro is increasing and further land use intensification poses a great threat to biodiversity. In synergy wih land use, climate change is jeopardizing current patterns and levels of biodiversity with the potential to displace communities, which may have unpredictable consequences for ecosystem service provisioning in the future. N2 - Gradienten der Biodiversität, wie der Breitengradient der Artenvielfalt, gehören zu den bestbeschriebenen Mustern in der Ökologie. Dennoch bleiben die Mechanismen, die diese Gradienten steuern, unzureichend untersucht. Bergmassive eignen sich aufgrund ihrer hohen Artenvielfalt, ihrer räumlichen Begrenzung, der gleichmäßigen Veränderung abiotischer Faktoren mit der Höhe und ihres weltweiten Auftretens optimal zur Erforschung der Triebkräfte globaler Biodiversitätsmuster. Jedoch werden Gebirgs-Ökosysteme vermehrt durch menschliche Landnutzung und den Klimawandel bedroht. Da der Wissenstand über die Auswirkungen solcher Veränderungen auf die Biodiversität von Bergmassiven und zugehörigen Ökosystemdienstleistungen gering ist, nimmt die Erforschung von Höhengradienten auch aus der Perspektive des Artenschutzes eine besondere Bedeutung ein. In Ergänzung zur traditionellen, auf Taxonomie beruhenden Biodiversitätsforschung, wird die Wichtigkeit der Untersuchung funktioneller Merkmale und deren Bedeutung für Beziehungen zwischen Biodiversität und Ökosystemfunktionen (BEF) zunehmend anerkannt. In meiner Doktorarbeit untersuche ich entlang von Höhen- und Landnutzungsgradienten am Kilmandscharo (Tansania) die Muster und Triebkräfte der Artenvielfalt von Säugetieren und Dungkäfern als auch die Faktoren, die den Dungabbau durch Dungkäfer unter verschiedenen Aussterbe-Szenarien bestimmen. Säugetiere sind nicht nur charismatisch, sie nehmen auch wichtige Rollen in Ökosystemen ein. So erfüllen Säugetiere wichtige Ökosystemdienstleistungen wie die Verbreitung von Samen und sind maßgeblich am Nährstoffkreislauf durch den Umsatz großer Mengen von Biomasse beteiligt. Im zweiten Kapitel dieser Arbeit stelle ich dar, dass die Diversität und Biomasse der Säugetiergemeinschaft am Kilimandscharo eine unimodale Verteilung mit der Höhe aufweist. Dieses Muster wurde vor allem durch die Nettoprimärproduktion, ein Maß für die Nahrungsverfügbarkeit der Säugetiere, und den Schutzstatus der Untersuchungsgebiete bestimmt. Aufgrund ihrer Größe und Endothermie kann man schlussfolgern, dass für Säugetiere, im Unterschied zu den meisten Arthropoden, Nahrungsverfügbarkeit die Triebkraft der Diversität darstellt. Meine Resultate bestätigen diese Vorhersage. Die signifikant höhere Diversität und Biomasse der Säugetiere im Kilmandscharo Nationalpark und in anderen geschützten Gebieten unterstreicht die Wichtigkeit des Habitatschutzes für den Erhalt der Artenvielfalt großer Säugetiere in tropischen Bergmassiven. Dungkäfer stehen in enger Beziehung zu Säugetieren, da sie Säugetierdung als Nahrungs- und Nistmaterial benötigen. Dungkäfer übernehmen ebenfalls wichtige Ökosystemdienstleistungen: Sie spielen eine bedeutende Rolle im Nährstoffkreislauf und tragen entscheidend zur Bioturbation, der sekundären Verbreitung von Samen und der Unterdrückung von Schädlingen bei. Im dritten Kapitel weise ich nach, dass die Artenvielfalt der Dungkäfer mit der Höhe abnimmt, während die Abundanz der Käfer eine eingipfelige Verteilung zeigt. Im Unterschied zu den Säugetieren wurde die Diversität der Dungkäfer vor allem durch die Temperatur gesteuert. Obwohl ich versuchte, die vorhandenen Dungressourcen der Säugetiere möglichst genau durch die Berechung des Kotabsatzes zu quantifizieren, stellte ich keinen Einfluss von Ressourcenverfügbarkeit auf die Dungkäfer-Diversität fest. Stattdessen führte eine höhere Temperatur zu erhöhter Dungkäfer-Diversität. Abgesehen von ihrer Rolle als wichtige Ökosystemdienstleister stellen Dungkäfer auch Modellorganismen für BEF-Studien dar, da sie eine leicht zu quantifizierende Ressource benötigen. Im vierten Kapitel untersuche ich den Dungabbau von Dungkäfern entlang des Höhengradienten mithilfe eines Ausschlussexperiments: in der Gegenwart der gesamten Dungkäfergemeinschaft, unter dem Ausschluss großer Dungkäfer und in der Abwesenheit aller Dungkäfer. Der Dungabbau war am größten, wenn der Abbau durch die gesamte Dungkäfergemeinschaft erfolgen konnte. Waren nur kleine Dungkäfer anwesend, waren die Dungabbauraten deutlich geringer als in der Gegenwart großer Dungkäfer, während sie im Falle des Ausschlusses aller Dungkäfer minimal wurden. Außerdem konnte ich nachweisen, dass die Triebkräfte des Dungabbaus von dem Zustand der Dungkäfergemeinschaft abhingen. Während die mittlere Körpergröße von Dungkäfern der wichtigste Faktor darstellte, wenn die Lebensgemeinschaft vollständig war, erlangte die Artenvielfalt an Bedeutung, wenn große Dungkäfer abwesend waren. Im gestörtesten Zustand des Systems, wo der Dungabbau ohne Dungkäfer erfolgte, war Temperatur der einzige Faktor, der den Dungabbau bestimmte. Abiotische Faktoren nehmen an Wichtigkeit als Triebkräfte von