@phdthesis{Grohmann2010, author = {Grohmann, Constanze}, title = {Termite mediated heterogeneity of soil and vegetation patternsin a semi-arid savanna ecosystem in Namibia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-54318}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Termites are the most important soil ecosystem engineers of semi-arid and arid habitats. They enhance decomposition processes as well as the subsequent mineralisation of nutrients by bacteria and fungi. Through their construction of galleries, nests and mounds, they promote soil turnover and influence the distribution of nutrients and also alter texture and hydrological properties of soils, thereby affecting the heterogeneity of their ecosystem. The main aim of the present thesis was to define the impact of termites on ecosys-tem functioning in a semi-arid ecosystem. In a baseline study, I assessed the diversity of termite taxa in relation to the amount of precipitation, the vegetation patterns and the land use systems at several sites in Namibia. Subsequently, I focussed on a species that is highly abundant in many African savannas, the fungus growing and mound building species Macro-termes michaelseni (Sj{\"o}stedt, 1914). I asked how this species influences the spatial hetero-geneity of soil and vegetation patterns. From repeated samplings at 13 sites in Namibia, I obtained 17 termite taxa of 15 genera. While the type of land use seems to have a minor effect on the termite fauna, the mean annual precipitation explained 96\% and the Simpson index of vascular plant diversity 81\% of the variation in taxa diversity. The number of termite taxa increased with both of these explanation variables. In contrast to former studies on Macrotermes mounds in several regions of Africa that I reviewed, soil analyses from M. michaelseni mounds in the central Namibian savanna revealed that they contain much higher nitrogen contents when compared to their parent material. Further analyses revealed that nitrate forms a major component of the nitrogen content in termite mounds. As nitrate solves easily in water, evaporation processes are most probably responsible for the transport of solved nitrates to the mound surface and their accumulation there. The analysed mounds in central Namibia contained higher sand propor-tions compared to the mounds of the former studies. Through the higher percentage of coarse and middle sized pores, water moves more easily in sandy soils compared to more clayey soils. In consequence, evaporation-driven nitrate accumulation can occur in the studied mounds at high rates. Hochgerechnet auf den Gesamtumfang der H{\"u}gel bedeckte das pro Jahr von einem bewohnten H{\"u}gel erodierte Material theoretisch einen 1 m breiten Kreisring um den Schwemmkegel des H{\"u}gels 2,4 mm hoch. Der entsprechende Wert f{\"u}r unbewohnte H{\"u}gel betrug 1,0 mm. To assess the amount of soil that erodes from termite mounds, I fastened four strong, 65 cm wide plastic bags at 14 mounds each and collected the soil that eroded during five rainfall events. Projected to the total mound circumference, the amount of soil eroded covers theoretically a 1 m wide circular ring around the pediment of an inhabited mound up to a height of 2.4 mm per year. For uninhabited mounds, the height of this soil layer would be 1.0 mm. Per hectare, roughly 245 kg eroded per year from the mounds. However, as the erosion rate depends on several factors such as rainfall intensity, soil texture and point of time within the rainy season, this is only a vague estimate. In order to determine up to which distance the soil erosion from the mounds still influences the chemical characteristics of the adjacent topsoil, I took samples from depth of 0-10 cm at 1, 5 and 25 m distances, respectively, from four different mounds and from the mounds themselves. The non-metric multidimensional scaling of the soil properties showed strong differences between mound and off-mound samples. Soil characteristics within the samples from the mounds did not differ largely. Similarly, I found no strong differences between the samples taken from the different distances from the mound. From these results I conclude that through the construction of foraging galleries and sheetings (soil constructions with which some termite species cover their food items), the soil eroding from termite mounds is quickly mixed with deeper soil layers. In consequence, mound material does not accumulate in the mound's vicinity. In order to reveal how plant growth is influenced by termite mound material, we assessed the number of grass and herb individuals as well as the biomass of plants growing in situ on the base of mounds compared to adjacent sites. While the numbers of both grass and herb individuals were significantly lower compared to adjacent sites, the total biomass of plants growing on the base of mounds was significantly higher. Reverse results were obtained by pot experiments with radish (Raphanus sativus subsp. sativus) and sorghum (Sorghum sp.) growth. Both species grew significantly weaker on mound soil compared to adjacent soil. The contradictory results concerning the biomass of in situ and pot experi-ments are most probably caused by the disturbance of the original soil structure during the potting process. The material was subsequently compacted through watering the plants. In contrast, Macrotermes mounds are pervaded by many macropores which seem to be essential for the plant roots to penetrate the soil. In the last part of this thesis, I posed the question how mounds of M. michaelseni are distributed and what factors might be responsible for this pattern. Former studies showed that mound size is correlated with the size of its inhabiting colony. With several multi-scale analyses, I revealed that larger inhabited mounds were regularly distributed. Additionally, mounds which were closer together tended to be smaller than on average. This indicates that intraspecific competition controls the distribution and size of colonies and their mounds. Former studies concerning Odontotermes mounds substantiated that they are local hotspots of primary productivity and animal abundance. Based on these findings, simulations revealed that a regular distribution of these mounds leads to a greater ecosystem-wide productivity compared to a random arrangement. As in the present study, plant biomass was higher at the mounds compared to off-mound sites, this might hold true for M. michaelseni mounds. From the results of this thesis, I draw the conclusion that through their mound building activities, M. michaelseni strongly influences the distribution patterns of soil nutrients within the central Namibian savanna. These termites create sharp contrasts in nutrient levels and vegetation patterns between mound soils and off-mound soils and enhance the heterogeneity of their habitats. Former studies revealed that habitat hetero-geneity is important in generating species diversity and species richness in turn is correlated positively with biomass production and positively affects ecosystem services. In conclusion, the present thesis underlines the importance of M. michaelseni for ecosystem functioning of the central Namibian savanna.}, subject = {Termiten}, language = {en} } @phdthesis{Groh2013, author = {Groh, Janos Michael}, title = {Pathogenic impact of immune cells in mouse models of neuronal ceroid lipofuscinosis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-77684}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {The neuronal ceroid lipofuscinoses (NCLs) are fatal neurodegenerative disorders in which the visual system is affected in early stages of disease. A typical accompanying feature is neuroinflammation, the pathogenic impact of which is presently unknown. In this study, the role of inflammatory cells in the pathogenesis was investigated in Palmitoyl-protein thioesterase 1-deficient (Ppt1-/-) and Ceroidlipofuscinosis, neuronal 3-deficient (Cln3-/-) mice, models of the infantile and juvenile forms of NCL, respectively. Focusing predominantly on the visual system, an infiltration of CD8+ cytotoxic Tlymphocytes and an activation of microglia/macrophage-like cells was observed early in disease. To analyze the pathogenic impact of lymphocytes, Ppt1-/- mice were crossbred with mice lacking lymphocytes (Rag1-/-) and axonal transport, perturbation and neuronal survival were scored. Lack of lymphocytes led to a significant amelioration of neuronal disease and reconstitution experiments revealed a crucial role of CD8+ cytotoxic T-lymphocytes. Lack of lymphocytes also caused an improved clinical phenotype and extended longevity. To investigate the impact of microglia/macrophage-like cells, Ppt1-/- and Cln3-/- mice were crossbred with mice lacking sialoadhesin (Sn-/-), a monocyte lineage-restricted cell adhesion molecule important for interactions between macrophage-like cells and lymphocytes. Similar to the lack of lymphocytes, absence of sialoadhesin significantly ameliorated the disease in Ppt1-/- and Cln3-/- mice. Taken together, both T-lymphocytes and microglia/macrophage-like cells were identified as pathogenic mediators in two distinct forms of fatal inherited neurodegenerative storage disorders. These studies expand the concept of secondary inflammation as a common pathomechanistic feature in some neurological diseases and provide novel insights that may be crucial for developing treatment strategies for different forms of NCL.}, subject = {Nervendegeneration}, language = {en} } @article{GrohRoessler2020, author = {Groh, Claudia and R{\"o}ssler, Wolfgang}, title = {Analysis of Synaptic Microcircuits in the Mushroom Bodies of the Honeybee}, series = {Insects}, volume = {11}, journal = {Insects}, number = {1}, issn = {2075-4450}, doi = {10.3390/insects11010043}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200774}, year = {2020}, abstract = {Mushroom bodies (MBs) are multisensory integration centers in the insect brain involved in learning and memory formation. In the honeybee, the main sensory input region (calyx) of MBs is comparatively large and receives input from mainly olfactory and visual senses, but also from gustatory/tactile modalities. Behavioral plasticity following differential brood care, changes in sensory exposure or the formation of associative long-term memory (LTM) was shown to be associated with structural plasticity in synaptic microcircuits (microglomeruli) within olfactory and visual compartments of the MB calyx. In the same line, physiological studies have demonstrated that MB-calyx microcircuits change response properties after associative learning. The aim of this review is to provide an update and synthesis of recent research on the plasticity of microcircuits in the MB calyx of the honeybee, specifically looking at the synaptic connectivity between sensory projection neurons (PNs) and MB intrinsic neurons (Kenyon cells). We focus on the honeybee as a favorable experimental insect for studying neuronal mechanisms underlying complex social behavior, but also compare it with other insect species for certain aspects. This review concludes by highlighting open questions and promising routes for future research aimed at understanding the causal relationships between neuronal and behavioral plasticity in this charismatic social insect.