TY - JOUR A1 - Garitano-Trojaola, Andoni A1 - Sancho, Ana A1 - Götz, Ralph A1 - Eiring, Patrick A1 - Walz, Susanne A1 - Jetani, Hardikkumar A1 - Gil-Pulido, Jesus A1 - Da Via, Matteo Claudio A1 - Teufel, Eva A1 - Rhodes, Nadine A1 - Haertle, Larissa A1 - Arellano-Viera, Estibaliz A1 - Tibes, Raoul A1 - Rosenwald, Andreas A1 - Rasche, Leo A1 - Hudecek, Michael A1 - Sauer, Markus A1 - Groll, Jürgen A1 - Einsele, Hermann A1 - Kraus, Sabrina A1 - Kortüm, Martin K. T1 - Actin cytoskeleton deregulation confers midostaurin resistance in FLT3-mutant acute myeloid leukemia JF - Communications Biology N2 - The presence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with an unfavorable prognosis. FLT3 inhibitors, such as midostaurin, are used clinically but fail to entirely eradicate FLT3-ITD+AML. This study introduces a new perspective and highlights the impact of RAC1-dependent actin cytoskeleton remodeling on resistance to midostaurin in AML. RAC1 hyperactivation leads resistance via hyperphosphorylation of the positive regulator of actin polymerization N-WASP and antiapoptotic BCL-2. RAC1/N-WASP, through ARP2/3 complex activation, increases the number of actin filaments, cell stiffness and adhesion forces to mesenchymal stromal cells (MSCs) being identified as a biomarker of resistance. Midostaurin resistance can be overcome by a combination of midostaruin, the BCL-2 inhibitor venetoclax and the RAC1 inhibitor Eht1864 in midostaurin-resistant AML cell lines and primary samples, providing the first evidence of a potential new treatment approach to eradicate FLT3-ITD+AML. Garitano-Trojaola et al. used a combination of human acute myeloid leukemia (AML) cell lines and primary samples to show that RAC1-dependent actin cytoskeleton remodeling through BCL2 family plays a key role in resistance to the FLT3 inhibitor, Midostaurin in AML. They showed that by targeting RAC1 and BCL2, Midostaurin resistance was diminished, which potentially paves the way for an innovate treatment approach for FLT3 mutant AML. KW - actin KW - acute myeloid leukaemia Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260709 VL - 4 IS - 1 ER - TY - JOUR A1 - Eisenhuth, Nicole A1 - Vellmer, Tim A1 - Rauh, Elisa T. A1 - Butter, Falk A1 - Janzen, Christian J. T1 - A DOT1B/Ribonuclease H2 Protein Complex Is Involved in R-Loop Processing, Genomic Integrity, and Antigenic Variation in Trypanosoma brucei JF - mbio N2 - The parasite Trypanosoma brucei periodically changes the expression of protective variant surface glycoproteins (VSGs) to evade its host's immune sys-tem in a process known as antigenic variation. One route to change VSG expres-sion is the transcriptional activation of a previously silent VSG expression site (ES), a subtelomeric region containing the VSG genes. Homologous recombination of a different VSG from a large reservoir into the active ES represents another route. The conserved histone methyltransferase DOT1B is involved in transcriptional silencing of inactive ES and influences ES switching kinetics. The molecular machin-ery that enables DOT1B to execute these regulatory functions remains elusive, however. To better understand DOT1B-mediated regulatory processes, we purified DOT1B-associated proteins using complementary biochemical approaches. We iden-tified several novel DOT1B interactors. One of these was the RNase H2 complex, previously shown to resolve RNA-DNA hybrids, maintain genome integrity, and play a role in antigenic variation. Our study revealed that DOT1B depletion results in an increase in RNA-DNA hybrids, accumulation of DNA damage, and ES switch-ing events. Surprisingly, a similar pattern of VSG deregulation was observed in RNase H2 mutants. We propose that both proteins act together in resolving R-loops to ensure genome integrity and contribute to the tightly regulated process of anti-genic variation. KW - DOT1B KW - R-loop KW - antigenic variation KW - chromatin structure KW - genomic integrity Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260698 VL - 12 IS - 6 ER - TY - JOUR A1 - Helmprobst, Frederik A1 - Kneitz, Susanne A1 - Klotz, Barbara A1 - Naville, Magali A1 - Dechaud, Corentin A1 - Volff, Jean-Nicolas A1 - Schartl, Manfred T1 - Differential expression of transposable elements in the medaka melanoma model JF - PLoS One N2 - Malignant melanoma incidence is rising worldwide. Its treatment in an advanced state is difficult, and the prognosis of this severe disease is still very poor. One major source of these difficulties is the high rate of metastasis and increased genomic instability leading to a high mutation rate and the development of resistance against therapeutic approaches. Here we investigate as one source of genomic instability the contribution of activation of transposable elements (TEs) within the tumor. We used the well-established medaka melanoma model and RNA-sequencing to investigate the differential expression of TEs in wildtype and transgenic fish carrying melanoma. We constructed a medaka-specific TE sequence library and identified TE sequences that were specifically upregulated in tumors. Validation by qRT- PCR confirmed a specific upregulation of a LINE and an LTR element in malignant melanomas of transgenic fish. KW - melanoma KW - genomics KW - transposable elements KW - cancer genomics KW - malignant tumors KW - gene prediction KW - human genomics KW - retrotransposons Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260615 VL - 16 IS - 10 ER - TY - JOUR A1 - Njovu, Henry K. A1 - Steffan-Dewenter, Ingolf A1 - Gebert, Friederike A1 - Schellenberger Costa, David A1 - Kleyer, Michael A1 - Wagner, Thomas A1 - Peters, Marcell K. T1 - Plant traits mediate the effects of climate on phytophagous beetle diversity on Mt. Kilimanjaro JF - Ecology N2 - Patterns of insect diversity along elevational gradients are well described in ecology. However, it remains little tested how variation in the quantity, quality, and diversity of food resources influence these patterns. Here we analyzed the direct and indirect effects of climate, food quantity (estimated by net primary productivity), quality (variation in the specific leaf area index, leaf nitrogen to phosphorus and leaf carbon to nitrogen ratio), and food diversity (diversity of leaf traits) on the species richness of phytophagous beetles along the broad elevation and land use gradients of Mt. Kilimanjaro, Tanzania. We sampled beetles at 65 study sites located in both natural and anthropogenic habitats, ranging from 866 to 4,550 m asl. We used path analysis to unravel the direct and indirect effects of predictor variables on species richness. In total, 3,154 phytophagous beetles representing 19 families and 304 morphospecies were collected. We found that the species richness of phytophagous beetles was bimodally distributed along the elevation gradient with peaks at the lowest (˜866 m asl) and upper mid-elevations (˜3,200 m asl) and sharply declined at higher elevations. Path analysis revealed temperature- and climate-driven changes in primary productivity and leaf trait diversity to be the best predictors of changes in the species richness of phytophagous beetles. Species richness increased with increases in mean annual temperature, primary productivity, and with increases in the diversity of leaf traits of local ecosystems. Our study demonstrates that, apart from temperature, the quantity and diversity of food resources play a major role in shaping diversity gradients of phytophagous insects. Drivers of global change, leading to a change of leaf traits and causing reductions in plant diversity and productivity, may consequently reduce the diversity of herbivore assemblages. KW - plant functional traits KW - altitudinal gradient KW - Chrysomelidae KW - Curculionidae KW - diversity gradients KW - elevation gradient KW - functional diversity KW - herbivorous beetles KW - herbivory KW - more-individuals hypothesis KW - phytophagous beetles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257343 VL - 102 IS - 12 ER - TY - JOUR A1 - Audretsch, Christof A1 - Gratani, Fabio A1 - Wolz, Christiane A1 - Dandekar, Thomas T1 - Modeling of stringent-response reflects nutrient stress induced growth impairment and essential amino acids in different Staphylococcus aureus mutants JF - Scientific Reports N2 - Stapylococcus aureus colonises the nose of healthy individuals but can also cause a wide range of infections. Amino acid (AA) synthesis and their availability is crucial to adapt to conditions encountered in vivo. Most S. aureus genomes comprise all genes required for AA biosynthesis. Nevertheless, different strains require specific sets of AAs for growth. In this study we show that regulation inactivates pathways under certain conditions which result in these observed auxotrophies. We analyzed in vitro and modeled in silico in a Boolean semiquantitative model (195 nodes, 320 edges) the regulatory impact of stringent response (SR) on AA requirement in S. aureus HG001 (wild-type) and in mutant strains lacking the metabolic regulators RSH, CodY and CcpA, respectively. Growth in medium lacking single AAs was analyzed. Results correlated qualitatively to the in silico predictions of the final model in 92% and quantitatively in 81%. Remaining gaps in our knowledge are evaluated and discussed. This in silico model is made fully available and explains how integration of different inputs is achieved in SR and AA metabolism of S. aureus. The in vitro data and in silico modeling stress the role of SR and central regulators such as CodY for AA metabolisms in S. aureus. KW - bacteriology KW - cellular signalling networks Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260313 VL - 11 IS - 1 ER - TY - JOUR A1 - Hurd, Paul J. A1 - Grübel, Kornelia A1 - Wojciechowski, Marek A1 - Maleszka, Ryszard A1 - Rössler, Wolfgang T1 - Novel structure in the nuclei of honey bee brain neurons revealed by immunostaining JF - Scientific Reports N2 - In the course of a screen designed to produce antibodies (ABs) with affinity to proteins in the honey bee brain we found an interesting AB that detects a highly specific epitope predominantly in the nuclei of Kenyon cells (KCs). The observed staining pattern is unique, and its unfamiliarity indicates a novel previously unseen nuclear structure that does not colocalize with the cytoskeletal protein f-actin. A single rod-like assembly, 3.7-4.1 mu m long, is present in each nucleus of KCs in adult brains of worker bees and drones with the strongest immuno-labelling found in foraging bees. In brains of young queens, the labelling is more sporadic, and the rod-like structure appears to be shorter (similar to 2.1 mu m). No immunostaining is detectable in worker larvae. In pupal stage 5 during a peak of brain development only some occasional staining was identified. Although the cellular function of this unexpected structure has not been determined, the unusual distinctiveness of the revealed pattern suggests an unknown and potentially important protein assembly. One possibility is that this nuclear assembly is part of the KCs plasticity underlying the brain maturation in adult honey bees. Because no labelling with this AB is detectable in brains of the fly Drosophila melanogaster and the ant Camponotus floridanus, we tentatively named this antibody AmBNSab (Apis mellifera Brain Neurons Specific antibody). Here we report our results to make them accessible to a broader community and invite further research to unravel the biological role of this curious nuclear structure in the honey bee central brain. KW - mushroom body calyx KW - synaptic complexes KW - bodies KW - insect KW - plasticity KW - insights KW - genome KW - model KW - proteins KW - methylation KW - biological techniques KW - cell biology KW - developmental biology KW - molecular biology KW - neuroscience Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260059 VL - 11 ER - TY - JOUR A1 - Pauli, Martin A1 - Paul, Mila M. A1 - Proppert, Sven A1 - Mrestani, Achmed A1 - Sharifi, Marzieh A1 - Repp, Felix A1 - Kürzinger, Lydia A1 - Kollmannsberger, Philip A1 - Sauer, Markus A1 - Heckmann, Manfred A1 - Sirén, Anna-Leena T1 - Targeted volumetric single-molecule localization microscopy of defined presynaptic structures in brain sections JF - Communications Biology N2 - Revealing the molecular organization of anatomically precisely defined brain regions is necessary for refined understanding of synaptic plasticity. Although three-dimensional (3D) single-molecule localization microscopy can provide the required resolution, imaging more than a few micrometers deep into tissue remains challenging. To quantify presynaptic active zones (AZ) of entire, large, conditional detonator hippocampal mossy fiber (MF) boutons with diameters as large as 10 mu m, we developed a method for targeted volumetric direct stochastic optical reconstruction microscopy (dSTORM). An optimized protocol for fast repeated axial scanning and efficient sequential labeling of the AZ scaffold Bassoon and membrane bound GFP with Alexa Fluor 647 enabled 3D-dSTORM imaging of 25 mu m thick mouse brain sections and assignment of AZs to specific neuronal substructures. Quantitative data analysis revealed large differences in Bassoon cluster size and density for distinct hippocampal regions with largest clusters in MF boutons. Pauli et al. develop targeted volumetric dSTORM in order to image large hippocampal mossy fiber boutons (MFBs) in brain slices. They can identify synaptic targets of individual MFBs and measured size and density of Bassoon clusters within individual untruncated MFBs at nanoscopic resolution. KW - mossy fiber synapses KW - CA3 pyrimidal cells KW - CA2+ channels KW - active zone KW - hippocampal KW - release KW - plasticity KW - proteins KW - platform KW - reveals Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259830 VL - 4 ER - TY - JOUR A1 - Pütz, Stephanie M. A1 - Kram, Jette A1 - Rauh, Elisa A1 - Kaiser, Sophie A1 - Toews, Romy A1 - Lueningschroer-Wang, Yi A1 - Rieger, Dirk A1 - Raabe, Thomas T1 - Loss of p21-activated kinase Mbt/PAK4 causes Parkinson-like symptoms in Drosophila JF - Disease Models & Mechanisms N2 - Parkinson's disease (PD) provokes bradykinesia, resting tremor, rigidity and postural instability, and also non-motor symptoms such as depression, anxiety, sleep and cognitive impairments. Similar phenotypes can be induced in Drosophila melanogaster through modification of PD-relevant genes or the administration of PD inducing toxins. Recent studies correlated deregulation of human p21-activated kinase 4 (PAK4) with PD, leaving open the question of a causative relationship of mutations in this gene for manifestation of PD symptoms. To determine whether flies lacking the PAK4 homolog Mushroom bodies tiny (Mbt) show PD-like phenotypes, we tested for a variety of PD criteria. Here, we demonstrate that mbt mutant flies show PD-like phenotypes including age-dependent movement deficits, reduced life expectancy and fragmented sleep. They also react to a stressful situation with higher immobility, indicating an influence of Mbt on emotional behavior. Loss of Mbt function has a negative effect on the number of dopaminergic protocerebral anterior medial (PAM) neurons, most likely caused by a proliferation defect of neural progenitors. The age-dependent movement deficits are not accompanied by a corresponding further loss of PAM neurons. Previous studies highlighted the importance of a small PAM subgroup for age-dependent PD motor impairments. We show that impaired motor skills are caused by a lack of Mbt in this PAM subgroup. In addition, a broader re-expression of Mbt in PAM neurons improves life expectancy. Conversely, selective Mbt knockout in the same cells shortens lifespan. We conclude that mutations in Mbt/PAK4 can play a causative role in the development of PD phenotypes. KW - Sleep fragmentation KW - Life expectancy KW - Emotional behavior KW - Dopaminergic PAM cluster neurons KW - Drosophila KW - Parkinson's disease KW - Mbt KW - PAK4 KW - Negative geotaxis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259222 VL - 14 IS - 6 ER - TY - JOUR A1 - Schmitz, Werner A1 - Koderer, Corinna A1 - El-Mesery, Mohamed A1 - Gobik, Sebastian A1 - Sampers, Rene A1 - Straub, Anton A1 - Kübler, Alexander Christian A1 - Seher, Axel T1 - Metabolic fingerprinting of murine L929 fibroblasts as a cell-based tumour suppressor model system for methionine restriction JF - International Journal of Molecular Sciences N2 - Since Otto Warburg reported in 1924 that cancer cells address their increased energy requirement through a massive intake of glucose, the cellular energy level has offered a therapeutic anticancer strategy. Methionine restriction (MetR) is one of the most effective approaches for inducing low-energy metabolism (LEM) due to the central position in metabolism of this amino acid. However, no simple in vitro system for the rapid analysis of MetR is currently available, and this study establishes the murine cell line L929 as such a model system. L929 cells react rapidly and efficiently to MetR, and the analysis of more than 150 different metabolites belonging to different classes (amino acids, urea and tricarboxylic acid cycle (TCA) cycles, carbohydrates, etc.) by liquid chromatography/mass spectrometry (LC/MS) defines a metabolic fingerprint and enables the identification of specific metabolites representing normal or MetR conditions. The system facilitates the rapid and efficient testing of potential cancer therapeutic metabolic targets. To date, MS studies of MetR have been performed using organisms and yeast, and the current LC/MS analysis of the intra- and extracellular metabolites in the murine cell line L929 over a period of 5 days thus provides new insights into the effects of MetR at the cellular metabolic level. KW - methionine restriction KW - caloric restriction KW - mass spectrometry KW - LC/MS KW - liquid chromatography/mass spectrometry KW - metabolism KW - L929 KW - amino acid Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259198 SN - 1422-0067 VL - 22 IS - 6 ER - TY - JOUR A1 - Peters, Simon A1 - Kaiser, Lena A1 - Fink, Julian A1 - Schumacher, Fabian A1 - Perschin, Veronika A1 - Schlegel, Jan A1 - Sauer, Markus A1 - Stigloher, Christian A1 - Kleuser, Burkhard A1 - Seibel, Juergen A1 - Schubert-Unkmeir, Alexandra T1 - Click-correlative light and electron microscopy (click-AT-CLEM) for imaging and tracking azido-functionalized sphingolipids in bacteria JF - Scientific Reports N2 - Sphingolipids, including ceramides, are a diverse group of structurally related lipids composed of a sphingoid base backbone coupled to a fatty acid side chain and modified terminal hydroxyl group. Recently, it has been shown that sphingolipids show antimicrobial activity against a broad range of pathogenic microorganisms. The antimicrobial mechanism, however, remains so far elusive. Here, we introduce 'click-AT-CLEM', a labeling technique for correlated light and electron microscopy (CLEM) based on the super-resolution array tomography (srAT) approach and bio-orthogonal click chemistry for imaging of azido-tagged sphingolipids to directly visualize their interaction with the model Gram-negative bacterium Neisseria meningitidis at subcellular level. We observed ultrastructural damage of bacteria and disruption of the bacterial outer membrane induced by two azido-modified sphingolipids by scanning electron microscopy and transmission electron microscopy. Click-AT-CLEM imaging and mass spectrometry clearly revealed efficient incorporation of azido-tagged sphingolipids into the outer membrane of Gram-negative bacteria as underlying cause of their antimicrobial activity. KW - antimicrobials KW - biological techniques KW - imaging KW - microbiology KW - microbiology techniques KW - microscopy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259147 VL - 11 IS - 1 ER - TY - JOUR A1 - Heydarian, Motaharehsadat A1 - Schweinlin, Matthias A1 - Schwarz, Thomas A1 - Rawal, Ravisha A1 - Walles, Heike A1 - Metzger, Marco A1 - Rudel, Thomas A1 - Kozjak-Pavlovic, Vera T1 - Triple co-culture and perfusion bioreactor for studying the interaction between Neisseria gonorrhoeae and neutrophils: A novel 3D tissue model for bacterial infection and immunity JF - Journal of Tissue Engineering N2 - Gonorrhea, a sexually transmitted disease caused by the bacteria Neisseria gonorrhoeae, is characterized by a large number of neutrophils recruited to the site of infection. Therefore, proper modeling of the N. gonorrhoeae interaction with neutrophils is very important for investigating and understanding the mechanisms that gonococci use to evade the immune response. We have used a combination of a unique human 3D tissue model together with a dynamic culture system to study neutrophil transmigration to the site of N. gonorrhoeae infection. The triple co-culture model consisted of epithelial cells (T84 human colorectal carcinoma cells), human primary dermal fibroblasts, and human umbilical vein endothelial cells on a biological scaffold (SIS). After the infection of the tissue model with N. gonorrhoeae, we introduced primary human neutrophils to the endothelial side of the model using a perfusion-based bioreactor system. By this approach, we were able to demonstrate the activation and transmigration of neutrophils across the 3D tissue model and their recruitment to the site of infection. In summary, the triple co-culture model supplemented by neutrophils represents a promising tool for investigating N. gonorrhoeae and other bacterial infections and interactions with the innate immunity cells under conditions closely resembling the native tissue environment. KW - Triple co-culture KW - biomimetic 3D tissue model KW - Neisseria gonorrhoeae KW - perfusion-based bioreactor system KW - neutrophil transmigration Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259032 VL - 12 ER - TY - JOUR A1 - Liang, Chunguang A1 - Bencurova, Elena A1 - Psota, Eric A1 - Neurgaonkar, Priya A1 - Prelog, Martina A1 - Scheller, Carsten A1 - Dandekar, Thomas T1 - Population-predicted MHC class II epitope presentation of SARS-CoV-2 structural proteins correlates to the case fatality rates of COVID-19 in different countries JF - International Journal of Molecular Sciences N2 - We observed substantial differences in predicted Major Histocompatibility Complex II (MHCII) epitope presentation of SARS-CoV-2 proteins for different populations but only minor differences in predicted MHCI epitope presentation. A comparison of this predicted epitope MHC-coverage revealed for the early phase of infection spread (till day 15 after reaching 128 observed infection cases) highly significant negative correlations with the case fatality rate. Specifically, this was observed in different populations for MHC class II presentation of the viral spike protein (p-value: 0.0733 for linear regression), the envelope protein (p-value: 0.023), and the membrane protein (p-value: 0.00053), indicating that the high case fatality rates of COVID-19 observed in some countries seem to be related with poor MHC class II presentation and hence weak adaptive immune response against these viral envelope proteins. Our results highlight the general importance of the SARS-CoV-2 structural proteins in immunological control in early infection spread looking at a global census in various countries and taking case fatality rate into account. Other factors such as health system and control measures become more important after the early spread. Our study should encourage further studies on MHCII alleles as potential risk factors in COVID-19 including assessment of local populations and specific allele distributions. KW - COVID-19 KW - population coverage KW - MHC II KW - MHC I KW - B-cell KW - T-cell KW - epitope mapping KW - lethality rate KW - infection spread KW - SARS-CoV-2 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258936 SN - 1422-0067 VL - 22 IS - 5 ER - TY - JOUR A1 - Meir, Michael A1 - Kannapin, Felix A1 - Diefenbacher, Markus A1 - Ghoreishi, Yalda A1 - Kollmann, Catherine A1 - Flemming, Sven A1 - Germer, Christoph-Thomas A1 - Waschke, Jens A1 - Leven, Patrick A1 - Schneider, Reiner A1 - Wehner, Sven A1 - Burkard, Natalie A1 - Schlegel, Nicolas T1 - Intestinal epithelial barrier maturation by enteric glial cells is GDNF-dependent JF - International Journal of Molecular Sciences N2 - Enteric glial cells (EGCs) of the enteric nervous system are critically involved in the maintenance of intestinal epithelial barrier function (IEB). The underlying mechanisms remain undefined. Glial cell line-derived neurotrophic factor (GDNF) contributes to IEB maturation and may therefore be the predominant mediator of this process by EGCs. Using GFAP\(^{cre}\) x Ai14\(^{floxed}\) mice to isolate EGCs by Fluorescence-activated cell sorting (FACS), we confirmed that they synthesize GDNF in vivo as well as in primary cultures demonstrating that EGCs are a rich source of GDNF in vivo and in vitro. Co-culture of EGCs with Caco2 cells resulted in IEB maturation which was abrogated when GDNF was either depleted from EGC supernatants, or knocked down in EGCs or when the GDNF receptor RET was blocked. Further, TNFα-induced loss of IEB function in Caco2 cells and in organoids was attenuated by EGC supernatants or by recombinant GDNF. These barrier-protective effects were blunted when using supernatants from GDNF-deficient EGCs or by RET receptor blockade. Together, our data show that EGCs produce GDNF to maintain IEB function in vitro through the RET receptor. KW - enteric glial cells KW - neurotrophic factors KW - intestinal epithelial barrier KW - GDNF5 KW - RET6 KW - inflammatory bowel disease KW - enteric nervous system KW - gut barrier KW - intercellular junctions Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258913 SN - 1422-0067 VL - 22 IS - 4 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 - 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 - 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 - JOUR A1 - Ono, Mitsuaki A1 - Sonoyama, Wataru A1 - Nema, Kazuki A1 - Hara, Emilio Satoshi A1 - Oida, Yasutaka A1 - Pham, Hai Thanh A1 - Yamamoto, Katushi A1 - Hirota, Kazuo A1 - Sugama, Kazushige A1 - Sebald, Walter A1 - Kuboki, Takuo T1 - Regeneration of calvarial defects with Escherichia coli-derived rhBMP-2 adsorbed in PLGA membrane JF - Cells Tissues Organs N2 - Objective: Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) has been shown to be as effective as mammalian cell-derived BMP-2. However, several in vitro and in vivo experiments are still necessary to validate the effectiveness of E-BMP-2 due to the difference in synthesis process, mainly related to protein nonglycosylation. The objective of this study was to investigate whether biodegradable polylactide-co-glycolide (PLGA) membrane is a suitable carrier for E-BMP-2 delivery for bone regeneration of critical-sized defects in rat calvaria. Materials and Methods: First, the osteoinductive effect of E-BMP-2 was confirmed in vitro in mouse bone marrow stromal cells by analysis of osteocalcin mRNA levels, and calcium deposition was detected by alizarin red staining. Before in vivo experiments, the release profile of E-BMP-2 from PLGA membranes was determined by ELISA. E-BMP-2 (0, 1, 5 and 10 μg/μl) was applied for ectopic and orthotopic bone formation and was analyzed by X-ray, micro-CT and histology. Results: Release-profile testing showed that PLGA membrane could retain 94% of the initially applied E-BMP-2. Ectopic bone formation assay revealed that combination of E-BMP-2/PLGA membrane strongly induced bone formation. Stronger osteoinductivity with complete repair of critical-sized defects was observed only with PLGA membranes adsorbed with 5 and 10 μg/μl of E-BMP-2, whereas no bone formation was observed in the groups that received no membrane or 0-μg/μl dose of E-BMP-2. Conclusion: PLGA membrane was shown to be a suitable carrier for sustained release of E-BMP-2, and the E-BMP-2/PLGA membrane combination was demonstrated to be efficient in bone regeneration in a model of critical-sized defects. KW - Escherichia coli-derived recombinant human bone morphogenetic protein-2 KW - Bone regeneration KW - Polylactide-co-glycolide KW - Ectopic bone formation Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196680 SN - 1422-6405 SN - 1422-6421 N1 - This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. VL - 198 IS - 5 SP - 367 EP - 376 ER - TY - JOUR A1 - Grob, Robin A1 - Heinig, Niklas A1 - Grübel, Kornelia A1 - Rössler, Wolfgang A1 - Fleischmann, Pauline N. T1 - Sex-specific and caste-specific brain adaptations related to spatial orientation in Cataglyphis ants JF - Journal of Comparative Neurology N2 - Cataglyphis desert ants are charismatic central place foragers. After long-ranging foraging trips, individual workers navigate back to their nest relying mostly on visual cues. The reproductive caste faces other orientation challenges, i.e. mate finding and colony foundation. Here we compare brain structures involved in spatial orientation of Cataglyphis nodus males, gynes, and foragers by quantifying relative neuropil volumes associated with two visual pathways, and numbers and volumes of antennal lobe (AL) olfactory glomeruli. Furthermore, we determined absolute numbers of synaptic complexes in visual and olfactory regions of the mushroom bodies (MB) and a major relay station of the sky-compass pathway to the central complex (CX). Both female castes possess enlarged brain centers for sensory integration, learning, and memory, reflected in voluminous MBs containing about twice the numbers of synaptic complexes compared with males. Overall, male brains are smaller compared with both female castes, but the relative volumes of the optic lobes and CX are enlarged indicating the importance of visual guidance during innate behaviors. Male ALs contain greatly enlarged glomeruli, presumably involved in sex-pheromone detection. Adaptations at both the neuropil and synaptic levels clearly reflect differences in sex-specific and caste-specific demands for sensory processing and behavioral plasticity underlying spatial orientation. KW - antennal lobe KW - synaptic plasticity KW - polymorphism KW - optic lobes KW - mushroom bodies KW - learning and memory KW - central complex Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257299 VL - 529 IS - 18 ER - TY - JOUR A1 - Villagomez, Gemma N. A1 - Nürnberger, Fabian A1 - Requier, Fabrice A1 - Schiele, Susanne A1 - Steffan-Dewenter, Ingo T1 - Effects of temperature and photoperiod on the seasonal timing of Western honey bee colonies and an early spring flowering plant JF - Ecology and Evolution N2 - Temperature and photoperiod are important Zeitgebers for plants and pollinators to synchronize growth and reproduction with suitable environmental conditions and their mutualistic interaction partners. Global warming can disturb this temporal synchronization since interacting species may respond differently to new combinations of photoperiod and temperature under future climates, but experimental studies on the potential phenological responses of plants and pollinators are lacking. We simulated current and future combinations of temperature and photoperiod to assess effects on the overwintering and spring phenology of an early flowering plant species (Crocus sieberi) and the Western honey bee (Apis mellifera). We could show that increased mean temperatures in winter and early spring advanced the flowering phenology of C. sieberi and intensified brood rearing activity of A. mellifera but did not advance their brood rearing activity. Flowering phenology of C. sieberi also relied on photoperiod, while brood rearing activity of A. mellifera did not. The results confirm that increases in temperature can induce changes in phenological responses and suggest that photoperiod can also play a critical role in these responses, with currently unknown consequences for real-world ecosystems in a warming climate. KW - Apis mellifera KW - climate change KW - rocus sieberi KW - phenology KW - plant–pollinator interaction KW - temporal mismatch Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258770 VL - 11 IS - 12 ER - TY - JOUR A1 - Roth, Nicolas A1 - Hacker, Herrmann Heinrich A1 - Heidrich, Lea A1 - Friess, Nicolas A1 - García-Barroas, Enrique A1 - Habel, Jan Christian A1 - Thorn, Simon A1 - Müler, Jörg T1 - Host specificity and species colouration mediate the regional decline of nocturnal moths in central European forests JF - Ecography N2 - The high diversity