Ökosystemdienstleistungen zu, je mehr das System gestört ist. Zusammenfassend wird in dieser Dissertation gezeigt, dass die Triebkräfte der Artenvielfalt entlang weitreichender klimatischer Gradienten am Kilimandscharo von der thermoregulatorischen Strategie der Organismen abhängen. Während die Diversität von Säugetieren vor allem durch die Nahrungsverfügbarkeit beeinflusst wurde, wurde die Dungkäfer-Diversität vor allem durch die Temperatur gesteuert. Außerdem sind geschützte Flächen für den Erhalt der Artenvielfalt großer Säugetiere unerlässlich. Weiterhin veranschauliche ich die herausragende Bedeutung großer Dungkäfer für den Dungabbau, da letzterer deutlich abnahm, wenn große Dungkäfer ausgeschlossen wurden. Betreffend der Landnutzung war insgesamt kein Einfluss auf die Dungkäfer- oder Säugetier-Diversität oder den Dungabbau durch Dungkäfer feststellbar. Anders sah es auf Ebene der am meisten spezialisierten trophischen Gilden der Säugetiere und funktionellen Gruppen der Dungkäfer aus: Hier waren bereits negative Auswirkungen sichtbar. Obwohl unter dem derzeitigen gemäßigten Ausmaß der Landnutzung am Kilimandscharo eine hohe Artenvielfalt aufrechterhalten werden kann, steigt der Druck durch das Bevölkerungswachstum, und eine zunehmende Intensivierung der Landwirtschaft stellt eine große Bedrohung für die Biodiversität dar. Im Zusammenspiel mit der Landnutzung gefährdet der Klimawandel das Niveau und die Verteilung der Biodiversität, mit dem Potential, Gemeinschaften von Organismen zu verdrängen, was unvorhersagbare Auswirkungen auf die Bereitstellung von Ökosystemdienstleistungen in der Zukunft haben könnte. KW - Kilimandscharo KW - Biodiversität KW - Säugetiere KW - Zersetzer KW - Scarabaeidae KW - Höhengradient KW - Landnutzungsgradient KW - Arten-Energy-Theory KW - Ökologie KW - Diversität KW - elevational gradient KW - land use KW - species-energy-theory KW - ecology KW - ecosystem service Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191950 ER - TY - JOUR A1 - Ganuza, Cristina A1 - Redlich, Sarah A1 - Uhler, Johannes A1 - Tobisch, Cynthia A1 - Rojas-Botero, Sandra A1 - Peters, Marcell K. A1 - Zhang, Jie A1 - Benjamin, Caryl S. A1 - Englmeier, Jana A1 - Ewald, Jörg A1 - Fricke, Ute A1 - Haensel, Maria A1 - Kollmann, Johannes A1 - Riebl, Rebekka A1 - Uphus, Lars A1 - Müller, Jörg A1 - Steffan-Dewenter, Ingolf T1 - Interactive effects of climate and land use on pollinator diversity differ among taxa and scales JF - Science Advances N2 - Changes in climate and land use are major threats to pollinating insects, an essential functional group. Here, we unravel the largely unknown interactive effects of both threats on seven pollinator taxa using a multiscale space-for-time approach across large climate and land-use gradients in a temperate region. Pollinator community composition, regional gamma diversity, and community dissimilarity (beta diversity) of pollinator taxa were shaped by climate-land-use interactions, while local alpha diversity was solely explained by their additive effects. Pollinator diversity increased with reduced land-use intensity (forest < grassland < arable land < urban) and high flowering-plant diversity at different spatial scales, and higher temperatures homogenized pollinator communities across regions. Our study reveals declines in pollinator diversity with land-use intensity at multiple spatial scales and regional community homogenization in warmer and drier climates. Management options at several scales are highlighted to mitigate impacts of climate change on pollinators and their ecosystem services. KW - climate KW - land use KW - pollinator diversity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301303 VL - 8 IS - 18 ER - TY - JOUR A1 - Fricke, Ute A1 - Steffan-Dewenter, Ingolf A1 - Zhang, Jie A1 - Tobisch, Cynthia A1 - Rojas-Botero, Sandra A1 - Benjamin, Caryl S. A1 - Englmeier, Jana A1 - Ganuza, Cristina A1 - Haensel, Maria A1 - Riebl, Rebekka A1 - Uhler, Johannes A1 - Uphus, Lars A1 - Ewald, Jörg A1 - Kollmann, Johannes A1 - Redlich, Sarah T1 - Landscape diversity and local temperature, but not climate, affect arthropod predation among habitat types JF - PLoS ONE N2 - Arthropod predators are important for ecosystem functioning by providing top-down regulation of insect herbivores. As predator communities and activity are influenced by biotic and abiotic factors on different spatial scales, the strength of top-down regulation (‘arthropod predation’) is also likely to vary. Understanding the combined effects of potential drivers on arthropod predation is urgently needed with regard to anthropogenic climate and land-use change. In a large-scale study, we recorded arthropod predation rates using artificial caterpillars on 113 plots of open herbaceous vegetation embedded in contrasting habitat types (forest, grassland, arable field, settlement) along climate and land-use gradients in Bavaria, Germany. As potential drivers we included habitat characteristics (habitat type, plant species richness, local mean temperature