}, language = {en} } @phdthesis{Groh2005, author = {Groh, Claudia}, title = {Environmental influences on the development of the female honeybee brain Apis mellifera}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-17388}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {F{\"u}r die Honigbiene spielt der Geruchssinn eine entscheidende Rolle bei der Kommunikation innerhalb des Sozialstaates. Kastenspezifische, auf uweltbedingten Einfl{\"u}ssen basierende sowie altersbedingte Unterschiede im olfaktorisch gesteuerten Verhalten liefern ein hervorragendes Modellsystem f{\"u}r diese Studie, um die Entwicklung und Funktion neuronaler Plastizit{\"a}t im olfaktorischen System zu untersuchen. Diese Studie konzentriert sich auf Unterschiede zwischen K{\"o}niginnen und Arbeiterinnen, den beiden weiblichen Kasten innerhalb des Bienestaates, sowie auf umweltbedingte Plastizit{\"a}t. Diploide Eier, aus denen sich K{\"o}niginnen und Arbeiterinnen entwickeln, sind genetisch identisch. Dennoch entwickeln sich K{\"o}niginnen wesentlich schneller zum Adulttier als Arbeiterinnen, sind als Imago gr{\"o}ßer, leben wesentlich l{\"a}nger und zeigen andere Verhaltensweisen. Diese Unterschiede werden durch eine differentielle larvale F{\"u}tterung initiiert. Im Anschluss an das Larvenstadium und somit nach erfolgter Kastendetermination, entwickeln sich die Bienen {\"u}ber eine Puppenphase (verdeckelte Phase) zum Imago. Adulte Bienen klimatisieren das zentrale Brutareal auf einer mittleren Temperatur von 35°C konstant. Bienen, die bei niedrigeren Temperaturen innerhalb des physiologisch relevanten Bereichs aufwachsen, weisen Defizite im olfaktorischen Lernverhalten und in der Tanzkommunikation auf. M{\"o}gliche neuronale Korrelate f{\"u}r altersbedingte, temperatur- und kastenspezifische Unterschiede im olfaktorisch gesteuerten Verhalten sollten in dieser Arbeit betrachtet werden. Die strukturellen Analysen konzentrierten sich dabei auf prim{\"a}re (Antennalloben) und sekund{\"a}re (Pilzk{\"o}rper-Calyces)olfaktorische Verarbeitungszentren im Gehirn von sich entwickelnden und adulten Tieren beider Kasten. Synchron verdeckelte Brutzellen beider Kasten wurden unter kontrollierten Bedingungen im Inkubator herangezogen. Neuroanatomische Untersuchungen wurden an fixierten Gewebeschnitten mittels einer Doppelfluoreszenzf{\"a}rbung mit Fluor-Phalloidin und anti-Synapsin Immuncytochemie durchgef{\"u}hrt. Diese Doppelmarkierung erm{\"o}glichte die Visualisierung und Quantifizierung individueller Synapsenkomplexe (Microglomeruli) im Pilzk{\"o}rper-Calyx. Phalloidin bindet an verschiedene F-Aktin Isoformen und kann zum Nachweis von F-Aktin im Insektennervensystem verwendet werden. F-Aktin wird w{\"a}hrend der Entwicklung in Wachstumskegeln und in adulten Gehirnen in pr{\"a}synaptischen Endigungen und dendritischen Dornen exprimiert. Pr{\"a}synaptische Elemente wurden durch den Einsatz eines spezifischen Antik{\"o}rpers gegen das Drosophila-Vesikeltransportprotein Synapsin I charakterisiert. Mit Hilfe der konfokalen Laser-Scanning Mikroskopie wurde die exakte r{\"a}umliche Zuordnung der Fluoreszenzsignale anhand optischer Schnitte durch die Pr{\"a}parate realisiert. Anhand dieser Methodik konnten erstmals {\"u}ber reine Volumenanalysen hinausgehende Messungen zur synaptischen Strukturplastizit{\"a}t im Pilzk{\"o}rper-Calyx durchgef{\"u}hrt werden. Die Untersuchungen an Gehirnen in den verschiedenen Puppenstadien zeigten Unterschiede im Entwicklungsverlauf der Gehirne mit dem Fokus auf die Bildung antennaler Glomeruli und calycaler Microglomeruli. Unterschiede in der Gehirnentwicklung verdeutlichten die ontogenetische Plastizit{\"a}t des Gehirns der Honigbiene. Entsprechend der k{\"u}rzeren Puppenphase der K{\"o}niginnen bildeten sich sowohl antennale Glomeruli als auch alle Untereinheiten (Lippe, Collar, Basalring) des Calyx etwa drei Tage fr{\"u}her aus. Direkt nach dem Schlupf zeigten quantitative Analysen innerhalb der Pilzk{\"o}rper-Calyces eine signifikant geringere Anzahl an Microglomeruli bei K{\"o}niginnen. Diese neuronale Strukturplastizit{\"a}t auf verschiedenen Ebenen der olfaktorischen Informationsverarbeitung korreliert mit der kastenspezifischen Arbeitsteilung. Die Arbeit liefert Erkenntnisse {\"u}ber den Einfluss eines wichtigen kontrollierten Umweltparameters, der Bruttemperatur, w{\"a}hrend der Puppenphase auf die synaptische Organisation der adulten Pilzk{\"o}rper-Calyces. Bereits geringe Unterschiede in der Aufzuchtstemperatur (1°C) beeinflussten signifikant die Anzahl von Microglomeruli in der Lippenregion des Calyx beider weiblicher Kasten. Die maximale Anzahl an MG entwickelte sich bei Arbeiterinnen bei 34.5°C, bei K{\"o}niginnen aber bei 33.5°C. Neben dieser entwicklungsbedingten neuronalen Plastizit{\"a}t zeigt diese Studie eine starke altersbedingte Strukturplastizit{\"a}t der MG w{\"a}hrend der relativ langen Lebensdauer von Bienenk{\"o}niginnen. Hervorzuheben ist, dass die Anzahl an MG in der olfaktorischen Lippenregion mit dem Alter anstieg (~55\%), in der angrenzenden visuellen Collarregion jedoch abnahm (~33\%). Die in der vorliegenden Arbeite erstmals gezeigte umweltbedingte Entwicklungsplastizit{\"a}t sowie altersbedingte synaptische Strukturplastizit{\"a}t in den sensorischen Eingangsregionen der Pilzk{\"o}rper-Calyces k{\"o}nnte kasten- und altersspezifischen Anpassungen im Verhalten zugrunde liegen.}, subject = {Biene}, language = {en} } @article{GroenewegvanRoyenFenzetal.2014, author = {Groeneweg, Femke L. and van Royen, Martin E. and Fenz, Susanne and Keizer, Veer I. P. and Geverts, Bart and Prins, Jurrien and de Kloet, E. Ron and Houtsmuller, Adriaan B. and Schmidt, Thomas S. and Schaaf, Marcel J. M.}, title = {Quantitation of Glucocorticoid Receptor DNA-Binding Dynamics by Single-Molecule Microscopy and FRAP}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {3}, doi = {10.1371/journal.pone.0090532}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117085}, pages = {e90532}, year = {2014}, abstract = {Recent advances in live cell imaging have provided a wealth of data on the dynamics of transcription factors. However, a consistent quantitative description of these dynamics, explaining how transcription factors find their target sequences in the vast amount of DNA inside the nucleus, is still lacking. In the present study, we have combined two quantitative imaging methods, single-molecule microscopy and fluorescence recovery after photobleaching, to determine the mobility pattern of the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), two ligand-activated transcription factors. For dexamethasone-activated GR, both techniques showed that approximately half of the population is freely diffusing, while the remaining population is bound to DNA. Of this DNA-bound population about half the GRs appeared to be bound for short periods of time (similar to 0.7 s) and the other half for longer time periods (similar to 2.3 s). A similar pattern of mobility was seen for the MR activated by aldosterone. Inactive receptors (mutant or antagonist-bound receptors) show a decreased DNA binding frequency and duration, but also a higher mobility for the diffusing population. Likely, very brief (<= 1 ms) interactions with DNA induced by the agonists underlie this difference in diffusion behavior. Surprisingly, different agonists also induce different mobilities of both receptors, presumably due to differences in ligand-induced conformational changes and receptor complex formation. In summary, our data provide a consistent quantitative model of the dynamics of GR and MR, indicating three types of interactions with DNA, which fit into a model in which frequent low-affinity DNA binding facilitates the search for high-affinity target sequences.}, language = {en} } @article{GrobTritscherGruebeletal.2021, author = {Grob, Robin and Tritscher, Clara and Gr{\"u}bel, Kornelia and Stigloher, Christian and Groh, Claudia and Fleischmann, Pauline N. and R{\"o}ssler, Wolfgang}, title = {Johnston's organ and its central projections in Cataglyphis desert ants}, series = {Journal of Comparative Neurology}, volume = {529}, journal = {Journal of Comparative Neurology}, number = {8}, doi = {10.1002/cne.25077}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225679}, pages = {2138 -- 2155}, year = {2021}, abstract = {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.}, language = {en} } @article{GrobHeinigGruebeletal.2021, author = {Grob, Robin and Heinig, Niklas and Gr{\"u}bel, Kornelia and R{\"o}ssler, Wolfgang and Fleischmann, Pauline N.}, title = {Sex-specific and caste-specific brain adaptations related to spatial orientation in Cataglyphis ants}, series = {Journal of Comparative Neurology}, volume = {529}, journal = {Journal of Comparative Neurology}, number = {18}, doi = {10.1002/cne.25221}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257299}, pages = {3882-3892}, year = {2021}, abstract = {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.}, language = {en} } @article{GrobFleischmannGruebeletal.2017, author = {Grob, Robin and Fleischmann, Pauline N. and Gr{\"u}bel, Kornelia and Wehner, R{\"u}diger and R{\"o}ssler, Wolfgang}, title = {The role of celestial compass information in Cataglyphis ants during learning walks and for neuroplasticity in the central complex and mushroom bodies}, series = {Frontiers in Behavioral Neuroscience}, volume = {11}, journal = {Frontiers in Behavioral Neuroscience}, number = {226}, doi = {10.3389/fnbeh.2017.00226}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159235}, year = {2017}, abstract = {Central place foragers are faced with the challenge to learn the position of their nest entrance in its surroundings, in order to find their way back home every time they go out to search for food. To acquire navigational information at the beginning of their foraging career, Cataglyphis noda performs learning walks during the transition from interior worker to forager. These small loops around the nest entrance are repeatedly interrupted by strikingly accurate back turns during which the ants stop and precisely gaze back to the nest entrance—presumably to learn the landmark panorama of the nest surroundings. However, as at this point the complete navigational toolkit is not yet available, the ants are in need of a reference system for the compass component of the path integrator to align their nest entrance-directed gazes. In order to find this directional reference system, we systematically manipulated the skylight information received by ants during learning walks in their natural habitat, as it has been previously suggested that the celestial compass, as part of the path integrator, might provide such a reference system. High-speed video analyses of distinct learning walk elements revealed that even exclusion from the skylight polarization pattern, UV-light spectrum and the position of the sun did not alter the accuracy of the look back to the nest behavior. We therefore conclude that C. noda uses a different reference system to initially align their gaze directions. However, a comparison of neuroanatomical changes in the central complex and the mushroom bodies before and after learning walks revealed that exposure to UV light together with a naturally changing polarization pattern was essential to induce neuroplasticity in these high-order sensory integration centers of the ant brain. This suggests a crucial role of celestial information, in particular a changing polarization pattern, in initially calibrating the celestial compass system.