of insects has limited the volume of long-term community data with a high taxonomic resolution and considerable geographic replications, especially in forests. Therefore, trends and causes of changes are poorly understood. Here we analyse trends in species richness, abundance and biomass of nocturnal macro moths in three quantitative data sets collected over four decades in forests in southern Germany. Two local data sets, one from coppiced oak forests and one from high oak forests included 125K and 48K specimens from 559 and 532 species, respectively. A third regional data set, representing all forest types in the temperate zone of central Europe comprised 735K specimens from 848 species. Generalized additive mixed models revealed temporal declines in species richness (−38%), abundance (−53%) and biomass (−57%) at the regional scale. These were more pronounced in plant host specialists and in dark coloured species. In contrast, the local coppiced oak forests showed an increase, in species richness (+62%), while the high oak forests showed no clear trends. Left and right censoring as well as cross validation confirmed the robustness of the analyses, which led to four conclusions. First, the decline in insects appears in hyper diverse insect groups in forests and affects species richness, abundance and biomass. Second, the pronounced decline in host specialists suggests habitat loss as an important driver of the observed decline. Third, the more severe decline in dark species might be an indication of global warming as a potential driver. Fourth, the trends in coppiced oak forests indicate that maintaining complex and diverse forest ecosystems through active management may be a promising conservation strategy in order to counteract negative trends in biodiversity, alongside rewilding approaches. KW - climate change KW - colour patterns KW - global change KW - Lepidoptera KW - macro moths KW - specialists KW - time series Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258731 VL - 44 IS - 6 ER - TY - JOUR A1 - Vey, Johannes A1 - Kapsner, Lorenz A. A1 - Fuchs, Maximilian A1 - Unberath, Philipp A1 - Veronesi, Giulia A1 - Kunz, Meik T1 - A toolbox for functional analysis and the systematic identification of diagnostic and prognostic gene expression signatures combining meta-analysis and machine learning JF - Cancers N2 - The identification of biomarker signatures is important for cancer diagnosis and prognosis. However, the detection of clinical reliable signatures is influenced by limited data availability, which may restrict statistical power. Moreover, methods for integration of large sample cohorts and signature identification are limited. We present a step-by-step computational protocol for functional gene expression analysis and the identification of diagnostic and prognostic signatures by combining meta-analysis with machine learning and survival analysis. The novelty of the toolbox lies in its all-in-one functionality, generic design, and modularity. It is exemplified for lung cancer, including a comprehensive evaluation using different validation strategies. However, the protocol is not restricted to specific disease types and can therefore be used by a broad community. The accompanying R package vignette runs in ~1 h and describes the workflow in detail for use by researchers with limited bioinformatics training. KW - bioinformatics tool KW - R package KW - machine learning KW - meta-analysis KW - biomarker signature KW - gene expression analysis KW - survival analysis KW - functional analysis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193240 SN - 2072-6694 VL - 11 IS - 10 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 - Sivarajan, Rinu A1 - Kessie, David Komla A1 - Oberwinkler, Heike A1 - Pallmann, Niklas A1 - Walles, Thorsten A1 - Scherzad, Agmal A1 - Hackenberg, Stephan A1 - Steinke, Maria T1 - Susceptibility of Human Airway Tissue Models Derived From Different Anatomical Sites to Bordetella pertussis and Its Virulence Factor Adenylate Cyclase Toxin JF - Frontiers in Cellular and Infection Microbiology N2 - To study the interaction of human pathogens with their host target structures, human tissue models based on primary cells are considered suitable. Complex tissue models of the human airways have been used as infection models for various viral and bacterial pathogens. The Gram-negative bacterium Bordetella pertussis is of relevant clinical interest since whooping cough has developed into a resurgent infectious disease. In the present study, we created three-dimensional tissue models of the human ciliated nasal and tracheo-bronchial mucosa. We compared the innate immune response of these models towards the B. pertussis virulence factor adenylate cyclase toxin (CyaA) and its enzymatically inactive but fully pore-forming toxoid CyaA-AC\(^-\). Applying molecular biological, histological, and microbiological assays, we found that 1 µg/ml CyaA elevated the intracellular cAMP level but did not disturb the epithelial barrier integrity of nasal and tracheo-bronchial airway mucosa tissue models. Interestingly, CyaA significantly increased interleukin 6, interleukin 8, and human beta defensin 2 secretion in nasal tissue models, whereas tracheo-bronchial tissue models were not significantly affected compared to the controls. Subsequently, we investigated the interaction of B. pertussis with both differentiated primary nasal and tracheo-bronchial tissue models and demonstrated bacterial adherence and invasion without observing host cell type-specific significant differences. Even though the nasal and the tracheo-bronchial mucosa appear similar from a histological perspective, they are differentially susceptible to B. pertussis CyaA in vitro. Our finding that nasal tissue models showed an increased innate immune response towards the B. pertussis virulence factor CyaA compared to tracheo-bronchial tissue models may reflect the key role of the nasal airway mucosa as the first line of defense against airborne pathogens. KW - human nasal epithelial cells KW - human tracheo-bronchial epithelial cells KW - human airway mucosa tissue models KW - adenylate cyclase toxin KW - Bordetella pertussis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-253302 SN - 2235-2988 VL - 11 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 - Eiring, Patrick A1 - McLaughlin, Ryan A1 - Matikonda, Siddharth S. A1 - Han, Zhongying A1 - Grabenhorst, Lennart A1 - Helmerich, Dominic A. A1 - Meub, Mara A1 - Beliu, Gerti A1 - Luciano, Michael A1 - Bandi, Venu A1 - Zijlstra, Niels A1 - Shi, Zhen-Dan A1 - Tarasov, Sergey G. A1 - Swenson, Rolf A1 - Tinnefeld, Philip A1 - Glembockyte, Viktorija A1 - Cordes, Thorben A1 - Sauer, Markus A1 - Schnermann, Martin J. T1 - Targetable conformationally restricted cyanines enable photon-count-limited applications JF - Angewandte Chemie Internationale Edition N2 - Cyanine dyes are exceptionally useful probes for a range of fluorescence-based applications, but their photon output can be limited by trans-to-cis photoisomerization. We recently demonstrated that appending a ring system to the pentamethine cyanine ring system improves the quantum yield and extends the fluorescence lifetime. Here, we report an optimized synthesis of persulfonated variants that enable efficient labeling of nucleic acids and proteins. We demonstrate that a bifunctional sulfonated tertiary amide significantly improves the optical properties of the resulting bioconjugates. These new conformationally restricted cyanines are compared to the parent cyanine derivatives in a range of contexts. These include their use in the plasmonic hotspot of a DNA-nanoantenna, in single-molecule Förster-resonance energy transfer (FRET) applications, far-red fluorescence-lifetime imaging microscopy (FLIM), and single-molecule localization microscopy (SMLM). These efforts define contexts in which eliminating cyanine isomerization provides meaningful benefits to imaging performance. KW - biology KW - super-resolution microscopy KW - conformational restriction KW - cyanine dyes KW - DNA nanotechnology KW - fluorescent dyes KW - single-molecule fluorescence spectroscopy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256559 VL - 60 IS - 51 ER - TY - JOUR A1 - Leverkus, Alexandro B. A1 - Thorn, Simon A1 - Gustafsson, Lena A1 - Noss, Reed A1 - Müller, Jörg A1 - Pausas, Juli G. A1 - Lindenmayer, David B. T1 - Environmental policies to cope with novel disturbance regimes–steps to address a world scientists’ warning to humanity JF - Environmental Research Letters N2 - No abstract available. KW - global change KW - novel disturbance KW - regime shift KW - forest management KW - risk management Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254180 SN - 1748-9326 VL - 16 IS - 2 ER - TY - JOUR A1 - Heidrich, Lea A1 - Pinkert, Stefan A1 - Brandl, Roland A1 - Bässler, Claus A1 - Hacker, Hermann A1 - Roth, Nicolas A1 - Busse, Annika A1 - Müller, Jörg A1 - Friess, Nicolas T1 - Noctuid and geometrid moth assemblages show divergent elevational gradients in body size and color lightness JF - Ecography N2 - Previous macroecological studies have suggested that larger and darker insects are favored in cold environments and that the importance of body size and color for the absorption of solar radiation is not limited to diurnal insects. However, whether these effects hold true for local communities and are consistent across taxonomic groups and sampling years remains unexplored. This study examined the variations in body size and color lightness of the two major families of nocturnal moths, Geometridae and Noctuidae, along an elevational gradient of 700 m in Southern Germany. An assemblage-based analysis was performed using community-weighted means and a fourth-corner analysis to test for variations in color and body size among communities as a function of elevation. This was followed by a species-level analysis to test whether species occurrence and abundance along an elevation gradient were related to these traits, after controlling for host plant availability. In both 2007 and 2016, noctuid moth assemblages became larger and darker with increasing elevation, whereas geometrids showed an opposite trend in terms of color lightness and no clear trend in body size. In single species models, the abundance of geometrids, but not of noctuids, was driven by habitat availability. In turn, the abundance of dark-colored noctuids, but not geometrids increased with elevation. While body size and color lightness affect insect physiology and the ability to cope with harsh conditions, divergent trait–environment relationships between both families underline that findings of coarse-scale studies are not necessarily transferable to finer scales. Local abundance and occurrence of noctuids are shaped by morphological traits, whereas that of geometrids are rather shaped by local habitat availability, which can modify their trait–environment-relationship. We discuss potential explanations such as taxon-specific flight characteristics and the effect of microclimatic conditions. KW - insects KW - color lightness KW - body size KW - elevation KW - habitat availability KW - flight characteristics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256694 VL - 44 IS - 8 ER - TY - JOUR A1 - Panzer, Sabine A1 - Zhang, Chong A1 - Konte, Tilen A1 - Bräuer, Celine A1 - Diemar, Anne A1 - Yogendran, Parathy A1 - Yu-Strzelczyk, Jing A1 - Nagel, Georg A1 - Gao, Shiqiang A1 - Terpitz, Ulrich T1 - Modified Rhodopsins From Aureobasidium pullulans Excel With Very High Proton-Transport Rates JF - Frontiers in Molecular Biosciences N2 - Aureobasidium pullulans is a black fungus that can adapt to various stressful conditions like hypersaline, acidic, and alkaline environments. The genome of A. pullulans exhibits three genes coding for putative opsins ApOps1, ApOps2, and ApOps3. We heterologously expressed these genes in mammalian cells and Xenopus oocytes. Localization in the plasma membrane was greatly improved by introducing additional membrane trafficking signals at the N-terminus and the C-terminus. In patch-clamp and two-electrode-voltage clamp experiments, all three proteins showed proton pump activity with maximal activity in green light. Among them, ApOps2 exhibited the most pronounced proton pump activity with current amplitudes occasionally extending 10 pA/pF at 0 mV. Proton pump activity was further supported in the presence of extracellular weak organic acids. Furthermore, we used site-directed mutagenesis to reshape protein functions and thereby implemented light-gated proton channels. We discuss the difference to other well-known proton pumps and the potential of these rhodopsins for optogenetic applications. KW - black yeast KW - photoreceptor KW - microbial rhodopsins KW - optogenetics KW - proton channel KW - membrane trafficking KW - fungal rhodopsins KW - Aureobasidium Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-249248 SN - 2296-889X VL - 8 ER - TY - JOUR A1 - Shityakov, Sergey A1 - Skorb, Ekaterina V. A1 - Förster, Carola Y. A1 - Dandekar, Thomas T1 - Scaffold Searching of FDA and EMA-Approved Drugs Identifies Lead Candidates for Drug Repurposing in Alzheimer’s Disease JF - Frontiers in Chemistry N2 - Clinical trials of novel therapeutics for Alzheimer’s Disease (AD) have consumed a significant amount of time and resources with largely negative results. Repurposing drugs already approved by the Food and Drug Administration (FDA), European Medicines Agency (EMA), or Worldwide for another indication is a more rapid and less expensive option. Therefore, we apply the scaffold searching approach based on known amyloid-beta (Aβ) inhibitor tramiprosate to screen the DrugCentral database (n = 4,642) of clinically tested drugs. As a result, menadione bisulfite and camphotamide substances with protrombogenic and neurostimulation/cardioprotection effects were identified as promising Aβ inhibitors with an improved binding affinity (ΔGbind) and blood-brain barrier permeation (logBB). Finally, the data was also confirmed by molecular dynamics simulations using implicit solvation, in particular as Molecular Mechanics Generalized Born Surface Area (MM-GBSA) model. Overall, the proposed in silico pipeline can be implemented through the early stage rational drug design to nominate some lead candidates for AD, which will be further validated in vitro and in vivo, and, finally, in a clinical trial. KW - scaffold search KW - approved drugs KW - drug repurposing KW - alzheimer's disease KW - chemical similarity KW - molecular modeling Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-248703 SN - 2296-2646 VL - 9 ER - TY - JOUR A1 - Britz, Sebastian A1 - Markert, Sebastian Matthias A1 - Witvliet, Daniel A1 - Steyer, Anna Maria A1 - Tröger, Sarah A1 - Mulcahy, Ben A1 - Kollmannsberger, Philip A1 - Schwab, Yannick A1 - Zhen, Mei A1 - Stigloher, Christian T1 - Structural Analysis of the Caenorhabditis elegans Dauer Larval Anterior Sensilla by Focused Ion Beam-Scanning Electron Microscopy JF - Frontiers in Neuroanatomy N2 - At the end of the first larval stage, the nematode Caenorhabditis elegans developing in harsh environmental conditions is able to choose an alternative developmental path called the dauer diapause. Dauer larvae exhibit different physiology and behaviors from non-dauer larvae. Using focused ion beam-scanning electron microscopy (FIB-SEM), we volumetrically reconstructed the anterior sensory apparatus of C. elegans dauer larvae with unprecedented precision. We provide a detailed description of some neurons, focusing on structural details that were unknown or unresolved by previously published studies. They include the following: (1) dauer-specific branches of the IL2 sensory neurons project into the periphery of anterior sensilla and motor or putative sensory neurons at the sub-lateral cords; (2) ciliated endings of URX sensory neurons are supported by both ILso and AMso socket cells near the amphid openings; (3) variability in amphid sensory dendrites among dauers; and (4) somatic RIP interneurons maintain their projection into the pharyngeal nervous system. Our results support the notion that dauer larvae structurally expand their sensory system to facilitate searching for more favorable environments. KW - FIB-SEM KW - 3D reconstruction KW - neuroanatomy KW - IL2 branching KW - amphids KW - Caenorhabditis elegans (C. elegans) KW - dauer Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-249622 SN - 1662-5129 VL - 15 ER - TY - JOUR A1 - Kuhlemann, Alexander A1 - Beliu, Gerti A1 - Janzen, Dieter A1 - Petrini, Enrica Maria A1 - Taban, Danush A1 - Helmerich, Dominic A. A1 - Doose, Sören A1 - Bruno, Martina A1 - Barberis, Andrea A1 - Villmann, Carmen A1 - Sauer, Markus A1 - Werner, Christian T1 - Genetic Code Expansion and Click-Chemistry Labeling to Visualize GABA-A Receptors by Super-Resolution Microscopy JF - Frontiers in Synaptic Neuroscience N2 - Fluorescence labeling of difficult to access protein sites, e.g., in confined compartments, requires small fluorescent labels that can be covalently tethered at well-defined positions with high efficiency. Here, we report site-specific labeling of the extracellular domain of γ-aminobutyric acid type A (GABA-A) receptor subunits by genetic code expansion (GCE) with unnatural amino acids (ncAA) combined with bioorthogonal click-chemistry labeling with tetrazine dyes in HEK-293-T cells and primary cultured neurons. After optimization of GABA-A receptor expression and labeling efficiency, most effective variants were selected for super-resolution microscopy and functionality testing by whole-cell patch clamp. Our results show that GCE with ncAA and bioorthogonal click labeling with small tetrazine dyes represents a versatile method for highly efficient site-specific fluorescence labeling of proteins in a crowded environment, e.g., extracellular protein domains in confined compartments such as the synaptic cleft. KW - super-resolution microscopy (SRM) KW - click-chemistry KW - dSTORM KW - GABA-A receptor KW - genetic code expansion Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-251035 SN - 1663-3563 VL - 13 ER - TY - JOUR A1 - Borges, Alyssa R. A1 - Link, Fabian A1 - Engstler, Markus A1 - Jones, Nicola G. T1 - The Glycosylphosphatidylinositol Anchor: A Linchpin for Cell Surface Versatility of Trypanosomatids JF - Frontiers in Cell and Developmental Biology N2 - The use of glycosylphosphatidylinositol (GPI) to anchor proteins to the cell surface is widespread among eukaryotes. The GPI-anchor is covalently attached to the C-terminus of a protein and mediates the protein’s attachment to the outer leaflet of the lipid bilayer. GPI-anchored proteins have a wide range of functions, including acting as receptors, transporters, and adhesion molecules. In unicellular eukaryotic parasites, abundantly expressed GPI-anchored proteins are major virulence factors, which support infection and survival within distinct host environments. While, for example, the variant surface glycoprotein (VSG) is the major component of the cell surface of the bloodstream form of African trypanosomes, procyclin is the most abundant protein of the procyclic form which is found in the invertebrate host, the tsetse fly vector. Trypanosoma cruzi, on the other hand, expresses a variety of GPI-anchored molecules on their cell surface, such as mucins, that interact with their hosts. The latter is also true for Leishmania, which use GPI anchors to display, amongst others, lipophosphoglycans on their surface. Clearly, GPI-anchoring is a common feature in trypanosomatids and the fact that it has been maintained throughout eukaryote evolution indicates its adaptive value. Here, we explore and discuss GPI anchors as universal evolutionary building blocks that support the great variety of surface molecules of trypanosomatids. KW - cell surface proteome KW - evolution KW - GPI-anchor KW - Kinetoplastea Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-249253 SN - 2296-634X VL - 9 ER - TY - JOUR A1 - Osmanoglu, Özge A1 - Khaled AlSeiari, Mariam A1 - AlKhoori, Hasa Abduljaleel A1 - Shams, Shabana A1 - Bencurova, Elena A1 - Dandekar, Thomas A1 - Naseem, Muhammad T1 - Topological Analysis of the Carbon-Concentrating CETCH Cycle and a Photorespiratory Bypass Reveals Boosted CO\(_2\)-Sequestration by Plants JF - Frontiers in Bioengineering and Biotechnology N2 - Synthetically designed alternative photorespiratory pathways increase the biomass of tobacco and rice plants. Likewise, some in planta–tested synthetic carbon-concentrating cycles (CCCs) hold promise to increase plant biomass while diminishing atmospheric carbon dioxide burden. Taking these individual contributions into account, we hypothesize that the integration of bypasses and CCCs will further increase plant productivity. To test this in silico, we reconstructed a metabolic model by integrating photorespiration and photosynthesis with the synthetically designed alternative pathway 3 (AP3) enzymes and transporters. We calculated fluxes of the native plant system and those of AP3 combined with the inhibition of the glycolate/glycerate transporter by using the YANAsquare package. The activity values corresponding to each enzyme in photosynthesis, photorespiration, and for synthetically designed alternative pathways were estimated. Next, we modeled the effect of the crotonyl-CoA/ethylmalonyl-CoA/hydroxybutyryl-CoA cycle (CETCH), which is a set of natural and synthetically designed enzymes that fix CO₂ manifold more than the native Calvin–Benson–Bassham (CBB) cycle. We compared estimated fluxes across various pathways in the native model and under an introduced CETCH cycle. Moreover, we combined CETCH and AP3-w/plgg1RNAi, and calculated the fluxes. We anticipate higher carbon dioxide–harvesting potential in plants with an AP3 bypass and CETCH–AP3 combination. We discuss the in vivo implementation of these strategies for the improvement of C3 plants and in natural high carbon harvesters. KW - CO2-sequestration KW - photorespiration KW - elementary modes KW - synthetic pathways KW - carboxylation KW - metabolic modeling KW - CETCH cycle Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-249260 SN - 2296-4185 VL - 9 ER - TY - JOUR A1 - Colizzi, Francesca Sara A1 - Beer, Katharina A1 - Cuti, Paolo A1 - Deppisch, Peter A1 - Martínez Torres, David A1 - Yoshii, Taishi A1 - Helfrich-Förster, Charlotte T1 - Antibodies Against the Clock Proteins Period and Cryptochrome Reveal the Neuronal Organization of the Circadian Clock in the Pea Aphid JF - Frontiers in Physiology N2 - Circadian clocks prepare the organism to cyclic environmental changes in light, temperature, or food availability. Here, we characterized the master clock in the brain of a strongly photoperiodic insect, the aphid Acyrthosiphon pisum, immunohistochemically with antibodies against A. pisum Period (PER), Drosophila melanogaster Cryptochrome (CRY1), and crab Pigment-Dispersing Hormone (PDH). The latter antibody detects all so far known PDHs and PDFs (Pigment-Dispersing Factors), which play a dominant role in the circadian system of many arthropods. We found that, under long days, PER and CRY are expressed in a rhythmic manner in three regions of the brain: the dorsal and lateral protocerebrum and the lamina. No staining was detected with anti-PDH, suggesting that aphids lack PDF. All the CRY1-positive cells co-expressed PER and showed daily PER/CRY1 oscillations of high amplitude, while the PER oscillations of the CRY1-negative PER neurons were of considerable lower amplitude. The CRY1 oscillations were highly synchronous in all neurons, suggesting that aphid CRY1, similarly to Drosophila CRY1, is light sensitive and its oscillations are synchronized by light-dark cycles. Nevertheless, in contrast to Drosophila CRY1, aphid CRY1 was not degraded by light, but steadily increased during the day and decreased during the night. PER was always located in the nuclei of the clock neurons, while CRY was predominantly cytoplasmic and revealed the projections of the PER/CRY1-positive neurons. We traced the PER/CRY1-positive neurons through the aphid protocerebrum discovering striking similarities with the circadian clock of D. melanogaster: The CRY1 fibers innervate the dorsal and lateral protocerebrum and putatively connect the different PER-positive neurons with each other. They also run toward the pars intercerebralis, which controls hormone release via the neurohemal organ, the corpora cardiaca. In contrast to Drosophila, the CRY1-positive fibers additionally travel directly toward the corpora cardiaca and the close-by endocrine gland, corpora allata. This suggests a direct link between the circadian clock and the photoperiodic control of hormone release that can be studied in the future. KW - aphids KW - circadian clock KW - cryptochrome KW - period KW - hemiptera KW - insects KW - photoperiodism Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-242909 SN - 1664-042X VL - 12 ER - TY - JOUR A1 - Schmidt, Thomas S. B. A1 - Hayward, Matthew R. A1 - Coelho, Luiis P. A1 - Li, Simone S. A1 - Costea, Paul I. A1 - Voigt, Anita Y. A1 - Wirbel, Jakob A1 - Maistrenko, Oleksandr M. A1 - Alves, Renato J. C. A1 - Bergsten, Emma A1 - de Beaufort, Carine A1 - Sobhani, Iradj A1 - Heintz-Buschart, Anna A1 - Sunagawa, Shinichi A1 - Zeller, Georg A1 - Wilmes, Paul A1 - Bork, Peer T1 - Extensive transmission of microbes along the gastrointestinal tract JF - eLife N2 - The gastrointestinal tract is abundantly colonized by microbes, yet the translocation of oral species to the intestine is considered a rare aberrant event, and a hallmark of disease. By studying salivary and fecal microbial strain populations of 310 species in 470 individuals from five countries, we found that transmission to, and subsequent colonization of, the large intestine by oral microbes is common and extensive among healthy individuals. We found evidence for a vast majority of oral species to be transferable, with increased levels of transmission in colorectal cancer and rheumatoid arthritis patients and, more generally, for species described as opportunistic pathogens. This establishes the oral cavity as an endogenous reservoir for gut microbial strains, and oral-fecal transmission as an important process that shapes the gastrointestinal microbiome in health and disease. KW - Colonization KW - Annotation KW - Dynamics KW - Accurate KW - Strains KW - Barrier KW - Health KW - Acids KW - Research Article KW - Computational and Systems Biology KW - Microbiology and Infectious Disease KW - microbiome KW - gastrointestinal tract KW - colorectal cancer KW - rheumatoid arthritis KW - metagenomics Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228954 VL - 8 ER - TY - JOUR A1 - Krones, David A1 - Rühling, Marcel A1 - Becker, Katrin Anne A1 - Kunz, Tobias C. A1 - Sehl, Carolin A1 - Paprotka, Kerstin A1 - Gulbins, Erich A1 - Fraunholz, Martin T1 - Staphylococcus aureus α-Toxin Induces Acid Sphingomyelinase Release From a Human Endothelial Cell Line JF - Frontiers in Microbiology N2 - Staphylococcus aureus (S. aureus) is well known to express a plethora of toxins of which the pore-forming hemolysin A (α-toxin) is the best-studied cytolysin. Pore-forming toxins (PFT) permeabilize host membranes during infection thereby causing concentration-dependent effects in host cell membranes ranging from disordered ion fluxes to cytolysis. Host cells possess defense mechanisms against PFT attack, resulting in endocytosis of the breached membrane area and delivery of repair vesicles to the insulted plasma membrane as well as a concurrent release of membrane repair enzymes. Since PFTs from several pathogens have been shown to recruit membrane repair components, we here investigated whether staphylococcal α-toxin is able to induce these mechanisms in endothelial cells. We show that S. aureus α-toxin induced increase in cytosolic Ca2+ in endothelial cells, which was accompanied by p38 MAPK phosphorylation. Toxin challenge led to increased endocytosis of an extracellular fluid phase marker as well as increased externalization of LAMP1-positive membranes suggesting that peripheral lysosomes are recruited to the insulted plasma membrane. We further observed that thereby the lysosomal protein acid sphingomyelinase (ASM) was released into the cell culture medium. Thus, our results show that staphylococcal α-toxin triggers mechanisms in endothelial cells, which have been implicated in membrane repair after damage of other cell types by different toxins. KW - acid sphingomyelinase KW - staphylococcal alpha-toxin KW - sphingomyelinase release KW - lysosomal recruitment KW - Staphylococcus aureus Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244843 SN - 1664-302X VL - 12 ER - TY - JOUR A1 - Scherer, Marc A1 - Fleishman, Sarel J. A1 - Jones, Patrik R. A1 - Dandekar, Thomas A1 - Bencurova, Elena T1 - Computational Enzyme Engineering Pipelines for Optimized Production of Renewable Chemicals JF - Frontiers in Bioengineering and Biotechnology N2 - To enable a sustainable supply of chemicals, novel biotechnological solutions are required that replace the reliance on fossil resources. One potential solution is to utilize tailored biosynthetic modules for the metabolic conversion of CO2 or organic waste to chemicals and fuel by microorganisms. Currently, it is challenging to commercialize biotechnological processes for renewable chemical biomanufacturing because of a lack of highly active and specific biocatalysts. As experimental methods to engineer biocatalysts are time- and cost-intensive, it is important to establish efficient and reliable computational tools that can speed up the identification or optimization of selective, highly active, and stable enzyme variants for utilization in the biotechnological industry. Here, we review and suggest combinations of effective state-of-the-art software and online tools available for computational enzyme engineering pipelines to optimize metabolic pathways for the biosynthesis of renewable chemicals. Using examples relevant for biotechnology, we explain the underlying principles of enzyme engineering and design and illuminate future directions for automated optimization of biocatalysts for the assembly of synthetic metabolic pathways. KW - computational KW - enzyme KW - engineering KW - design KW - biomanufacturing KW - biofuel KW - microbes KW - metabolism Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-240598 SN - 2296-4185 VL - 9 ER - TY - JOUR A1 - Hartmann, Oliver A1 - Reissland, Michaela A1 - Maier, Carina R. A1 - Fischer, Thomas A1 - Prieto-Garcia, Cristian A1 - Baluapuri, Apoorva A1 - Schwarz, Jessica A1 - Schmitz, Werner A1 - Garrido-Rodriguez, Martin A1 - Pahor, Nikolett A1 - Davies, Clare C. A1 - Bassermann, Florian A1 - Orian, Amir A1 - Wolf, Elmar A1 - Schulze, Almut A1 - Calzado, Marco A. A1 - Rosenfeldt, Mathias T. A1 - Diefenbacher, Markus E. T1 - Implementation of CRISPR/Cas9 Genome Editing to Generate Murine Lung Cancer Models That Depict the Mutational Landscape of Human Disease JF - Frontiers in Cell and Developmental Biology N2 - Lung cancer is the most common cancer worldwide and the leading cause of cancer-related deaths in both men and women. Despite the development of novel therapeutic interventions, the 5-year survival rate for non-small cell lung cancer (NSCLC) patients remains low, demonstrating the necessity for novel treatments. One strategy to improve translational research is the development of surrogate models reflecting somatic mutations identified in lung cancer patients as these impact treatment responses. With the advent of CRISPR-mediated genome editing, gene deletion as well as site-directed integration of point mutations enabled us to model human malignancies in more detail than ever before. Here, we report that by using CRISPR/Cas9-mediated targeting of Trp53 and KRas, we recapitulated the classic murine NSCLC model Trp53fl/fl:lsl-KRasG12D/wt. Developing tumors were indistinguishable from Trp53fl/fl:lsl-KRasG12D/wt-derived tumors with regard to morphology, marker expression, and transcriptional profiles. We demonstrate the applicability of CRISPR for tumor modeling in vivo and ameliorating the need to use conventional genetically engineered mouse models. Furthermore, tumor onset was not only achieved in constitutive Cas9 expression but also in wild-type animals via infection of lung epithelial cells with two discrete AAVs encoding different parts of the CRISPR machinery. While conventional mouse