and mean relative humidity during artificial caterpillar exposure), landscape diversity (0.5–3.0-km, six scales), climate (multi-annual mean temperature, ‘MAT’) and interactive effects of habitat type with other drivers. We observed no substantial differences in arthropod predation rates between the studied habitat types, related to plant species richness and across the Bavarian-wide climatic gradient, but predation was limited when local mean temperatures were low and tended to decrease towards higher relative humidity. Arthropod predation rates increased towards more diverse landscapes at a 2-km scale. Interactive effects of habitat type with local weather conditions, plant species richness, landscape diversity and MAT were not observed. We conclude that landscape diversity favours high arthropod predation rates in open herbaceous vegetation independent of the dominant habitat in the vicinity. This finding may be harnessed to improve top-down control of herbivores, e.g. agricultural pests, but further research is needed for more specific recommendations on landscape management. The absence of MAT effects suggests that high predation rates may occur independent of moderate increases of MAT in the near future. KW - arthropod predators KW - habitat types KW - landscape diversity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301292 VL - 17 IS - 4 ER - TY - JOUR A1 - Fricke, Ute A1 - Redlich, Sarah A1 - Zhang, Jie A1 - Tobisch, Cynthia A1 - Rojas-Botero, Sandra A1 - Benjamin, Caryl S. A1 - Englmeier, Jana A1 - Ganuza, Cristina A1 - Riebl, Rebekka A1 - Uhler, Johannes A1 - Uphus, Lars A1 - Ewald, Jörg A1 - Kollmann, Johannes A1 - Steffan-Dewenter, Ingolf T1 - Plant richness, land use and temperature differently shape invertebrate leaf-chewing herbivory on plant functional groups JF - Oecologia N2 - Higher temperatures can increase metabolic rates and carbon demands of invertebrate herbivores, which may shift leaf-chewing herbivory among plant functional groups differing in C:N (carbon:nitrogen) ratios. Biotic factors influencing herbivore species richness may modulate these temperature effects. Yet, systematic studies comparing leaf-chewing herbivory among plant functional groups in different habitats and landscapes along temperature gradients are lacking. This study was conducted on 80 plots covering large gradients of temperature, plant richness and land use in Bavaria, Germany. We investigated proportional leaf area loss by chewing invertebrates (‘herbivory’) in three plant functional groups on open herbaceous vegetation. As potential drivers, we considered local mean temperature (range 8.4–18.8 °C), multi-annual mean temperature (range 6.5–10.0 °C), local plant richness (species and family level, ranges 10–51 species, 5–25 families), adjacent habitat type (forest, grassland, arable field, settlement), proportion of grassland and landscape diversity (0.2–3 km scale). We observed differential responses of leaf-chewing herbivory among plant functional groups in response to plant richness (family level only) and habitat type, but not to grassland proportion, landscape diversity and temperature—except for multi-annual mean temperature influencing herbivory on grassland plots. Three-way interactions of plant functional group, temperature and predictors of plant richness or land use did not substantially impact herbivory. We conclude that abiotic and biotic factors can assert different effects on leaf-chewing herbivory among plant functional groups. At present, effects of plant richness and habitat type outweigh effects of temperature and landscape-scale land use on herbivory among legumes, forbs and grasses. KW - climate KW - ecosystem function KW - land use KW - plant guilds KW - plant–insect interactions Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325079 VL - 199 IS - 2 ER - TY - THES A1 - Fricke, Ute T1 - Herbivory, predation and pest control in the context of climate and land use T1 - Herbivorie, Prädation und Schädlingskontrolle im Kontext von Klima und Landnutzung N2 - Chapter 1 – General introduction Anthropogenic land-use and climate change are the major drivers of the global biodiversity loss. Yet, biodiversity is essential for human well-being, as we depend on the availability of potable water, sufficient food and further benefits obtained from nature. Each species makes a somewhat unique contribution to these ecosystem services. Furthermore, species tolerate environmental stressors, such as climate change, differently. Thus, biodiversity is both the "engine" and the "insurance" for human well-being in a changing climate. Here, I investigate the effects of temperature and land use on herbivory (Chapter 2), predation (Chapter 3) and pest control (Chapter 4), and at the same time identify features of habitats (e.g. plant richness, proximity to different habitat types) and landscapes (e.g. landscape diversity, proportion of oilseed rape area) as potential management targets in an adaptation strategy to climate change. Finally, I discuss