}, language = {en} } @phdthesis{Grob2022, author = {Grob, Robin}, title = {The Function of Learning Walks of \({Cataglyphis Ants}\): Behavioral and Neuronal Analyses}, doi = {10.25972/OPUS-29017}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-290173}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Humans and animals alike use the sun, the moon, and the stars to guide their ways. However, the position of celestial cues changes depending on daytime, season, and place on earth. To use these celestial cues for reliable navigation, the rotation of the sky has to be compensated. While humans invented complicated mechanisms like the Antikythera mechanism to keep track of celestial movements, animals can only rely on their brains. The desert ant Cataglyphis is a prime example of an animal using celestial cues for navigation. Using the sun and the related skylight polarization pattern as a compass, and a step integrator for distance measurements, it can determine a vector always pointing homewards. This mechanism is called path integration. Since the sun's position and, therefore, also the polarization pattern changes throughout the day, Cataglyphis have to correct this movement. If they did not compensate for time, the ants' compass would direct them in different directions in the morning and the evening. Thus, the ants have to learn the solar ephemeris before their far-reaching foraging trips. To do so, Cataglyphis ants perform a well-structured learning-walk behavior during the transition phase from indoor worker to outdoor forager. While walking in small loops around the nest entrance, the ants repeatedly stop their forward movements to perform turns. These can be small walked circles (voltes) or tight turns about the ants' body axes (pirouettes). During pirouettes, the ants gaze back to their nest entrance during stopping phases. These look backs provide a behavioral read-out for the state of the path integrator. The ants "tell" the observer where they think their nest is, by looking back to it. Pirouettes are only performed by Cataglyphis ants inhabiting an environment with a prominent visual panorama. This indicates, that pirouettes are performed to learn the visual panorama. Voltes, on the other hand, might be used for calibrating the celestial compass of the ants. In my doctoral thesis, I employed a wide range of state-of-the-art techniques from different disciplines in biology to gain a deeper understanding of how navigational information is acquired, memorized, used, and calibrated during the transition phase from interior worker to outdoor forager. I could show, that celestial orientation cues that provide the main compass during foraging, do not guide the ants during the look-backbehavior of initial learning walks. Instead Cataglyphis nodus relies on the earth's magnetic field as a compass during this early learning phase. While not guiding the ants during their first walks outside of the nest, excluding the ants from perceiving the natural polarization pattern of the skylight has significant consequences on learning-related plasticity in the ants' brain. Only if the ants are able to perform their learning-walk behavior under a skylight polarization pattern that changes throughout the day, plastic neuronal changes in high-order integration centers are induced. Especially the mushroom bogy collar, a center for learning and memory, and the central complex, a center for orientation and motor control, showed an increase in volume after learning walks. This underlines the importance of learning walks for calibrating the celestial compass. The magnetic compass might provide the necessary stable reference system for the ants to calibrate their celestial compass and learn the position of landmark information. In the ant brain, visual information from the polarization-sensitive ocelli converge in tight apposition with neuronal afferents of the mechanosensitive Johnston's organ in the ant's antennae. This makes the ants' antennae an interesting candidate for studying the sensory bases of compass calibration in Cataglyphis ants. The brain of the desert navigators is well adapted to successfully accomplish their navigational needs. Females (gynes and workers) have voluminous mushroom bodies, and the synaptic complexity to store large amount of view-based navigational information, which they acquire during initial learning walks. The male Cataglyphis brain is better suited for innate behaviors that support finding a mate. The results of my thesis show that the well adapted brain of C. nodus ants undergoes massive structural changes during leaning walks, dependent on a changing celestial polarization pattern. This underlies the essential role of learning walks in the calibration of orientation systems in desert ants.}, subject = {Cataglyphis}, language = {en} } @article{GrittnerBairdStoeckl2022, author = {Grittner, Rebecca and Baird, Emily and St{\"o}ckl, Anna}, title = {Spatial tuning of translational optic flow responses in hawkmoths of varying body size}, series = {Journal of Comparative Physiology A}, volume = {208}, journal = {Journal of Comparative Physiology A}, number = {2}, issn = {1432-1351}, doi = {10.1007/s00359-021-01530-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266565}, pages = {279-296}, year = {2022}, abstract = {To safely navigate their environment, flying insects rely on visual cues, such as optic flow. Which cues insects can extract from their environment depends closely on the spatial and temporal response properties of their visual system. These in turn can vary between individuals that differ in body size. How optic flow-based flight control depends on the spatial structure of visual cues, and how this relationship scales with body size, has previously been investigated in insects with apposition compound eyes. Here, we characterised the visual flight control response limits and their relationship to body size in an insect with superposition compound eyes: the hummingbird hawkmoth Macroglossum stellatarum. We used the hawkmoths' centring response in a flight tunnel as a readout for their reception of translational optic flow stimuli of different spatial frequencies. We show that their responses cut off at different spatial frequencies when translational optic flow was presented on either one, or both tunnel walls. Combined with differences in flight speed, this suggests that their flight control was primarily limited by their temporal rather than spatial resolution. We also observed strong individual differences in flight performance, but no correlation between the spatial response cutoffs and body or eye size.}, language = {en} } @phdthesis{Grimmig2015, author = {Grimmig, Tanja Maria}, title = {Immunity, Inflammation and Cancer: The role of Foxp3, TLR7 and TLR8 in gastrointestinal cancer}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125248}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Regulatory T cells (Treg) expressing the transcription factor forkhead box protein P3 (Foxp3) have been demonstrated to mediate evasion from anti-tumor immune responses during tumor progression. Moreover, Foxp3 expression by tumor cells themselves may allow them to counteract effector T cell responses, resulting in a survival benefit of the tumor. For gastrointestinal cancers, in particular pancreatic and colorectal cancer (CRC), the clinical relevance of Foxp3 is not clear to date. Therefore the aim of this study was to analyze its impact in CRC and pancreatic cancer. To determine the relevance of Foxp3 for tumor progression and patient survival, gene and protein analysis of human pancreatic and colon cancer cell lines as well as tumor tissues from patients with CRC was performed. The results derived from the patients with CRC were correlated with clinicopathological parameters and patients' overall survival. Cancer cell mediated Foxp3 expression in vitro was demonstrated in human pancreatic cancer cell lines PANC1, PaCa DD 135, PaCa DD 159 and PaCa DD 185 as well as in human colon cancer cell lines SW480 and SW620. Additionally, Foxp3 expressing cancer cells were found in ex vivo tumor tissue samples of patients with CRC. The percentage of Foxp3+ cancer cells increased from stages UICC I/II to UICC III/IV compared to normal tissue. Moreover, high tumor cell mediated Foxp3 expression was associated with poor prognosis compared to patients with low Foxp3 expression. In contrast, low and high Foxp3 level in tumor infiltrating Treg cells demonstrated no significant differences in patients' overall survival. Correlation analysis demonstrated a significant association of Foxp3 cancer cell expression with the expression of immunosuppressive cytokines IL-10 and TGF-β. These findings suggest that Immunosuppressive cytokines such as IL-10 and TGF-β released by rather Foxp3+ cancer cells than Foxp3+ Treg cells may inhibit the activation of naive T cells, hence limiting antitumor immune responses and favoring tumorigenesis and progression. Chronic inflammation has been shown to be an important epigenetic and environmental factor in numerous tumor entities. Recent data suggest that tumorigenesis and tumor progression may be associated with inflammation-triggered activation of Toll-like receptors (TLR). In this study, the specific impact of both TLR7 and TLR8 expression and signaling on tumor cell proliferation and chemoresistance is analyzed in inflammation linked CRC and pancreatic cancer. By gene and protein expression analysis of human pancreatic and colon cancer cell lines TLR7 and TLR8 expression was determined in vitro. Additionally, expression of TLR7/TLR8 in UICC stage I-IV pancreatic cancer, chronic pancreatitis and normal pancreatic tissue was examined. For in vitro/in vivo studies TLR7/TLR8 overexpressing PANC1 cell lines were generated and analyzed for effects of TLR expression and stimulation on tumor cell proliferation and chemoresistance. Cancer cell mediated TLR7 and TLR8 expression in vitro was demonstrated in human colon cancer cell lines SW480, SW620 and HT-29 as well as in primary pancreatic cancer cell lines PaCa DD 135, PaCa DD 159 and PaCa DD 185. Additionally, TLR7 and TLR8 expressing tumor cells were found in ex vivo tissue samples of patients with pancreatic cancer and chronic pancreatitis. Significantly elevated expression levels of TLR7 and TLR8 were found in advanced tumor stages (UICC III) compared to early tumor stages (UICC II) and chronic pancreatitis. No or occasionally low expression was detected in normal pancreatic tissue. In contrast to the tissues from patients with pancreatic cancer or chronic pancreatitis, established pancreatic tumor cell lines express only very low levels of TLR7 and TLR8. Therefore, for in vitro and xenograft studies TLR7 or TLR8 overexpressing PANC1 cells were generated. Proliferation promoting effects of TLR7 and TLR8 expression and stimulation with R848 were detected in vitro. Additionally, increased tumor growth of TLR expressing PANC1 cells was demonstrated in subcutaneously injected Balb/c nude mice. Interestingly, activation of TLR7 or TLR8 induced not only an increase in tumor cell proliferation but also a strong chemoresistance of PANC1 cells against 5-fluorouracil (5-FU). Moreover, treatment with R848 resulted in elevated expression levels of NF-κB, COX-2 and inflammatory cytokines IL-1β, IL-8 and TNF-α, suggesting TLR7/8 signaling to contribute to an inflammatory, anti-apoptotic and proliferation promoting tumor microenvironment. These findings emphasize the particular role of TLR7 and TLR8 in inflammation related cancers and their relevance as potential targets for cancer therapy.  }, subject = {Bauchspeicheldr{\"u}senkrebs}, language = {en} } @article{GrimmKleinKopeketal.2016, author = {Grimm, Jonathan B. and Klein, Teresa and Kopek, Benjamin G. and Shtengel, Gleb and Hess, Harald F. and Sauer, Markus and Lavis, Luke D.}, title = {Synthesis of a far-red photoactivatable silicon-containing rhodamine for super-resolution microscopy}, series = {Angewandte Chemie International Edition}, volume = {55}, journal = {Angewandte Chemie International Edition}, number = {5}, doi = {10.1002/anie.201509649}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-191069}, pages = {1723-1727}, year = {2016}, abstract = {The rhodamine system is a flexible framework for building small-molecule fluorescent probes. Changing N-substitution patterns and replacing the xanthene oxygen with a dimethylsilicon moiety can shift the absorption and fluorescence emission maxima of rhodamine dyes to longer wavelengths. Acylation of the rhodamine nitrogen atoms forces the molecule to adopt a nonfluorescent lactone form, providing a convenient method to make fluorogenic compounds. Herein, we take advantage of all of these structural manipulations and describe a novel photoactivatable fluorophore based on a Si-containing analogue of Q-rhodamine. This probe is the first example of a "caged" Si-rhodamine, exhibits higher photon counts compared to established localization microscopy dyes, and is sufficiently red-shifted to allow multicolor imaging. The dye is a useful label for super-resolution imaging and constitutes a new scaffold for far-red fluorogenic molecules.