models require extensive husbandry to integrate new genetic features allowing for gene targeting, basic molecular methods suffice to inflict the desired genetic alterations in vivo. Utilizing the CRISPR toolbox, in vivo cancer research and modeling is rapidly evolving and enables researchers to swiftly develop new, clinically relevant surrogate models for translational research. KW - non-small cell lung cancer KW - CRISPR-Cas9 KW - mouse model KW - lung cancer KW - MYC KW - JUN Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230949 SN - 2296-634X VL - 9 ER - TY - JOUR A1 - Lehenberger, Maximilian A1 - Foh, Nina A1 - Göttlein, Axel A1 - Six, Diana A1 - Biedermann, Peter H. W. T1 - Nutrient-Poor Breeding Substrates of Ambrosia Beetles Are Enriched With Biologically Important Elements JF - Frontiers in Microbiology N2 - Fungus-farming within galleries in the xylem of trees has evolved independently in at least twelve lineages of weevils (Curculionidae: Scolytinae, Platypodinae) and one lineage of ship-timber beetles (Lymexylidae). Jointly these are termed ambrosia beetles because they actively cultivate nutritional “ambrosia fungi” as their main source of food. The beetles are obligately dependent on their ambrosia fungi as they provide them a broad range of essential nutrients ensuring their survival in an extremely nutrient-poor environment. While xylem is rich in carbon (C) and hydrogen (H), various elements essential for fungal and beetle growth, such as nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), and manganese (Mn) are extremely low in concentration. Currently it remains untested how both ambrosia beetles and their fungi meet their nutritional requirements in this habitat. Here, we aimed to determine for the first time if galleries of ambrosia beetles are generally enriched with elements that are rare in uncolonized xylem tissue and whether these nutrients are translocated to the galleries from the xylem by the fungal associates. To do so, we examined natural galleries of three ambrosia beetle species from three independently evolved farming lineages, Xyleborinus saxesenii (Scolytinae: Xyleborini), Trypodendron lineatum (Scolytinae: Xyloterini) and Elateroides dermestoides (Lymexylidae), that cultivate unrelated ambrosia fungi in the ascomycete orders Ophiostomatales, Microascales, and Saccharomycetales, respectively. Several elements, in particular Ca, N, P, K, Mg, Mn, and S, were present in high concentrations within the beetles’ galleries but available in only very low concentrations in the surrounding xylem. The concentration of elements was generally highest with X. saxesenii, followed by T. lineatum and E. dermestoides, which positively correlates with the degree of sociality and productivity of brood per gallery. We propose that the ambrosia fungal mutualists are translocating essential elements through their hyphae from the xylem to fruiting structures they form on gallery walls. Moreover, the extremely strong enrichment observed suggests recycling of these elements from the feces of the insects, where bacteria and yeasts might play a role. KW - ambrosia beetle KW - ecological stoichiometry KW - microbiome KW - nutrients KW - macro- and micro-elements KW - element translocation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237602 SN - 1664-302X VL - 12 ER - TY - JOUR A1 - Kunz, Tobias C. A1 - Rühling, Marcel A1 - Moldovan, Adriana A1 - Paprotka, Kerstin A1 - Kozjak-Pavlovic, Vera A1 - Rudel, Thomas A1 - Fraunholz, Martin T1 - The Expandables: Cracking the Staphylococcal Cell Wall for Expansion Microscopy JF - Frontiers in Cellular and Infection Microbiology N2 - Expansion Microscopy (ExM) is a novel tool improving the resolution of fluorescence microscopy by linking the sample into a hydrogel that gets physically expanded in water. Previously, we have used ExM to visualize the intracellular Gram-negative pathogens Chlamydia trachomatis, Simkania negevensis, and Neisseria gonorrhoeae. Gram-positive bacteria have a rigid and thick cell wall that impedes classic expansion strategies. Here we developed an approach, which included a series of enzymatic treatments resulting in isotropic 4× expansion of the Gram-positive pathogen Staphylococcus aureus. We further demonstrate the suitability of the technique for imaging of planktonic bacteria as well as endocytosed, intracellular bacteria at a spatial resolution of approximately 60 nm with conventional confocal laser scanning microscopy. KW - high-resolution imaging KW - endosomes KW - autophagosomes KW - host-pathogen interaction KW - expansion microscopy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-232292 SN - 2235-2988 VL - 11 ER - TY - JOUR A1 - Geisinger, Adriana A1 - Rodríguez-Casuriaga, Rosana A1 - Benavente, Ricardo T1 - Transcriptomics of Meiosis in the Male Mouse JF - Frontiers in Cell and Developmental Biology N2 - Molecular studies of meiosis in mammals have been long relegated due to some intrinsic obstacles, namely the impossibility to reproduce the process in vitro, and the difficulty to obtain highly pure isolated cells of the different meiotic stages. In the recent years, some technical advances, from the improvement of flow cytometry sorting protocols to single-cell RNAseq, are enabling to profile the transcriptome and its fluctuations along the meiotic process. In this mini-review we will outline the diverse methodological approaches that have been employed, and some of the main findings that have started to arise from these studies. As for practical reasons most studies have been carried out in males, and mostly using mouse as a model, our focus will be on murine male meiosis, although also including specific comments about humans. Particularly, we will center on the controversy about gene expression during early meiotic prophase; the widespread existing gap between transcription and translation in meiotic cells; the expression patterns and potential roles of meiotic long non-coding RNAs; and the visualization of meiotic sex chromosome inactivation from the RNAseq perspective. KW - meiosis KW - transcriptomics KW - RNAseq KW - meiotic prophase KW - spermatogenesis KW - lncRNAs KW - MSCI KW - spermatogenic cell sorting Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231032 SN - 2296-634X VL - 9 ER - TY - JOUR A1 - Dapergola, Eleni A1 - Menegazzi, Pamela A1 - Raabe, Thomas A1 - Hovhanyan, Anna T1 - Light Stimuli and Circadian Clock Affect Neural Development in Drosophila melanogaster JF - Frontiers in Cell and Developmental Biology N2 - Endogenous clocks enable organisms to adapt cellular processes, physiology, and behavior to daily variation in environmental conditions. Metabolic processes in cyanobacteria to humans are under the influence of the circadian clock, and dysregulation of the circadian clock causes metabolic disorders. In mouse and Drosophila, the circadian clock influences translation of factors involved in ribosome biogenesis and synchronizes protein synthesis. Notably, nutrition signals are mediated by the insulin receptor/target of rapamycin (InR/TOR) pathways to regulate cellular metabolism and growth. However, the role of the circadian clock in Drosophila brain development and the potential impact of clock impairment on neural circuit formation and function is less understood. Here we demonstrate that changes in light stimuli or disruption of the molecular circadian clock cause a defect in neural stem cell growth and proliferation. Moreover, we show that disturbed cell growth and proliferation are accompanied by reduced nucleolar size indicative of impaired ribosomal biogenesis. Further, we define that light and clock independently affect the InR/TOR growth regulatory pathway due to the effect on regulators of protein biosynthesis. Altogether, these data suggest that alterations in InR/TOR signaling induced by changes in light conditions or disruption of the molecular clock have an impact on growth and proliferation properties of neural stem cells in the developing Drosophila brain. KW - neuroblast growth KW - proliferation KW - circadian clock KW - light stimuli Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231049 SN - 2296-634X VL - 9 ER - TY - JOUR A1 - Eisenreich, Wolfgang A1 - Rudel, Thomas A1 - Heesemann, Jürgen A1 - Goebel, Werner T1 - Persistence of Intracellular Bacterial Pathogens—With a Focus on the Metabolic Perspective JF - Frontiers in Cellular and Infection Microbiology N2 - Persistence has evolved as a potent survival strategy to overcome adverse environmental conditions. This capability is common to almost all bacteria, including all human bacterial pathogens and likely connected to chronic infections caused by some of these pathogens. Although the majority of a bacterial cell population will be killed by the particular stressors, like antibiotics, oxygen and nitrogen radicals, nutrient starvation and others, a varying subpopulation (termed persisters) will withstand the stress situation and will be able to revive once the stress is removed. Several factors and pathways have been identified in the past that apparently favor the formation of persistence, such as various toxin/antitoxin modules or stringent response together with the alarmone (p)ppGpp. However, persistence can occur stochastically in few cells even of stress-free bacterial populations. Growth of these cells could then be induced by the stress conditions. In this review, we focus on the persister formation of human intracellular bacterial pathogens, some of which belong to the most successful persister producers but lack some or even all of the assumed persistence-triggering factors and pathways. We propose a mechanism for the persister formation of these bacterial pathogens which is based on their specific intracellular bipartite metabolism. We postulate that this mode of metabolism ultimately leads, under certain starvation conditions, to the stalling of DNA replication initiation which may be causative for the persister state. KW - persistence KW - mechanisms of persister formation KW - intracellular bacterial pathogens KW - stress conditions KW - ATP-DnaA complex KW - DNA replication initiation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222348 SN - 2235-2988 VL - 10 ER - TY - JOUR A1 - Grubbs, Kirk J. A1 - Surup, Frank A1 - Biedermann, Peter H. W. A1 - McDonald, Bradon R. A1 - Klassen, Jonathan L. A1 - Carlson, Caitlin M. A1 - Clardy, Jon A1 - Currie, Cameron R. T1 - Cycloheximide-Producing Streptomyces Associated With Xyleborinus saxesenii and Xyleborus affinis Fungus-Farming Ambrosia Beetles JF - Frontiers in Microbiology N2 - Symbiotic microbes help a myriad of insects acquire nutrients. Recent work suggests that insects also frequently associate with actinobacterial symbionts that produce molecules to help defend against parasites and predators. Here we explore a potential association between Actinobacteria and two species of fungus-farming ambrosia beetles, Xyleborinus saxesenii and Xyleborus affinis. We isolated and identified actinobacterial and fungal symbionts from laboratory reared nests, and characterized small molecules produced by the putative actinobacterial symbionts. One 16S rRNA phylotype of Streptomyces (XylebKG-1) was abundantly and consistently isolated from the galleries and adults of X. saxesenii and X. affinis nests. In addition to Raffaelea sulphurea, the symbiont that X. saxesenii cultivates, we also repeatedly isolated a strain of Nectria sp. that is an antagonist of this mutualism. Inhibition bioassays between Streptomyces griseus XylebKG-1 and the fungal symbionts from X. saxesenii revealed strong inhibitory activity of the actinobacterium toward the fungal antagonist Nectria sp. but not the fungal mutualist R. sulphurea. Bioassay guided HPLC fractionation of S. griseus XylebKG-1 culture extracts, followed by NMR and mass spectrometry, identified cycloheximide as the compound responsible for the observed growth inhibition. A biosynthetic gene cluster putatively encoding cycloheximide was also identified in S. griseus XylebKG-1. The consistent isolation of a single 16S phylotype of Streptomyces from two species of ambrosia beetles, and our finding that a representative isolate of this phylotype produces cycloheximide, which inhibits a parasite of the system but not the cultivated fungus, suggests that these actinobacteria may play defensive roles within these systems. KW - symbiosis KW - mutualism KW - insect fungal interactions KW - antimicrobial KW - Insect symbiois Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212449 VL - 11 ER - TY - JOUR A1 - Ye, Mingyu A1 - Keicher, Markus A1 - Gentschev, Ivaylo A1 - Szalay, Aladar A. T1 - Efficient selection of recombinant fluorescent vaccinia virus strains and rapid virus titer determination by using a multi-well plate imaging system JF - Biomedicines N2 - Engineered vaccinia virus (VACV) strains are used extensively as vectors for the development of novel cancer vaccines and cancer therapeutics. In this study, we describe for the first time a high-throughput approach for both fluorescent rVACV generation and rapid viral titer measurement with the multi-well plate imaging system, IncuCyte\(^®\)S3. The isolation of a single, well-defined plaque is critical for the generation of novel recombinant vaccinia virus (rVACV) strains. Unfortunately, current methods of rVACV engineering via plaque isolation are time-consuming and laborious. Here, we present a modified fluorescent viral plaque screening and selection strategy that allows one to generally obtain novel fluorescent rVACV strains in six days, with a minimum of just four days. The standard plaque assay requires chemicals for fixing and staining cells. Manual plaque counting based on visual inspection of the cell culture plates is time-consuming. Here, we developed a fluorescence-based plaque assay for quantifying the vaccinia virus that does not require a cell staining step. This approach is less toxic to researchers and is reproducible; it is thus an improvement over the traditional assay. Lastly, plaque counting by virtue of a fluorescence-based image is very convenient, as it can be performed directly on the computer. KW - fluorescent recombinant vaccinia virus KW - plaque isolation KW - IncuCyte\(^®\)S3 KW - plaque assay Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-245104 SN - 2227-9059 VL - 9 IS - 8 ER - TY - JOUR A1 - Hepbasli, Denis A1 - Gredy, Sina A1 - Ullrich, Melanie A1 - Reigl, Amelie A1 - Abeßer, Marco A1 - Raabe, Thomas A1 - Schuh, Kai T1 - Genotype- and Age-Dependent Differences in Ultrasound Vocalizations of SPRED2 Mutant Mice Revealed by Machine Deep Learning JF - Brain Sciences N2 - Vocalization is an important part of social communication, not only for humans but also for mice. Here, we show in a mouse model that functional deficiency of Sprouty-related EVH1 domain-containing 2 (SPRED2), a protein ubiquitously expressed in the brain, causes differences in social ultrasound vocalizations (USVs), using an uncomplicated and reliable experimental setting of a short meeting of two individuals. SPRED2 mutant mice show an OCD-like behaviour, accompanied by an increased release of stress hormones from the hypothalamic–pituitary–adrenal axis, both factors probably influencing USV usage. To determine genotype-related differences in USV usage, we analyzed call rate, subtype profile, and acoustic parameters (i.e., duration, bandwidth, and mean peak frequency) in young and old SPRED2-KO mice. We recorded USVs of interacting male and female mice, and analyzed the calls with the deep-learning DeepSqueak software, which was trained to recognize and categorize the emitted USVs. Our findings provide the first classification of SPRED2-KO vs. wild-type mouse USVs using neural networks and reveal significant differences in their development and use of calls. Our results show, first, that simple experimental settings in combination with deep learning are successful at identifying genotype-dependent USV usage and, second, that SPRED2 deficiency negatively affects the vocalization usage and social communication of mice. KW - SPRED KW - SPRED2 KW - mice KW - neural networks KW - ultrasound vocalizations KW - DeepSqueak Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-248525 SN - 2076-3425 VL - 11 IS - 10 ER - TY - JOUR A1 - Redlich, Sarah A1 - Martin, Emily A. A1 - Steffan‐Dewenter, Ingolf T1 - Sustainable landscape, soil and crop management practices enhance biodiversity and yield in conventional cereal systems JF - Journal of Applied Ecology N2 - Input‐driven, modern agriculture is commonly associated with large‐scale threats to biodiversity, the disruption of ecosystem services and long‐term risks to food security and human health. A switch to more sustainable yet highly productive farming practices seems unavoidable. However, an integrative evaluation of targeted management schemes at field and landscape scales is currently lacking. Furthermore, the often‐disproportionate influence of soil conditions and agrochemicals on yields may mask the benefits of biodiversity‐driven ecosystem services. Here, we used a real‐world ecosystem approach to identify sustainable management practices for enhanced functional biodiversity and yield on 28 temperate wheat fields. Using path analysis, we assessed direct and indirect links between soil, crop and landscape management with natural enemies and pests, as well as follow‐on effects on yield quantity and quality. A paired‐field design with a crossed insecticide‐fertilizer experiment allowed us to control for the relative influence of soil characteristics and agrochemical inputs. We demonstrate that biodiversity‐enhancing management options such as reduced tillage, crop rotation diversity and small field size can enhance natural enemies without relying on agrochemical inputs. Similarly, we show that in this system controlling pests and weeds by agrochemical means is less relevant than expected for final crop productivity. Synthesis and applications. Our study highlights soil, crop and landscape management practices that can enhance beneficial biodiversity while reducing agrochemical usage and negative environmental impacts of conventional agriculture. The diversification of cropping systems and conservation tillage are practical measures most farmers can implement without productivity losses. Combining local measures with improved landscape management may also strengthen the sustainability and resilience of cropping systems in light of future global change. KW - crop management KW - ecological intensification KW - landscape heterogeneity KW - natural enemies KW - pests KW - soil characteristics KW - sustainable intensification KW - wheat yield Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228345 VL - 58 IS - 3 SP - 507 EP - 517 ER - TY - JOUR A1 - Schilcher, Felix A1 - Thamm, Markus A1 - Strube-Bloss, Martin A1 - Scheiner, Ricarda T1 - Opposing actions of octopamine and tyramine on honeybee vision JF - Biomolecules N2 - The biogenic amines octopamine and tyramine are important neurotransmitters in insects and other protostomes. They play a pivotal role in the sensory responses, learning and memory and social organisation of honeybees. Generally, octopamine and tyramine are believed to fulfil similar roles as their deuterostome counterparts epinephrine and norepinephrine. In some cases opposing functions of both amines have been observed. In this study, we examined the functions of tyramine and octopamine in honeybee responses to light. As a first step, electroretinography was used to analyse the effect of both amines on sensory sensitivity at the photoreceptor level. Here, the maximum receptor response was increased by octopamine and decreased by tyramine. As a second step, phototaxis experiments were performed to quantify the behavioural responses to light following treatment with either amine. Octopamine increased the walking speed towards different light sources while tyramine decreased it. This was independent of locomotor activity. Our results indicate that tyramine and octopamine act as functional opposites in processing responses to light. KW - biogenic amines KW - neurotransmitter KW - phototaxis KW - ERG KW - behaviour KW - modulation KW - visual system KW - octopamine KW - tyramine KW - Apis mellifera Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246214 SN - 2218-273X VL - 11 IS - 9 ER - TY - JOUR A1 - Hartke, Juliane A1 - Waldvogel, Ann‐Marie A1 - Sprenger, Philipp P. A1 - Schmitt, Thomas A1 - Menzel, Florian A1 - Pfenninger, Markus A1 - Feldmeyer, Barbara T1 - Little parallelism in genomic signatures of local adaptation in two sympatric, cryptic sister species JF - Journal of Evolutionary Biology N2 - Species living in sympatry and sharing a similar niche often express parallel phenotypes as a response to similar selection pressures. The degree of parallelism within underlying genomic levels is often unexplored, but can give insight into the mechanisms of natural selection and adaptation. Here, we use multi‐dimensional genomic associations to assess the basis of local and climate adaptation in two sympatric, cryptic Crematogaster levior ant species along a climate gradient. Additionally, we investigate the genomic basis of chemical communication in both species. Communication in insects is mainly mediated by cuticular hydrocarbons (CHCs), which also protect against water loss and, hence, are subject to changes via environmental acclimation or adaptation. The combination of environmental and chemical association analyses based on genome‐wide Pool‐Seq data allowed us to identify single nucleotide polymorphisms (SNPs) associated with climate and with chemical differences. Within species, CHC changes as a response to climate seem to be driven by phenotypic plasticity, since there is no overlap between climate‐ and CHC‐associated SNPs. The only exception is the odorant receptor OR22c, which may be a candidate for population‐specific CHC recognition in one of the species. Within both species, climate is significantly correlated with CHC differences, as well as to allele frequency differences. However, associated candidate SNPs, genes and functions are largely species‐specific and we find evidence for minimal parallel evolution only on the level of genomic regions (J = 0.04). This highlights that even closely related species may follow divergent evolutionary trajectories when expressing similar adaptive phenotypes. KW - BayPass KW - environmental association analysis KW - Formicidae KW - mutualism KW - parallel evolution KW - population divergence Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228355 VL - 34 IS - 6 SP - 937 EP - 952 ER - TY - JOUR A1 - Diers, J. A1 - Wagner, J. A1 - Baum, P. A1 - Lichthardt, S. A1 - Kastner, C. A1 - Matthes, N. A1 - Matthes, H. A1 - Germer, C.‐T. A1 - Löb, S. A1 - Wiegering, A. T1 - Nationwide in‐hospital mortality rate following rectal resection for rectal cancer according to annual hospital volume in Germany JF - BJS Open N2 - Background The impact of hospital volume after rectal cancer surgery is seldom investigated. This study aimed to analyse the impact of annual rectal cancer surgery cases per hospital on postoperative mortality and failure to rescue. Methods All patients diagnosed with rectal cancer and who had a rectal resection procedure code from 2012 to 2015 were identified from nationwide administrative hospital data. Hospitals were grouped into five quintiles according to caseload. The absolute number of patients, postoperative deaths and failure to rescue (defined as in‐hospital mortality after a documented postoperative complication) for severe postoperative complications were determined. Results Some 64 349 patients were identified. The overall in‐house mortality rate was 3·9 per cent. The crude in‐hospital mortality rate ranged from 5·3 per cent in very low‐volume hospitals to 2·6 per cent in very high‐volume centres, with a distinct trend between volume categories (P < 0·001). In multivariable logistic regression analysis using hospital volume as random effect, very high‐volume hospitals (53 interventions/year) had a risk‐adjusted odds ratio of 0·58 (95 per cent c.i. 0·47 to 0·73), compared with the baseline in‐house mortality rate in very low‐volume hospitals (6 interventions per year) (P < 0·001). The overall postoperative complication rate was comparable between different volume quintiles, but failure to rescue decreased significantly with increasing caseload (15·6 per cent after pulmonary embolism in the highest volume quintile versus 38 per cent in the lowest quintile; P = 0·010). Conclusion Patients who had rectal cancer surgery in high‐volume hospitals showed better outcomes and reduced failure to rescue rates for severe complications than those treated in low‐volume hospitals. KW - rectal resection KW - rectal cancer KW - mortality rate Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212878 VL - 4 IS - 2 SP - 310 EP - 319 ER - TY - JOUR A1 - Habenstein, Jens A1 - Thamm, Markus A1 - Rössler, Wolfgang T1 - Neuropeptides as potential modulators of behavioral transitions in the ant Cataglyphis nodus JF - Journal of Comparative Neurology N2 - Age‐related behavioral plasticity is a major prerequisite for the ecological success of insect societies. Although ecological aspects of behavioral flexibility have been targeted in many studies, the underlying intrinsic mechanisms controlling the diverse changes in behavior along the individual life history of social insects are not completely understood. Recently, the neuropeptides allatostatin‐A, corazonin, and tachykinin have been associated with the regulation of behavioral transitions in social insects. Here, we investigated changes in brain localization and expression of these neuropeptides following major behavioral transitions in Cataglyphis nodus ants. Our immunohistochemical analyses in the brain revealed that the overall branching pattern of neurons immunoreactive (ir) for the three neuropeptides is largely independent of the behavioral stages. Numerous allatostatin‐A‐ and tachykinin‐ir neurons innervate primary sensory neuropils and high‐order integration centers of the brain. In contrast, the number of corazonergic neurons is restricted to only four neurons per brain hemisphere with cell bodies located in the pars lateralis and axons extending to the medial protocerebrum and the retrocerebral complex. Most interestingly, the cell‐body volumes of these neurons are significantly increased in foragers compared to freshly eclosed ants and interior workers. Quantification of mRNA expression levels revealed a stage‐related change in the expression of allatostatin‐A and corazonin mRNA in the brain. Given the presence of the neuropeptides in major control centers of the brain and the neurohemal organs, these mRNA‐changes strongly suggest an important modulatory role of both neuropeptides in the behavioral maturation of Cataglyphis ants. KW - allatostatin‐A KW - corazonin KW - division of labor KW - neuropeptides KW - social insects KW - tachykinin KW - Cataglyphis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244751 VL - 529 IS - 12 SP - 3155 EP - 3170 ER - TY - JOUR A1 - Hagge, Jonas A1 - Müller, Jörg A1 - Birkemoe, Tone A1 - Buse, Jörn A1 - Christensen, Rune Haubo Bojesen A1 - Gossner, Martin M. A1 - Gruppe, Axel A1 - Heibl, Christoph A1 - Jarzabek‐Müller, Andrea A1 - Seibold, Sebastian A1 - Siitonen, Juha A1 - Soutinho, João Gonçalo A1 - Sverdrup‐Thygeson, Anne A1 - Thorn, Simon A1 - Drag, Lukas T1 - What does a threatened saproxylic beetle look like? Modelling extinction risk using a new morphological trait database JF - Journal of Animal Ecology N2 - The extinction of species is a non‐random process, and understanding why some species are more likely to go extinct than others is critical for conservation efforts. Functional trait‐based approaches offer a promising tool to achieve this goal. In forests, deadwood‐dependent (saproxylic) beetles comprise a major part of threatened species, but analyses of their extinction risk have been hindered by the availability of suitable morphological traits. To better understand the mechanisms underlying extinction in insects, we investigated the relationships between morphological features and the extinction risk of saproxylic beetles. Specifically, we hypothesised that species darker in colour, with a larger and rounder body, a lower mobility, lower sensory perception and more robust mandibles are at higher risk. We first developed a protocol for morphological trait measurements and present a database of 37 traits for 1,157 European saproxylic beetle species. Based on 13 selected, independent traits characterising aspects of colour, body shape, locomotion, sensory perception and foraging, we used a proportional‐odds multiple linear mixed‐effects model to model the German Red List categories of 744 species as an ordinal index of extinction risk. Six out of 13 traits correlated significantly with extinction risk. Larger species as well as species with a broad and round body had a higher extinction risk than small, slim and flattened species. Species with short wings had a higher extinction risk than those with long wings. On the contrary, extinction risk increased with decreasing wing load and with higher mandibular aspect ratio (shorter and more robust mandibles). Our study provides new insights into how morphological traits, beyond the widely used body size, determine the extinction risk of saproxylic beetles. Moreover, our approach shows that the morphological characteristics of beetles can be comprehensively represented by a selection of 13 traits. We recommend them as a starting point for functional analyses in the rapidly growing field of ecological and conservation studies of deadwood. KW - deadwood KW - extinction risk KW - forest biodiversity KW - forestry KW - functional traits KW - morphometry KW - red lists KW - saproxylic beetles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244717 VL - 90 IS - 8 SP - 1934 EP - 1947 ER - TY - JOUR A1 - Bässler, Claus A1 - Brandl, Roland A1 - Müller, Jörg A1 - Krah, Franz S. A1 - Reinelt, Arthur A1 - Halbwachs, Hans T1 - Global analysis reveals an environmentally driven latitudinal pattern in mushroom size across fungal species JF - Ecology Letters N2 - Although macroecology is a well‐established field, much remains to be learned about the large‐scale variation of fungal traits. We conducted a global analysis of mean fruit body size of 59 geographical regions worldwide, comprising 5340 fungal species exploring the response of fruit body size to latitude, resource availability and temperature. The results showed a hump‐shaped relationship between mean fruit body size and distance to the equator. Areas with large fruit bodies were characterised by a high seasonality and an intermediate mean temperature. The responses of mutualistic species and saprotrophs were similar. These findings support the resource availability hypothesis, predicting large fruit bodies due to a seasonal resource surplus, and the thermoregulation hypothesis, according to which small fruit bodies offer a strategy to avoid heat and cold stress and therefore occur at temperature extremes. Fruit body size may thus be an adaptive trait driving the large‐scale distribution of fungal species. KW - Fungal traits KW - global biomes KW - latitudinal gradient KW - mean fruit body size KW - saprobic and ectomycorrhizal basidiomycetes Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239808 VL - 24 IS - 4 SP - 658 EP - 667 ER - TY - JOUR A1 - Höhne, Christin A1 - Prokopov, Dmitry A1 - Kuhl, Heiner A1 - Du, Kang A1 - Klopp, Christophe A1 - Wuertz, Sven A1 - Trifonov, Vladimir A1 - Stöck, Matthias T1 - The immune system of sturgeons and paddlefish (Acipenseriformes): a review with new data from a chromosome‐scale sturgeon genome JF - Reviews in Aquaculture N2 - Sturgeon immunity is relevant for basic evolutionary and applied research, including caviar‐ and meat‐producing aquaculture, protection of wild sturgeons and their re‐introduction through conservation aquaculture. Starting from a comprehensive overview of immune organs, we discuss pathways of innate and adaptive immune systems in a vertebrate phylogenetic and genomic context. The thymus as a key organ of adaptive immunity in sturgeons requires future molecular studies. Likewise, data on immune functions of sturgeon‐specific pericardial and meningeal tissues are largely missing. Integrating immunological and endocrine functions, the sturgeon