the similarities and differences between factors influencing herbivory, predation and pest control, while placing the observations in the context of climate change as a multifaceted phenomenon, and highlighting starting points for sustainable insect pest management (Chapter 5). Chapter 2 – Plant richness, land use and temperature differently shape invertebrate leaf-chewing herbivory on major plant functional groups Invertebrate herbivores are temperature-sensitive. Rising temperatures increase their metabolic rates and thus their demand for carbon-rich relative to protein-rich resources, which can lead to changes in the diets of generalist herbivores. Here, we quantified leaf-area loss to chewing invertebrates among three plant functional groups (legumes, non-leguminous forbs and grasses), which largely differ in C:N (carbon:nitrogen) ratio. This reseach was conducted along spatial temperature and land-use gradients in open herbaceous vegetation adjacent to different habitat types (forest, grassland, arable field, settlement). Herbivory largely differed among plant functional groups and was higher on legumes than forbs and grasses, except in open areas in forests. There, herbivory was similar among plant functional groups and on legumes lower than in grasslands. Also the presence of many plant families lowered herbivory on legumes. This suggests that open areas in forests and diverse vegetation provide certain protection against leaf damage to some plant families (e.g. legumes). This could be used as part of a conservation strategy for protected species. Overall, the effects of the dominant habitat type in the vicinity and diverse vegetation outweighed those of temperature and large-scale land use (e.g. grassland proportion, landscape diversity) on herbivory of legumes, forbs and grasses at the present time. Chapter 3 – Landscape diversity and local temperature, but not climate, affect arthropod predation among habitat types Herbivorous insects underlie top-down regulation by arthropod predators. Thereby, predation rates depend on predator community composition and behaviour, which is shaped by temperature, plant richness and land use. How the interaction of these factors affects the regulatory performance of predators was unknown. Therefore, we assessed arthropod predation rates on artificial caterpillars along temperature, and land-use gradients. On plots with low local mean temperature (≤ 7°C) often not a single caterpillar was attacked, which may be due to the temperature-dependent inactivity of arthropods. However, multi-annual mean temperature, plant richness and the dominant habitat type in the vicinity did not substantially affect arthropod predation rates. Highest arthropod predation rates were observed in diverse landscapes (2-km scale) independently of the locally dominanting habitat type. As landscape diversity, but not multi-annual mean temperature, affected arthropod predation rates, the diversification of landscapes may also support top-down regulation of herbivores independent of moderate increases of multi-annual mean temperature in the near future. Chapter 4 – Pest control and yield of winter oilseed rape depend on spatiotemporal crop-cover dynamics and flowering onset: implications for global warming Winter oilseed rape is an important oilseed crop in Europe, yet its seed yield is diminished through pests such as the pollen beetle and stem weevils. Damage from pollen beetles depends on pest abundances, but also on the timing of infestation relative to crop development as the bud stage is particularly vulnerable. The development of both oilseed rape and pollen beetles is temperature-dependent, while temperature effects on pest abundances are yet unknown, which brings opportunities and dangers to oilseed rape cropping under increased temperatures. We obtained measures of winter oilseed rape (flowering time, seed yield) and two of its major pests (pollen beetle, stem weevils) for the first time along both land-use and temperature gradients. Infestation with stem weevils was not influenced by any temperature or land-use aspect considered, and natural pest regulation of pollen beetles in terms of parasitism rates of pollen beetle larvae was low (< 30%), except on three out of 29 plots. Nonetheless, we could identify conditions favouring low pollen beetle abundances per plant and high seed yields. Low pollen beetle densities were favoured by a constant oilseed rape area relative to the preceding year (5-km scale), whereas a strong reduction in area (> 40%) caused high pest densities (concentration effect). This occurred more frequently in warmer regions, due to drought around sowing, which contributed to increased pollen beetle numbers in those regions. Yet, in warmer regions, oilseed rape flowered early, which possibly led to partial escape from pollen beetle infestation in the most vulnerable bud stage. This is also suggested by higher seed yields of early flowering oilseed rape fields, but not per se at higher temperatures. Thus, early