}, language = {en} } @article{GrimmHufnagelWobseretal.2018, author = {Grimm, Johannes and Hufnagel, Anita and Wobser, Marion and Borst, Andreas and Haferkamp, Sebastian and Houben, Roland and Meierjohann, Svenja}, title = {BRAF inhibition causes resilience of melanoma cell lines by inducing the secretion of FGF1}, series = {Oncogenesis}, volume = {7}, journal = {Oncogenesis}, number = {71}, doi = {10.1038/s41389-018-0082-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177261}, year = {2018}, abstract = {Approximately half of all melanoma patients harbour activating mutations in the serine/threonine kinase BRAF. This is the basis for one of the main treatment strategies for this tumor type, the targeted therapy with BRAF and MEK inhibitors. While the initial responsiveness to these drugs is high, resistance develops after several months, frequently at sites of the previously responding tumor. This indicates that tumor response is incomplete and that a certain tumor fraction survives even in drug-sensitive patients, e.g., in a therapy-induced senescence-like state. Here, we show in several melanoma cell lines that BRAF inhibition induces a secretome with stimulating effect on fibroblasts and naive melanoma cells. Several senescence-associated factors were found to be transcribed and secreted in response to BRAF or MEK inhibition, among them members of the fibroblast growth factor family. We identified the growth factor FGF1 as mediator of resilience towards BRAF inhibition, which limits the pro-apoptotic effects of the drug and activates fibroblasts to secrete HGF. FGF1 regulation was mediated by the PI3K pathway and by FRA1, a direct target gene of the MAPK pathway. When FGFR inhibitors were applied in parallel to BRAF inhibitors, resilience was broken, thus providing a rationale for combined therapeutical application.}, language = {en} } @phdthesis{Grimm2019, author = {Grimm, Johannes}, title = {Autocrine and paracrine effects of BRAF inhibitor induced senescence in melanoma}, doi = {10.25972/OPUS-18116}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181161}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The FDA approval of targeted therapy with BRAFV600E inhibitors like vemurafenib and dabrafenib in 2011 has been the first major breakthrough in the treatment of metastatic melanoma since almost three decades. Despite increased progression free survival and elevated overall survival rates, complete responses are scarce due to resistance development approximately six months after the initial drug treatment. It was previously shown in our group that melanoma cells under vemurafenib pressure in vitro and in vivo exhibit features of drug-induced senescence. It is known that some cell types, which undergo this cell cycle arrest, develop a so-called senescence associated secretome and it has been reported that melanoma cell lines also upregulate the expression of different factors after senescence induction. This work describes the effect of the vemurafenib-induced secretome on cells. Conditioned supernatants of vemurafenib-treated cells increased the viability of naive fibroblast and melanoma cell lines. RNA analysis of donor melanoma cells revealed elevated transcriptional levels of FGF1, MMP2 and CCL2 in the majority of tested cell lines under vemurafenib pressure, and I could confirm the secretion of functional proteins. Similar observations were also done after MEK inhibition as well as in a combined BRAF and MEK inhibitor treatment situation. Interestingly, the transcription of other FGF ligands (FGF7, FGF17) was also elevated after MEK/ERK1/2 inhibition. As FGF receptors are therapeutically relevant, I focused on the analysis of FGFR-dependent processes in response to BRAF inhibition. Recombinant FGF1 increased the survival rate of melanoma cells under vemurafenib pressure, while inhibition of the FGFR pathway diminished the viability of melanoma cells in combination with vemurafenib and blocked the stimulatory effect of vemurafenib conditioned medium. The BRAF inhibitor induced secretome is regulated by active PI3K/AKT signaling, and the joint inhibition of mTor and BRAFV600E led to decreased senescence induction and to a diminished induction of the secretome-associated genes. In parallel, combined inhibition of MEK and PI3K also drastically decreased mRNA levels of the relevant secretome components back to basal levels. In summary, I could demonstrate that BRAF inhibitor treated melanoma cell lines acquire a specific PI3K/AKT dependent secretome, which is characterized by FGF1, CCL2 and MMP2. This secretome is able to stimulate other cells such as naive melanoma cells and fibroblasts and contributes to a better survival under drug pressure. These data are therapeutically highly relevant, as they imply the usage of novel drug combinations, especially specific FGFR inhibitors, with BRAF inhibitors in the clinic.}, subject = {Inhibitor}, language = {en} } @phdthesis{Griffoni2019, author = {Griffoni, Chiara}, title = {Towards advanced immunocompetent skin wound models for in vitro drug evaluation}, doi = {10.25972/OPUS-19212}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-192125}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Current preclinical models used to evaluate novel therapies for improved healing include both in vitro and in vivo methods. However, ethical concerns related to the use of animals as well as the poor physiological translation between animal and human skin wound healing designate in vitro models as a highly relevant and promising platforms for healing investigation. While current in vitro 3D skin models recapitulate a mature tissue with healing properties, they still represent a simplification of the in vivo conditions, where for example the inflammatory response originating after wound formation involves the contribution of immune cells. Macrophages are among the main contributors to the inflammatory response and regulate its course thanks to their plasticity. Therefore, their implementation into in vitro skin could greatly increase the physiological relevance of the models. As no full-thickness immunocompetent skin model containing macrophages has been reported so far, the parameters necessary for a successful triple co-culture of fibroblasts, keratinocytes and macrophages were here investigated. At first, cell source and culture timed but also an implementation strategy for macrophages were deter-mined. The implementation of macrophages into the skin model focused on the minimization of the culture time to preserve immune cell viability and phenotype, as the environment has a major influence on cell polarization and cytokine production. To this end, incorporation of macrophages in 3D gels prior to the combination with skin models was selected to better mimic the in vivo environment. Em-bedded in collagen hydrogels, macrophages displayed a homogeneous cell distribution within the gel, preserving cell viability, their ability to respond to stimuli and their capability to migrate through the matrix, which are all needed during the involvement of macrophages in the inflammatory response. Once established how to introduce macrophages into skin models, different culture media were evaluated for their effects on primary fibroblasts, keratinocytes and macrophages, to identify a suitable medium composition for the culture of immunocompetent skin. The present work confirmed that each cell type requires a different supplement combination for maintaining functional features and showed for the first time that media that promote and maintain a mature skin structure have negative effects on primary macrophages. Skin differentiation media negatively affected macrophages in terms of viability, morphology, ability to respond to pro- and anti-inflammatory stimuli and to migrate through a collagen gel. The combination of wounded skin equivalents and macrophage-containing gels con-firmed that culture medium inhibits macrophage participation in the inflammatory response that oc-curs after wounding. The described macrophage inclusion method for immunocompetent skin creation is a promising approach for generating more relevant skin models. Further optimization of the co-cul-ture medium will potentially allow mimicking a physiological inflammatory response, enabling to eval-uate the effects novel drugs designed for improved healing on improved in vitro models.}, subject = {Haut}, language = {en} } @article{GrebinykPrylutskaGrebinyketal.2019, author = {Grebinyk, Anna and Prylutska, Svitlana and Grebinyk, Sergii and Prylutskyy, Yuriy and Ritter, Uwe and Matyshevska, Olga and Dandekar, Thomas and Frohme, Marcus}, title = {Complexation with C\(_{60}\) fullerene increases doxorubicin efficiency against leukemic cells in vitro}, series = {Nanoscale Research Letters}, volume = {14}, journal = {Nanoscale Research Letters}, number = {61}, doi = {10.1186/s11671-019-2894-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228257}, year = {2019}, abstract = {Conventional anticancer chemotherapy is limited because of severe side effects as well as a quickly evolving multidrug resistance of the tumor cells. To address this problem, we have explored a C\(_{60}\) fullerene-based nanosized system as a carrier for anticancer drugs for an optimized drug delivery to leukemic cells.Here, we studied the physicochemical properties and anticancer activity of C\(_{60}\) fullerene noncovalent complexes with the commonly used anticancer drug doxorubicin. C\(_{60}\)-Doxorubicin complexes in a ratio 1:1 and 2:1 were characterized with UV/Vis spectrometry, dynamic light scattering, and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The obtained analytical data indicated that the 140-nm complexes were stable and could be used for biological applications. In leukemic cell lines (CCRF-CEM, Jurkat, THP1 and Molt-16), the nanocomplexes revealed 3.5 higher cytotoxic potential in comparison with the free drug in a range of nanomolar concentrations. Also, the intracellular drug's level evidenced C\(_{60}\) fullerene considerable nanocarrier function.The results of this study indicated that C\(_{60}\) fullerene-based delivery nanocomplexes had a potential value for optimization of doxorubicin efficiency against leukemic cells.}, language = {en} } @article{GrebinykPrylutskaChepurnaetal.2019, author = {Grebinyk, Anna and Prylutska, Svitlana and Chepurna, Oksana and Grebinyk, Sergii and Prylutskyy, Yuriy and Ritter, Uwe and Ohulchanskyy, Tymish Y. and Matyshevska, Olga and Dandekar, Thomas and Frohme, Marcus}, title = {Synergy of chemo- and photodynamic therapies with C\(_{60}\) Fullerene-Doxorubicin nanocomplex}, series = {Nanomaterials}, volume = {9}, journal = {Nanomaterials}, number = {11}, issn = {2079-4991}, doi = {10.3390/nano9111540}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193140}, year = {2019}, abstract = {A nanosized drug complex was explored to improve the efficiency of cancer chemotherapy, complementing it with nanodelivery and photodynamic therapy. For this, nanomolar amounts of a non-covalent nanocomplex of Doxorubicin (Dox) with carbon nanoparticle C\(_{60}\) fullerene (C\(_{60}\)) were applied in 1:1 and 2:1 molar ratio, exploiting C\(_{60}\) both as a drug-carrier and as a photosensitizer. The fluorescence microscopy analysis of human leukemic CCRF-CEM cells, in vitro cancer model, treated with nanocomplexes showed Dox's nuclear and C\(_{60}\)'s extranuclear localization. It gave an opportunity to realize a double hit strategy against cancer cells based on Dox's antiproliferative activity and C\(_{60}\)'s photoinduced pro-oxidant activity. When cells were treated with 2:1 C\(_{60}\)-Dox and irradiated at 405 nm the high cytotoxicity of photo-irradiated C\(_{60}\)-Dox enabled a nanomolar concentration of Dox and C\(_{60}\) to efficiently kill cancer cells in vitro. The high pro-oxidant and pro-apoptotic efficiency decreased IC\(_{50}\) 16, 9 and 7 × 10\(^3\)-fold, if compared with the action of Dox, non-irradiated nanocomplex, and C\(_{60}\)'s photodynamic effect, correspondingly. Hereafter, a strong synergy of therapy arising from the combination of C\(_{60}\)-mediated Dox delivery and C\(_{60}\) photoexcitation was revealed. Our data indicate that a combination of chemo- and photodynamic therapies with C\(_{60}\)-Dox nanoformulation provides a promising synergetic approach for cancer treatment.