head kidney resembles that of teleosts. Recently identified pattern recognition receptors in sturgeon require research on downstream regulation. We review first acipenseriform data on Toll‐like receptors (TLRs), type I transmembrane glycoproteins expressed in membranes and endosomes, initiating inflammation and host defence by molecular pattern‐induced activation. Retinoic acid‐inducible gene‐I‐like (RIG‐like) receptors of sturgeons present RNA and key sensors of virus infections in most cell types. Sturgeons and teleosts share major components of the adaptive immune system, including B cells, immunoglobulins, major histocompatibility complex and the adaptive cellular response by T cells. The ontogeny of the sturgeon innate and onset of adaptive immune genes in different organs remain understudied. In a genomics perspective, our new data on 100 key immune genes exemplify a multitude of evolutionary trajectories after the sturgeon‐specific genome duplication, where some single‐copy genes contrast with many duplications, allowing tissue specialization, sub‐functionalization or both. Our preliminary conclusion should be tested by future evolutionary bioinformatics, involving all >1000 immunity genes. This knowledge update about the acipenseriform immune system identifies several important research gaps and presents a basis for future applications. KW - evolution KW - genomics KW - immune genes KW - immune organs KW - immune system KW - sturgeon Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239865 VL - 13 IS - 3 SP - 1709 EP - 1729 ER - TY - JOUR A1 - Kastner, Carolin A1 - Hendricks, Anne A1 - Deinlein, Hanna A1 - Hankir, Mohammed A1 - Germer, Christoph-Thomas A1 - Schmidt, Stefanie A1 - Wiegering, Armin T1 - Organoid Models for Cancer Research — From Bed to Bench Side and Back JF - Cancers N2 - Simple Summary Despite significant strides in multimodal therapy, cancers still rank within the first three causes of death especially in industrial nations. A lack of individualized approaches and accurate preclinical models are amongst the major barriers that limit the development of novel therapeutic options and drugs. Recently, the 3D culture system of organoids was developed which stably retains the genetic and phenotypic characteristics of the original tissue, healthy as well as diseased. In this review, we summarize current data and evidence on the relevance and reliability of such organoid culture systems in cancer research, focusing on their role in drug investigations (in a personalized manner). Abstract Organoids are a new 3D ex vivo culture system that have been applied in various fields of biomedical research. First isolated from the murine small intestine, they have since been established from a wide range of organs and tissues, both in healthy and diseased states. Organoids genetically, functionally and phenotypically retain the characteristics of their tissue of origin even after multiple passages, making them a valuable tool in studying various physiologic and pathophysiologic processes. The finding that organoids can also be established from tumor tissue or can be engineered to recapitulate tumor tissue has dramatically increased their use in cancer research. In this review, we discuss the potential of organoids to close the gap between preclinical in vitro and in vivo models as well as clinical trials in cancer research focusing on drug investigation and development. KW - cancer KW - tumor disease KW - organoid KW - patient-derived organoid (PDOs) KW - patient-derived tumor organoid (PDTO) Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246307 SN - 2072-6694 VL - 13 IS - 19 ER - TY - JOUR A1 - Othman, Eman M. A1 - Bekhit, Amany A. A1 - Anany, Mohamed A. A1 - Dandekar, Thomas A1 - Ragab, Hanan M. A1 - Wahid, Ahmed T1 - Design, Synthesis, and Anticancer Screening for Repurposed Pyrazolo[3,4-d]pyrimidine Derivatives on Four Mammalian Cancer Cell Lines JF - Molecules N2 - The present study reports the synthesis of new purine bioisosteres comprising a pyrazolo[3,4-d]pyrimidine scaffold linked to mono-, di-, and trimethoxy benzylidene moieties through hydrazine linkages. First, in silico docking experiments of the synthesized compounds against Bax, Bcl-2, Caspase-3, Ki67, p21, and p53 were performed in a trial to rationalize the observed cytotoxic activity for the tested compounds. The anticancer activity of these compounds was evaluated in vitro against Caco-2, A549, HT1080, and Hela cell lines. Results revealed that two (5 and 7) of the three synthesized compounds (5, 6, and 7) showed high cytotoxic activity against all tested cell lines with IC50 values in the micro molar concentration. Our in vitro results show that there is no significant apoptotic effect for the treatment with the experimental compounds on the viability of cells against A549 cells. Ki67 expression was found to decrease significantly following the treatment of cells with the most promising candidate: drug 7. The overall results indicate that these pyrazolopyrimidine derivatives possess anticancer activity at varying doses. The suggested mechanism of action involves the inhibition of the proliferation of cancer cells. KW - pyrazolo[3,4-d]pyrimidine KW - anticancer activity KW - apoptosis KW - Ki67 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239734 SN - 1420-3049 VL - 26 IS - 10 ER - TY - JOUR A1 - Makbul, Cihan A1 - Khayenko, Vladimir A1 - Maric, Hans Michael A1 - Böttcher, Bettina T1 - Conformational Plasticity of Hepatitis B Core Protein Spikes Promotes Peptide Binding Independent of the Secretion Phenotype JF - Microorganisms N2 - Hepatitis B virus is a major human pathogen, which forms enveloped virus particles. During viral maturation, membrane-bound hepatitis B surface proteins package hepatitis B core protein capsids. This process is intercepted by certain peptides with an “LLGRMKG” motif that binds to the capsids at the tips of dimeric spikes. With microcalorimetry, electron cryo microscopy and peptide microarray-based screens, we have characterized the structural and thermodynamic properties of peptide binding to hepatitis B core protein capsids with different secretion phenotypes. The peptide “GSLLGRMKGA” binds weakly to hepatitis B core protein capsids and mutant capsids with a premature (F97L) or low-secretion phenotype (L60V and P5T). With electron cryo microscopy, we provide novel structures for L60V and P5T and demonstrate that binding occurs at the tips of the spikes at the dimer interface, splaying the helices apart independent of the secretion phenotype. Peptide array screening identifies “SLLGRM” as the core binding motif. This shortened motif binds only to one of the two spikes in the asymmetric unit of the capsid and induces a much smaller conformational change. Altogether, these comprehensive studies suggest that the tips of the spikes act as an autonomous binding platform that is unaffected by mutations that affect secretion phenotypes. KW - hepatitis B core protein KW - hepatitis B virus KW - peptide inhibitor of envelopment KW - isothermal titration calorimetry KW - electron cryo microscopy KW - low-secretion phenotype mutants KW - peptide microarray Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236720 SN - 2076-2607 VL - 9 IS - 5 ER - TY - JOUR A1 - Yu, Yidong A1 - Wolf, Ann-Katrin A1 - Thusek, Sina A1 - Heinekamp, Thorsten A1 - Bromley, Michael A1 - Krappmann, Sven A1 - Terpitz, Ulrich A1 - Voigt, Kerstin A1 - Brakhage, Axel A. A1 - Beilhack, Andreas T1 - Direct Visualization of Fungal Burden in Filamentous Fungus-Infected Silkworms JF - Journal of Fungi N2 - Invasive fungal infections (IFIs) are difficult to diagnose and to treat and, despite several available antifungal drugs, cause high mortality rates. In the past decades, the incidence of IFIs has continuously increased. More recently, SARS-CoV-2-associated lethal IFIs have been reported worldwide in critically ill patients. Combating IFIs requires a more profound understanding of fungal pathogenicity to facilitate the development of novel antifungal strategies. Animal models are indispensable for studying fungal infections and to develop new antifungals. However, using mammalian animal models faces various hurdles including ethical issues and high costs, which makes large-scale infection experiments extremely challenging. To overcome these limitations, we optimized an invertebrate model and introduced a simple calcofluor white (CW) staining protocol to macroscopically and microscopically monitor disease progression in silkworms (Bombyx mori) infected with the human pathogenic filamentous fungi Aspergillus fumigatus and Lichtheimia corymbifera. This advanced silkworm A. fumigatus infection model could validate knockout mutants with either attenuated, strongly attenuated or unchanged virulence. Finally, CW staining allowed us to efficiently visualize antifungal treatment outcomes in infected silkworms. Conclusively, we here present a powerful animal model combined with a straightforward staining protocol to expedite large-scale in vivo research of fungal pathogenicity and to investigate novel antifungal candidates. KW - fungal infection model KW - calcofluor white staining KW - Aspergillus KW - Lichtheimia KW - silkworm Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228855 SN - 2309-608X VL - 7 IS - 2 ER - TY - JOUR A1 - Link, Fabian A1 - Borges, Alyssa R. A1 - Jones, Nicola G. A1 - Engstler, Markus T1 - To the Surface and Back: Exo- and Endocytic Pathways in Trypanosoma brucei JF - Frontiers in Cell and Developmental Biology N2 - Trypanosoma brucei is one of only a few unicellular pathogens that thrives extracellularly in the vertebrate host. Consequently, the cell surface plays a critical role in both immune recognition and immune evasion. The variant surface glycoprotein (VSG) coats the entire surface of the parasite and acts as a flexible shield to protect invariant proteins against immune recognition. Antigenic variation of the VSG coat is the major virulence mechanism of trypanosomes. In addition, incessant motility of the parasite contributes to its immune evasion, as the resulting fluid flow on the cell surface drags immunocomplexes toward the flagellar pocket, where they are internalized. The flagellar pocket is the sole site of endo- and exocytosis in this organism. After internalization, VSG is rapidly recycled back to the surface, whereas host antibodies are thought to be transported to the lysosome for degradation. For this essential step to work, effective machineries for both sorting and recycling of VSGs must have evolved in trypanosomes. Our understanding of the mechanisms behind VSG recycling and VSG secretion, is by far not complete. This review provides an overview of the trypanosome secretory and endosomal pathways. Longstanding questions are pinpointed that, with the advent of novel technologies, might be answered in the near future. KW - cell surface KW - African trypanosomes KW - endocytosis KW - exocytosis KW - membrane recycling KW - Rab KW - clathrin Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244682 SN - 2296-634X VL - 9 ER - TY - JOUR A1 - Voulgari-Kokota, Anna A1 - Steffan-Dewenter, Ingolf A1 - Keller, Alexander T1 - Susceptibility of Red Mason Bee Larvae to Bacterial Threats Due to Microbiome Exchange with Imported Pollen Provisions JF - Insects N2 - Solitary bees are subject to a variety of pressures that cause severe population declines. Currently, habitat loss, temperature shifts, agrochemical exposure, and new parasites are identified as major threats. However, knowledge about detrimental bacteria is scarce, although they may disturb natural microbiomes, disturb nest environments, or harm the larvae directly. To address this gap, we investigated 12 Osmia bicornis nests with deceased larvae and 31 nests with healthy larvae from the same localities in a 16S ribosomal RNA (rRNA) gene metabarcoding study. We sampled larvae, pollen provisions, and nest material and then contrasted bacterial community composition and diversity in healthy and deceased nests. Microbiomes of pollen provisions and larvae showed similarities for healthy larvae, whilst this was not the case for deceased individuals. We identified three bacterial taxa assigned to Paenibacillus sp. (closely related to P. pabuli/amylolyticus/xylanexedens), Sporosarcina sp., and Bacillus sp. as indicative for bacterial communities of deceased larvae, as well as Lactobacillus for corresponding pollen provisions. Furthermore, we performed a provisioning experiment, where we fed larvae with untreated and sterilized pollens, as well as sterilized pollens inoculated with a Bacillus sp. isolate from a deceased larva. Untreated larval microbiomes were consistent with that of the pollen provided. Sterilized pollen alone did not lead to acute mortality, while no microbiome was recoverable from the larvae. In the inoculation treatment, we observed that larval microbiomes were dominated by the seeded bacterium, which resulted in enhanced mortality. These results support that larval microbiomes are strongly determined by the pollen provisions. Further, they underline the need for further investigation of the impact of detrimental bacterial acquired via pollens and potential buffering by a diverse pollen provision microbiome in solitary bees. KW - Osmia bicornis KW - solitary bee KW - bacterial transmission KW - microbiome KW - pollen provisions KW - pathogen KW - secondary invader KW - Paenibacillus KW - Bacillus KW - Sporosarcina Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-207948 SN - 2075-4450 VL - 11 IS - 6 ER - TY - JOUR A1 - Li, Kunkun A1 - Prada, Juan A1 - Damineli, Daniel S. C. A1 - Liese, Anja A1 - Romeis, Tina A1 - Dandekar, Thomas A1 - Feijó, José A. A1 - Hedrich, Rainer A1 - Konrad, Kai Robert T1 - An optimized genetically encoded dual reporter for simultaneous ratio imaging of Ca\(^{2+}\) and H\(^{+}\) reveals new insights into ion signaling in plants JF - New Phytologist N2 - Whereas the role of calcium ions (Ca\(^{2+}\)) in plant signaling is well studied, the physiological significance of pH‐changes remains largely undefined. Here we developed CapHensor, an optimized dual‐reporter for simultaneous Ca\(^{2+}\) and pH ratio‐imaging and studied signaling events in pollen tubes (PTs), guard cells (GCs), and mesophyll cells (MCs). Monitoring spatio‐temporal relationships between membrane voltage, Ca\(^{2+}\)‐ and pH‐dynamics revealed interconnections previously not described. In tobacco PTs, we demonstrated Ca\(^{2+}\)‐dynamics lag behind pH‐dynamics during oscillatory growth, and pH correlates more with growth than Ca\(^{2+}\). In GCs, we demonstrated abscisic acid (ABA) to initiate stomatal closure via rapid cytosolic alkalization followed by Ca2+ elevation. Preventing the alkalization blocked GC ABA‐responses and even opened stomata in the presence of ABA, disclosing an important pH‐dependent GC signaling node. In MCs, a flg22‐induced membrane depolarization preceded Ca2+‐increases and cytosolic acidification by c. 2 min, suggesting a Ca\(^{2+}\)/pH‐independent early pathogen signaling step. Imaging Ca2+ and pH resolved similar cytosol and nuclear signals and demonstrated flg22, but not ABA and hydrogen peroxide to initiate rapid membrane voltage‐, Ca\(^{2+}\)‐ and pH‐responses. We propose close interrelation in Ca\(^{2+}\)‐ and pH‐signaling that is cell type‐ and stimulus‐specific and the pH having crucial roles in regulating PT growth and stomata movement. KW - abscisic acid (ABA) KW - calcium KW - flg22 KW - guard cells KW - imaging KW - ion signaling KW - pH KW - pollen tube Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239847 VL - 230 IS - 6 SP - 2292 EP - 2310 ER - TY - JOUR A1 - Kriegel, Peter A1 - Fritze, Michael‐Andreas A1 - Thorn, Simon T1 - Surface temperature and shrub cover drive ground beetle (Coleoptera: Carabidae) assemblages in short‐rotation coppices JF - Agricultural and Forest Entomology N2 - Increasing demand for biomass has led to an on‐going intensification of fuel wood plantations with possible negative effects on open land biodiversity. Hence, ecologists increasingly call for measures that reduce those negative effects on associated biodiversity. However, our knowledge about the efficiency of such measures remains scarce. We investigated the effects of gap implementation in short rotation coppices (SRCs) on carabid diversity and assemblage composition over 3 years, with pitfall traps in gaps, edges and interiors. In parallel, we quantified soil surface temperature, shrub‐ and herb cover. Edges had the highest number of species and abundances per trap, whereas rarefied species richness was significantly lower in short rotation coppice interiors than in other habitat types. Carabid community composition differed significantly between habitat types. The main environmental drivers were temperature for number of species and abundance and shrub cover for rarefied species richness. We found significantly higher rarefied species richness in gaps compared with interiors. Hence, we argue that gap implementation benefits overall diversity in short rotation coppices. Furthermore, the differences in species community composition between habitat types through increased species turnover support carabid diversity in short rotation coppices. These positive effects were largely attributed to microclimate conditions. However, to maintain positive effects, continuous management of herb layer might be necessary. KW - Carabidae KW - fuel wood KW - short‐rotation coppice KW - shrub‐cover KW - temperature Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239873 VL - 23 IS - 4 SP - 400 EP - 410 ER - TY - JOUR A1 - Sauer, Markus A1 - Juranek, Stefan A. A1 - Marks, James A1 - De Magis, Alessio A1 - Kazemier, Hinke G A1 - Hilbig, Daniel A1 - Benhalevy, Daniel A1 - Wang, Xiantao A1 - Hafner, Markus A1 - Paeschke, Katrin T1 - DHX36 prevents the accumulation of translationally inactive mRNAs with G4-structures in untranslated regions JF - Nature Communications N2 - Translation efficiency can be affected by mRNA stability and secondary structures, including G-quadruplex structures (G4s). The highly conserved DEAH-box helicase DHX36/RHAU resolves G4s on DNA and RNA in vitro, however a systems-wide analysis of DHX36 targets and function is lacking. We map globally DHX36 binding to RNA in human cell lines and find it preferentially interacting with G-rich and G4-forming sequences on more than 4500 mRNAs. While DHX36 knockout (KO) results in a significant increase in target mRNA abundance, ribosome occupancy and protein output from these targets decrease, suggesting that they were rendered translationally incompetent. Considering that DHX36 targets, harboring G4s, preferentially localize in stress granules, and that DHX36 KO results in increased SG formation and protein kinase R (PKR/EIF2AK2) phosphorylation, we speculate that DHX36 is involved in resolution of rG4 induced cellular stress. KW - RNA metabolism KW - Translation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227486 VL - 10 IS - 2421 ER - TY - JOUR A1 - Habenstein, Jens A1 - Schmitt, Franziska A1 - Liessem, Sander A1 - Ly, Alice A1 - Trede, Dennis A1 - Wegener, Christian A1 - Predel, Reinhard A1 - Rössler, Wolfgang A1 - Neupert, Susanne T1 - Transcriptomic, peptidomic, and mass spectrometry imaging analysis of the brain in the ant Cataglyphis nodus JF - Journal of Neurochemistry N2 - Behavioral flexibility is an important cornerstone for the ecological success of animals. Social Cataglyphis nodus ants with their age‐related polyethism characterized by age‐related behavioral phenotypes represent a prime example for behavioral flexibility. We propose neuropeptides as powerful candidates for the flexible modulation of age‐related behavioral transitions in individual ants. As the neuropeptidome of C. nodus was unknown, we collected a comprehensive peptidomic data set obtained by transcriptome analysis of the ants’ central nervous system combined with brain extract analysis by Q‐Exactive Orbitrap mass spectrometry (MS) and direct tissue profiling of different regions of the brain by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) MS. In total, we identified 71 peptides with likely bioactive function, encoded on 49 neuropeptide‐, neuropeptide‐like, and protein hormone prepropeptide genes, including a novel neuropeptide‐like gene (fliktin). We next characterized the spatial distribution of a subset of peptides encoded on 16 precursor proteins with high resolution by MALDI MS imaging (MALDI MSI) on 14 µm brain sections. The accuracy of our MSI data were confirmed by matching the immunostaining patterns for tachykinins with MSI ion images from consecutive brain sections. Our data provide a solid framework for future research into spatially resolved qualitative and quantitative peptidomic changes associated with stage‐specific behavioral transitions and the functional role of neuropeptides in Cataglyphis ants. KW - brain KW - MALDI imaging KW - neuropeptides KW - neuropeptidomics KW - social insect KW - transcriptomics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239917 VL - 158 IS - 2 SP - 391 EP - 412 ER - TY - JOUR A1 - Wohlwend, Michael R. A1 - Craven, Dylan A1 - Weigelt, Patrick A1 - Seebens, Hanno A1 - Winter, Marten A1 - Kreft, Holger A1 - Zurell, Damaris A1 - Sarmento Cabral, Juliano A1 - Essl, Franz A1 - van Kleunen, Mark A1 - Pergl, Jan A1 - Pyšek, Petr A1 - Knight, Tiffany M. T1 - Anthropogenic and environmental drivers shape diversity of naturalized plants across the Pacific JF - Diversity and Distributions N2 - Aim The Pacific exhibits an exceptional number of naturalized plant species, but the drivers of this high diversity and the associated compositional patterns remain largely unknown. Here, we aim to (a) improve our understanding of introduction and establishment processes and (b) evaluate whether this information is sufficient to create scientific conservation tools, such as watchlists. Location Islands in the Pacific Ocean, excluding larger islands such as New Zealand, Japan, the Philippines and Indonesia. Methods We combined information from the most up‐to‐date data sources to quantify naturalized plant species richness and turnover across island groups and investigate the effects of anthropogenic, biogeographic and climate drivers on these patterns. In total, we found 2,672 naturalized plant species across 481 islands and 50 island groups, with a total of 11,074 records. Results Most naturalized species were restricted to few island groups, and most island groups have a low number of naturalized species. Island groups with few naturalized species were characterized by a set of widespread naturalized species. Several plant families that contributed many naturalized species globally also did so in the Pacific, particularly Fabaceae and Poaceae. However, many families were significantly over‐ or under‐represented in the Pacific naturalized flora compared to other regions of the world. Naturalized species richness increased primarily with increased human activity and island altitude/area, whereas similarity between island groups in temperature along with richness differences was most important for beta diversity. Main conclusions The distribution and richness of naturalized species can be explained by a small set of drivers. The Pacific region contains many naturalized plant species also naturalized in other regions in the world, but our results highlight key differences such as a stronger role of anthropogenic drivers in shaping diversity patterns. Our results establish a basis for predicting and preventing future naturalizations in a threatened biodiversity hotspot. KW - anthropogenic drivers KW - beta diversity KW - island biogeography KW - naturalized species KW - Pacific Ocean KW - plant invasion Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239925 VL - 27 IS - 6 SP - 1120 EP - 1133 ER - TY - JOUR A1 - Sponsler, Douglas B. A1 - Bratman, Eve Z. T1 - Beekeeping in, of or for the city? A socioecological perspective on urban apiculture JF - People and Nature N2 - The term ‘urban beekeeping’ connotes a host of meanings—sociopolitical, commercial, ecological and personal—beyond the mere description of where bees and beekeepers happen to coincide. Yet, these meanings are seldom articulated explicitly or brought into critical engagement with the relevant fields of urban ecology and political ecology. Beginning with a brief account of the history of urban beekeeping in the United States, we draw upon urban ecological theory to construct a conceptual model of urban beekeeping that distinguishes beekeeping in, of and for the city. In our model, beekeeping in the city describes the mere importation of the traditionally rural practice of beekeeping into urban spaces for the private reasons of the individual beekeeper, whereas beekeeping of the city describes beekeeping that is consciously tailored to the urban context, often accompanied by (semi)professionalization of beekeepers and the formation of local expert communities (i.e. beekeeping associations). Beekeeping for the city describes a shift in mindset in which beekeeping is directed to civic ends beyond the boundaries of the beekeeping community per se. Using this framework, we identify and discuss specific socioecological assets and liabilities of urban beekeeping, and how these relate to beekeeping in, of and for the city. We then formulate actionable guidelines for maturing the practice of urban beekeeping into a beneficent and self‐critical form of urban ecological citizenship; these include fostering self‐regulation within the beekeeping community, harnessing beekeeping as a ‘gateway’ experience for a broader rapprochement between urban residents and nature, and recognizing the political‐ecological context of beekeeping with respect to matters of socioecological justice. KW - environmental justice KW - honey bee KW - multispecies studies KW - policy KW - pollinator KW - urban greening Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239949 VL - 3 IS - 3 SP - 550 EP - 559 ER - TY - JOUR A1 - Mayr, Antonia V. A1 - Keller, Alexander A1 - Peters, Marcell K. A1 - Grimmer, Gudrun A1 - Krischke, Beate A1 - Geyer, Mareen A1 - Schmitt, Thomas A1 - Steffan‐Dewenter, Ingolf T1 - Cryptic species and hidden ecological interactions of halictine bees along an elevational gradient JF - Ecology and Evolution N2 - Changes of abiotic and biotic conditions along elevational gradients represent serious challenges to organisms which may promote the turnover of species, traits and biotic interaction partners. Here, we used molecular methods to study cuticular hydrocarbon (CHC) profiles, biotic interactions and phylogenetic relationships of halictid bees of the genus Lasioglossum along a 2,900 m elevational gradient at Mt. Kilimanjaro, Tanzania. We detected a strong species turnover of morphologically indistinguishable taxa with phylogenetically clustered cryptic species at high elevations, changes in CHC profiles, pollen resource diversity, and a turnover in the gut and body surface microbiome of bees. At high elevations, increased proportions of saturated compounds in CHC profiles indicate physiological adaptations to prevent desiccation. More specialized diets with higher proportions of low‐quality Asteraceae pollen imply constraints in the availability of food resources. Interactive effects of climatic conditions on gut and surface microbiomes, CHC profiles, and pollen diet suggest complex feedbacks among abiotic conditions, ecological interactions, physiological adaptations, and phylogenetic constraints as drivers of halictid bee communities at Mt. Kilimanjaro. KW - COI KW - cuticular chemistry KW - elevational gradient KW - Halictidae KW - microbiome metabarcoding KW - pollen metabarcoding Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238853 VL - 11 IS - 12 SP - 7700 EP - 7712 ER - TY - JOUR A1 - Vogel, Sebastian A1 - Prinzing, Andreas A1 - Bußler, Heinz A1 - Müller, Jörg A1 - Schmidt, Stefan A1 - Thorn, Simon T1 - Abundance, not diversity, of host beetle communities determines abundance and diversity of parasitoids in deadwood JF - Ecology and Evolution N2 - Most parasites and parasitoids are adapted to overcome defense mechanisms of their specific hosts and hence colonize a narrow range of host species. Accordingly, an increase in host functional or phylogenetic dissimilarity is expected to increase the species diversity of parasitoids. However, the local diversity of parasitoids may be driven by the accessibility and detectability of hosts, both increasing with increasing host abundance. Yet, the relative importance of these two mechanisms remains unclear. We parallelly reared communities of saproxylic beetle as potential hosts and associated parasitoid Hymenoptera from experimentally felled trees. The dissimilarity of beetle communities was inferred from distances in seven functional traits and from their evolutionary ancestry. We tested the effect of host abundance, species richness, functional, and phylogenetic dissimilarities on the abundance, species richness, and Shannon diversity of parasitoids. Our results showed an increase of abundance, species richness, and Shannon diversity of parasitoids with increasing beetle abundance. Additionally, abundance of parasitoids increased with increasing species richness of beetles. However, functional and phylogenetic dissimilarity showed no effect on the diversity of parasitoids. Our results suggest that the local diversity of parasitoids, of ephemeral and hidden resources like saproxylic beetles, is highest when resources are abundant and thereby detectable and accessible. Hence, in some cases, resources do not need to be diverse to promote parasitoid diversity. KW - barcoding KW - deadwood KW - experiment KW - host–parasitoid interaction KW - natural enemy KW - specialization Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238892 VL - 11 IS - 11 SP - 6881 EP - 6888 ER - TY - JOUR A1 - Leidinger, Ludwig A1 - Vedder, Daniel A1 - Cabral, Juliano Sarmento T1 - Temporal environmental variation may impose differential selection on both genomic and ecological traits JF - Oikos N2 - The response of populations and species to changing conditions determines how community composition will change functionally, including via trait shifts. Selection from standing variation has been suggested to be more efficient than acquiring new mutations. Yet, studies on community trait composition and trait selection largely focus on phenotypic variation in ecological traits, whereas the underlying genomic traits remain understudied. Using a genome‐explicit, niche‐ and individual‐based model, we address the potential interactions between genomic and ecological traits shaping communities under an environmental selective forcing, namely temporal positively autocorrelated environmental fluctuation. In this model, all ecological traits are explicitly coded by the genome. For our experiments, we initialized 90 replicate communities, each with ca 350 initial species, characterized by random genomic and ecological trait combinations, on a 2D spatially explicit landscape with two orthogonal gradients (temperature and resource use). We exposed each community to two contrasting scenarios: without (i.e. static environments) and with temporal variation. We then analyzed emerging compositions of both genomic and ecological traits at the community, population and genomic levels. Communities in variable environments were species poorer than in static environments, and populations more abundant, whereas genomes had lower genetic linkage, mean genetic variation and a non‐significant tendency towards higher numbers of genes. The surviving genomes (i.e. those selected by variable environments) coded for enhanced environmental tolerance and smaller biomass, which resulted in faster life cycles and thus also in increased potential for evolutionary rescue. Under temporal environmental variation, larger, less linked genomes retained more variation in mean dispersal ability at the population level than at genomic level, whereas the opposite trend emerged for biomass. Our results provide clues to how sexually‐reproducing diploid plant communities might react to variable environments and highlights the importance of genomic traits and their interaction with ecological traits for eco‐evolutionary responses to changing climates. KW - environmental variability KW - genomic traits KW - mechanistic model KW - rapid evolution KW - standing variation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238945 VL - 130 IS - 7 SP - 1100 EP - 1115 ER - TY - JOUR A1 - Haack, Stephanie A1 - Baiker, Sarah A1 - Schlegel, Jan A1 - Sauer, Markus A1 - Sparwasser, Tim A1 - Langenhorst, Daniela A1 - Beyersdorf, Niklas T1 - Superagonistic CD28 stimulation induces IFN‐γ release from mouse T helper 1 cells in vitro and in vivo JF - European Journal of Immunology N2 - Like human Th1 cells, mouse Th1 cells also secrete IFN‐γ upon stimulation with a superagonistic anti‐CD28 monoclonal antibody (CD28‐SA). Crosslinking of the CD28‐SA via FcR and CD40‐CD40L interactions greatly increased IFN‐γ release. Our data stress the utility of the mouse as a model organism for immune responses in humans. KW - CD28 KW - Th1 cells KW - cytokine release KW - interferon γ KW - Superagonistic antibody Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239028 VL - 51 IS - 3 SP - 738 EP - 741 ER - TY - JOUR A1 - Sieger, Charlotte Sophie A1 - Hovestadt, Thomas T1 - The degree of spatial variation relative to temporal variation influences evolution of dispersal JF - Oikos N2 - In the face of ongoing global climate and land use change, organisms have multiple possibilities to cope with the modification of their environment. The two main possibilities are to either adapt locally or disperse to a more suitable habitat. The evolution of both local adaptation and dispersal interacts and can be influenced by the spatial and temporal variation (of e.g. temperature or precipitation). In an individual based model (IBM), we explore evolution of phenotypes in landscapes with varying degree of spatial relative to global temporal variation in order to examine its influence on the evolution of dispersal, niche optimum and niche width. The relationship between temporal and spatial variation did neither influence the evolution of local adaptation in the niche optimum nor of niche widths. Dispersal probability is highly influenced by the spatio‐temporal relationship: with increasing spatial variation, dispersal probability decreases. Additionally, the shape of the distribution of the trait values over patch attributes switches from hump‐ to U‐shaped. At low spatial variance more individuals emigrate from average habitats, at high spatial variance more from extreme habitats. The comparatively high dispersal probability in extreme patches of landscapes with a high spatial variation can be explained by evolutionary succession of two kinds of adaptive response. Early in the simulations, extreme patches in landscapes with a high spatial variability act as sink habitats, where population persistence depends on highly dispersive individuals with a wide niche. With ongoing evolution, local adaptation of the remaining individuals takes over, but simultaneously a possible bet‐hedging strategy promotes higher dispersal probabilities in those habitats. Here, in generations that experience extreme shifts from the temporal mean of the patch attribute, the expected fitness becomes higher for dispersing individuals than for philopatric individuals. This means that under certain circumstances, both local adaptation and high dispersal probability can be selected for for coping with the projected environmental changes in the future. KW - bet-hedging KW - dispersal KW - ecological niche KW - evolution KW - individual based model KW - spatial variation KW - temporal variation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239049 VL - 129 IS - 11 SP - 1611 EP - 1622 ER - TY - JOUR A1 - Schenk, Mariela A1 - Krauss, Jochen A1 - Holzschuh, Andrea T1 - Desynchronizations in bee-plant interactions cause severe fitness losses in solitary bees JF - Journal of Animal Ecology N2 - 1. Global warming can disrupt mutualistic interactions between solitary bees and plants when increasing temperature differentially changes the timing of interacting partners. One possible scenario is for insect phenology to advance more rapidly than plant phenology. 