flowering (e.g. cultivar selection) and the interannual coordination of oilseed rape area offer opportunities for environmental-friendly pollen beetle management. Chapter 5 – General discussion Anthropogenic land-use and climate change are major threats to biodiversity, and consequently to ecosystem functions, although I could show that ecosystem functions such as herbivory and predation barely responded to temperature along a spatial gradient at present time. Yet, it is important to keep several points in mind: (i) The high rate of climate warming likely reduces the time that species will have to adapt to temperature in the future; (ii) Beyond mean temperatures, many aspects of climate will change; (iii) The compensation of biodiversity loss through functional redundancy in arthropod communities may be depleted at some point; (iv) Measures of ecosystem functions are limited by methodological filters, so that changes may be captured incompletely. Although much uncertainty of the effects of climate and land-use change on ecosystem functions remains, actions to halt biodiversity loss and to interfere with natural processes in an environmentally friendly way, e.g. reduction of herbivory on crops, are urgently needed. With this thesis, I contribute options to the environment-friendly regulation of herbivory, which are at least to some extent climate resilient, and at the same time make a contribution to halt biodiversity loss. Yet, more research and a transformation process is needed to make human action more sustainable. In terms of crop protection, this means that the most common method of treating pests with fast-acting pesticides is not necessarily the most sustainable. To realize sustainable strategies, collective efforts will be needed targeted at crop damage prevention through reducing pest populations and densities in the medium to long term. The sooner we transform human action from environmentally damaging to biodiversity promoting, the higher is our insurance asset that secures human well-being under a changing climate. N2 - Kapitel 1 – Allgemeine Einleitung Intensive Landnutzung und Klimawandel sind die Hauptursachen des globalen Rückgangs der biologischen Vielfalt. Diese ist jedoch wichtig für das menschliche Wohlergehen, da wir von der Verfügbarkeit von trinkbarem Wasser, Nahrungsmitteln und weiteren Leistungen der Natur abhängig sind. Dazu leistet jede Art einen gewissermaßen einzigartigen Beitrag. Darüber hinaus kommen verschiedene Arten unterschiedlich gut mit umweltbedingten Stressfaktoren wie z.B. dem Klimawandel aus. Dadurch ist die biologische Vielfalt sowohl der "Motor" als auch die "Versicherung" für das menschliche Wohlergehen in einem sich verändernden Klima. Hier untersuche ich die Auswirkungen von Temperatur und Landnutzung auf Pflanzenfraß („Herbivorie“, Kapitel 2), Räuber-Beute-Beziehungen („Prädation“, Kapitel 3) und die Regulation von Schädlingen im Raps (Kapitel 4), und betrachte gleichzeitig Merkmale von Lebensräumen (z.B. Reichtum an Pflanzenarten und -familien, Nähe zu unterschiedlichen Lebensraumtypen) und Landschaften (z.B. Vielfältigkeit der Landschaft, Anteil der Rapsanbaufläche) als mögliche Ansatzpunkte für Anpassungsstrategien an den Klimawandel. Abschließend erörtere ich die Gemeinsamkeiten und Unterschiede der Faktoren, die Herbivorie, Prädation und Schädlingskontrolle beeinflussen, ordne diese in den Kontext des Klimawandels als vielseitiges Phänomen ein, und betone mögliche Ansatzpunkte für den nachhaltigen Pflanzenschutz (Kapitel 5). Kapitel 2 – Pflanzenreichtum, Landnutzung und Temperatur beeinflussen die Schädigung verschiedener funktioneller Pflanzengruppen durch blattfressende Wirbellose unterschiedlich Wirbellose Pflanzenfresser (z.B. Grashüpfer) sind temperaturempfindlich. Steigende Temperaturen erhöhen ihre Stoffwechselrate und damit ihren Bedarf an kohlenstoffreichen im Vergleich zu proteinreichen Ressourcen, was zu einer Ernährungsumstellung von pflanzenfressenden Generalisten führen kann. Hier erfassten wir die Blattschädigung durch kauende Wirbellose an drei funktionellen Pflanzengruppen (Leguminosen, andere krautige Pflanzen, Gräser), welche sich in ihrem C:N (Kohlenstoff:Stickstoff) Verhältnis unterscheiden. Die Erfassung führten wir entlang von räumlichen Temperatur- und Landnutzungsgradienten in offener krautiger Vegetation angrenzend an verschiedene Lebensraumtypen (Forst, Grünland, Ackerfläche, Siedlung) durch. Die Blattschädigung verschiedener funktioneller Pflanzengruppen variierte stark und war an Leguminosen höher als an krautigen Pflanzen oder Gräsern, außer auf Offenflächen im Forst. Dort waren die Blattschädigungen der funktionellen Pflanzengruppen ähnlich und die Schädigung an Leguminosen niedriger als im Grünland. Auch das Vorhandensein vieler Pflanzenfamilien verringerte die Blattschädigung an Leguminosen. Dies legt nahe, dass Offenflächen im Forst und vielfältige Vegetation einen gewissen Schutz gegen Blattschädigung an manchen Pflanzenfamilien (z.B. Leguminoses) bieten. Dies könnte im Rahmen