}, language = {en} } @article{GrebinykPrylutskaBuchelnikovetal.2019, author = {Grebinyk, Anna and Prylutska, Svitlana and Buchelnikov, Anatoliy and Tverdokhleb, Nina and Grebinyk, Sergii and Evstigneev, Maxim and Matyshevska, Olga and Cherepanov, Vsevolod and Prylutskyy, Yuriy and Yashchuk, Valeriy and Naumovets, Anton and Ritter, Uwe and Dandekar, Thomas and Frohme, Marcus}, title = {C60 fullerene as an effective nanoplatform of alkaloid Berberine delivery into leukemic cells}, series = {Pharmaceutics}, volume = {11}, journal = {Pharmaceutics}, number = {11}, issn = {1999-4923}, doi = {10.3390/pharmaceutics11110586}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193216}, pages = {586}, year = {2019}, abstract = {A herbal alkaloid Berberine (Ber), used for centuries in Ayurvedic, Chinese, Middle-Eastern, and native American folk medicines, is nowadays proved to function as a safe anticancer agent. Yet, its poor water solubility, stability, and bioavailability hinder clinical application. In this study, we have explored a nanosized carbon nanoparticle—C60 fullerene (C60)—for optimized Ber delivery into leukemic cells. Water dispersions of noncovalent C60-Ber nanocomplexes in the 1:2, 1:1, and 2:1 molar ratios were prepared. UV-Vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM) evidenced a complexation of the Ber cation with the negatively charged C60 molecule. The computer simulation showed that π-stacking dominates in Ber and C\(_{60}\) binding in an aqueous solution. Complexation with C\(_{60}\) was found to promote Ber intracellular uptake. By increasing C\(_{60}\) concentration, the C\(_{60}\)-Ber nanocomplexes exhibited higher antiproliferative potential towards CCRF-CEM cells, in accordance with the following order: free Ber < 1:2 < 1:1 < 2:1 (the most toxic). The activation of caspase 3/7 and accumulation in the sub-G1 phase of CCRF-CEM cells treated with C\(_{60}\)-Ber nanocomplexes evidenced apoptosis induction. Thus, this study indicates that the fast and easy noncovalent complexation of alkaloid Ber with C\(_{60}\) improved its in vitro efficiency against cancer cells.}, language = {en} } @phdthesis{Grebinyk2021, author = {Grebinyk, Anna}, title = {Synergistic Chemo- and Photodynamic Treatment of Cancer Cells with C\(_{60}\) Fullerene Nanocomplexes}, doi = {10.25972/OPUS-22207}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222075}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Recent progress in nanotechnology has attracted interest to a biomedical application of the carbon nanoparticle C60 fullerene (C60) due to its unique structure and versatile biological activity. In the current study the dual functionality of C60 as a photosensitizer and a drug nanocarrier was exploited to improve the efficiency of chemotherapeutic drugs towards human leukemic cells. Pristine C60 demonstrated time-dependent accumulation with predominant mitochondrial localization in leukemic cells. C60's effects on leukemic cells irradiated with high power single chip LEDs of different wavelengths were assessed to find out the most effective photoexcitation conditions. A C60-based noncovalent nanosized system as a carrier for an optimized drug delivery to the cells was evaluated in accordance to its physicochemical properties and toxic effects. Finally, nanomolar amounts of C60-drug nanocomplexes in 1:1 and 2:1 molar ratios were explored to improve the efficiency of cell treatment, complementing it with photodynamic approach. A proposed treatment strategy was developed for C60 nanocomplexes with the common chemotherapeutic drug Doxorubicin, whose intracellular accumulation and localization, cytotoxicity and mechanism of action were investigated. The developed strategy was revealed to be transferable to an alternative potent anticancer drug - the herbal alkaloid Berberine. Hereafter, a strong synergy of treatments arising from the combination of C60-mediated drug delivery and C60 photoexcitation was revealed. Presented data indicate that a combination of chemo- and photodynamic treatments with C60-drug nanoformulations could provide a promising synergetic approach for cancer treatment.}, subject = {cancer}, language = {en} } @phdthesis{Graver2015, author = {Graver, Shannon}, title = {Molecular and cellular cross talk between angiogenic, immune and DNA mismatch repair pathways}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-108302}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {VEGF is a main driver of tumor angiogenesis, playing an important role not only in the formation of new blood vessels, but also acts as a factor for cell migration, proliferation, survival and apoptosis. Angiogenesis is a universal function shared by most solid tumors and its inhibition was thought to have the potential to work across a broad patient population. Clinical evidence has shown that inhibiting pathological angiogenesis only works in a subset of patients and the identification of those patients is an important step towards personalized cancer care. The first approved antiangiogenic therapy was bevacizumab (Avastin®), a monoclonal antibody targeting VEGF in solid tumors including CRC, BC, NSCLC, RCC and others. In addition to endothelial cells, VEGF receptors are present on a number of different cell types including tumor cells, monocytes and macrophages. The work presented in this thesis looked at the in vitro cellular changes in tumor cells and leukocytes in response to the inhibition of VEGF signaling with the use of bevacizumab. In the initial experiments, VEGF was induced by hypoxia in tumor cells to evaluate changes in survival, proliferation, migration and changes in gene or protein expression. There was a minimal direct response of VEGF inhibition in tumor cells that could be attributed to bevacizumab treatment, with minor variations in some of the cell lines screened but no uniform or specific response noted. MMR deficiency often results in microsatellite instability (MSI) in tumors, as opposed to microsatellite stable (MSS) tumors, and accounts for up to 15\% of colorectal carcinomas (CRCs). It has been suggested in clinical data that MMR deficient tumors responded better to bevacizumab regimens, therefore further research used isogenic paired CRC tumor cell lines (MMR deficient and proficient). Furthermore, a DNA damaging agent was added to the treatment regimen, the topoisomerase inhibitor SN-38 (the active metabolite of irinotecan). Inhibiting VEGF using bevacizumab significantly inhibited the ability of MMR deficient tumor cells to form anchor dependent colonies, however conversely, bevacizumab treatment before damaging cells with SN-38, showed a significant increase in colony numbers. Moreover, VEGF inhibition by bevacizumab pretreatment also significantly increased the mutation fraction in MMR deficient cells as measured by transiently transfecting a dinucleotide repeat construct, suggesting VEGF signaling may have an intrinsic role in MMR deficient cells. A number of pathways were analyzed in addition to changes in gene expression profiles resulting in the identification of JNK as a possible VEGF targeted pathway. JUN expression was also reduced in these conditions reinforcing this hypothesis, however the intricate molecular mechanisms remain to be elucidated. In order to remain focused on the clinical application of the findings, it was noted that some cytokines were differentially regulated by bevacizumab between MMR proficient and deficient cells. Treatment regimens employed in vitro attempted to mimic the clinical setting by inducing DNA damage, then allowing cells to recover with or without VEGF using bevacizumab treatment. Inflammatory cytokines, CCL7 and CCL8, were found to have higher expression in the MMR deficient cell line with bevacizumab after DNA damage, therefore the cross talk via tumor derived factors to myeloid cells was analyzed. Gene expression changes in monocytes induced by tumor conditioned media showed CCL18 to be a bevacizumab regulated gene by MMR deficient cells and less so in MMR proficient cells. CCL18 has been described as a prognostic marker in gastric, colorectal and ovarian cancers, however the significance is dependent on tumor type. CCL18 primarily exerts its function on the adaptive immune system to trigger a TH2 response in T cells, but is also described to increase non-specific phagocytosis. The results of this study did show an increase in the phagocytic activity of macrophages in the presence of bevacizumab that was significantly more apparent in MMR deficient cells. Furthermore, after DNA damage MMR deficient cells treated with bevacizumab released a cytokine mix that induced monocyte migration in a bevacizumab dependent manner, showing a functional response with the combination of MMR deficiency and bevacizumab. In summary, the work in this thesis has shown evidence of immune cell modulation that is specific to MMR deficient tumor cells that may translate into a marker for the administration of bevacizumab in a clinical setting. VEGF ist ein zentraler Regulator der Tumor-Angiogenese, und spielt eine wichtige Rolle nicht nur in der Bildung von neuen Blutgef{\"a}ßen, sondern ist auch f{\"u}r die Migration, Proliferation, das {\"U}berleben und Apoptose von Tumorzellen essentiell. Angiogenese ist eine der universellen Funktionen, welche das Wachstum der meisten soliden Tumoren charakterisiert. Eine der klassischen therapeutischen Ideen wurde auf der Basis entwickelt, dass die spezifische Hemmung der Angiogenese das Potenzial hat in einer breiten Patientenpopulation einen klinischen Effekt zu zeigen. Die klinische Erfahrung und Anwendung hat jedoch gezeigt, dass die Hemmung der pathologischen Angiogenese nur in einem Teil der Patienten einen therapeutischen Nutzen aufweist. Somit stellt die Identifikation derjenigen Patienten, welche von der anti-angiogenen Therapie profitieren, einen wichtiger Schritt zur personalisierten Krebsbehandlung dar. Die erste zugelassene antiangiogene Therapie war Bevacizumab (Avastin®), ein monoklonaler Antik{\"o}rper gegen VEGF, welcher unter anderem in soliden Tumoren wie CRC, BC, nicht-kleinzelligem Lungenkrebs (NSCLC) und dem Nierenzellkarzinom angewandt wird. VEGF-Rezeptoren befinden sich nicht nur auf Endothelzellen, sondern sind auch auf einer Anzahl von verschiedenen Zelltypen, einschließlich Tumorzellen, Monozyten und Makrophagen nachweisbar. Die in dieser Arbeit vorgestellten Ergebnisse befassen sich mit den zellul{\"a}ren Ver{\"a}nderungen an Tumorzellen und Leukozyten als Reaktion auf die Hemmung der VEGF-Signalkaskade durch Bevacizumab in-vitro. In den Initialen Experimenten wurde VEGF durch Hypoxie in Tumorzellen induziert und Ver{\"a}nderungen der {\"U}berlebensrate, der Proliferation, Migration als auch in der Gen- oder Protein-Expression gemessen. Es konnte eine minimale direkte Reaktion der VEGF-Hemmung auf Tumorzellen beobachtet werden, welche auf die Bevacizumab Behandlung zur{\"u}ckgef{\"u}hrt werden k{\"o}nnte. Es zeigten sich aber auch geringf{\"u}gige Abweichungen in einigen der verwendeten