2. However, empirical evidence for fitness consequences due to temporal mismatches is lacking for pollinators and it remains unknown if bees have developed strategies to mitigate fitness losses following temporal mismatches. 3. We tested the effect of temporal mismatches on the fitness of three spring-emerging solitary bee species, including one pollen specialist. Using flight cages, we simulated (i) a perfect synchronization (from a bee perspective): bees and flowers occur simultaneously, (ii) a mismatch of 3days and (iii) a mismatch of 6days, with bees occurring earlier than flowers in the latter two cases. 4. A mismatch of 6days caused severe fitness losses in all three bee species, as few bees survived without flowers. Females showed strongly reduced activity and reproductive output compared to synchronized bees. Fitness consequences of a 3-day mismatch were species-specific. Both the early-spring species Osmia cornuta and the mid-spring species Osmia bicornis produced the same number of brood cells after a mismatch of 3days as under perfect synchronization. However, O.cornuta decreased the number of female offspring, whereas O.bicornis spread the brood cells over fewer nests, which may increase offspring mortality, e.g. due to parasitoids. The late-spring specialist Osmia brevicornis produced fewer brood cells even after a mismatch of 3days. Additionally, our results suggest that fitness losses after temporal mismatches are higher during warm than cold springs, as the naturally occurring temperature variability revealed that warm temperatures during starvation decreased the survival rate of O.bicornis. 5. We conclude that short temporal mismatches can cause clear fitness losses in solitary bees. Although our results suggest that bees have evolved species-specific strategies to mitigate fitness losses after temporal mismatches, the bees were not able to completely compensate for impacts on their fitness after temporal mismatches with their food resources. KW - conditional sex allocation KW - emergence KW - mitigation strategies KW - mutualism KW - phenological shift KW - pollination KW - species interactions KW - pollinator interactions KW - climate-change KW - phenological response Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228533 VL - 87 IS - 1 ER - TY - JOUR A1 - Christopher D., Pull A1 - Ugelvig, Line V. A1 - Wiesenhofer, Florian A1 - Anna V., Grasse A1 - Tragust, Simon A1 - Schmitt, Thomas A1 - Brown, Mark JF A1 - Cremer, Sylvia T1 - Destructive disinfection of infected brood prevents systemic disease spread in ant colonies JF - eLIFE N2 - In social groups, infections have the potential to spread rapidly and cause disease outbreaks. Here, we show that in a social insect, the ant Lasius neglectus, the negative consequences of fungal infections (Metarhizium brunneum) can be mitigated by employing an efficient multicomponent behaviour, termed destructive disinfection, which prevents further spread of the disease through the colony. Ants specifically target infected pupae during the pathogens non-contagious incubation period, utilising chemical 'sickness cues' emitted by pupae. They then remove the pupal cocoon, perforate its cuticle and administer antimicrobial poison, which enters the body and prevents pathogen replication from the inside out. Like the immune system of a metazoan body that specifically targets and eliminates infected cells, ants destroy infected brood to stop the pathogen completing its lifecycle, thus protecting the rest of the colony. Hence, in an analogous fashion, the same principles of disease defence apply at different levels of biological organisation. KW - division of labor KW - Fungal cell-walls KW - Leaf cutting ants KW - Metarhizium anisopliae KW - Beauveria bassiana Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223728 VL - 7 ER - TY - THES A1 - Eiring, Patrick T1 - Super-resolution microscopy of plasma membrane receptors T1 - Hochauflösende Mikroskopie von Plasmamembran Rezeptoren N2 - Plasma membrane receptors are the most crucial and most commonly studied components of cells, since they not only ensure communication between the extracellular space and cells, but are also responsible for the regulation of cell cycle and cell division. The composition of the surface receptors, the so-called "Receptome", differs and is characteristic for certain cell types. Due to their significance, receptors have been important target structures for diagnostic and therapy in cancer medicine and often show aberrant expression patterns in various cancers compared to healthy cells. However, these aberrations can also be exploited and targeted by different medical approaches, as in the case of personalized immunotherapy. In addition, advances in modern fluorescence microscopy by so-called single molecule techniques allow for unprecedented sensitive visualization and quantification of molecules with an attainable spatial resolution of 10-20 nm, allowing for the detection of both stoichiometric and expression density differences. In this work, the single molecule sensitive method dSTORM was applied to quantify the receptor composition of various cell lines as well as in primary samples obtained from patients with hematologic malignancies. The focus of this work lies on artefact free quantification, stoichiometric analyses of oligomerization states and co localization analyses of membrane receptors. Basic requirements for the quantification of receptors are dyes with good photoswitching properties and labels that specifically mark the target structure without generating background through non-specific binding. To ensure this, antibodies with a predefined DOL (degree of labeling) were used, which are also standard in flow cytometry. First background reduction protocols were established on cell lines prior analyses in primary patient samples. Quantitative analyses showed clear expression differences between the cell lines and the patient cells, but also between individual patients. An important component of this work is the ability to detect the oligomerization states of receptors, which enables a more accurate quantification of membrane receptor densities compared to standard flow cytometry. It also provides information about the activation of a certain receptor, for example of FLT3, a tyrosine kinase, dimerizing upon activation. For this purpose, different well-known monomers and dimers were compared to distinguish the typical localization statistics of single bound antibodies from two or more antibodies that are in proximity. Further experiments as well as co localization analyses proved that antibodies can bind to closely adjacent epitopes despite their size. These analytical methods were subsequently applied for quantification and visualization of receptors in two clinically relevant examples. Firstly, various therapeutically relevant receptors such as CD38, BCMA and SLAMF7 for multiple myeloma, a malignant disease of plasma cells, were analyzed and quantified on patient cells. Furthermore, the influence of TP53 and KRAS mutations on receptor expression levels was investigated using the multiple myeloma cell lines OPM2 and AMO1, showing clear differences in certain receptor quantities. Secondly, FLT3 which is a therapeutic target receptor for acute myeloid leukemia, was quantified and stoichiometrically analyzed on both cell lines and patient cells. In addition, cells that have developed resistance against midostaurin were compared with cells that still respond to this type I tyrosine-kinase-inhibitor for their FLT3 receptor expression and oligomerization state. N2 - Plasmamembranrezeptoren sind die wohl wichtigsten und meist untersuchten Komponenten einer Zelle, da sie nicht nur die Kommunikation zwischen dem extrazellulären Bereich und den Zellen gewährleisten, sondern auch für die Regulierung des Zellzyklus und der Zellteilung zuständig sind. Dabei unterscheidet sich die Zusammensetzung der Oberflächenrezeptoren, das sogenannte „Rezeptom“, und ist charakteristisch für bestimme Zelltypen. Aufgrund ihrer Bedeutsamkeit sind Rezeptoren wichtige Zielstrukturen für Diagnose und Therapie in der Krebsmedizin, welche häufig bei verschiedensten Krebserkrankungen im Vergleich zu gesunden Zellen aberrante Expressionsmuster aufweisen. Diese Abweichungen können sich allerdings auch zu Nutze gemacht werden und zum Ziel verschiedener medizinischer Behandlungsmethoden, wie es bei der personalisierten Immuntherapie der Fall ist, werden. Zusätzlich hat der Fortschritt in der modernen Fluoreszenzmikroskopie durch sogenannte Einzelmolekültechniken, es auch erlaubt, eine noch nie dagewesene empfindliche Visualisierung und Quantifizierung von Molekülen mit einer räumlichen Auflösung von 10-20 nm zu erreichen, wodurch sowohl stöchiometrische Unterschiede, als auch Unterschiede in der Expressionsdichte detektiert werden können. In dieser Arbeit wurde die einzelmolekülsensitive Methode dSTORM genutzt, um die Rezeptorkomposition von verschiedenen Zelllinien aber auch von primären Patientenzellen mit zugrundeliegenden hämatologischen Erkrankungen zu quantifizieren. Schwerpunkte dieser Arbeit sind dabei die artefaktfreie Quantifizierung, stöchiometrische Analysen von Oligomerisierungszuständen, sowie die Kolokalisationsanalyse von Membranrezeptoren. Grundvoraussetzung für die Quantifizierung von Rezeptoren sind dabei gut schaltbare Farbstoffe, sowie Label, welche die Zielstruktur spezifisch markieren ohne dabei Hintergrund durch unspezifische Bindung zu generieren. Um dies zu gewährleisten, kamen Antikörper mit einem vordefinierten DOL (degree of labeling; engl. für: Markierungsgrad) zum Einsatz, welche auch in der Durchflusszytometrie standardmäßig eingesetzt werden. Protokolle zur Hintergrundreduktion wurden dabei an Zelllinien etabliert, bevor Primärzellen von Krebspatienten analysiert wurden. Durch quantitative Analysen konnten dabei deutliche Expressionsunterschiede zwischen den Zelllinien und den Patientenzellen, aber auch zwischen den verschiedenen Patienten gezeigt werden. Ein wichtiger Bestandteil dieser Arbeit ist die Fähigkeit, den Oligomerisierungszustand von Rezeptoren zu erkennen, was eine genauere Quantifizierung der Membran-rezeptordichten im Vergleich zur Durchflusszytometrie ermöglicht. Allerdings können diese Oligomerisierungszustände auch Informationen über die Aktivierung eines Rezeptors beinhalten, wie zum Beispiel von FLT3, einer Tyrosinkinase, welche zur Aktivierung dimerisieren muss. Hierfür wurden verschiedene bekannte Monomere und Dimere verglichen, um die typische Lokalisationsstatistik von vereinzelten gebundenen Antikörpern mit der von zwei oder mehr Antikörpern, welche nah beieinanderliegen, zu vergleichen. Durch weitere Etablierungsexperimente sowie Kolokalisationsanalysen konnte außerdem bewiesen werden, dass Antikörper trotz ihrer Größe auch an nah benachbarte Epitope binden können. Diese Analyseverfahren wurden im weiteren Verlauf zur Quantifizierung und Visualisierung von Rezeptoren an zwei klinisch relevanten Beispielen angewendet. Zum einen wurden verschiedene therapeutisch relevante Rezeptoren wie z.B. CD38, BCMA und SLAMF7 für das Multiple Myelom, einer malignen Erkrankung von Plasmazellen, auf Patientenzellen analysiert und quantifiziert. Zusätzlich wurde der Einfluss von TP53 und KRAS Mutationen auf die Rezeptorexpressionen anhand der Multiplen Myelom Zelllinien OPM2 und AMO1 untersucht, bei denen eindeutige Unterschiede in der Rezeptorexpression detektiert wurden. Zum anderen wurde FLT3, welches ein therapeutischer Zielrezeptor für die akute myeloische Leukämie ist, sowohl auf Zelllinien als auch auf Patientenzellen quantifiziert und stöchiometrisch analysiert. Hierbei wurden auch Zellen welche eine Midostaurinresistenz entwickelt haben mit Zellen, welche auf diesen Typ I Tyrosinkinase Inhibitor ansprechen, auf ihre FLT3 Rezeptorexpression und ihren Oligomerisierungszustand verglichen. KW - Fluoreszenzmikroskopie KW - Membranrezeptor KW - Hochaufgelöste Fluoreszenzmikroskopie KW - Super-resolution microscopy KW - Membrane receptor Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250048 ER - TY - JOUR A1 - Mayer, Alexander E. A1 - Löffler, Mona C. A1 - Loza Valdés, Angel E. A1 - Schmitz, Werner A1 - El-Merahbi, Rabih A1 - Trujillo-Viera, Jonathan A1 - Erk, Manuela A1 - Zhang, Thianzhou A1 - Braun, Ursula A1 - Heikenwalder, Mathias A1 - Leitges, Michael A1 - Schulze, Almut A1 - Sumara, Grzegorz T1 - The kinase PKD3 provides negative feedback on cholesterol and triglyceride synthesis by suppressing insulin signaling JF - Science Signaling N2 - Hepatic activation of protein kinase C (PKC) isoforms by diacylglycerol (DAG) promotes insulin resistance and contributes to the development of type 2 diabetes (T2D). The closely related protein kinase D (PKD) isoforms act as effectors for DAG and PKC. Here, we showed that PKD3 was the predominant PKD isoform expressed in hepatocytes and was activated by lipid overload. PKD3 suppressed the activity of downstream insulin effectors including the kinase AKT and mechanistic target of rapamycin complex 1 and 2 (mTORC1 and mTORC2). Hepatic deletion of PKD3 in mice improved insulin-induced glucose tolerance. However, increased insulin signaling in the absence of PKD3 promoted lipogenesis mediated by SREBP (sterol regulatory element-binding protein) and consequently increased triglyceride and cholesterol content in the livers of PKD3-deficient mice fed a high-fat diet. Conversely, hepatic-specific overexpression of a constitutively active PKD3 mutant suppressed insulin-induced signaling and caused insulin resistance. Our results indicate that PKD3 provides feedback on hepatic lipid production and suppresses insulin signaling. Therefore, manipulation of PKD3 activity could be used to decrease hepatic lipid content or improve hepatic insulin sensitivity. KW - Protein kinase D3 (PKD3) KW - cholesterol KW - diacylglycerol (DAG) KW - liver KW - metabolism Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250025 ET - accepted manuscript ER - TY - THES A1 - Habenstein, Jens T1 - Neuropeptides in the brain of \(Cataglyphis\) \(nodus\) ants and their role as potential modulators of behavior T1 - Neuropeptide im Gehirn von \(Cataglyphis\) \(nodus\) Ameisen und ihre Rolle als potenzielle Modulatoren von Verhalten N2 - An adequate task allocation among colony members is of particular importance in large insect societies. Some species exhibit distinct polymorphic worker classes which are responsible for a specific range of tasks. However, much more often the behavior of the workers is related to the age of the individual. Ants of the genus Cataglyphis (Foerster 1850) undergo a marked age-related polyethism with three distinct behavioral stages. Newly emerged ants (callows) remain more or less motionless in the nest for the first day. The ants subsequently fulfill different tasks inside the darkness of the nest for up to four weeks (interior workers) before they finally leave the nest to collect food for the colony (foragers). This thesis focuses on the neuronal substrate underlying the temporal polyethism in Cataglyphis nodus ants by addressing following major objectives: (1) Investigating the structures and neuronal circuitries of the Cataglyphis brain to understand potential effects of neuromodulators in specific brain neuropils. (2) Identification and localization of neuropeptides in the Cataglyphis brain. (3) Examining the expression of suitable neuropeptide candidates during behavioral maturation of Cataglyphis workers. The brain provides the fundament for the control of the behavioral output of an insect. Although the importance of the central nervous system is known beyond doubt, the functional significance of large areas of the insect brain are not completely understood. In Cataglyphis ants, previous studies focused almost exclusively on major neuropils while large proportions of the central protocerebrum have been often disregarded due to the lack of clear boundaries. Therefore, I reconstructed a three-dimensional Cataglyphis brain employing confocal laser scanning microscopy. To visualize synapsin-rich neuropils and fiber tracts, a combination of fluorescently labeled antibodies, phalloidin (a cyclic peptide binding to filamentous actin) and anterograde tracers was used. Based on the unified nomenclature for insect brains, I defined traceable criteria for the demarcation of individual neuropils. The resulting three-dimensional brain atlas provides information about 33 distinct synapse-rich neuropils and 30 fiber tracts, including a comprehensive description of the olfactory and visual tracts in the Cataglyphis brain. This three-dimensional brain atlas further allows to assign present neuromodulators to individual brain neuropils. Neuropeptides represent the largest group of neuromodulators in the central nervous system of insects. They regulate important physiological and behavioral processes and have therefore recently been associated with the regulation of the temporal polyethism in social insects. To date, the knowledge of neuropeptides in Cataglyphis ants has been mainly derived from neuropeptidomic data of Camponotus floridanus ants and only a few neuropeptides have been characterized in Cataglyphis. Therefore, I performed a comprehensive transcriptome analysis in Cataglyphis nodus ants and identified peptides by using Q-Exactive Orbitrap mass spectrometry (MS) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. This resulted in the characterization of 71 peptides encoded on 49 prepropeptide genes, including a novel neuropeptide-like gene (fliktin). In addition, high-resolution MALDI-TOF MS imaging (MALDI-MSI) was applied for the first time in an ant brain to localize peptides on thin brain cryosections. Employing MALDI-MSI, I was able to visualize the spatial distribution of 35 peptides encoded on 16 genes. To investigate the role of neuropeptides during behavioral maturation, I selected suitable neuropeptide candidates and analyzed their spatial distributions and expression levels following major behavioral transitions. Based on recent studies, I suggested the neuropeptides allatostatin-A (Ast-A), corazonin (Crz) and tachykinin (TK) as potential regulators of the temporal polyethism. The peptidergic neurons were visualized in the brain of C. nodus ants using immunohistochemistry. Independent of the behavioral stages, numerous Ast-A- and TK-immunoreactive (-ir) neurons innervate important high-order integration centers and sensory input regions with cell bodies dispersed all across the cell body rind. In contrast, only four corazonergic neurons per hemisphere were found in the Cataglyphis brain. Their somata are localized in the pars lateralis with axons projecting to the medial protocerebrum and the retrocerebral complex. Number and branching patterns of the Crz-ir neurons were similar across behavioral stages, however, the volume of the cell bodies was significantly larger in foragers than in the preceding behavioral stages. In addition, quantitative PCR analyses displayed increased Crz and Ast-A mRNA levels in foragers, suggesting a concomitant increase of the peptide levels. The task-specific expression of Crz and Ast-A along with the presence in important sensory input regions, high-order integration center, and the neurohormonal organs indicate a sustaining role of the neuropeptides during behavioral maturation of Cataglyphis workers. The present thesis contains a comprehensive reference work for the brain anatomy and the neuropeptidome of Cataglyphis ants. I further demonstrated that neuropeptides are suitable modulators for the temporal polyethism of Cataglyphis workers. The complete dataset provides a solid framework for future neuroethological studies in Cataglyphis ants as well as for comparative studies on insects. This may help to improve our understanding of the functionality of individual brain neuropils and the role of neuropeptides, particularly during behavioral maturation in social insects. N2 - Eine adäquate Aufgabenverteilung unter den Koloniemitgliedern ist in großen Insektengesellschaften von besonderer Bedeutung. Einige Arten weisen polymorphe Arbeiterklassen auf, die jeweils für einen bestimmten Aufgabenbereich zuständig sind. Viel häufiger jedoch steht das Verhalten der Arbeiterinnen im Zusammenhang mit dem Alter der Individuen. Ameisen der Gattung Cataglyphis (Foerster 1850) weisen einen ausgeprägten alterskorrelierten Polyethismus auf, der sich durch drei unterschiedliche Verhaltensstadien kennzeichnet. Neu geschlüpfte Ameisen (Callows) verharren den ersten Tag mehr oder weniger bewegungslos im Nest. Anschließend erfüllen die Ameisen in der Dunkelheit des Nestes bis zu vier Wochen lang verschiedene Aufgaben (Interior), bevor sie schließlich das Nest verlassen, um Nahrung für die Kolonie zu sammeln (Forager). Diese Arbeit konzentriert sich auf die neuronalen Grundlagen, die dem alterskorrelierten Polyethismus bei Cataglyphis nodus Ameisen zugrunde liegt, indem folgende Hauptziele verfolgt werden: (1) Untersuchung der Strukturen und der neuronalen Schaltkreise des Cataglyphis-Gehirns, um mögliche Effekte von Neuromodulatoren in spezifischen Hirnneuropilen besser zu verstehen. (2) Identifizierung und Lokalisierung von Neuropeptiden im Gehirn von Cataglyphis Ameisen. (3) Untersuchung der Expression geeigneter Neuropeptid-Kandidaten im Zuge der Verhaltensreifung von Cataglyphis Arbeitern. Das Gehirn bildet die Grundlage für die Steuerung des Verhaltens von Insekten. Obwohl die tragende Rolle des zentralen Nervensystems für das Verhalten zweifelsfrei bekannt ist, sind die funktionellen Aufgaben großer Bereiche des Insektengehirns nicht vollständig erforscht. Bei Cataglyphis Ameisen konzentrierten sich vorangegangene Studien fast ausschließlich auf die Hauptneuropile, während große Teile des zentralen Protocerebrums mangels klarer Abgrenzungen weitgehend unberücksichtigt geblieben sind. Daher habe ich ein dreidimensionales Cataglyphis-Gehirn mit Hilfe der konfokalen Laser-Scanning-Mikroskopie rekonstruiert. Um die synapsinreichen Neuropile und Nerventrakte zu visualisieren, wurde eine Kombination aus fluoreszenzgekoppelten Antikörpern, Phalloidin (ein zyklisches Peptid, das an filamentöses Aktin bindet) und anterograden Tracern verwendet. Basierend auf der einheitlichen Nomenklatur für Insektengehirne definierte ich nachvollziehbare Kriterien für die Abgrenzung der einzelnen Neuropile. Die resultierende dreidimensionale neuronale Karte liefert Informationen über 33 verschiedene synapsinreiche Neuropile und 30 Nerventrakte, einschließlich einer umfassenden Beschreibung der olfaktorischen und visuellen Trakte im Cataglyphis-Gehirn. Dieser dreidimensionale Hirnatlas erlaubt es darüber hinaus, die vorhandenen Neuromodulatoren einzelnen Neuropilen des Gehirns zuzuordnen. Neuropeptide stellen die umfangreichste Gruppe an Neuromodulatoren im zentralen Nervensystem von Insekten dar. Sie regulieren wichtige physiologische Prozesse und Verhaltensweisen und wurden deshalb in jüngerer Vergangenheit mit der Regulation des alterskorrelierenden Polyethismus bei sozialen Insekten in Verbindung gebracht. Bislang wurde das Wissen über Neuropeptide bei Cataglyphis Ameisen hauptsächlich aus neuropeptidomischen Daten von Camponotus floridanus Ameisen abgeleitet und nur wenige Neuropeptide wurden bei Cataglyphis charakterisiert. Daher führte ich eine umfassende Transkriptomanalyse bei Cataglyphis nodus Ameisen durch und identifizierte Peptide mit Hilfe der Q-Exactive Orbitrap Massenspektrometrie (MS) und der Matrix-assistierte Laser Desorption-Ionisierung Time-of-Flight (MALDI-TOF) MS. Hierdurch konnten insgesamt 71 Peptide charakterisiert werden, die auf 49 Präpropeptid-Genen kodiert sind, einschließlich eines neuartigen Neuropeptid-ähnlichen Gens (Fliktin). Darüber hinaus wurde das hochauflösende MALDI-TOF MS-Imaging (MALDI-MSI) zum ersten Mal in einem Ameisenhirn angewandt, um Peptide auf dünnen Hirnkryoschnitten zu lokalisieren. Mittels MALDI-MSI konnte ich die räumliche Verteilung von 35 Peptiden sichtbar machen, die auf 16 Genen kodiert sind. Um die Rolle der Neuropeptide während der Verhaltensreifung zu untersuchen, wählte ich geeignete Neuropeptid-Kandidaten aus und analysierte deren räumliche Verteilung und Expressionsniveaus im Zuge wichtiger Verhaltensübergänge. Basierend auf aktuellen Studien schlug ich die Neuropeptide Allatostatin-A (Ast-A), Corazonin (Crz) und Tachykinin (TK) als mögliche Regulatoren des alterskorrelierenden Polyethismus vor. Die peptidergen Neurone wurden im Gehirn von C. nodus Ameisen mittels Immunhistochemie sichtbar gemacht. Unabhängig von den Verhaltensstadien innervieren die zahlreichen Ast-A- und TK-immunreaktiven (-ir) Neuronen wichtige Integrationszentren höherer Ordnung sowie sensorische Eingangsregionen, während ihre Zellkörper über die gesamte Zellkörperschicht verteilt sind. Im Gegensatz dazu wurden im Cataglyphis-Gehirn nur vier corazonerge Neuronen pro Hemisphäre gefunden. Ihre Somata sind in der Pars lateralis lokalisiert, deren Axone in das mediale Protocerebrum und den retrozerebralen Komplex projizieren. Anzahl und Verzweigungsmuster der Crz-ir Neuronen waren in allen Verhaltensstadien ähnlich, jedoch war das Volumen der Zellkörper bei Foragern signifikant größer als in den vorangegangenen Verhaltensstadien. Darüber hinaus zeigten quantitative PCR Analysen erhöhte Crz- und Ast-A mRNA-Level in Foragern, was auf einen gleichzeitigen Anstieg der Peptidspiegel schließen lässt. Die aufgabenspezifische Expression von Crz und Ast-A sowie deren Präsenz in wichtigen sensorischen Eingangsbereichen, Integrationszentren höherer Ordnung und den neurohormonellen Organen weisen auf eine tragende Rolle der Neuropeptide während der Verhaltensreifung von Cataglyphis Arbeiterinnen hin. Die vorliegende Arbeit beinhaltet ein umfassendes Nachschlagewerk für die Hirnanatomie und das Neuropeptidom von Cataglyphis Ameisen. Zudem konnte ich demonstrieren, dass Neuropeptide geeignete Modulatoren für den alterskorrelierenden Polyethismus von Cataglyphis Arbeitern sind. Der komplette Datensatz bietet eine solide Grundlage für zukünftige, neuroethologische Studien an Cataglyphis Ameisen sowie vergleichenden Studien in Insekten. Hierdurch kann unser Verständnis über die Funktionalität einzelner Hirnneuropile und die Rolle von Neuropeptiden, insbesondere während der Verhaltensreifung sozialer Insekten, in Zukunft verbessert werden. KW - Cataglyphis KW - Neuropeptide KW - Neuroethologie KW - Insektenstaaten KW - polyethism KW - neuropeptides KW - neuroethology KW - neuromodulation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-249618 ER - TY - JOUR A1 - Roth, Nicolas A1 - Doerfler, Inken A1 - Bässler, Claus A1 - Blaschke, Markus A1 - Bussler, Heinz A1 - Gossner, Martin M. A1 - Heideroth, Antje A1 - Thorn, Simon A1 - Weisser, Wolfgang W. A1 - Müller, Jörg T1 - Decadal effects of landscape-wide enrichment of dead wood on saproxylic organisms in beech forests of different historic management intensity JF - Diversity and Distributions N2 - Aim: European temperate forests have lost dead wood and the associated biodiversity owing to intensive management over centuries. Nowadays, some of these forests are being restored by enrichment with dead wood, but mostly only at stand scales. Here, we investigated effects of a seminal dead-wood enrichment strategy on saproxylic organisms at the landscape scale. Location: Temperate European beech forest in southern Germany. Methods: In a before-after control-impact design, we compared assemblages and gamma diversities of saproxylic organisms in strictly protected old-growth forest areas (reserves) and historically moderately and intensively managed forest areas before and a decade after starting a landscape-wide strategy of dead-wood enrichment. Results: Before enrichment with dead wood, the gamma diversity of saproxylic organisms in historically intensively managed forest stands was significantly lower than in reserves and historically moderately managed forest stands; this difference disappeared after 10 years of dead-wood enrichment. The species composition of beetles in forest stands of the three historical management intensities differed before the enrichment strategy, but a decade thereafter, the species compositions of previously intensively logged and forest reserve plots were similar. However, the differences in fungal species composition between historical management categories before and after 10 years of enrichment persisted. Main conclusions: Our results demonstrate that intentional enrichment of