des Artenschutzes einen Beitrag zum Erhalt geschützter Arten leisten. Insgesamt überwogen die Auswirkungen des vorherrschenden Lebensraumtyps in der näheren Umgebung und vielfältiger Vegetation zum jetzigen Zeitpunkt den Einfluss von Temperatur und großräumiger Landnutzung (z.B. Grünlandanteil, Vielfältigkeit der Landschaft) auf die Blattschädigung an Leguminosen, krautigen Pflanzen und Gräsern. Kapitel 3 – Vielfältige Landschaften und die lokale Temperatur, jedoch nicht das Klima, beeinflussen die Prädationsleistung von Gliederfüßern in verschiedenen Lebensräumen Pflanzenfressende Insekten unterliegen der Top-Down-Regulation durch räuberisch-lebende Gliederfüßer. Der Beitrag, den diese zur Top-Down-Regulation leisten hängt jedoch unter anderem von der Zusammensetzung ihrer Artengemeinschaft und von ihrem Verhalten ab. Beides wird durch Temperatur, Pflanzenreichtum und Landnutzung beeinflusst. Wie sich das Zusammenspiel dieser Faktoren auf die Regulationsleistung von Räubern auswirkt war bis dato unbekannt. Deshalb untersuchten wir die Attackierung von räuberischen Gliederfüßern auf Beuteattrappen (Knetraupen) entlang von Temperatur- und Landnutzungsgradienten. Auf Studienflächen mit niedriger lokaler Mitteltemperatur (≤ 7°C) wurde oft keine einzige Knetraupe attackiert, was sich möglicherweise auf die temperatureabhängige Inaktivität von Gliederfüßern zurückführen lässt. Die Durchschnittstemperatur im mehrjährigen Mittel, das Pflanzenreichtum und der vorherrschende Lebensraumtyp hingegen zeigten keinen substanziellen Einfluss auf die Attackierung der Knetraupen durch räuberische Gliederfüßer. Am höchsten waren die Attackierungsraten in vielfältigen Landschaften (2-km Skala) unabhängig vom lokal vorherrschenden Lebensraumtyp. Da vielfältige Landschaften, nicht jedoch die Durchschnittstemperatur im mehrjährigen Mittel, die Attackierungsraten beeinflussten, können Maßnahmen zur Diversifizierung von Landschaften möglicherweise unabhängig von moderat steigenden mehrjährigen Mitteltemperaturen in naher Zukunft die Top-Down-Regulation von Pflanzenfressern begünstigen. Kapitel 4 – Schädlingskontrolle und Ertrag im Winterraps sind von der räumlich-zeitlichen Dynamik der Rapsanbaufläche sowie vom Blühzeitpunkt abhängig: Implikationen für die globale Erwärmung Winterraps ist eine wichtige Ölpflanze in Europa, doch die Erträge werden insbesondere durch Schädlinge wie Rapsglanzkäfer und Stängelrüssler gemindert. Die Schädigung durch den Rapsglanzkäfer ist abhängig vom Schädlingsaufkommen, aber auch vom Befallszeitpunkt in Bezug zum Entwicklungsstadium des Winterraps, wobei das Knospenstadium besonders empfindlich ist. Die Entwicklung von Raps und Rapsglanzkäfer ist temperaturabhängig, wohingegen Temperatureffekte auf Schädlingsabundanzen unbekannt sind, sodass höhere Temperaturen sowohl Chancen als auch Gefahren mitsichbringen. Wir führten Messungen an Winterrapspflanzen (Blühzeitpunkt, Samenertrag) und zwei seiner Hauptschädlinge (Rapsglanzkäfer, Stängelrüssler) erstmalig entlang von Landnutzungs- und Temperaturgradienten durch. Der Befall mit Stängelrüsslern wurde nicht von den untersuchten Temperatur- und Landschaftsparametern beeinflusst und die natürliche Schädlingskontrolle von Rapsglanzkäferlarven in Bezug auf Parasitierungsraten war mit Ausnahme von drei von 29 Standorten gering (< 30%). Nichtsdestotrotz konnten wir Bedingungen identifizieren, die niedrige Befallszahlen mit Rapsglanzkäfern und hohe Samenerträge begünstigen. Geringe Rapsglanzkäferdichten wurden durch eine konstante Rapsanbaufläche relativ zum Vorjahr (5-km Skala) begünstigt, wohingegen eine starke Reduktion in der Anbaufläche (> 40%) zu hohem Befall führte (Konzentrationseffekt). Aufgrund von Trockenheit in warmen Regionen rund um den Saattermin trat dies häufiger in warmen Regionen auf, was zu einem stärkeren Befall mit Rapsglanzkäfern in diesen Regionen beitrug. In wärmeren Regionen kam der Raps jedoch auch früher zur Blüte, was es ihm vermutlich ermöglichte, dem Rapsglanzkäferbefall im empfindlichsten Knospenstadium einigermaßen zu entgehen. Dies zeigte sich auch daran, dass eine frühe Blüte, nicht jedoch höhere Temperaturen, zu höheren Erträgen führte. Eine frühe Blüte (z.B. durch Sortenwahl) und die jahresübergreifende Koordination der Rapsanbaufläche bieten Möglichkeiten für die umweltfreundliche Schädlingskontrolle von Rapsglanzkäfern. Kapitel 5 – Allgemeine Diskussion Der durch den Menschen verursachte Landnutzungs- und Klimawandel stellt eine große Gefahr für die biologische Vielfalt und damit auch für die Funktionalität von Ökosystemen dar, obwohl ich zeigen konnte, dass natürliche Abläufe wie Pflanzenfraß und Räuber-Beute-Beziehungen kaum auf Temperaturunterschiede entlang eines räumlichen Gradients reagierten. Dennoch ist es wichtig mehrere Punkte zu beachten: (i) Die Rate, mit der sich die Erde erwärmt, wird Arten in Zukunft weniger Zeit lassen sich an die herschende Temperatur anzupassen; (ii) Neben der Erderwärmung werden sich viele weitere Aspekte des Klimas verändern; (iii) Die