Zellinien, die keine einheitliche Interpretation erlauben oder auf eine uniformelle Reaktion hinweisen w{\"u}rden. Das ph{\"a}notypische Korrelat einer „Mismatch" Reparatur (MMR)-Defizienz ist die Mikrosatelliteninstabilit{\"a}t im Gegensatz zu mikrosatellitenstabilen Tumoren und findet sich bei bis zu 15\% der kolorektalen Karzinomen (CRC) wieder. Klinischen Daten deuten daraufhin, dass Bevacizumab besser in MMR-defizienten Tumoren wirkt. Daher wurden die weiteren Untersuchungen in gepaarten MMR stabilen und MMR instabilen CRC-Tumorzelllinien (MMR defizient und kompetent) durchgef{\"u}hrt. Weiterhin wurde ein DNA-sch{\"a}digendes Agens, SN-38, ein Topoisomerase-Inhibitor (der aktive Metabolit von Irinotecan) dem Behandlungsschema zugef{\"u}gt. Es zeigte sich, dass die Hemmung von VEGF mittels Bevacizumab die F{\"a}higkeit der MMR defizienten Tumorzellen Kolonien zu bilden signifikant inhibiert. Im Gegensatz dazu, hatte die Behandlung von Bevacizumab vor der Zugabe des DNA sch{\"a}digenden Agens zu einer vermehrten Kolonienzahl gef{\"u}hrt. Außerdem erh{\"o}hte die Vorbehandlung mit Bevacizumab deutlich die Mutationsrate in MMR-defizienten Zellen, was durch die transiente Transfektion eines Dinukleotid-Repeat-Konstrukts nachgewiesen werden konnte. Dies deutete darauf hin, dass VEGF eine intrinsische Rolle in der Signalkaskade des MMR-Systems haben k{\"o}nnte. Deshalb wurde eine Anzahl von Signalalkaskaden zus{\"a}tzlich zu Ver{\"a}nderungen von Genexpressionsprofilen untersucht und JNK als m{\"o}gliche Verbindungsstelle der beiden Signalkaskaden, VEGF und MMR, identifiziert. Diese Hypothese wurde zus{\"a}tzlich unterst{\"u}tzt durch die Tatsache, dass die JUN Expression unter diesen experimentellen Bedingungen reduziert war. Die Aufkl{\"a}rung der komplexen molekularen Mechanismen der potentiellen Interaktion bleibt zuk{\"u}nftigen Untersuchungen vorbehalten. In Hinblick auf die klinische Konsequenz der erhaltenen Ergebnisse war es auff{\"a}llig, dass einige Zytokine durch Bevacizumab in den MMR defizienten Zellen im Gegensatz zu den MMR kompetenten Zellen unterschiedlich reguliert wurden. Die in-vitro verwendeten Behandlungsschemata waren den klinisch zur Anwendung kommenden Protokollen nachempfunden. Zuerst wurde ein DNA-Schaden gesetzt, und den Zellen erm{\"o}glicht, sich mit oder ohne Bevacizumab zu erholen. Es konnte gezeigt werden, dass die inflammatorischen Zytokine CCL7 und CCL8 eine h{\"o}here Expression in der MMR-defiziente Zelllinie in Kombination mit Bevacizumab aufweisen. Daher wurde ein m{\"o}glicher Crosstalk zwischen von Tumorzellen sezernierten Faktoren und myeloischen Zellen weiter verfolgt. Ver{\"a}nderungen der Genexpression in Monozyten durch Tumorzell- konditionierte Medien zeigte CCL18 als ein Bevacizumab reguliertes Gen in MMR-defizienten Zellen, aber nicht in MMR kompetenten Zellen. CCL18 {\"u}bt seine Funktion prim{\"a}r im adaptiven Immunsystems aus um eine TH2-Antwort in T-Zellen auszul{\"o}sen Ausserdem wird eine Erh{\"o}hung der nicht-spezifische Phagozytose als weitere Funktion beschrieben. CCL18 wurde bereits als prognostischer Marker in Magen-, Dickdarm- und Eierstockkrebsarten beschrieben; die klinische Bedeutung ist jedoch abh{\"a}ngig von Tumortyp. Die Ergebnisse dieser Arbeit zeigen, dass eine Erh{\"o}hung der phagozytischen Aktivit{\"a}t von Makrophagen in Gegenwart von Bevacizumab wesentlich deutlicher in MMR-defizienten Zellen ausgepr{\"a}gt war. Weiterhin wurde gefunden, dass nach DNA-Sch{\"a}digung in Bevacizumab behandelten MMR-defizienten Zellen Zytokine freigesetzt werden, welche eine Monozytenmigration in einer Bevacizumab-abh{\"a}ngigen Weise induzieren. Dies weist auf eine funktionelle Interaktion von MMR-Defizienz und Bevacizumab hin. Zus{\"a}tzlich zeigen die Ergebnisse dieser Arbeit eine Immunzellmodulation, die spezifisch f{\"u}r Mismatch-Reparatur defiziente Tumorzellen ist und in der klinischen Praxis als Marker f{\"u}r die Verabreichung von Bevacizumab verwendet werden k{\"o}nnte.}, subject = {Vascular endothelial Growth Factor}, language = {en} } @article{GrausLiRathjeetal.2023, author = {Graus, Dorothea and Li, Kunkun and Rathje, Jan M. and Ding, Meiqi and Krischke, Markus and M{\"u}ller, Martin J. and Cuin, Tracey Ann and Al-Rasheid, Khaled A. S. and Scherzer, S{\"o}nke and Marten, Irene and Konrad, Kai R. and Hedrich, Rainer}, title = {Tobacco leaf tissue rapidly detoxifies direct salt loads without activation of calcium and SOS signaling}, series = {New Phytologist}, volume = {237}, journal = {New Phytologist}, number = {1}, doi = {10.1111/nph.18501}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312152}, pages = {217 -- 231}, year = {2023}, abstract = {Salt stress is a major abiotic stress, responsible for declining agricultural productivity. Roots are regarded as hubs for salt detoxification, however, leaf salt concentrations may exceed those of roots. How mature leaves manage acute sodium chloride (NaCl) stress is mostly unknown. To analyze the mechanisms for NaCl redistribution in leaves, salt was infiltrated into intact tobacco leaves. It initiated pronounced osmotically-driven leaf movements. Leaf downward movement caused by hydro-passive turgor loss reached a maximum within 2 h. Salt-driven cellular water release was accompanied by a transient change in membrane depolarization but not an increase in cytosolic calcium ion (Ca\(^{2+}\)) level. Nonetheless, only half an hour later, the leaves had completely regained turgor. This recovery phase was characterized by an increase in mesophyll cell plasma membrane hydrogen ion (H\(^{+}\)) pumping, a salt uptake-dependent cytosolic alkalization, and a return of the apoplast osmolality to pre-stress levels. Although, transcript numbers of abscisic acid- and Salt Overly Sensitive pathway elements remained unchanged, salt adaptation depended on the vacuolar H\(^{+}\)/Na\(^{+}\)-exchanger NHX1. Altogether, tobacco leaves can detoxify sodium ions (Na\(^{+}\)) rapidly even under massive salt loads, based on pre-established posttranslational settings and NHX1 cation/H+ antiport activity. Unlike roots, signaling and processing of salt stress in tobacco leaves does not depend on Ca\(^{2+}\) signaling.}, language = {en} } @article{GrassingerFlorenMuelleretal.2021, author = {Grassinger, Julia Maria and Floren, Andreas and M{\"u}ller, Tobias and Cerezo-Echevarria, Argi{\~n}e and Beitzinger, Christoph and Conrad, David and T{\"o}rner, Katrin and Staudacher, Marlies and Aupperle-Lellbach, Heike}, title = {Digital lesions in dogs: a statistical breed analysis of 2912 cases}, series = {Veterinary Sciences}, volume = {8}, journal = {Veterinary Sciences}, number = {7}, issn = {2306-7381}, doi = {10.3390/vetsci8070136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242690}, year = {2021}, abstract = {Breed predispositions to canine digital neoplasms are well known. However, there is currently no statistical analysis identifying the least affected breeds. To this end, 2912 canine amputated digits submitted from 2014-2019 to the Laboklin GmbH \& Co. KG for routine diagnostics were statistically analyzed. The study population consisted of 155 different breeds (most common: 634 Mongrels, 411 Schnauzers, 197 Labrador Retrievers, 93 Golden Retrievers). Non-neoplastic processes were present in 1246 (43\%), tumor-like lesions in 138 (5\%), and neoplasms in 1528 cases (52\%). Benign tumors (n = 335) were characterized by 217 subungual keratoacanthomas, 36 histiocytomas, 35 plasmacytomas, 16 papillomas, 12 melanocytomas, 9 sebaceous gland tumors, 6 lipomas, and 4 bone tumors. Malignant neoplasms (n = 1193) included 758 squamous cell carcinomas (SCC), 196 malignant melanomas (MM), 76 soft tissue sarcomas, 52 mast cell tumors, 37 non-specified sarcomas, 29 anaplastic neoplasms, 24 carcinomas, 20 bone tumors, and 1 histiocytic sarcoma. Predisposed breeds for SCC included the Schnauzer (log OR = 2.61), Briard (log OR = 1.78), Rottweiler (log OR = 1.54), Poodle (log OR = 1.40), and Dachshund (log OR = 1.30). Jack Russell Terriers (log OR = -2.95) were significantly less affected by SCC than Mongrels. Acral MM were significantly more frequent in Rottweilers (log OR = 1.88) and Labrador Retrievers (log OR = 1.09). In contrast, Dachshunds (log OR = -2.17), Jack Russell Terriers (log OR = -1.88), and Rhodesian Ridgebacks (log OR = -1.88) were rarely affected. This contrasted with the well-known predisposition of Dachshunds and Rhodesian Ridgebacks to oral and cutaneous melanocytic neoplasms. Further studies are needed to explain the underlying reasons for breed predisposition or "resistance" to the development of specific acral tumors and/or other sites.}, language = {en} } @article{GrafeLinsenmair1989, author = {Grafe, U. and Linsenmair, Karl Eduard}, title = {Protogynous sex change in the Reed Frog: Hyperolius viridiflavus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30990}, year = {1989}, abstract = {Observations on captive reed frogs Hyperolius viridijlavus ommatostictus showed that seven out of 24 females changed into males. Sex change occurred without any hormone treatment and resulted in completely functional males. The adaptive value is discussed in terms of maximizing life-time reproductive success. Hyperolius r. ommatostictus is the first amphibian known to show functional sex reversal.}, language = {en} } @article{GrafeSchmuckLinsenmair1992, author = {Grafe, T. Ulmar and Schmuck, Richard and Linsenmair, Karl Eduard}, title = {Reproductive energetics of the African Reed Frogs, Hyperolius viridiflavus and Hyperolius marmoratus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31187}, year = {1992}, abstract = {No abstract available}, language = {en} } @article{GrafePreiningerSztatecsnyetal.2012, author = {Grafe, T. Ulmar and Preininger, Doris and Sztatecsny, Marc and Kasah, Rosli and Dehling, J. Maximilian and Proksch, Sebastian and H{\"o}dl, Walter}, title = {Multimodal Communication in a Noisy Environment: A Case Study of the Bornean Rock Frog Staurois parvus}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {5}, doi = {10.1371/journal.pone.0037965}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133718}, year = {2012}, abstract = {High background noise is an impediment to signal detection and perception. We report the use of multiple solutions to improve signal perception in the acoustic and visual modality by the Bornean rock frog, Staurois parvus. We discovered that vocal communication was not impaired by continuous abiotic background noise characterised by fast-flowing water. Males modified amplitude, pitch, repetition rate and duration of notes within their advertisement call. The difference in sound pressure between advertisement calls and background noise at the call dominant frequency of 5578 Hz was 8 dB, a difference sufficient for receiver detection. In addition, males used several visual signals to communicate with conspecifics with foot flagging and foot flashing being the most common and conspicuous visual displays, followed by arm waving, upright posture, crouching, and an open-mouth display. We used acoustic playback experiments to test the efficacy-based alerting signal hypothesis of multimodal communication. In support of the alerting hypothesis, we found that acoustic signals and foot flagging are functionally linked with advertisement calling preceding foot flagging. We conclude that S. parvus has solved the problem of continuous broadband low-frequency noise by both modifying its advertisement call in multiple ways and by using numerous visual signals. This is the first example of a frog using multiple acoustic and visual solutions to communicate in an environment characterised by continuous noise.