dead wood at the landscape scale is a powerful tool for rapidly restoring saproxylic beetle communities and for restoring wood-inhabiting fungal communities, which need longer than a decade for complete restoration. We propose that a strategy of area-wide active restoration combined with some permanent strict refuges is a promising means of promoting the biodiversity of age-long intensively managed Central European beech forests. KW - dead-wood enrichment KW - integrative management strategy KW - land sharing KW - lowland beech forests KW - saproxylic organisms Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227061 VL - 25 IS - 3 ER - TY - THES A1 - Schuster, Sarah T1 - Analysis of \(Trypanosoma\) \(brucei\) motility and the infection process in the tsetse fly vector T1 - Analyse der Motilität von \(Trypanosoma\) \(brucei\) und dem Infektionsprozess in der Tsetsefliege N2 - African trypanosomes are protist pathogens that are infective for a wide spectrum of mammalian hosts. Motility has been shown to be essential for their survival and represents an important virulence factor. Trypanosoma brucei is transmitted by the bite of the bloodsucking tsetse fly, the only vector for these parasites. The voyage through the fly is complex and requires several migration, proliferation and differentiation steps, which take place in a defined order and in specific fly tissues. The first part of this doctoral thesis deals with the establishment of the trypanosome tsetse system as a new model for microswimmer analysis. There is an increasing interdisciplinary interest in microbial motility, but a lack of accessible model systems. Therefore, this work introduces the first enclosed in vivo host parasite system that is suitable for analysis of diverse microswimmer types in specific microenvironments. Several methods were used and adapted to gain unprecedented insights into trypanosome motion, the fly´s interior architecture and the physical interaction between host and parasite. This work provides a detailed overview on trypanosome motile behavior as a function of development in diverse host surroundings. In additional, the potential use of artificial environments is shown. This can be used to partly abstract the complex fly architecture and analyze trypanosome motion in defined nature inspired geometries. In the second part of the thesis, the infection of the tsetse fly is under investigation. Two different trypanosome forms exist in the blood: proliferative slender cells and cell cycle arrested stumpy cells. Previous literature states that stumpy cells are pre adapted to survive inside the fly, whereas slender cells die shortly after ingestion. However, infection experiments in our laboratory showed that slender cells were also potentially infective. During this work, infections were set up so as to minimize the possibility of stumpy cells being ingested, corroborating the observation that slender cells are able to infect flies. Using live cell microscopy and fluorescent reporter cell lines, a comparative analysis of the early development following infection with either slender or stumpy cells was performed. The experiments showed, for the first time, the survival of slender trypanosomes and their direct differentiation to the procyclic midgut stage, contradicting the current view in the field of research. Therefore, we can shift perspectives in trypanosome biology by proposing a revised life cycle model of T. brucei, where both bloodstream stages are infective for the vector. N2 - Afrikanische Trypanosomen sind pathogene Protisten, die ein breites Spektrum von Säugetierwirten infizieren. Es wurde gezeigt, dass die Zellmotilität für das Überleben der Parasiten essenziell ist und einen wichtigen Virulenzfaktor darstellt. Trypanosoma brucei wird durch den Biss der blutsaugenden Tsetsefliege übertragen, dem einzigen Vektor für diese Parasiten. Der Entwicklungszyklus in der Fliege ist komplex und beinhaltet mehrere Migrations-, Proliferations- und Differenzierungsschritte, die in einer definierten Reihenfolge und in spezifischen Fliegenorganen stattfinden. Der erste Teil dieser Doktorarbeit beschäftigt sich mit der Etablierung des Trypanosomen Tsetse Systems als ein neues Modell für Motilitätsanalysen. Es besteht ein wachsendes interdisziplinäres Interesse an mikrobieller Motilität, aber es fehlen zugängliche Mikroschwimmersysteme. Deswegen stellt diese Arbeit das erste abgeschlossene in vivo Wirt Parasit System vor, das für Analysen von verschiedenen Mikroschwimmertypen in spezifischen Umgebungen geeignet ist. Verschiedene Methoden wurden benutzt und adaptiert, um sowohl Einblicke in die Trypanosomenbewegung, die innere Fliegenarchitektur als auch die physikalischen Wechselwirkungen zwischen Wirt und Parasit zu erhalten. Diese Arbeit bietet einen detaillierten Überblick über das motile Verhalten von Trypanosomen als Funktion der Entwicklung in diversen Wirtsumgebungen. Zusätzlich ist die potenzielle Nutzung von artifiziellen Umgebungen gezeigt. Diese können benutzt werden, um die komplexe Architektur der Fliege teilweise zu abstrahieren und die Trypanosomenbewegung in definierten und von der Nature inspirierten Geometrien zu analysieren. Im zweiten Teil dieser Arbeit wurde die Infektion der Fliege genauer betrachtet. Im Blut existieren zwei verschiedene Trypanosomenformen: proliferierende ‘slender’ und Zellzyklus arretierte ‘stumpy’ Zellen. Bisherige Literatur besagt, dass stumpy Zellen präadaptiert sind, um in der Fliege zu überleben, wohingegen slender Zellen kurz nach der Aufnahme sterben. Dennoch konnten Infektionsexperimente in unserem Labor zeigen, dass auch slender Zellen potenziell infektiös sind. Während dieser Arbeit wurden weitere Infektionen so durchgeführt, dass die Möglichkeit für die Aufnahme von stumpy Zellen minimiert wurde und die Infektionskapazität der slender Zellen bestätigt werden konnte. Durch Lebendzell Mikroskopie mit fluoreszenten Reporterzelllinien wurde eine vergleichende Analyse für die frühe Entwicklung von slender und stumpy Parasiten nach der Infektion durchgeführt. Die Experimente zeigten zum ersten Mal das Überleben von slender Trypanosomen in der Tsetsefliege und ihre direkte Differenzierung in das prozyklische Mitteldarmstadium. Sie widersprechen demnach der aktuellen Auffassung im Forschungsbereich. Demzufolge können wir von einem Perspektivwechsel in der Trypanosomenbiologie sprechen und schlagen einen revidierten Lebenszyklus für T. brucei vor, in dem beide Blutstromformen für den Vektor infektiös sind. KW - Motilität KW - Trypanosomen KW - Tsetsefliege KW - Parasit KW - tsetse fly KW - motility KW - trypanosome KW - vector-parasite interaction KW - microswimming Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-192691 ER - TY - THES A1 - Andreska, Thomas T1 - Effects of dopamine on BDNF / TrkB mediated signaling and plasticity on cortico-striatal synapses T1 - Effekte von Dopamin auf BDNF / TrkB vermittelte Signalwege und Plastizität an cortico-striatalen Synapsen N2 - Progressive loss of voluntary movement control is the central symptom of Parkinson's disease (PD). Even today, we are not yet able to cure PD. This is mainly due to a lack of understanding the mechanisms of movement control, network activity and plasticity in motor circuits, in particular between the cerebral cortex and the striatum. Brain-derived neurotrophic factor (BDNF) has emerged as one of the most important factors for the development and survival of neurons, as well as for synaptic plasticity. It is thus an important target for the development of new therapeutic strategies against neurodegenerative diseases. Together with its receptor, the Tropomyosin receptor kinase B (TrkB), it is critically involved in development and function of the striatum. Nevertheless, little is known about the localization of BDNF within presynaptic terminals in the striatum, as well as the types of neurons that produce BDNF in the cerebral cortex. Furthermore, the influence of midbrain derived dopamine on the control of BDNF / TrkB interaction in striatal medium spiny neurons (MSNs) remains elusive so far. Dopamine, however, appears to play an important role, as its absence leads to drastic changes in striatal synaptic plasticity. This suggests that dopamine could regulate synaptic activity in the striatum via modulation of BDNF / TrkB function. To answer these questions, we have developed a sensitive and reliable protocol for the immunohistochemical detection of endogenous BDNF. We find that the majority of striatal BDNF is provided by glutamatergic, cortex derived afferents and not dopaminergic inputs from the midbrain. In fact, we found BDNF in cell bodies of neurons in layers II-III and V of the primary and secondary motor cortex as well as layer V of the somatosensory cortex. These are the brain areas that send dense projections to the dorsolateral striatum for control of voluntary movement. Furthermore, we could show that these projection neurons significantly downregulate the expression of BDNF during the juvenile development of mice between 3 and 12 weeks. In parallel, we found a modulatory effect of dopamine on the translocation of TrkB to the cell surface in postsynaptic striatal Medium Spiny Neurons (MSNs). In MSNs of the direct pathway (dMSNs), which express dopamine receptor 1 (DRD1), we observed the formation of TrkB aggregates in the 6-hydroxydopamine (6-OHDA) model of PD. This suggests that DRD1 activity controls TrkB surface expression in these neurons. In contrast, we found that DRD2 activation has opposite effects in MSNs of the indirect pathway (iMSNs). Activation of DRD2 promotes a rapid decrease in TrkB surface expression which was reversible and depended on cAMP. In parallel, stimulation of DRD2 led to induction of phospho-TrkB (pTrkB). This effect was significantly slower than the effect on TrkB surface expression and indicates that TrkB is transactivated by DRD2. Together, our data provide evidence that dopamine triggers dual modes of plasticity on striatal MSNs by acting on TrkB surface expression in DRD1 and DRD2 expressing MSNs. This surface expression of the receptor is crucial for the binding of BDNF, which is released from corticostriatal afferents. This leads to the induction of TrkB-mediated downstream signal transduction cascades and long-term potentiation (LTP). Therefore, the dopamine-mediated translocation of TrkB could be a mediator that modulates the balance between dopaminergic and glutamatergic signaling to allow synaptic plasticity in a spatiotemporal manner. This information and the fact that TrkB is segregated to persistent aggregates in PD could help to improve our understanding of voluntary movement control and to develop new therapeutic strategies beyond those focusing on dopaminergic supply. N2 - Der fortschreitende Verlust der willkürlichen Bewegungskontrolle ist ein zentrales Symptom der Parkinson-Krankheit (PD). Auch heute sind wir noch nicht in der Lage, PD zu heilen. Dafür verantwortlich ist hauptsächlich ein mangelndes Verständnis von Mechanismen der Bewegungskontrolle, Netzwerkaktivität und Plastizität in motorischen Schaltkreisen, insbesondere zwischen Hirnrinde und Striatum. Der neurotrophe Faktor BDNF ist einer der wichtigsten Faktoren für die Entwicklung und das Überleben von Neuronen sowie für synaptische Plastizität im zentralen Nervensystem. BDNF ist daher ein Target für die Entwicklung neuer therapeutischer Strategien gegen neurodegenerative Erkrankungen. Zusammen mit seinem Rezeptor, der Tropomyosin-Rezeptorkinase B (TrkB), ist BDNF maßgeblich an der Entwicklung und Funktion des Striatums beteiligt. Dennoch ist nur wenig bekannt, wo BDNF an Synapsen im Striatum lokalisiert ist, und wo BDNF in Neuronen der Hirnrinde synthetisiert wird. Außerdem ist der Einfluss von Dopamin aus dem Mittelhirn auf die Kontrolle der BDNF / TrkB-Interaktion in striatalen Medium-Spiny-Neuronen (MSNs) bisher unklar. Dopamin scheint jedoch eine wichtige Rolle zu spielen, da dessen Abwesenheit zu drastischen Veränderungen der striatalen Plastizität führt. Dopamin könnte synaptische Plastizität im Striatum über eine Modulation der BDNF / TrkB-Interaktion regulieren. Um diese Fragen beantworten zu können, haben wir ein sensitives und zuverlässiges Protokoll für den immunhistochemischen Nachweis von endogenem BDNF entwickelt. Wir fanden heraus, dass BDNF im Striatum vor allem in glutamatergen Synapsen von Projektion aus dem Kortex lokalisiert ist und nicht in Terminalen dopaminerger Neurone aus dem Mittelhirn. Tatsächlich fanden wir BDNF in den Zellkörpern von Neuronen in den Schichten II-III und V des primären und sekundären motorischen Kortex sowie Schicht V des somatosensorischen Kortex. Es sind jene Hirnareale, welche dichte Projektionen zum dorsolateralen Striatum senden und entscheidend an der Steuerung von willkürlichen Bewegungen beteiligt sind. Weiterhin konnten wir zeigen, dass eben jene Projektionsneurone die Bildung von BDNF während der juvenilen Entwicklung von Mäusen zwischen 3 und 12 Wochen signifikant herunter regulieren. In striatalen MSN fanden wir zudem einen modulatorischen Effekt von Dopamin auf die Translokation von TrkB zur Zelloberfläche. In MSNs des direkten Signalweges (dMSNs), welche Dopaminrezeptor 1 (DRD1) exprimieren, konnten wir die Bildung von TrkB-Aggregaten im 6-Hydroxydopamin (6-OHDA) - Rattenmodell der Parkinson Erkankung beobachten. Dies deutet darauf hin, dass die DRD1-Aktivität die TrkB-Oberflächenexpression in diesen Neuronen steuert. Im Gegensatz dazu fanden wir heraus, dass die DRD2-Aktivierung in MSNs des indirekten Signalweges (iMSNs) eine gegensätzliche Wirkung hat. Die Aktivierung von DRD2 führt zu einer schnellen Reduktion der TrkB-Oberflächenexpression, die reversibel und von cAMP abhängig ist. Außerdem führte die Stimulation von DRD2 zu einer Induktion von Phospho-TrkB (pTrkB). Dieser Effekt war deutlich langsamer als die Wirkung auf die TrkB-Oberflächenexpression und deutet auf eine Transaktivierung von TrkB über DRD2 hin. Insgesamt scheint Dopamin entgegengesetzte Plastizitätsmodi in striatalen MSNs auszulösen, indem es auf die TrkB-Oberflächenexpression in DRD1- und DRD2-exprimierenden MSNs einwirkt. Diese Oberflächenexpression des Rezeptors ist entscheidend für die Bindung von BDNF, welches aus kortiko-striatalen Afferenzen freigesetzt wird. Dies führt zur Induktion von TrkB-vermittelten-Signaltransduktionskaskaden und Langzeitpotenzierung (LTP). Daher könnte die dopamin-vermittelte Translokalisation von TrkB das Gleichgewicht zwischen dopaminergen und glutamatergen Signalen modulieren, um die synaptische Plastizität in einer räumlich-zeitlich abgestimmten Weise zu ermöglichen. Diese Information und die Tatsache, dass TrkB bei PD stabile Aggregate bildet, könnte dazu beitragen, unser Verständnis der willkürlichen Bewegungskontrolle zu verbessern und neue therapeutische Strategien zu entwickeln, die über jene hinausgehen, welche sich auf die dopaminerge Versorgung konzentrieren. KW - Brain-derived neurotrophic factor KW - Parkinson Krankheit KW - Plastizität KW - Motorisches Lernen KW - Basalganglien KW - Brain-derived neurotrophic factor KW - TrkB KW - Basal Ganglia KW - Motor learning KW - Parkinson's disease KW - Synaptic plasticity KW - Striatum KW - Medium spiny neurons KW - Cortico-striatal projection neurons Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-174317 ER - TY - THES A1 - Aydinli, Muharrem T1 - Software unterstützte Analyse von regulatorischen Elementen in Promotoren mittels AIModules T1 - Software backed Analysis of regulatory Elements of Promoters with AIModules N2 - Die Regulation der Genexpression steht am Anfang vieler zellbiologischer Prozesse wie beispielsweise dem Zellwachstum oder der Differenzierung. Gene werden an Promotoren transkribiert, wobei ein Promotor selbst aus vielen logischen Einheiten aufgebaut ist, den Transkriptionsfaktorbindestellen (TFBSs). Diese können sehr nah beieinander liegen, aber auch weit entfernt voneinander sein. Sie werden spezifisch von Transkriptionsfaktoren (TFs) gebunden, die die Transkritptionsrate z.B. verstärken (Enhancer) oder schwächen (Silencer) können. Zwei oder mehr dieser TFBSs mit bestimmtem Abstand werden als "Module" zusammengefasst, die über Spezies hinweg konserviert sein können. Typischerweise findet man Module in Zellen mit einem Zellkern. Spezies mit gemeinsamen Modulen können ein Hinweis auf die gemeinsame phylogenetische Abstammung darstellen, aber auch gemeinsame Funktionsmechanismen von TFs über Gene hinweg aufdecken. Heutzutage sind verschiedene Anwendungen verfügbar, mit denen nach TFBSs in DNA gesucht werden kann. Zum Zeitpunkt des Verfassens dieser Arbeit sind aber nur zwei kommerzielle Produkte bekannt, die nicht nur TFBSs, sondern auch Module erkennen. Deshalb stellen wir hier die freie und quelloffene Lösung "AIModules" vor, die diese Lücke füllt und einen Webservice zur Verfügung stellt, der es erlaubt nach TFBSs sowie nach Modulen auf DNA- und auf RNA-Abschnitten zu suchen. Für die Motivesuche werden entweder Matrizen aus der Jaspar Datenbank oder Matrizen vom Anwender verwendet. Darüberhinaus zeigen wir, dass unser Tool für die TF Suche nur Sekunden benötigt, wohingegen conTraV3 mindestens eine Stunde für dieselbe Analyse braucht. Zusätzlich kann der Anwender bei unserem Tool den Grad der Konserviertheit für TFs mit angeben und wir zeigen, dass wir mit unserer Lösung, die die Jaspar Datenbank heranzieht, mehr Module finden, als ein kommerziell verfügbares Produkt. Weiterhin kann mit unserer Lösung auch auf RNA-Sequenzen nach regulatorischen Motiven gesucht werden, wenn der Anwender die dafür nötigen Matrizen liefert. Wir zeigen dies am Beispiel von Polyadenylierungsstellen. Zusammenfassend stellen wir ein Werkzeug vor, das erstens frei und quelloffen ist und zweitens entweder auf Servern veröffentlicht werden kann oder On-Site auf einem Notebook läuft. Unser Tool erlaubt es Promotoren zu analysieren und nach konservierten Modulen sowie TFBSs in Genfamilien sowie nach regulatorischen Elementen in mRNA wie z.B. Polyadenylierungsstellen oder andere regulatorische Elemente wie beispielsweise Enhancern oder Silencern in genomischer DNA zu suchen. N2 - Regulation of gene expression is at the root of many processes in cellular biology such as cell growth and differentiation. Promotors are the starting points for the transcription of a gene. The promotor itself consists of transcription factor binding sites (TFBSs) which can be closely located or vastly apart. They are recognized and bound by transcription factors (TFs) which themselves can e.g. enhance or silence the transcribing process by the RNA polymerases. Two or more of those transcription factor binding sites within a certain range are called a "module". Typically, those are found in cells with a nucleus and they may be conserved throughout species. The knowledge of modules may indicate a phylogenetic relationship among species but may also provide insight into the concerted actions of TFs on different genes. Currently there are a number of tools available that can enable a user to find TFBSs on DNA. But at the time of assembling this thesis, there are only two commercial software products available, that can not only detect TFs but also modules. Therefore, we present a free and open source solution that fills this gap by providing a web service that searches for TFBSs and modules on DNA as well as RNA stretches, called "AIModules". For that, matrices from the Jaspar database or user input matrices are used for motif discovery. Additionally, we show that our tool does TF analysis in seconds, whereas tools like conTraV3 took at least an hour. Furthermore, for the module search the user can specify the degree of conservation of the TFs. We show that with our solution using the JASPAR database we find more modules than a commercially available tool. Moreover, with our application RNA stretches can also be searched for regulatory motifs if suitable matrices are provided. We illustrate this for polyadenylation sites. Thus, our solution is free and open source, and can be deployed on servers as well as provided on-site on a notebook. We provide a tool to analyze promotors and search for conserved modules as well as common TFBSs in gene families, search for regulatory elements in mRNA such as polyadenylation sites or other regulatory elements such as enhancers or silencers in genomic DNA. KW - Genregulation KW - Promotor KW - Transkriptionsfaktor KW - Modulsuche KW - RNA Motivsuche KW - Modul KW - Module search KW - RNA motiv serach KW - module search Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-248025 ER - TY - THES A1 - Maistrenko, Oleksandr T1 - Pangenome analysis of bacteria and its application in metagenomics T1 - Bakterielle Pan-Genome und ihre Anwendungen in der Metagenomik N2 - The biosphere harbors a large quantity and diversity of microbial organisms that can thrive in all environments. Estimates of the total number of microbial species reach up to 1012, of which less than 15,000 have been characterized to date. It has been challenging to delineate phenotypically, evolutionary and ecologically meaningful lineages such as for example, species, subspecies and strains. Even within recognized species, gene content can vary considerably between sublineages (for example strains), a problem that can be addressed by analyzing pangenomes, defined as the non-redundant set of genes within a phylogenetic clade, as evolutionary units. Species considered to be ecologically and evolutionary coherent units, however to date it is still not fully understood what are primary habitats and ecological niches of many prokaryotic species and how environmental preferences drive their genomic diversity. Majority of comparative genomics studies focused on a single prokaryotic species in context of clinical relevance and ecology. With accumulation of sequencing data due to genomics and metagenomics, it is now possible to investigate trends across many species, which will facilitate understanding of pangenome evolution, species and subspecies delineation. The major aims of this thesis were 1) to annotate habitat preferences of prokaryotic species and strains; 2) investigate to what extent these environmental preferences drive genomic diversity of prokaryotes and to what extent phylogenetic constraints limit this diversification; 3) explore natural nucleotide identity thresholds to delineate species in bacteria in metagenomics gene catalogs; 4) explore species delineation for applications in subspecies and strain delineation in metagenomics. The first part of the thesis describes methods to infer environmental preferences of microbial species. This data is a prerequisite for the analyses performed in the second part of the thesis which explores how the structure of bacterial pangenomes is predetermined by past evolutionary history and how is it linked to environmental preferences of the species. The main finding in this subchapter that habitat preferences explained up to 49% of the variance for pangenome structure, compared to 18% by phylogenetic inertia. In general, this trend indicates that phylogenetic inertia does not limit evolution of pangenome size and diversity, but that convergent evolution may overcome phylogenetic constraints. In this project we show that core genome size is associated with higher environmental ubiquity of species. It is likely this is due to the fact that species need to have more versatile genomes and most necessary genes need to be present in majority of genomes of that species to be highly prevalent. Taken together these findings may be useful for future predictive analyses of ecological niches in newly discovered species. The third part of the thesis explores data-driven, operational species boundaries. I show that homologous genes from the same species from different genomes tend to share at least 95% of nucleotide identity, while different species within the same genus have lower nucleotide identity. This is in line with other studies showing that genome-wide natural species boundary might be in range of 90-95% of nucleotide identity. Finally, the fourth part of the thesis discusses how challenges in species delineation are relevant for the identification of meaningful within-species groups, followed by a discussion on how advancements in species delineation can be applied for classification of within-species genomic diversity in the age of metagenomics. N2 - Die Biosphäre beherbergt eine große Zahl verschiedener Mikroorganismen, die fast alle bekannten Lebensräume besiedeln können. Die Gesamtzahl mikrobieller Spezies liegt Schätzungen zu Folge bei bis zu 1012, von denen jedoch bis heute erst 15.000 beschrieben worden sind. Die Beschreibung von phänotypisch, evolutionsbiologisch und ökologisch kohärenten Spezies, Sub-Spezies oder Stämmen stellt Forscher vor konzeptionelle Herausforderungen. Selbst innerhalb anerkannter Spezies kann die Kombination einzelner Gene oft stark variieren. Diese Beobachtung ist die Grundlage der Analyse von Pan-Genomen. also der Konstellation originärer Gene innerhalb einer Abstammunsglinie, als evolutionsbiologische Einheiten. Spezies entsprechen prinzipiell ökologisch und evolutionär kohärenten Einheiten, jedoch sind die primären Habitate und ökologischen Nischen vieler prokaryotischer Spezies bis heute nur unzureichend beschrieben, insbesondere mit Blick auf den Einfluss ökologischer Präferenzen auf die Evolution von Genomen. Die Mehrheit vergleichender genomischer Studien untersucht einzelne prokaryotische Spezies mit Bezug auf deren klinische oder ökologische Relevanz. Aufgrund der wachsenden Verfügbarkeit genomischer Daten ist es nun jedoch möglich, vergleichende Studien über Speziesgrenzen hinweg durchzuführen, um allgemeine Prinzipien der Evolution von Pan-Genomen, Spezies und Sub-Spezies zu untersuchen. Die wesentlichen Ziele der vorliegenden Arbeit waren 1) die Annotation von Habitatpräferenzen prokaryotischer Spezies und Stämme; 2) die Quantifizierung des Einflusses von Umwelt und Evolutionsgeschichte (Phylogenie) auf die genomische Diversität von Prokaryoten; 3) die Bestimmung natürlicher Schwellenwerte der Genomsequenzähnlichkeit zwischen Spezies, auch anhand von Genkatalogen; 4) die Untersuchung der Abgrenzung zwischen Spezies, Sub-Spezies und Stämmen mithilfe metagenomischer Daten. Im ersten Teil der Arbeit werden Methoden zur Bestimmung ökologischer Präferenzen mikrobieller Spezies beschrieben. Die so gewonnenen Daten dienen in der Folge als Grundlage für die Quantifizierung von Umwelt- und evolutionsgeschichtlichen Einflüssen auf die Struktur und Evolution bakterieller Pan-Genome im zweiten Teil der Arbeit. Ein zentrales Ergebnis dieser Untersuchung war, dass bis zu 49% der strukturellen Varianz in Pan-Genomen durch Habitatpräferenzen erklärt werden kann, im Gegensatz zu lediglich 18% durch phylogenetische Trägheitseffekte. Dies zeigt, dass die Größe und Diversität von Pan-Genomen nicht phylogenetisch limitiert ist, insbesondere in Fällen von konvergenter Evolution. Große Kern-Genome sind ferner mit einer weiten ökologischen Verbreitung von Spezies assoziiert; eine mögliche Erklärung ist, dass weit verbreitete Spezies vielseitigere Genome mit mehr notwendigen Genen besitzen, die ein Überleben in vielfältigen Umgebungen ermöglichen. Die vorgelegte Arbeit kann weiterhin einen Beitrag zur Vorhersage ökologischer Profile neu beschriebener Spezies leisten. Im dritten Teil der Arbeit werden datenbezogene, operationelle Definition von Spezies-Grenzen untersucht. Es konnte gezeigt werden, dass Gene verschiedener Genome innerhalb derselben Spezies normalerweise mindestens 95% Ähnlichkeit der Nukleotidsequenz aufweisen, während die Ähnlichkeit zwischen Spezies desselben Genus geringer ausfällt. Dieser Wert liegt im Rahmen früherer Schätzungen. Der vierte Teil der Arbeit beschreibt abschließend die Herausforderungen bei der Bestimmung von evolutionären Linien innerhalb von Spezies und diskutiert anschließend, wie konzeptionelle Entwicklungen in dieser Frage für die Klassifizierung und Quantifizierung von Diversität anhand metagenomischer Daten genutzt werden kann. KW - Pangenom KW - phylogenetische Trägheit KW - Lebensraum KW - Stammvielfalt KW - mikrobielle Ökologie und Evolution KW - pangenome KW - phylogenetic inertia KW - habitat KW - strain diversity KW - microbial ecology and evolution KW - metagenomics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214996 ER - TY - JOUR A1 - Boff, Samuel A1 - Friedel, Anna T1 - Dynamics of nest occupation and homing of solitary bees in painted trap nests JF - Ecological Entomology N2 - 1. The oil‐collecting bee Centris analis (Fabricius, 1804) is an important pollinator for the Neotropical region. The species can be attracted to nest in human‐made cavities. Such trap nests or insect hotels offer the opportunity to study the behaviour of populations in semifield conditions. 2. We studied a newly established trap nest aggregation of C. analis in Mato Grosso do Sul, Brazil and tested the effect that differentially painted nesting options have on the rate of nest foundation, and on the ability of relocating the nest when returning from a foraging trip (homing behaviour). Moreover, we tested if the duration of foraging trips decreased with time. 3. We found that females preferred to nest in painted nests compared to unpainted nests, with blue nests being the most occupied ones, followed by purple, yellow, white, and green. Furthermore, bees improved their homing behaviour with time, however, nest colour did not seem to have an effect on this process. Moreover, we found that bees reduce the duration of their foraging trips with time. This could be an indicator of improved foraging efficiency through learning. 