Aufrechterhaltung von natürlichen Abläufen unter Artenverlust durch funktionale Redundanz könnte irgendwann erschöpft sein; (iv) Die Messung natürlicher Abläufe ist durch methodische Filter limitiert, sodass Änderungen unter Umständen unvollständig abgebildet werden. Obwohl Ungewissheiten bezüglich der Auswirkungen des Landnutzungs- und Klimawandels auf natürliche Abläufe bestehen bleiben, werden dringlich Maßnahmen benötigt, die zum Erhalt der biologischen Vielfalt beitragen und die es ermöglichen umweltfreundlich in natürliche Abläufe einzugreifen wie z.B. die Abmilderung von Pflanzenfraß an Kulturpflanzen. Mit dieser Doktorarbeit, zeige ich Ansatzpunkte für Maßnahmen zur umweltfreundlichen Regulation von Pflanzenfraß auf, die zumindest zu einem gewissen Grad Klima-resilient sind und zugleich einen Beitrag zur Eindämmung des Artensterbens leisten. Um das menschliche Handeln nachhaltiger zu machen, bedarf es neben weiterer Forschung eines Transformationsprozesses. Für den Pflanzenschutz bedeutet dies, dass die gängigste Methode der Schädlingsbekämpfung mit schnell wirkenden Pestiziden nicht unbedingt die nachhaltigste ist. Um nachhaltige Strategien zu realisieren werden gemeinschaftliche Bemühungen nötig sein, die sich der Vorbeugung von Schäden an Kulturpflanzen durch die mittel- bis langfristigen Reduktion von Schädlingspopulationen und -dichten widmen. Je früher wir das menschliche Handeln von umweltschädigend zu biodiversitätsfördernd umwandeln, desto größer ist unser “Versicherungswert”, der das menschliche Wohlergehen in einem sich änderndem Klima gewährleistet. KW - Ökologie KW - Schädlingsbekämpfung KW - Landnutzung KW - Klimaänderung KW - Prädation KW - Pest management KW - Predation KW - Herbivory KW - land use KW - climate Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287328 ER - TY - JOUR A1 - Floren, Andreas A1 - Linsenmair, Karl Eduard A1 - Müller, Tobias T1 - Diversity and functional relevance of canopy arthropods in Central Europe JF - Diversity N2 - Although much is known about the ecology and functional importance of canopy arthropods in temperate forests, few studies have tried to assess the overall diversity and investigate the composition and dynamics of tree-specific communities. This has impeded a deeper understanding of the functioning of forests, and of how to maintain system services. Here, we present the first comprehensive data of whole arthropod communities, collected by insecticidal knockdown (fogging) from 1159 trees in 18 study areas in Central Europe during the last 25 years. The data includes 3,253,591 arthropods from 32 taxa (order, suborder, family) collected on 24 tree species from 18 genera. Fogging collects free-living, ectophytic arthropods in approximately the same number as they occur in the trees. To our knowledge, these are the most comprehensive data available today on the taxonomic composition of arboreal fauna. Assigning all arthropods to their feeding guild provided a proxy of their functional importance. The data showed that the canopy communities were regularly structured, with a clear dominance hierarchy comprised of eight ‘major taxa’ that represented 87% of all arthropods. Despite significant differences in the proportions of taxa on deciduous and coniferous trees, the composition of the guilds was very similar. The individual tree genera, on the other hand, showed significant differences in guild composition, especially when different study areas and years were compared, whereas tree-specific traits, such as tree height, girth in breast height or leaf cover, explained little of the overall variance. On the ordinal level, guild composition also differed significantly between managed and primary forests, with a simultaneous low within-group variability, indicating that management is a key factor determining the distribution of biodiversity and guild composition. KW - temperate forests KW - insecticidal knockdown KW - community structure KW - functional diversity KW - guild constancy KW - forest management KW - pristine forests KW - Bialowieza Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285924 SN - 1424-2818 VL - 14 IS - 8 ER - TY - JOUR A1 - Floren, Andreas A1 - Horchler, Peter J. A1 - Müller, Tobias T1 - The impact of the neophyte tree Fraxinus pennsylvanica [Marshall] on beetle diversity under climate change JF - Sustainability N2 - We studied the impact of the neophyte tree Fraxinus pennsylvanica on the diversity of beetles in floodplain forests along the river Elbe in Germany in 2016, 2017 and in 2020, where 80% of all Fraxinus excelsior trees had died following severe droughts. Beetles were collected by insecticidal knock-down from 121 trees (64 F. excelsior and 57 F. pennsylvanica) and identified to 547 species in 15,214 specimens. The trees sampled in 2016 and 2017 showed no signs of drought stress or ash dieback and serve as a reference for the comparison with the 2020 fauna. The data proved that F. excelsior harbours the most diverse beetle community, which differed also significantly