}, language = {en} } @article{GrafSebald1978, author = {Graf, T. and Sebald, Walter}, title = {The dicyclohexylcarbodiimide-binding protein of the mitochondrial ATPase complex from beef heart. Isolation and amino acid composition}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62806}, year = {1978}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{GrafLettenmaierMuelleretal.2022, author = {Graf, Marlene and Lettenmaier, Ludwig and M{\"u}ller, J{\"o}rg and Hagge, Jonas}, title = {Saproxylic beetles trace deadwood and differentiate between deadwood niches before their arrival on potential hosts}, series = {Insect Conservation and Diversity}, volume = {15}, journal = {Insect Conservation and Diversity}, number = {1}, doi = {10.1111/icad.12534}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-262507}, pages = {48 -- 60}, year = {2022}, abstract = {Deadwood provides a variety of habitats for saproxylic beetles. Whereas the understanding of the drivers promoting saproxylic beetle diversity has improved, the process of deadwood colonisation and beetle's potential to trace resources is poorly understood. However, the mechanisms facilitating deadwood detection by saproxylic beetles appears to be essential for survival, as deadwood is usually scattered in time and space. To investigate whether saproxylic beetles distinguish before their arrival on potential hosts between alive trees and deadwood (lying, stumps, standing), deadwood arrangement (aggregated, distributed) and different heights on standing resources (bottom = 0.5 m, middle = 4-5 m, top = 7.30-11.60 m), we sampled saproxylic beetles with sticky traps in a deadwood experiment. We found on average 67\% higher abundance, 100\% higher species numbers and 50-130\% higher species diversity of colonising saproxylic beetles consistently for all deadwood types compared to alive trees with a distinct community composition on lying deadwood compared to the other resource types. Aggregated deadwood arrangement, which is associated with higher sun-exposure, had a positive effect on species richness. The abundance, species number and diversity, was significantly higher for standing deadwood and alive trees at the bottom section of tree trunks. In contrast to living trees, however, the vertical position had an additional effect on the community composition on standing deadwood. Our results indicate that saproxylic beetles are attracted to potential deadwood habitats and actively select specific trunk sections before arriving on potential hosts. Furthermore, this study highlights the importance of sun-exposed resources for species richness in saproxylic beetles.}, language = {en} } @inproceedings{GotzSchartl1994, author = {Gotz, R. and Schartl, Manfred}, title = {The conservation of neurotrophic factors during vertebrate evolution}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61964}, year = {1994}, abstract = {No abstract available}, subject = {Physiologische Chemie}, language = {en} } @phdthesis{Gotthard2023, author = {Gotthard, Hannes}, title = {Targeting Colorectal Cancer Stem Cells with Hemibodies}, doi = {10.25972/OPUS-30309}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-303090}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {The cancer stem cell hypothesis is a cancer development model which elicited great interest in the last decades stating that cancer heterogeneity arises from a stem cell through asymmetrical division. The Cancer Stem Cell subset is described as the only population to be tumorigenic and having the potential to renew. Conventional therapy often fails to eradicate CSC resulting in tumor relapse. Consequently, it is of great inter-est to eliminate this subset of cells to provide the best patient outcome. In the last years several approaches to target CSC were developed, one of them being immunotherapeu-tic targeting with antibodies. Since markers associated with CSC are also expressed on normal stem cells or healthy adjacent tissue in colorectal cancer, dual targeting strate-gies are preferred over targeting only a single antigen. Subsequently, the idea of dual targeting two CSC markers in parallel by a newly developed split T cell-engaging anti-body format termed as Hemibodies emerged. In a preliminary single cell RNA sequenc-ing analysis of colorectal cancer cells CD133, CD24, CD166 and CEA were identified as suitable targets for the combinatorial targeting strategy. Therefore, this study focused on trispecific and trivalent Hemibodies comprising a split binding moiety against CD3 and a binding moiety against either CD133, CD24, CD166 or CEA to overcome the occurrence of resistance and to efficiently eradicate all tumor cells including the CSC compartment. The study showed that the Hemibody combinations CD133xCD24, CD133xCD166 and CD133xCEA are able to eliminate double positive CHO cells with high efficacy while having a high specificity indicated by no killing of single antigen positive cells. A thera-peutic window ranging between one to two log levels could be achieved for all combina-tions mentioned above. The combinations CD133xCD24 and CD133xCD166 further-more proved its efficacy and specificity on established colorectal cancer cell lines. Be-sides the evaluation of specificity and efficacy the already introduced 1st generation of Hemibodies could be improved into a 2nd generation Hemibody format with increased half-life, stability and production yield. In future experiments the applicability of above-mentioned Hemibodies will be proven on patient-derived micro tumors to also include variables like tumor microenvironment and infiltration.}, subject = {Monoklonaler bispezifischer Antik{\"o}rper}, language = {en} } @article{GoosDejungWehmanetal.2019, author = {Goos, Carina and Dejung, Mario and Wehman, Ann M. and M-Natus, Elisabeth and Schmidt, Johannes and Sunter, Jack and Engstler, Markus and Butter, Falk and Kramer, Susanne}, title = {Trypanosomes can initiate nuclear export co-transcriptionally}, series = {Nucleic Acids Research}, volume = {47}, journal = {Nucleic Acids Research}, number = {1}, doi = {10.1093/nar/gky1136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177709}, pages = {266-282}, year = {2019}, abstract = {The nuclear envelope serves as important messenger RNA (mRNA) surveillance system. In yeast and human, several control systems act in parallel to prevent nuclear export of unprocessed mRNAs. Trypanosomes lack homologues to most of the involved proteins and their nuclear mRNA metabolism is non-conventional exemplified by polycistronic transcription and mRNA processing by trans-splicing. We here visualized nuclear export in trypanosomes by intra- and intermolecular multi-colour single molecule FISH. We found that, in striking contrast to other eukaryotes, the initiation of nuclear export requires neither the completion of transcription nor splicing. Nevertheless, we show that unspliced mRNAs are mostly prevented from reaching the nucleus-distant cytoplasm and instead accumulate at the nuclear periphery in cytoplasmic nuclear periphery granules (NPGs). Further characterization of NPGs by electron microscopy and proteomics revealed that the granules are located at the cytoplasmic site of the nuclear pores and contain most cytoplasmic RNA-binding proteins but none of the major translation initiation factors, consistent with a function in preventing faulty mRNAs from reaching translation. Our data indicate that trypanosomes regulate the completion of nuclear export, rather than the initiation. Nuclear export control remains poorly understood, in any organism, and the described way of control may not be restricted to trypanosomes.}, language = {en} } @article{GoosDejungJanzenetal.2017, author = {Goos, Carina and Dejung, Mario and Janzen, Christian J. and Butter, Falk and Kramer, Susanne}, title = {The nuclear proteome of Trypanosoma brucei}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {7}, doi = {10.1371/journal.pone.0181884}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158572}, pages = {e0181884}, year = {2017}, abstract = {Trypanosoma brucei is a protozoan flagellate that is transmitted by tsetse flies into the mammalian bloodstream. The parasite has a huge impact on human health both directly by causing African sleeping sickness and indirectly, by infecting domestic cattle. The biology of trypanosomes involves some highly unusual, nuclear-localised processes. These include polycistronic transcription without classical promoters initiated from regions defined by histone variants, trans-splicing of all transcripts to the exon of a spliced leader RNA, transcription of some very abundant proteins by RNA polymerase I and antigenic variation, a switch in expression of the cell surface protein variants that allows the parasite to resist the immune system of its mammalian host. Here, we provide the nuclear proteome of procyclic Trypanosoma brucei, the stage that resides within the tsetse fly midgut. We have performed quantitative label-free mass spectrometry to score 764 significantly nuclear enriched proteins in comparison to whole cell lysates. A comparison with proteomes of several experimentally characterised nuclear and non-nuclear structures and pathways confirmed the high quality of the dataset: the proteome contains about 80\% of all nuclear proteins and less than 2\% false positives. Using motif enrichment, we found the amino acid sequence KRxR present in a large number of nuclear proteins. KRxR is a sub-motif of a classical eukaryotic monopartite nuclear localisation signal and could be responsible for nuclear localization of proteins in Kinetoplastida species. As a proof of principle, we have confirmed the nuclear localisation of six proteins with previously unknown localisation by expressing eYFP fusion proteins. While proteome data of several T. brucei organelles have been published, our nuclear proteome closes an important gap in knowledge to study trypanosome biology, in particular nuclear-related processes.}, language = {en} } @phdthesis{Goos2021, author = {Goos, Carina}, title = {Nuclear periphery granules of trypanosomes - A characterization of composition and function}, doi = {10.25972/OPUS-23436}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234368}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {The nuclear envelope serves as important mRNA surveillance system. In yeast and humans, several control mechanisms act in parallel to prevent nuclear export of unprocessed mRNAs. However, trypanosomes lack homologues to most of the proteins involved. In addition, gene expression in trypanosomes relies almost completely on post-transcriptional regulation as they transcribe mRNAs as long polycistrons, which are subsequently processed into individual mRNA molecules by trans-splicing. As trans-splicing is not error-free, unspliced mRNAs may be recognized and prevented from reaching the cytoplasm by a yet unknown mechanism. When trans-splicing is inhibited in trypanosomes, the formation of a novel RNA granule type at the cytoplasmic periphery of the nucleus, so called nuclear periphery granules (NPGs) was previously observed. To identify potential regulators of nuclear export control, changes in protein localization which occur when trans-splicing is inhibited, were globally analyzed during this work. For this, trypanosome nuclei were purified under conditions maintaining NPG attachment to the nucleus, in the absence and presence of trans-splicing. Mass spectrometry analyses identified 128 proteins which are specifically enriched in nuclear preparations of cells inhibited for trans-splicing. Amongst them are proteins, which change their localization to the nucleus or to the nuclear pores as well as many proteins that move into NPGs. Some of these proteins are promising candidates for nuclear export control proteins, as the changes in localization (to the nucleus or nuclear pores) were specific to the accumulation of unspliced mRNAs. The NPG proteome almost exclusively contains proteins involved in mRNA metabolism, mostly unique to trypanosomes, notably major translation initiation factors were absent. These data indicate that NPGs are RNP complexes which have started or completed nuclear export, but not yet entered translation. As a byproduct of these proteomic studies, a high-quality dataset of the yet unknown T. brucei nuclear proteome is provided, closing an important gap in knowledge to study trypanosome biology, in particular nuclear related processes. NPGs were characterized in more detail by microscopy. The granules are cytoplasmic and present in at least two different trypanosome life cycle stages. There are at least two distinct granule subsets, with differences in protein composition. A closer analysis of NPGs by electron microscopy revealed that the granules are electron dense structures, which are connected to nuclear pores by string-like structures. In order to approach the function of NPGs, on the one hand, the hypothesis that NPGs might be related to perinuclear germ granules of adult gonads of C. elegans was tested: we found no relation between the two granule types. On the other hand, initial single molecule mRNA FISH experiments performed in trypanosomes showed no accumulation of unspliced transcripts in NPGs, arguing against an involvement of the granules in mRNA quality control.