4. These findings could inform a new and fruitful line of research on the behaviour and ecology of trap nesting solitary bees. KW - foraging activities KW - nesting ecology KW - oil bees KW - painted nest preference Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224605 VL - 46 IS - 2 SP - 496 EP - 499 ER - TY - THES A1 - Solger, Franziska T1 - Central role of sphingolipids on the intracellular survival of \(Neisseria\) \(gonorrhoeae\) in epithelial cells T1 - Die zentrale Rolle von Sphingolipiden auf das intrazelluläre Überleben von \(Neisseria\) \(gonorrhoeae\) in Epithelzellen N2 - Neisseria gonorrhoeae are Gram-negative bacteria with diplococcal shape. As an obligate human pathogen, it is the causative agent of gonorrhoea, a sexually transmitted disease. Gonococci colonize a variety of mucosal tissues, mainly the urogenital tract in men and women. Occasionally N. gonorrhoeae invades the bloodstream, leading to disseminated gonococcal infection. These bacteria possess a repertoire of virulence factors, which expression patterns can be adapted to the environmental conditions of the host. Through the accumulation of antibiotic resistances and in absence of vaccines, some neisserial strains have the potential to spread globally and represent a major public health threat. Therefore, it is necessary to understand the exact molecular mechanisms underlying the successful infection and progression of gonococci within their host. This deeper understanding of neisserial infection and survival mechanisms is needed for the development of new therapeutic agents. In this work, the role of host-cell sphingolipids on the intracellular survival of N. gonorrhoeae was investigated. It was shown that different classes of sphingolipids strongly interact with invasive gonococci in epithelial cells. Therefore, novel and highly specific clickable sphingolipid analogues were applied to study these interactions with this pathogen. The formation of intra- and extracellular sphingosine vesicles, which were able to target gonococci, was observed. This direct interaction led to the uptake and incorporation of sphingosine into the neisserial membrane. Together with in vitro results, sphingosine was identified as a potential bactericidal reagent as part of the host cell defence. By using different classes of sphingolipids and their clickable analogues, essential structural features, which seem to trigger the bacterial uptake, were detected. Furthermore, effects of key enzymes of the sphingolipid signalling pathway were tested in a neutrophil infection model. In conclusion, the combination of click chemistry and infection biology made it possible to shed some light on the dynamic interplay between cellular sphingosine and N. gonorrhoeae. Thereby, a possible “catch-and-kill” mechanism could have been observed. N2 - Neisseria gonorrhoeae ist ein Gram-negatives Bakterium, welches als Diplokokke vorkommt. Als ein ausschließliches Humanpathogen sind Neisserien der Erreger für die sexuell übertragbare Infektionskrankheit Gonorrhö. Gonokokken besiedeln eine Vielzahl von Schleimhäuten, jedoch hauptsächlich den Urogenitaltrakt bei Männern und Frauen. Gelegentlich kann N. gonorrhoeae in die Blutbahn invadieren, was zu einer disseminierten Infektion führen kann. Diese Bakterien verfügen über ein Repertoire an Virulenzfaktoren, deren Expressionskombination den Umgebungsbedingungen des Wirts angepasst werden können. Durch die Anhäufung von Antibiotikaresistenzen und durch das Fehlen eines Impfstoffes, besteht die Gefahr, dass spezielle Neisserienstämme sich weltweit verbreiten und daher eine ernstzunehmende Bedrohung des Menschen sind. Daher ist es notwendig die zugrundeliegenden molekularen Mechanismen der erfolgreichen Infektion und Ausbreitung der Gonokokken im Wirt genauestens zu verstehen. Das detaillierte Wissen über die Neisserieninfektion und Überlebensmechanismen ist nötig für die Entwicklung neuer Therapieansätze. In dieser Arbeit wurde der Effekt von Sphingolipiden der Wirtszelle auf das intrazelluläre Überleben von N. gonorrhoeae untersucht. Es konnte gezeigt werden, dass unterschiedliche Klassen von Sphingolipiden stark mit invasiven Gonokokken in Epithelzellen interagieren. Um dies zu tun, wurden neue und hochspezifische clickbare Sphingolipidanaloge eingesetzt, um deren Interaktionen mit diesem Pathogen zu studieren. Die Formation von intra- als auch extrazellulären Sphingosinvesikeln, welche Gonokokken gezielt erreichten, konnte beobachtet werden. Diese direkte Interaktion führte zu einer Aufnahme und Einbau des Sphingosins in die Neisserienmembran. Zusammen mit in vitro Ergebnissen, konnte Sphingosin als potenzieller und antibakterieller Bestandteil des zellulären Abwehrsystems identifiziert werden. Weiterhin wurde durch die Verwendung unterschiedlicher Sphingolipidklassen und deren clickbaren Analoge wichtige Strukturen erkannt, die die bakterielle Aufnahme auslösen. Des Weiteren wurden die Auswirkungen von Schlüsselenzymen des Sphingolipidsignalwegs in einem Infektionsmodell mit Neutrophilen getestet. Abschließend ist zu sagen, dass die Kombination aus Click Chemie und Infektionsbiologie es ermöglicht hat, die dynamischen Wechselwirkungen zwischen zellulären Sphingosin und N. gonorrhoeae zu beleuchten. Dadurch konnte ein möglicher „catch-and-kill”-Mechanismus entdeckt werden. KW - Neisseria gonorrhoeae KW - Sphingosinkinase KW - Sphingosinanaloga KW - Click-Chemie KW - sphingosine KW - sphingolipids KW - Neisseria KW - intracellular KW - vesicles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-247534 ER - TY - THES A1 - Kehrberger, Sandra T1 - Effects of climate warming on the timing of flowering and emergence in a tritrophic relationship: plants - bees - parasitoids T1 - Auswirkungen der Klimaerwärmung auf die zeitliche Regulierung der Blüte und des Schlupfes in einer tritrophischen Beziehung: Pflanzen - Bienen - Parasitoide N2 - The right timing of phenological events is crucial for species fitness. Species should be highly synchronized with mutualists, but desynchronized with antagonists. With climate warming phenological events advance in many species. However, often species do not respond uniformly to warming temperatures. Species-specific responses to climate warming can lead to asynchrony or even temporal mismatch of interacting species. A temporal mismatch between mutualists, which benefit from each other, can have negative consequences for both interaction partners. For host-parasitoid interactions temporal asynchrony can benefit the host species, if it can temporally escape its parasitoid, with negative consequences for the parasitoid species, but benefit the parasitoid species if it increases synchrony with its host, which can negatively affect the host species. Knowledge about the drivers of phenology and the species-specific responses to these drivers are important to predict future effects of climate change on trophic interactions. In this dissertation I investigated how different drivers act on early flowering phenology and how climate warming affects the tritrophic relationship of two spring bees (Osmia cornuta & Osmia bicornis), an early spring plant (Pulsatilla vulgaris), which is one of the major food plants of the spring bees, and three main parasitoids of the spring bees (Cacoxenus indagator, Anthrax anthrax, Monodontomerus). In Chapter II I present a study in which I investigated how different drivers and their change over the season affect the reproductive success of an early spring plant. For that I recorded on eight calcareous grasslands around Würzburg, Germany the intra-seasonal changes in pollinator availability, number of co-flowering plants and weather conditions and studied how they affect flower visitation rates, floral longevity and seed set of the early spring plant P. vulgaris. I show that bee abundances and the number of hours, which allowed pollinator foraging, were low at the beginning of the season, but increased over time. However, flower visitation rates and estimated total number of bee visits were higher on early flowers of P. vulgaris than later flowers. Flower visitation rates were also positively related to seed set. Over time and with increasing competition for pollinators by increasing numbers of co-flowering plants flower visitation rates decreased. My data shows that a major driver for early flowering dates seems to be low interspecific competition for pollinators, but not low pollinator abundances and unfavourable weather conditions. Chapter III presents a study in which I investigated the effects of temperature on solitary bee emergence and on the flowering of their food plant and of co-flowering plants in the field. Therefore I placed bee cocoons of two spring bees (O. cornuta & O. bicornis) on eleven calcareous grasslands which differed in mean site temperature. On seven of these grasslands the early spring plant P. vulgaris occurred. I show that warmer temperatures advanced mean emergence in O. cornuta males. However, O. bicornis males and females of both species did not shift their emergence. Compared to the bees P. vulgaris advanced its flowering phenology more strongly with warmer temperatures. Co-flowering plants did not shift flowering onset. I suggest that with climate warming the first flowers of P. vulgaris face an increased risk of pollinator limitation whereas for bees a shift in floral resources may occur. In Chapter IV I present a study in which I investigated the effects of climate warming on host-parasitoid relationships. I studied how temperature and photoperiod affect emergence phenology in two spring bees (O. cornuta & O. bicornis) and three of their main parasitoids (C. indagator, A. anthrax, Monodontomerus). In a climate chamber experiment with a crossed design I exposed cocoons within nest cavities and cocoons outside of nest cavities to two different temperature regimes (long-term mean of Würzburg, Germany and long-term mean of Würzburg + 4 °C) and three photoperiods (Würzburg vs. Snåsa, Norway vs. constant darkness) and recorded the time of bee and parasitoid emergence. I show that warmer temperatures advanced emergence in all studied species, but bees advanced less strongly than parasitoids. Consequently, the time period between female bee emergence and parasitoid emergence decreased in the warm temperature treatment compared to the cold one. Photoperiod influenced the time of emergence only in cocoons outside of nest cavities (except O. bicornis male emergence). The data also shows that the effect of photoperiod compared to the effect of temperature on emergence phenology was much weaker. I suggest that with climate warming the synchrony of emergence phenologies of bees and their parasitoids will amplify. Therefore, parasitism rates in solitary bees might increase which can negatively affect reproductive success and population size. In this dissertation I show that for early flowering spring plants low interspecific competition for pollinators with co-flowering plants is a major driver of flowering phenology, whereas other drivers, like low pollinator abundances and unfavourable weather conditions are only of minor importance. With climate warming the strength of different drivers, which act on the timing of phenological events, can change, like temperature. I show that warmer temperatures advance early spring plant flowering more strongly than bee emergence and flowering phenology of later co-flowering plants. Furthermore, I show that warmer temperatures advance parasitoid emergence more strongly than bee emergence. Whereas temperature changes can lead to non-uniform temporal shifts, I demonstrate that geographic range shifts and with that altered photoperiods will not change emergence phenology in bees and their parasitoids. In the tritrophic system I investigated in this dissertation climate warming may negatively affect the reproductive success of the early spring plant and the spring bees but not of the parasitoids, which may even benefit from warming temperatures. N2 - Der richtige Zeitpunkt von phänologischen Ereignissen ist maßgeblich für das Überleben und die Fortpflanzung einer Art. Arten sollten eine möglichst hohe Synchronisation mit Mutualisten aufweisen, aber eine möglichst geringe mit Antagonisten. Die Klimaerwärmung führt dazu, dass sich bei vielen Arten phänologische Ereignisse verfrühen. Allerdings reagieren Arten unterschiedlich auf wärmere Temperaturen. Artspezifische Reaktionen auf die Klimaerwärmung können zu Asynchronität oder sogar zu zeitlicher Diskrepanz bei interagierenden Arten führen. Eine zeitliche Diskrepanz zwischen Mutualisten, die voneinander profitieren, kann sich negativ auf beide Interaktionspartner auswirken. Bei Wirt-Parasitoid Beziehungen kann der Wirt von einer zeitlichen Diskrepanz profitieren, wenn er seinem Parasitoid zeitlich entfliehen kann, was wiederum negative Folgen für den Parasitoid haben kann. Jedoch kann der Parasitoid profitieren, wenn er die Synchronisation mit seinem Wirt erhöhen kann, was wiederum den Wirt negativ beeinflussen kann. Das Wissen über die Treiber von phänologischen Ereignissen und die artspezifischen Reaktionen auf diese Treiber sind von Bedeutung um die Auswirkungen des Klimawandels auf trophische Beziehungen vorherzusagen. In meiner Doktorarbeit habe ich untersucht, wie verschiedene Treiber mit einer frühen Blüte zusammenhängen und wie der Klimawandel die tritrophische Beziehung von zwei Frühlingsbienen (Osmia cornuta & Osmia bicornis), einer Frühlingspflanzenart (Pulsatilla vulgaris), die eine der wichtigen Futterpflanzen der Bienen ist, und der drei Hauptparasitoiden der Frühlingsbienen (Cacoxenus indagator, Anthrax anthrax, Monodontomerus) beeinflusst. In Kapitel II präsentiere ich eine Studie, in der ich den Einfluss verschiedener Treiber und ihre saisonale Veränderung auf den Fortpflanzungserfolg einer Frühlingspflanzenart untersucht habe. Dazu habe ich auf acht Kalkmagerrasen bei Würzburg (Deutschland) die innersaisonalen Veränderungen der Bestäuberverfügbarkeit, der Anzahl an gleichzeitig blühenden Pflanzenarten und die Wetterbedingungen aufgezeichnet. Des Weiteren habe ich erforscht wie diese Faktoren die Blütenbesuchsrate, die Blütenlanglebigkeit und den Samenansatz der Frühlingspflanze P. vulgaris beeinflussen. Ich konnte zeigen, dass die Anzahl an Bienen und die Anzahl an Stunden, die ein Furagieren von Bestäubern ermöglicht hätten, am Anfang der Saison niedrig waren und mit der Zeit zunahmen. Jedoch war die Blütenbesuchsrate und die geschätzte Anzahl an Bienenbesuchen höher bei frühen als bei späten P. vulgaris Blüten. Die Blütenbesuchsrate wirkte sich auch positiv auf den Samenansatz aus. Die Blütenbesuchsrate nahm mit der Zeit und mit zunehmender Konkurrenz um Bestäuber durch eine zunehmende Anzahl an gleichzeitig blühenden Pflanzenarten ab. Meine Daten zeigen, dass ein Hauptreiber von frühen Blühzeitpunkten die geringe zwischenartliche Konkurrenz um Bestäuber ist, aber nicht die niedrige Bestäuberanzahl und ungünstige Wetterbedingungen. Kapitel III präsentiert eine Studie, in welcher ich die Auswirkungen der Temperatur auf den Schlupf von Solitärbienen und die Blüte ihrer Futterpflanzen und gleichzeitig blühenden Pflanzen im Freiland untersucht habe. Dafür habe ich Bienenkokons von zwei Frühlingsbienen (O. cornuta & O. bicornis) auf elf Kalkmagerrasen, die sich in der mittleren Flächentemperatur unterschieden, platziert. Auf sieben dieser Kalkmagerrasen kam die Frühlingspflanzenart P. vulgaris vor. Ich konnte zeigen, dass wärmere Temperaturen den mittleren Schlupf von O. cornuta Männchen verfrühen. Die Männchen von O. bicornis und die Weibchen beider Arten haben ihren Schlupfzeitpunkt jedoch nicht verschoben. Im Vergleich zu den Bienen verfrühte P. vulgaris seine Blühphänologie bei warmen Temperaturen stärker. Die gleichzeitig blühenden Pflanzenarten verschoben ihren Blühbeginn nicht. Die Daten zeigen, dass wärmere Temperaturen den Bienenschlupf weniger stark verfrühen als die Blüte ihrer Futterpflanze. Das lässt darauf schließen, dass mit dem Klimawandel die ersten Blüten von P. vulgaris ein erhöhtes Risiko haben nicht bestäubt zu werden, während die Bienen möglicherweise auf andere Blühressourcen ausweichen müssen. Kapitel IV beschreibt eine Studie, in welcher ich die Auswirkungen der Klimaerwärmung auf Wirt-Parasitoid Beziehungen untersucht habe. Dabei habe ich die Auswirkungen von Temperatur und Photoperiode auf die Schlupfphänologie zweier Frühlingsbienen (O. cornuta & O. bicornis) und drei ihrer Hauptparasitoide (C. indagator, A. anthrax, Monodontomerus) erforscht. In einem Klimakammerexperiment mit gekreuztem Design habe ich Kokons in Nesthöhlen und Kokons außerhalb von Nesthöhlen, zwei verschiedenen Temperaturregimen (Langzeitmittel von Würzburg, Deutschland und Langzeitmittel von Würzburg + 4 °C) und drei Photoperioden (Würzburg, Deutschland contra Snåsa, Norwegen contra Dauerdunkel) ausgesetzt und die Zeitpunkte des Bienen- und Parasitoidenschlupfes aufgezeichnet. Ich konnte zeigen, dass warme Temperaturen in allen untersuchten Arten den Schlupfzeitpunkt verfrühten, jedoch bei den Bienen weniger stark als bei den Parasitoiden. Eine Folge daraus ist, dass sich die Zeitspanne zwischen dem Schlupf der Bienenweibchen und dem Schlupf der Parasitoide im warmen Temperaturregime im Vergleich zum kalten verkürzte. Die Photoperiode hatte auf den Zeitpunkt des Schlupfes nur in Kokons außerhalb von Nisthöhlen einen Effekt (außer beim Schlupf von O. bicornis Männchen). Die Daten zeigen auch, dass der Effekt der Photoperiode auf die Schlupfphänologie im Vergleich zu dem Effekt der Temperatur viel schwächer war. Daraus schließe ich, dass sich im Zuge der Klimaerwärmung die Synchronisation der Schlupfphänologien von Bienen und ihren Parasitoiden verstärken wird. Eine Folge davon könnten erhöhte Parasitierungsraten bei Solitärbienen sein, welche den Reproduktionserfolg und die Populationsgröße negativ beeinflussen können. In dieser Doktorarbeit habe ich gezeigt, dass einer der Haupttreiber einer frühen Blüte bei Frühlingspflanzen geringe zwischenartliche Konkurrenz um Bestäuber mit später gleichzeitig blühenden Pflanzenarten ist, während andere Treiber, wie geringe Bestäuberabundanzen und ungünstige Wetterbedingungen nur von geringer Bedeutung sind. Im Zuge des Klimawandels könnte sich die Stärke verschiedener Treiber, die den Zeitpunkt von phänologischen Ereignissen beeinflussen, verändern. Ich konnte außerdem zeigen, dass wärmere Temperaturen die Blüte von frühen Frühlingspflanzen stärker verfrühen, als den Schlupf von Bienen und die Blüte von später gleichzeitig blühenden Pflanzenarten. Des Weiteren zeigte ich, dass wärmere Temperaturen den Schlupf von Parasitoiden stärker verfrühen als den Schlupf der Bienen. Ich konnte zeigen, dass während Temperaturveränderungen zu verschieden starken zeitlichen Verschiebungen führen können, Verschiebungen von geografischen Verbreitungsgebieten und damit geänderten Photoperioden die Schlupfphänologie von Bienen und ihren Parasitoiden wahrscheinlich nicht ändern werden. In dem tritrophischen System, das ich in dieser Doktorarbeit untersucht habe, könnte die Erwärmung des Klimas den Fortpflanzungserfolg der frühen Frühlingspflanze und der Frühlingsbienen negativ beeinflussen, aber wahrscheinlich nicht die der Parasitoide, die vielleicht sogar davon profitieren können. KW - Biene KW - Klimaänderung KW - Interaktion KW - Parasitoid KW - Pflanzen KW - Klimaerwärmung KW - Mutualismus KW - Antagonismus KW - Synchronisation KW - Phänologie Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213932 ER - TY - JOUR A1 - Rasa, Santa A1 - Nora-Krukle, Zaiga A1 - Henning, Nina A1 - Eliassen, Eva A1 - Shikova, Evelina A1 - Harrer, Thomas A1 - Scheibenbogen, Carmen A1 - Murovska, Modra A1 - Prusty, Bhupesh K. T1 - Chronic viral infections in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) JF - Journal of Translational Medicine N2 - Background and main text: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex and controversial clinical condition without having established causative factors. Increasing numbers of cases during past decade have created awareness among patients as well as healthcare professionals. Chronic viral infection as a cause of ME/CFS has long been debated. However, lack of large studies involving well-designed patient groups and validated experimental set ups have hindered our knowledge about this disease. Moreover, recent developments regarding molecular mechanism of pathogenesis of various infectious agents cast doubts over validity of several of the past studies. Conclusions: This review aims to compile all the studies done so far to investigate various viral agents that could be associated with ME/CFS. Furthermore, we suggest strategies to better design future studies on the role of viral infections in ME/CFS. KW - ME/CFS KW - Viral infections KW - Biomarkers Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224960 VL - 16 IS - 268 ER - TY - JOUR A1 - Grob, Robin A1 - Tritscher, Clara A1 - Grübel, Kornelia A1 - Stigloher, Christian A1 - Groh, Claudia A1 - Fleischmann, Pauline N. A1 - Rössler, Wolfgang T1 - Johnston's organ and its central projections in Cataglyphis desert ants JF - Journal of Comparative Neurology N2 - The Johnston's organ (JO) in the insect antenna is a multisensory organ involved in several navigational tasks including wind‐compass orientation, flight control, graviception, and, possibly, magnetoreception. Here we investigate the three dimensional anatomy of the JO and its neuronal projections into the brain of the desert ant Cataglyphis, a marvelous long‐distance navigator. The JO of C. nodus workers consists of 40 scolopidia comprising three sensory neurons each. The numbers of scolopidia slightly vary between different sexes (female/male) and castes (worker/queen). Individual scolopidia attach to the intersegmental membrane between pedicel and flagellum of the antenna and line up in a ring‐like organization. Three JO nerves project along the two antennal nerve branches into the brain. Anterograde double staining of the antennal afferents revealed that JO receptor neurons project to several distinct neuropils in the central brain. The T5 tract projects into the antennal mechanosensory and motor center (AMMC), while the T6 tract bypasses the AMMC via the saddle and forms collaterals terminating in the posterior slope (PS) (T6I), the ventral complex (T6II), and the ventrolateral protocerebrum (T6III). Double labeling of JO and ocellar afferents revealed that input from the JO and visual information from the ocelli converge in tight apposition in the PS. The general JO anatomy and its central projection patterns resemble situations in honeybees and Drosophila. The multisensory nature of the JO together with its projections to multisensory neuropils in the ant brain likely serves synchronization and calibration of different sensory modalities during the ontogeny of navigation in Cataglyphis. KW - ant brain KW - chordotonal organ KW - graviception KW - magnetic compass KW - multisensory integration KW - navigation KW - wind compass Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225679 VL - 529 IS - 8 SP - 2138 EP - 2155 ER - TY - JOUR A1 - Hojsgaard, Diego A1 - Schartl, Manfred T1 - Skipping sex: A nonrecombinant genomic assemblage of complementary reproductive modules JF - BioEssays N2 - The unusual occurrence and developmental diversity of asexual eukaryotes remain a puzzle. De novo formation of a functioning asexual genome requires a unique assembly of sets of genes or gene states to disrupt cellular mechanisms of meiosis and gametogenesis, and to affect discrete components of sexuality and produce clonal or hemiclonal offspring. We highlight two usually overlooked but essential conditions to understand the molecular nature of clonal organisms, that is, a nonrecombinant genomic assemblage retaining modifiers of the sexual program, and a complementation between altered reproductive components. These subtle conditions are the basis for physiologically viable and genetically balanced transitions between generations. Genomic and developmental evidence from asexual animals and plants indicates the lack of complementation of molecular changes in the sexual reproductive program is likely the main cause of asexuals' rarity, and can provide an explanatory frame for the developmental diversity and lability of developmental patterns in some asexuals as well as for the discordant time to extinction estimations. KW - amphimixis KW - apomixis KW - automixis KW - gynogenesis KW - hybridogenesis KW - parthenogenesis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225818 VL - 43 IS - 1 ER - TY - JOUR A1 - Müller, Jörg A1 - Ulyshen, Mike A1 - Seibold, Sebastian A1 - Cadotte, Marc A1 - Chao, Anne A1 - Bässler, Claus A1 - Vogel, Sebastian A1 - Hagge, Jonas A1 - Weiß, Ingmar A1 - Baldrian, Petr A1 - Tláskal, Vojtěch A1 - Thorn, Simon T1 - Primary determinants of communities in deadwood vary among taxa but are regionally consistent JF - Oikos N2 - The evolutionary split between gymnosperms and angiosperms has far‐reaching implications for the current communities colonizing trees. The inherent characteristics of dead wood include its role as a spatially scattered habitat of plant tissue, transient in time. Thus, local assemblages in deadwood forming a food web in a necrobiome should be affected not only by dispersal ability but also by host tree identity, the decay stage and local abiotic conditions. However, experiments simultaneously manipulating these potential community drivers in deadwood are lacking. To disentangle the importance of spatial distance and microclimate, as well as host identity and decay stage as drivers of local assemblages, we conducted two consecutive experiments, a 2‐tree species and 6‐tree species experiment with 80 and 72 tree logs, respectively, located in canopy openings and under closed canopies of a montane and a lowland forest. We sampled saproxylic beetles, spiders, fungi and bacterial assemblages from logs. Variation partitioning for community metrics based on a unified framework of Hill numbers showed consistent results for both studies: host identity was most important for sporocarp‐detected fungal assemblages, decay stage and host tree for DNA‐detected fungal assemblages, microclimate and decay stage for beetles and spiders and decay stage for bacteria. Spatial distance was of minor importance for most taxa but showed the strongest effects for arthropods. The contrasting patterns among the taxa highlight the need for multi‐taxon analyses in identifying the importance of abiotic and biotic drivers of community composition. Moreover, the consistent finding of microclimate as the primary driver for saproxylic beetles compared to host identity shows, for the first time that existing evolutionary host adaptions can be outcompeted by local climate conditions in deadwood. KW - deadwood experiments KW - dispersal KW - forest management KW - habitat filter KW - wood-inhabiting fungi Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228201 VL - 129 IS - 10 SP - 1579 EP - 1588 ER - TY - JOUR A1 - Sprenger, Philipp P. A1 - Müsse, Christian A1 - Hartke, Juliane A1 - Feldmeyer, Barbara A1 - Schmitt, Thomas A1 - Gebauer, Gerhard A1 - Menzel, Florian T1 - Dinner with the roommates: trophic niche differentiation and competition in a mutualistic ant‐ant association JF - Ecological Entomology N2 - 1. The potential for competition is highest among species in close association. Despite net benefits for both parties, mutualisms can involve costs, including food competition. This might be true for the two neotropical ants Camponotus femoratus and Crematogaster levior, which share the same nest in a presumably mutualistic association (parabiosis). 2. While each nest involves one Crematogaster and one Camponotus partner, both taxa were recently found to comprise two cryptic species that show no partner preferences and seem ecologically similar. Since these cryptic species often occur in close sympatry, they might need to partition their niches to avoid competitive exclusion. 3. Here, we investigated first, is there interference competition between parabiotic Camponotus and Crematogaster, and do they prefer different food sources under competition? And second, is there trophic niche partitioning between the cryptic species of either genus? 4. Using cafeteria experiments, neutral lipid fatty acid and stable isotope analyses, we found evidence for interference competition, but also trophic niche partitioning between Camponotus and Crematogaster. Both preferred protein‐ and carbohydrate‐rich baits, but at protein‐rich baits Ca. femoratus displaced Cr. levior over time, suggesting a potential discovery‐dominance trade‐off between parabiotic partners. Only limited evidence was found for trophic differentiation between the cryptic species of each genus. 5. Although we cannot exclude differentiation in other niche dimensions, we argue that neutral dynamics might mediate the coexistence of cryptic species. This model system is highly suitable for further studies of the maintenance of species diversity and the role of mutualisms in promoting species coexistence. KW - Cryptic species KW - Formicidae KW - neutral theory KW - niche partitioning KW - nutrition KW - parabiosis KW - species coexistence mechanism KW - trade‐offs Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228215 VL - 46 IS - 3 SP - 562 EP - 572 ER - TY - JOUR A1 - Du, Baoguo A1 - Ma, Yuhua A1 - Yáñez‐Serrano, Ana Maria A1 - Arab, Leila A1 - Fasbender, Lukas A1 - Alfarraj, Saleh A1 - Albasher, Gadah A1 - Hedrich, Rainer A1 - White, Philip J. A1 - Werner, Christiane A1 - Rennenberg, Heinz T1 - Physiological responses of date palm (Phoenix dactylifera) seedlings to seawater and flooding JF - New Phytologist N2 - In their natural environment along coast lines, date palms are exposed to seawater inundation and, hence, combined stress by salinity and flooding. To elucidate the consequences of this combined stress on foliar gas exchange and metabolite abundances in leaves and roots, date palm seedlings were exposed to flooding with seawater and its major constituents under controlled conditions. Seawater flooding significantly reduced CO\(_{2}\) assimilation, transpiration and stomatal conductance, but did not affect isoprene emission. A similar effect was observed upon NaCl exposure. By contrast, flooding with distilled water or MgSO\(_{4}\) did not affect CO\(_{2}\)/H\(_{2}\)O gas exchange or stomatal conductance significantly, indicating that neither flooding itself, nor seawater sulfate, contributed greatly to stomatal closure. Seawater exposure increased Na and Cl contents in leaves and roots, but did not affect sulfate contents significantly. Metabolite analyses revealed reduced abundances of foliar compatible solutes, such as sugars and sugar alcohols, whereas nitrogen compounds accumulated in roots. Reduced transpiration upon seawater exposure may contribute to controlling the movement of toxic ions to leaves and, therefore, can be seen as a mechanism to cope with salinity. The present results indicate that date palm seedlings are tolerant towards seawater exposure to some extent, and highly tolerant to flooding. KW - compatible solutes and other metabolites KW - date palm KW - flooding KW - salinity KW - shoot–root interaction KW - stomatal conductance KW - sulfate Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228226 VL - 229 IS - 6 SP - 3318 EP - 3329 ER - TY - JOUR A1 - Seibold, Sebastian A1 - Hothorn, Torsten A1 - Gossner, Martin M. A1 - Simons, Nadja K. A1 - Blüthgen, Nico A1 - Müller, Jörg A1 - Ambarlı, Didem A1 - Ammer, Christian A1 - Bauhus, Jürgen A1 - Fischer, Markus A1 - Habel, Jan C. A1 - Penone, Caterina A1 - Schall, Peter A1 - Schulze, Ernst‐Detlef A1 - Weisser, Wolfgang W. T1 - Insights from regional and short‐term biodiversity monitoring datasets are valuable: a reply to Daskalova et al. 2021 JF - Insect Conservation and Diversity N2 - Reports of major losses in insect biodiversity have stimulated an increasing interest in temporal population changes. Existing datasets are often limited to a small number of study sites, few points in time, a narrow range of land‐use intensities and only some taxonomic groups, or they lack standardised sampling. While new monitoring programs have been initiated, they still cover rather short time periods. Daskalova et al. 2021 (Insect Conservation and Diversity, 14, 1‐18) argue that temporal trends of insect populations derived from short time series are biased towards extreme trends, while their own analysis of an assembly of shorter‐ and longer‐term time series does not support an overall insect decline. With respect to the results of Seibold et al. 2019 (Nature, 574, 671–674) based on a 10‐year multi‐site time series, they claim that the analysis suffers from not accounting for temporal pseudoreplication. Here, we explain why the criticism of missing statistical rigour in the analysis of Seibold et al. (2019) is not warranted. Models that include ‘year’ as random effect, as suggested by Daskalova et al. (2021), fail to detect non‐linear trends and assume that consecutive years are independent samples which is questionable for insect time‐series data. We agree with Daskalova et al. (2021) that the assembly and analysis of larger datasets is urgently needed, but it will take time until such datasets are available. Thus, short‐term datasets are highly valuable, should be extended and analysed continually to provide a more detailed understanding of insect population changes under the influence of global change, and to trigger immediate conservation actions. KW - Arthropod KW - biodiversity KW - insect decline KW - land use KW - time series Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228309 VL - 14 IS - 1 SP - 144 EP - 148 ER - TY - THES A1 - Groma, Michaela T1 - Identification of a novel LysR-type transcriptional regulator in \(Staphylococcus\) \(aureus\) T1 - Identifizierung eines neuen Transkriptionsregulators vom LysR-Typ in \(Staphylococcus\) \(aureus\) N2 - Staphylococcus aureus is a facultative pathogen which causes a variety of infections. The treatment of staphylococcal infections is complicated because the bacteria is resistant to multiple common antibiotics. S. aureus is also known to express a variety of virulence factors which modulate the host’s immune response in order to colonize and invade certain host cells, leading to the host cell’s death. Among the virulence factors is a LysR-type transcriptional regulator (lttr) which is required for efficient colonization of secondary organs. In a recent report, which used transposon screening on S. aureus-infected mice, it was found that the amount of a novel lttr852 mutant bacteria recovered from the kidneys was significantly lower compared to the wildtype strains. This doctoral thesis therefore focused on phenotypical and molecular characterization of lttr852. An assessment of the S. aureus biofilm formation and the hemolysis revealed that lttr852 was not involved in the regulation of these virulence processes. RNA-sequencing for potential target genes of lttr852 identified differentially expressed genes that are involved in branched chain amino-acid biosynthesis, methionine sulfoxide reductase and copper transport, as well as a