in guild composition from F. pennsylvanica. Triggered by extremely dry and long summer seasons, the 2020 ash dieback had profound and forest-wide impacts. Several endangered, red-listed beetle species of Saxonia Anhalt had increased in numbers and became secondary pests on F. excelsior. Diversity decreased whilst numbers of xylobionts increased on all trees, reaching 78% on F. excelsior. Proportions of xylobionts remained constant on F. pennsylvanica. Phytophages were almost absent from all trees, but mycetophages increased on F. pennsylvanica. Our data suggest that as a result of the dieback of F. excelsior the neophyte F. pennsylvanica might become a rescue species for the European Ash fauna, as it provides the second-best habitat. We show how difficult it is to assess the dynamics and the ecological impact of neophytes, especially under conditions similar to those projected by climate change models. The diversity and abundance of canopy arthropods demonstrates their importance in understanding forest functions and maintenance of ecosystem services, illustrating that their consideration is essential for forest adaptation to climate change. KW - forest conversion KW - neophyte trees KW - ash dieback KW - beetle communities KW - ecosystem function Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262223 SN - 2071-1050 VL - 14 IS - 3 ER - TY - JOUR A1 - Fleischmann, Pauline N. A1 - Grob, Robin A1 - Rössler, Wolfgang T1 - Magnetosensation during re-learning walks in desert ants (Cataglyphis nodus) JF - Journal of Comparative Physiology A N2 - At the beginning of their foraging careers, Cataglyphis desert ants calibrate their compass systems and learn the visual panorama surrounding the nest entrance. For that, they perform well-structured initial learning walks. During rotational body movements (pirouettes), naïve ants (novices) gaze back to the nest entrance to memorize their way back to the nest. To align their gaze directions, they rely on the geomagnetic field as a compass cue. In contrast, experienced ants (foragers) use celestial compass cues for path integration during food search. If the panorama at the nest entrance is changed, foragers perform re-learning walks prior to heading out on new foraging excursions. Here, we show that initial learning walks and re-learning walks are structurally different. During re-learning walks, foragers circle around the nest entrance before leaving the nest area to search for food. During pirouettes, they do not gaze back to the nest entrance. In addition, foragers do not use the magnetic field as a compass cue to align their gaze directions during re-learning walk pirouettes. Nevertheless, magnetic alterations during re-learning walks under manipulated panoramic conditions induce changes in nest-directed views indicating that foragers are still magnetosensitive in a cue conflict situation. KW - path integration KW - landmark panorama KW - learning and memory KW - magnetic compass KW - navigation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-266556 SN - 1432-1351 VL - 208 IS - 1 ER - TY - JOUR A1 - Fischer, Thomas A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Prieto-Garcia, Cristian A1 - Klann, Kevin A1 - Pahor, Nikolett A1 - Schülein-Völk, Christina A1 - Baluapuri, Apoorva A1 - Polat, Bülent A1 - Abazari, Arya A1 - Gerhard-Hartmann, Elena A1 - Kopp, Hans-Georg A1 - Essmann, Frank A1 - Rosenfeldt, Mathias A1 - Münch, Christian A1 - Flentje, Michael A1 - Diefenbacher, Markus E. T1 - PTEN mutant non-small cell lung cancer require ATM to suppress pro-apoptotic signalling and evade radiotherapy JF - Cell & Bioscience N2 - Background Despite advances in treatment of patients with non-small cell lung cancer, carriers of certain genetic alterations are prone to failure. One such factor frequently mutated, is the tumor suppressor PTEN. These tumors are supposed to be more resistant to radiation, chemo- and immunotherapy. Results We demonstrate that loss of PTEN led to altered expression of transcriptional programs which directly regulate therapy resistance, resulting in establishment of radiation resistance. While PTEN-deficient tumor cells were not dependent on DNA-PK for IR resistance nor activated ATR during IR, they showed a significant dependence for the DNA damage kinase ATM. Pharmacologic inhibition of ATM, via KU-60019 and AZD1390 at non-toxic doses, restored and even synergized with IR in PTEN-deficient human and murine NSCLC cells as well in a multicellular organotypic ex vivo tumor model. Conclusion PTEN tumors are addicted to ATM to detect and repair radiation induced DNA damage. This creates an exploitable bottleneck. At least in cellulo and ex vivo we show that low concentration of ATM inhibitor is able to synergise with IR to treat PTEN-deficient tumors in genetically well-defined IR resistant lung cancer models. KW - PTEN KW - ATM KW - IR KW - NSCLC KW - radiotherapy KW - cancer KW - DNA-PK KW - PI3K Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-299865 SN - 2045-3701 VL - 12 ER -