reduced transcription of genes encoding urease and of components of pyrimidine nucleotides. Promoter fusion with GFP reporters as as well as OmniLog were used to identify conditions under which the lttr852 was active. The promoter studies showed that glucose and high temperatures diminish the lttr852 promoter activity in a time-dependent manner, while micro-aerobic conditions enhanced the promoter activity. Copper was found to be a limiting factor. In addition, the impact on promoter activity of the lttr852 was tested in the presence of various regulators, but no central link to the genes involved in virulence was identified. The present work, thus, showed that lttr852, a new member of the class of LysR-type transcriptional regulators in S. aureus, has an important role in the rapid adaptation of S. aureus to the changing microenvironment of the host. N2 - Staphylococcus aureus ist ein fakultativer Erreger, der eine Vielzahl von Infektionen verursacht. Die Behandlung von Staphylokokken-Infektionen ist aufgrund des Auftretens einer Resistenz gegen mehrere gängige Antibiotika kompliziert. Es ist bekannt, dass S. aureus eine Vielzahl von Virulenzfaktoren exprimiert, um die Immunantwort des Wirts zu umgehen, und so in bestimmte Wirtszellen einzudringen und diese zu kolonisieren, was zum Tod von Wirtszellen führen kann. Unter den Virulenzfaktoren befindet sich ein Transkriptions-regulator vom LysR-Typ (lttr), der für eine effiziente Besiedlung von Sekundärorganen erforderlich ist. In einem kürzlich durchgeführten Transposon-Screen, bei dem Mäuse mit S. aureus infiziert wurden, wurde ein neuartiger lttr, der lttr852 identifiziert, bei dem aus den Nieren gewonnenen Bakterien signifikant dezimiert waren. Diese Doktorarbeit befasste sich mit der phänotypischen und molekularen Charakterisierung von lttr852. Die Auswertung der Biofilmbildung und der Hämolyse von S. aureus ergab, dass lttr852 nicht an der Regulation dieser Virulenzprozesse beteiligt war. Die RNA-Sequenzierung für potenzielle Zielgene von lttr852 identifizierte sowohl eine erhöhte Expression von Genen, die in der Aminosäuren-Biosynthese, Methionin-Sulfoxid-Reduktase und dem Kupfertransport involviert sind, als auch eine verringerte Transkription von codierenden Genen der Urease und Komponenten der Pyrimidin Nukleotide. Die Promotorfusion mit dem GFP-Reporter sowie das OmniLog System wurden verwendet, um Bedingungen zu identifizieren unter denen das lttr852 aktiv ist. Die Promotorstudien ergaben, dass die Anwesenheit von Glucose und eine erhöhte Temperatur die Promotoraktivität von lttr852 zeitabhängig herabsetzt, wobei die Aktivität durch mikroaerobe Bedingungen begünstigt wird. Kupfer wurde als limitierender Faktor identifiziert. Außerdem wurde der Einfluss diverser Regulatoren auf die transkriptionelle Regulation von lttr852 kontrolliert, jedoch keine zentrale Rolle in der Regulation von Virulenzgenen zugewiesen. Damit konnte innerhalb der vorliegenden Arbeit gezeigt werden, dass lttr852, ein neues Mitglied der Klasse der LysR-Typ Transkriptionsregulatoren in S. aureus, eine wichtige Rolle in der schnellen Adaption von S. aureus an die wechselnde Mikroumgebungen des Wirts hat. KW - Staphylococcus aureus KW - transcriptional regulation KW - metabolic adaptation KW - secondary site infection KW - LysR-type Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246757 ER - TY - JOUR A1 - Reiling, Sarah J. A1 - Krohne, Georg A1 - Friedrich, Oliver A1 - Geary, Timothy G. A1 - Rohrbach, Petra T1 - Chloroquine exposure triggers distinct cellular responses in sensitive versus resistant Plasmodium falciparum parasites JF - Scientific Reports N2 - Chloroquine (CQ) treatment failure in Plasmodium falciparum parasites has been documented for decades, but the pharmacological explanation of this phenotype is not fully understood. Current concepts attribute CQ resistance to reduced accumulation of the drug at a given external CQ concentration ([CQ] ex) in resistant compared to sensitive parasites. The implication of this explanation is that the mechanisms of CQ-induced toxicity in resistant and sensitive strains are similar once lethal internal concentrations have been reached. To test this hypothesis, we investigated the mechanism of CQ-induced toxicity in CQ-sensitive (CQS) versus CQ-resistant (CQR) parasites by analyzing the time-course of cellular responses in these strains after exposure to varying [CQ] ex as determined in 72 h toxicity assays. Parasite killing was delayed in CQR parasites for up to 10 h compared to CQS parasites when exposed to equipotent [CQ] ex. In striking contrast, brief exposure (1 h) to lethal [CQ] ex in CQS but not CQR parasites caused the appearance of hitherto undescribed hemozoin (Hz)-containing compartments in the parasite cytosol. Hz-containing compartments were very rarely observed in CQR parasites even after CQ exposures sufficient to cause irreversible cell death. These findings challenge current concepts that CQ killing of malaria parasites is solely concentration-dependent, and instead suggest that CQS and CQR strains fundamentally differ in the consequences of CQ exposure. KW - Cellular imaging KW - Parasite development Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225123 VL - 8 IS - 11137 ER - TY - JOUR A1 - Thorn, Simon A1 - Seibold, Sebastian A1 - Leverkus, Alexandro B A1 - Michler, Thomas A1 - Müller, Jörg A1 - Noss, Reed F A1 - Stork, Nigel A1 - Vogel, Sebastian A1 - Lindenmayer, David B T1 - The living dead: acknowledging life after tree death to stop forest degradation JF - Frontiers in Ecology and the Environment N2 - Global sustainability agendas focus primarily on halting deforestation, yet the biodiversity crisis resulting from the degradation of remaining forests is going largely unnoticed. Forest degradation occurs through the loss of key ecological structures, such as dying trees and deadwood, even in the absence of deforestation. One of the main drivers of forest degradation is limited awareness by policy makers and the public on the importance of these structures for supporting forest biodiversity and ecosystem function. Here, we outline management strategies to protect forest health and biodiversity by maintaining and promoting deadwood, and propose environmental education initiatives to improve the general awareness of the importance of deadwood. Finally, we call for major reforms to forest management to maintain and restore deadwood; large, old trees; and other key ecological structures. KW - forest degradation KW - biodiversity KW - deadwood Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218575 VL - 18 IS - 9 SP - 505 EP - 512 ER - TY - THES A1 - Markert, Sebastian Matthias T1 - Enriching the understanding of synaptic architecture from single synapses to networks with advanced imaging techniques T1 - Vertiefung des Verständnisses synaptischer Architektur von der einzelnen Synapse bis zum Netzwerk mit modernsten bildgebenden Verfahren N2 - Because of its complexity and intricacy, studying the nervous system is often challenging. Fortunately, the small nematode roundworm Caenorhabditis elegans is well established as a model system for basic neurobiological research. The C. elegans model is also the only organism with a supposedly complete connectome, an organism-wide map of synaptic connectivity resolved by electron microscopy, which provides some understanding of how the nervous system works as a whole. However, the number of available data-sets is small and the connectome contains errors and gaps. One example of this concerns electrical synapses. Electrical synapses are formed by gap junctions and difficult to map due to their often ambiguous morphology in electron micrographs, leading to misclassification or omission. On the other hand, chemical synapses are more easily mapped, but many aspects of their mode of operation remain elusive and their role in the C. elegans connectome is oversimplified. A comprehensive understanding of signal transduction of neurons between each other and other cells will be indispensable for a comprehensive understanding of the nervous system. In this thesis, I approach these challenges with a combination of advanced light and electron microscopy techniques. First, this thesis describes a strategy to increase synaptic specificity in connectomics. Specifically, I classify gap junctions with a high degree of confidence. To achieve this, I utilized array tomography (AT). In this thesis, AT is adapted for high-pressure freezing to optimize for structure preservation and for super-resolution light microscopy; in this manner, I aim to bridge the gap between light and electron microscopy resolutions. I call this adaptation super-resolution array tomography (srAT). The srAT approach made it possible to clearly identify and map gap junctions with high precision and accuracy. The results from this study showcased the feasibility of incorporating electrical synapses into connectomes in a systematic manner, and subsequent studies have used srAT for other models and questions. As mentioned above, the C. elegans connectomic model suffers from a shortage of datasets. For most larval stages, including the special dauer larval stage, connectome data is completely missing up to now. To obtain the first partial connectome data-set of the C. elegans dauer larva, we used focused ion-beam scanning electron microscopy (FIB-SEM). This technique offers an excellent axial resolution and is useful for acquiring large volumes for connectomics. Together with our collaborators, I acquired several data-sets which enable the analysis of dauer stage-specific “re-wiring” of the nervous system and thus offer valuable insights into connectome plasticity/variability. While chemical synapses are easy to map relative to electrical synapses, signal transduction via chemical transmitters requires a large number of different proteins and molecular processes acting in conjunction in a highly constricted space. Because of the small spatial scale of the synapse, investigating protein function requires very high resolution, which electron tomography provides. I analyzed electron tomograms of a worm-line with a mutant synaptic protein, the serine/threonine kinase SAD-1, and found remarkable alterations in several architectural features. My results confirm and re-contextualize previous findings and provide new insight into the functions of this protein at the chemical synapse. Finally, I investigated the effectiveness of our methods on “malfunctioning,” synapses, using an amyotrophic lateral sclerosis (ALS) model. In the putative synaptopathy ALS, the mechanisms of motor neuron death are mostly unknown. However, mutations in the gene FUS (Fused in Sarcoma) are one known cause of the disease. The expression of the mutated human FUS in C. elegans was recently shown to produce an ALS-like phenotype in the worms, rendering C. elegans an attractive disease model for ALS. Together with our collaboration partners, I applied both srAT and electron tomography methods to “ALS worms” and found effects on vesicle docking. These findings help to explain electrophysiological recordings that revealed a decrease in frequency of mini excitatory synaptic currents, but not amplitudes, in ALS worms compared to controls. In addition, synaptic endosomes appeared larger and contained electron-dense filaments in our tomograms. These results substantiate the idea that mutated FUS impairs vesicle docking and also offer new insights into further molecular mechanisms of disease development in FUS-dependent ALS. Furthermore, we demonstrated the broader applicability of our methods by successfully using them on cultured mouse motor neurons. Overall, using the C. elegans model and a combination of light and electron microscopy methods, this thesis helps to elucidate the structure and function of neuronal synapses, towards the aim of obtaining a comprehensive model of the nervous system. N2 - Das Nervensystem ist ein definierendes Merkmal aller Tiere, unter anderem verantwortlich für Sinneswahrnehmung, Bewegung und „höhere“ Hirnfunktionen. Wegen dessen Komplexität und Feingliedrigkeit stellt das Erforschen des Nervensystems oft eine Herausforderung dar. Jedoch ist der kleine Fadenwurm Caenorhabditis elegans als Modellsystem für neurobiologische Grundlagenforschung gut etabliert. Erbesitzt eines der kleinsten und unveränderlichsten bekannten Nervensysteme. C.elegans ist auch das einzige Modell, für das ein annähernd vollständiges Konnektom vorliegt, eine durch Elektronenmikroskopie erstellte Karte der synaptischen Verbindungen eines gesamten Organismus, die Einblicke in die Funktionsweise des Nervensystems als Ganzes erlaubt. Allerdings ist die Anzahl der verfügbaren Datensätze gering und das Konnektom enthält Fehler und Lücken. Davon sind beispielsweise elektrische Synapsen betroffen. Elektrische Synapsen werden von Gap Junctions gebildet und sind auf Grund ihrer oft uneindeutigen Morphologie in elektronenmikroskopischen Aufnahmen schwierig zu kartieren, was dazu führt, dass einige falsch klassifiziert oder übersehen werden. Chemische Synapsen sind dagegen einfacher zu kartieren, aber viele Aspekte ihrer Funktionsweise sind schwer zu erfassen und ihre Rolle im Konnektom von C.elegans ist daher zu vereinfacht dargestellt. Ein umfassendes Verständnis der Signaltransduktion von Neuronen untereinander und zu anderen Zellen wird Voraussetzung für ein vollständiges Erfassen des Nervensystems sein. In der vorliegenden Arbeit gehe ich diese Herausforderungen mithilfe einer Kombination aus modernsten licht- und elektronenmikroskopischen Verfahren an. Zunächst beschreibt diese Arbeit eine Strategie, um die synaptische Spezifität in der Konnektomik zu erhöhen, indem ich Gap Junctions mit einem hohen Maß an Genauigkeit klassifiziere. Um dies zu erreichen, nutzte ich array tomography (AT), eine Technik, die Licht- und Elektronenmikrokopie miteinander korreliert. In dieser Arbeit wird AT adaptiert für Hochdruckgefrierung, um die Strukturerhaltung zu optimieren, sowie für ultrahochauflösende Lichtmikroskopie; so wird die Kluft zwischen den Auflösungsbereichen von Licht- und Elektronenmikroskopie überbrückt. Diese Adaption nenne ich super-resolution array tomography (srAT). Der srATAnsatz machte es möglich, Gap Junctions mit hoher Präzision und Genauigkeit klar zu identifizieren. Für diese Arbeit konzentrierte ich mich dabei auf Gap Junctions des retrovesikulären Ganglions von C.elegans. Die Ergebnisse dieser Studie veranschaulichen, wie es möglich wäre, elektrische Synapsen systematisch in Konnektome aufzunehmen. Nachfolgende Studien haben srAT auch auf andere Modelle und Fragestellungen angewandt ... KW - Caenorhabditis elegans KW - Synapse KW - Elektronenmikroskopie KW - Myatrophische Lateralsklerose KW - connectomics KW - focused ion-beam scanning electron microscopy KW - super-resolution array tomography Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189935 ER - TY - JOUR A1 - Scheer, Ulrich T1 - Boveri's research at the Zoological Station Naples: Rediscovery of his original microscope slides at the University of Würzburg JF - Marine Genomics N2 - Eric Davidson once wrote about Theodor Boveri: "From his own researches, and perhaps most important, his generalized interpretations, derive the paradigms that underlie modern inquiries into the genomic basis of embryogenesis" (Davidson, 1985). As luck would have it, the "primary data" of Boveri's experimental work, namely the microscope slides prepared by him and his wife Marcella during several stays at the Zoological Station in Naples (1901/02, 1911/12 and 1914), have survived at the University of Wurzburg. More than 600 slides exist and despite their age they are in a surprisingly good condition. The slides are labelled and dated in Boveri's handwriting and thus can be assigned to his published experimental work on sea urchin development. The results allowed Boveri to unravel the role of the cell nucleus and its chromosomes in development and inheritance. Here, I present an overview of the slides in the context of Boveri's work along with photographic images of selected specimens taken from the original slides. It is planned to examine the slides in more detail, take high-resolution focal image series of significant specimens and make them online available. KW - Sea urchin development KW - Polyspermy KW - Multipolar mitosis KW - Aneuploidy KW - Merogone experiments KW - Science history Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228453 VL - 40 ER - TY - THES A1 - Gründl, Marco T1 - Biochemical characterization of the MMB-Hippo crosstalk and its physiological relevance for heart development T1 - Biochemische Charakterisierung des MMB-Hippo Signalweges und dessen physiologische Rolle in der Herzentwicklung N2 - The Myb-MuvB (MMB) complex plays an essential role in the time-dependent transcriptional activation of mitotic genes. Recently, our laboratory identified a novel crosstalk between the MMB-complex and YAP, the transcriptional coactivator of the Hippo pathway, to coregulate a subset of mitotic genes (Pattschull et al., 2019). Several genetic studies have shown that the Hippo-YAP pathway is essential to drive cardiomyocyte proliferation during cardiac development (von Gise et al., 2012; Heallen et al., 2011; Xin et al., 2011). However, the exact mechanisms of how YAP activates proliferation of cardiomyocytes is not known. This doctoral thesis addresses the physiological role of the MMB-Hippo crosstalk within the heart and characterizes the YAP-B-MYB interaction with the overall aim to identify a potent inhibitor of YAP. The results reported in this thesis indicate that complete loss of the MMB scaffold protein LIN9 in heart progenitor cells results in thinning of ventricular walls, reduced cardiomyocyte proliferation and early embryonic lethality. Moreover, genetic experiments using mice deficient in SAV1, a core component of the Hippo pathway, and LIN9-deficient mice revealed that the correct function of the MMB complex is critical for proliferation of cardiomyocytes due to Hippo-deficiency. Whole genome transcriptome profiling as well as genome wide binding studies identified a subset of Hippo-regulated cell cycle genes as direct targets of MMB. By proximity ligation assay (PLA), YAP and B-MYB were discovered to interact in embryonal cardiomyocytes. Biochemical approaches, such as co-immunoprecipitation assays, GST-pulldown assays, and µSPOT-based peptide arrays were employed to characterize the YAP-B-MYB interaction. Here, a PY motif within the N-terminus of B-MYB was found to directly interact with the YAP WW-domains. Consequently, the YAP WW-domains were important for the ability of YAP to drive proliferation in cardiomyocytes and to activate MMB target genes in differentiated C2C12 cells. The biochemical information obtained from the interaction studies was utilized to develop a novel competitive inhibitor of YAP called MY-COMP (Myb-YAP competition). In MY-COMP, the protein fragment of B-MYB containing the YAP binding domain is fused to a nuclear localization signal. Co-immunoprecipitation studies as well as PLA revealed that the YAP-B-MYB interaction is robustly blocked by expression of MY-COMP. Adenoviral overexpression of MY-COMP in embryonal cardiomyocytes suppressed entry into mitosis and blocked the pro-proliferative function of YAP. Strikingly, characterization of the cellular phenotype showed that ectopic expression of MY-COMP led to growth defects, nuclear abnormalities and polyploidization in HeLa cells. Taken together, the results of this thesis reveal the mechanism of the crosstalk between the Hippo signaling pathway and the MMB complex in the heart and form the basis for interference with the oncogenic activity of the Hippo coactivator YAP. N2 - Der Myb-MuvB Komplex spielt eine essenzielle Rolle in der transkriptionellen Aktivierung von Zellzyklusgenen. Unser Labor hat kürzlich einen bis dahin unbekannten Mechanismus zwischen dem MMB-Komplex und Hippo-YAP Signalweg, der zur Aktivierung von Mitosegenen beiträgt, identifiziert. Der Hippo-YAP Signalweg ist beteiligt an der Gewebehomöostase und am Wachstum von Organen. So reguliert der Hippo-YAP Signalweg zum Beispiel während der Herzentwicklung die Proliferation von Herzmuskelzellen. Der exakte Mechanismus wie YAP die Zellteilung von Kardiomyozyten aktiviert, ist jedoch bisher nicht bekannt. In der vorliegenden Doktorarbeit wird das Zusammenspiel zwischen dem Hippo-Signalweg und dem MMB-Komplex im Herzen untersucht. Außerdem wird die Interaktion zwischen YAP und B-MYB biochemisch charakterisiert, um einen Inhibitor zu entwickeln, der die Aktivität von YAP vermindert. Die Ergebnisse dieser Doktorarbeit zeigen, dass der Verlust der zentralen Untereinheit des MMB-Komplexes, LIN9, in Vorläuferzellen der Kardiomyozyten zu einer Reduktion der Herzwand sowie zu einer niedrigeren Proliferationsrate von Herzmuskelzellen und einer erhöhten Embryonalsterblichkeit führt. Außerdem wurde in genetischen Experimenten mit Hippo- und LIN9-defizienten Mäusen gezeigt, dass der MMB-Komplex wichtig für die Aktivierung der Proliferation in Hippo-defizienten Kardiomyozyten ist. Eine globale Analyse der Transkription und Chromatinbindung von YAP und LIN9 im Herzen zeigte, dass eine Untergruppe von Zellzyklusgenen, die nach Inaktivierung des Hippo-Signalwegs vermehrt exprimiert werden, gleichzeitig den MMB-Komplex am Promoter gebunden haben. Durch Interaktionsstudien konnte gezeigt werden, dass YAP und B-MYB in embryonalen Kardiomyozyten miteinander interagieren. Die Bindung der beiden Transkriptionsfaktoren wurde durch Co-Immunpräzipitation, GST-Pulldown-Analysen und Peptid-Arrays biochemisch untersucht. Dabei wurde gezeigt, dass ein PY-Motiv im N-terminus von B-MYB direkt an die WW-Domänen von YAP bindet. Im Umkehrschluss wurde festgestellt, dass die WW-Domänen von YAP essenziell sind, um sowohl die Proliferation in Herzmuskelzellen als auch die Expression von Mitosegenen in differenzierten C2C12 Zellen zu aktivieren. Letztendlich wurden die Ergebnisse der Interaktionsstudie genutzt, um einen neuartigen kompetitiven Inhibitor von YAP zu entwickeln. Für MY-COMP (Myb-YAP Competition) wurde der Proteinabschnitt von B-MYB, der die YAP Bindedomäne enthält, mit einer Kernlokalisierungssequenz fusioniert. Bindestudien zeigten, dass MY-COMP die Interaktion zwischen YAP und B-MYB effektiv blockiert. Eine durch Adenoviren vermittelte Überexpression von MY-COMP in embryonalen Herzmuskelzellen resultierte in einer verminderten Anzahl von mitotischen Zellen. Somit wird durch Expression von MY-COMP, die proliferative Fähigkeit von YAP vermindert. Interessanterweise wurden in HeLa Zellen, die mit MY-COMP behandelt wurden, vermehrt Abnormalitäten der Zellkerne, polyploide Zellen sowie ein Wachstumsdefizit beobachtet. Zusammengefasst verdeutlichen die Ergebnisse dieser Doktorarbeit die Bedeutung des Zusammenspiels zwischen dem MMB-Komplex und dem Hippo-YAP-Signalweg für die Herzentwicklung und bilden die Grundlage, für die effektive Inhibierung der onkogenen Eigenschaften des Hippo-Coaktivators YAP. KW - Zellzyklus KW - Heart development KW - Hippo pathway KW - Myb-MuvB complex KW - Cardiomyocyte Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213328 ER - TY - JOUR A1 - Wolf, Matthias T1 - How to teach about what is a species JF - Biology N2 - To ask students what a species is always has something rhetorical about it. Too quickly comes the rote answer, often learned by heart without ever thinking about it: “A species is a reproductive community of populations (reproductively isolated from others), which occupies a specific niche in nature” (Mayr 1982). However, do two people look alike because they are twins or are they twins because they look alike? “Two organisms do not belong to the same species because they mate and reproduce, but they only are able to do so because they belong to the same species” (Mahner and Bunge 1997). Unfortunately, most biology (pre-university) teachers have no opinion on whether species are real or conceptual, simply because they have never been taught the question themselves, but rather one answer they still pass on to their students today, learned by heart without ever thinking about it. Species are either real or conceptual and, in my opinion, it is this “or” that we should teach about. Only then can we discuss those fundamental questions such as who or what is selected, who or what evolves and, finally, what is biodiversity and phylogenetics all about? Individuals related to each other by the tree of life. KW - biospecies KW - species as individuals KW - species as natural kinds KW - species concept KW - species problem Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241052 SN - 2079-7737 VL - 10 IS - 6 ER - TY - JOUR A1 - Othman, Eman M. A1 - Fathy, Moustafa A1 - Bekhit, Amany Abdlrehim A1 - Abdel-Razik, Abdel-Razik H. A1 - Jamal, Arshad A1 - Nazzal, Yousef A1 - Shams, Shabana A1 - Dandekar, Thomas A1 - Naseem, Muhammad T1 - Modulatory and toxicological perspectives on the effects of the small molecule kinetin JF - Molecules N2 - Plant hormones are small regulatory molecules that exert pharmacological actions in mammalian cells such as anti-oxidative and pro-metabolic effects. Kinetin belongs to the group of plant hormones cytokinin and has been associated with modulatory functions in mammalian cells. The mammalian adenosine receptor (A2a-R) is known to modulate multiple physiological responses in animal cells. Here, we describe that kinetin binds to the adenosine receptor (A2a-R) through the Asn253 residue in an adenosine dependent manner. To harness the beneficial effects of kinetin for future human use, we assess its acute toxicity by analyzing different biochemical and histological markers in rats. Kinetin at a dose below 1 mg/kg had no adverse effects on the serum level of glucose or on the activity of serum alanine transaminase (ALT) or aspartate aminotransferase (AST) enzymes in the kinetin treated rats. Whereas, creatinine levels increased after a kinetin treatment at a dose of 0.5 mg/kg. Furthermore, 5 mg/kg treated kinetin rats showed normal renal corpuscles, but a mild degeneration was observed in the renal glomeruli and renal tubules, as well as few degenerated hepatocytes were also observed in the liver. Kinetin doses below 5 mg/kg did not show any localized toxicity in the liver and kidney tissues. In addition to unraveling the binding interaction between kinetin and A2a-R, our findings suggest safe dose limits for the future use of kinetin as a therapeutic and modulatory agent against various pathophysiological conditions. KW - cytokinin kinetin KW - modulatory effects KW - in vivo toxicity KW - A2a-R receptor Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-223064 SN - 1420-3049 VL - 26 IS - 3 ER - TY - THES A1 - Zachary, Marie T1 - Functional characterization of small non-coding RNAs of \(Neisseria\) \(gonorrhoeae\) T1 - Funktionelle Charakterisierung kleiner nicht-kodierender RNAs in \(Neisseria\) \(gonorrhoeae\) N2 - During infection, bacteria need to adapt to a changing environment and have to endure various stress conditions. Small non-coding RNAs are considered as important regulators of bacterial gene expression and so allow quick adaptations by altering expression of specific target genes. Regulation of gene expression in the human-restricted pathogen Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhoea, is only poorly understood. The present study aims a better understanding of gene regulation in N. gonorrhoeae by studying small non-coding RNAs. The discovery of antisense RNAs for all opa genes led to the hypothesis of asRNA-mediated degradation of out-of-frame opa transcripts. Analysis of asRNA expression revealed a very low abundance of the transcripts and inclusion of another phase-variable gene in the study indicates that the asRNAs are not involved in degradation of out-of-frame transcripts. This doctoral thesis focuses on the analysis of trans-acting sRNAs. The sibling sRNAs NgncR_162 and NgncR_163 were discovered as post-transcriptional regulators altering expression of genes involved in metabolic processes, amino acid uptake and transcriptional regulation. A more detailed analysis by in silico and transcriptomic approaches showed that the sRNAs regulate a broad variety of genes coding for proteins of central metabolism, amino acid biosynthesis and degradation and several transport processes. Expression levels of the sibling sRNAs depend on the growth phase of the bacteria and on the growth medium. This indicates that NgncR_162 and NgncR_163 are involved in the adaptation of the gonococcal metabolism to specific growth conditions. This work further initiates characterisation of the sRNA NgncR_237. An in silico analysis showed details on sequence conservation and a possible secondary structure. A combination of in silico target prediction and differential RNA sequencing resulted in the identification of several target genes involved in type IV pilus biogenesis and DNA recombination. However, it was not successful to find induction conditions for sRNA expression. Interestingly, a possible sibling sRNA could be identified that shares the target interaction sequence with NgncR_237 and could therefore target the same mRNAs. In conclusion, this thesis provides further insights in gene regulation by non-coding RNAs in N. gonorrhoeae by analysing two pairs of sibling sRNAs modulating bacterial metabolism or possibly type IV pilus biogenesis. N2 - Bakterien müssen sich während des Infektionsprozesses an eine sich veränderte Umgebung anpassen und sind dabei zahlreichen Stressfaktoren ausgesetzt. Kleine, nicht-kodierende RNAs gelten als wichtige Regulatoren der bakteriellen Genexpression und ermöglichen daher eine schnelle Anpassung durch eine Veränderung der Expression spezifischer Ziel-Gene. Die Regulation der Genexpression des Humanpathogens Neisseria gonorrhoeae, Auslöser der Geschlechtskrankheit Gonorrhö, ist bis jetzt kaum verstanden. Die vorliegende Studie soll durch die Analyse kleiner, nicht-kodierender RNAs zum besseren Verständnis der Genregulation in Gonokokken beitragen. Durch die Entdeckung von antisense-RNAs für alle opa Gene wurde die Hypothese entwickelt, dass diese für den Abbau von opa Transkripten außerhalb des Leserahmens verantwortlich sind. Eine Analyse der asRNA Expression zeigte jedoch, dass diese sehr wenig exprimiert werden und auch die Untersuchung eines anderen phasenvariablen Gens weist darauf hin, dass die asRNAs keine Bedeutung für den Abbau von Transkripten außerhalb des Leserahmens haben. Der Schwerpunkt der Doktorarbeit liegt auf der Untersuchung trans-codierter sRNAs. Die Zwillings-sRNAs NgncR_162 und NgncR_163 agieren als post-transkriptionelle Regulatoren, die die Expression von Genen verändern, die bei Stoffwechselprozessen, Aminosäureaufnahme und transkriptioneller Regulation eine Rolle spielen. Eine detailliertere Analyse durch in silico- und Transkriptom-Studien zeigte, dass die sRNAs ein großes Spektrum an Genen regulieren, die für Proteine des Zentralstoffwechsels, der Aminosäurebiosynthese und des –abbaus, sowie zahlreicher Transportprozesse kodieren. Die Expressionslevel der Zwillings-sRNAs hängen von der Wachstumsphase der Bakterien und dem Wachstumsmedium ab. Das weist darauf hin, dass NgncR_162 und NgncR_163 eine Rolle bei der Adaptation des Stoffwechsels von Gonokokken zu bestimmten Wachstumsbedingungen spielen. In dieser Arbeit wird zudem die Charakterisierung der sRNA NgncR_237 initiiert. Im Rahmen von in silico Analysen wurde die Sequenzkonservierung und mögliche Sekundärstruktur untersucht. Eine Kombination aus in silico Zielgen-Vorhersage und differentieller RNA Sequenzierung führte zur Identifizierung zahlreicher Zielgene, die in der Biogenese von Typ IV Pili und DNA Rekombination eine Rolle spielen. Allerdings konnten keine Induktionsbedingungen für die sRNA Expression gefunden werden. Interessanterweise konnte eine mögliche Zwillings-sRNA identifiziert werden, die dieselbe Targetinteraktionsdomäne wie NgncR_237 hat und somit dieselben Zielgene regulieren könnte. Zusammenfassend ermöglicht diese Arbeit neue Einblicke in die Genregulation durch nicht-kodierende RNAs in Gonokokken, indem zwei Paare Zwillings-sRNAs analysiert wurden, die den bakteriellen Stoffwechsel anpassen oder möglicherweise eine Rolle in der Typ IV Pilus Biogenese spielen. KW - Neisseria gonorrhoeae KW - Non-coding RNA KW - Genregulation KW - regulation of gene expression Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-245826 ER -