}, subject = {Trypanosoma brucei}, language = {en} } @article{GomezHFelipeMedinaSanchezMartinetal.2016, author = {Gom{\´e}z-H, Laura and Felipe-Medina, Natalia and S{\´a}nchez-Mart{\´i}n, Manuel and Davies, Owen R. and Ramos, Isabel and Garc{\´i}a-Tu{\~n}{\´o}n, Ignacio and de Rooij, Dirk G. and Dereli, Ihsan and T{\´o}th, Attila and Barbero, Jos{\´e} Luis and Benavente, Ricardo and Llano, Elena and Pendas, Alberto M.}, title = {C14ORF39/SIX6OS1 is a constituent of the synaptonemal complex and is essential for mouse fertility}, series = {Nature Communications}, volume = {7}, journal = {Nature Communications}, doi = {10.1038/ncomms13298}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165907}, pages = {13298}, year = {2016}, abstract = {Meiotic recombination generates crossovers between homologous chromosomes that are essential for genome haploidization. The synaptonemal complex is a 'zipper'-like protein assembly that synapses homologue pairs together and provides the structural framework for processing recombination sites into crossovers. Humans show individual differences in the number of crossovers generated across the genome. Recently, an anonymous gene variant in C14ORF39/SIX6OS1 was identified that influences the recombination rate in humans. Here we show that C14ORF39/SIX6OS1 encodes a component of the central element of the synaptonemal complex. Yeast two-hybrid analysis reveals that SIX6OS1 interacts with the well-established protein synaptonemal complex central element 1 (SYCE1). Mice lacking SIX6OS1 are defective in chromosome synapsis at meiotic prophase I, which provokes an arrest at the pachytene-like stage and results in infertility. In accordance with its role as a modifier of the human recombination rate, SIX6OS1 is essential for the appropriate processing of intermediate recombination nodules before crossover formation.}, language = {en} } @phdthesis{Goldau2002, author = {Goldau, Rainer}, title = {Clinical evaluation of novel methods to determine dialysis parameters using conductivity cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-3125}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2002}, abstract = {During the last two decades an ongoing discussion about the necessary dose of dialysis brought the result that the urea based Kt/V value is significantly correlated to morbidity of the end stage renal disease (ESRD) patients. Even if it is not completely accepted, it seems to be more and more agreement of the nephrological community that for good dialysis practice Kt/V should be kept above 1.2 to 1.3 in the usual 3X4 hours per week dialysis schedule for patients without own residual clearance to assure long term quality of life, low morbidity and mortality. K is the clearance of urea the dialysis system can apply, t is the treatment time and V is the urea distribution volume of the patient, which is nearly equal to total body water. Kt/V has the unit of a drug dose (ml of drug per ml of patient volume) and therefore sometimes is called dialysis 'dose', even if this is subject of discussion because it implies that the dose can be described with only one urea related number. This work does not participate in this discussion. The premise of this work is more technical: Whatever the final result of the above discussion will be, a patient-friendly, precise cost-neutral and handy technical solution should be given to the hand of the interested nephrologist to continuously supervise the urea based Kt/V that is applied to the patient. Of course this is combined with the hope that the long term mortality can be decreased if a covering online dialysis success control is facilitated. The technical solution that has been chosen is based on the equivalence of the diffusion coefficients of sodium chloride and urea. It is central subject of the investigation if the diffusive behaviour of sodium is equal to that of urea crossing the dialysis filter membrane. The advantage that makes the principle so handy is that sodium can be measured very precise by standard conductivity cells as they are implemented in dialysis machines in large numbers. The only necessary hardware modification is a second conductivity cell downstream the dialyser to be able to measure the mass balance over the filter. This is more complicated with urea that can only be measured undergoing an enzymatic conversion to ammonium ions. The ammonium ions induce a membrane potential, which is measured with very sensitive amplifiers. A cooling chain for the enzyme must be maintained. To find and approve the conductivity based technical solution two in-vivo studies have been conducted. In the first study a conductivity step profile, varying the conductivity in static levels in a baseline - 7 min high - 7min low- baseline shape, was applied that can be utilised to measure the urea clearance very accurate. This principle has been described in 1982 in a patent application. In a sequence of 206 computer recorded dialysis sessions with 22 patients it was found that urea clearance could be electrolytically measured with a mean error+/-standard deviation of -1.46+/-4.75\% , n=494. The measurement of Kt/V according to a single pool model was of similar accuracy: 2.88+/-4.15\% . Although in accordance with other studies these findings at an average confirmed the high correlation of ionic and urea based clearance measurements, an effect was found that was not consistent with the theory that was existent so far. It was found in the first study that the accuracy of the step profile measurements were dependent of the size of the patient, in particular of the urea distribution volume. Moreover it was of relevance which part of the step profile was used: the high-low states, the baseline- low or the baseline-high states. This was a theoretical lack. Careful analysis led to the result that sodium transfer from and into the patient was the reason for the dependence. This led to the enhancement of the theory that seems to correctly describe the nature of the effect. A new demand now was to minimise the sodium transfer. This was limited using static step profiles because in the time it needs to become stable sodium is shifted. In consequence non-stable, dynamic short conductivity boli were developed that allowed to minimise the amount of sodium to be shifted to the limits of the technical resolution of the measurement systems. Also the associated mathematical tools to evaluate the boli had to be suited to the problem. After termination of this process a second study was conducted to approve the new method found. In this study with 10 patients and 93 sessions, 264 step profile measurements and 173 bolus ionic dialysance measurements it was found that the bolus measurements matched their related blood side urea clearance references with the outstanding accuracy of (error+/-SD) 0.06+/-4.76\%. The result was not significantly different (p=0.87) from the reference by student's t-test for paired data. The Kt/V reference according to the single pool variable volume urea kinetic model (sPVVUKM) was found to be matched by the bolus principle with 5.32+/-3.9\% accuracy and a correlation of 0.98. The remaining difference of 5.32\% can be attributed to the neglect of the urea generation rate. Also the step profile was found to be very precise here. The error versus sPVVUKM was 0.05\%+/-5\%, r=0.96. However it did not image the neglect of urea generation correctly. Also a two pool modelling that comprises an internal compartimentation of the fluid pools of the patient was applied to the continuously recorded data. This two pool urea kinetic model (2PUKM) is regarded to be a more precise theoretical approach and now includes the urea generation. It found the bolus principle to deviate -3.04 +/- 14.3\%, n.s., p=0.13. The high standard deviation is due to the complexity of the model. Further from the developed theory a simplified method to roughly measure the sodium distribution volume could be derived. This method was tested in-vitro versus a container with dialysate of known volume and in-vivo versus the urea distribution volume. The in-vitro results were -19.9+/-34\%, r=0.92, n.s, p=0.916. In-vivo they were found to be -7.4+/-23.2\%, r=0.71, n.s., p=0.39. Due to dilution theory the sodium and urea distribution volumes virtually appear to be very similar using this method, although they absolutely differ significantly. Facing the strong simplifications that were made before applying this theory these results seem to be very encouraging that it could be possible to develop a principle to measure not only K but also V electrolytically. This would allow a true Kt/V measurement. The empirical urea distribution volume measurement using anthropometrical formulas has been compared to analytical methods. It has been found that the use Watson's formula with a -13\% correction gives good results. The correction should be applied with great care because it increases Kt/V just on a arithmetical base to the disadvantage of the patient. Also electrolytical plasma sodium measurement was evaluated and can be measured using a mixed analytic-empirical formula with an accuracy of 4.3+/-1.2\%. In summary, conductivity based methods seem to be a convenient method to measure several dialysis parameters of some clinical interest without effort. The results of this work meanwhile are implemented with substantial numbers into commonly available dialysis machines and the experience of the first time shows that the principle is well accepted by the clinicians.}, subject = {H{\"a}modialyse}, language = {en} } @phdthesis{Gogishvili2006, author = {Gogishvili, Tea}, title = {Immunotherapy of allergic disorders in a mouse model of allergic airway inflammation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-19304}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {Allergische Erkrankungen sind St{\"o}rungen, bei denen es zu Immunfehlregulationen kommt und die bei empf{\"a}nglichen Individuen zur Entstehung von Allergen spezifischen T-Helfer 2 (TH2) Immunantworten f{\"u}hren. Neuere Untersuchungen deuten darauf hin, dass die f{\"u}r Soforttypallergien charakteristischen TH2 Immunantworten sowohl durch nat{\"u}rlich vorkommende CD4+CD25+ regulatorische T Zellen (Treg) als auch durch Antigen induzierte IL-10-secreting CD4+ regulatorische T Zellen kontrolliert werden k{\"o}nnen. Weiterhin gibt es Hinweise, dass eine erfolgreiche Allergen spezifische Immuntherapie {\"u}ber die Induktion von IL-10 sezernierenden T reg Zellen vermittelt wird. In ersten Teil der Arbeit wird die Effizienz einer Allergen spezifischen Immuntherapie (SIT) in einem Mausmodel f{\"u}r allergische Atemwegsentz{\"u}ndung demonstriert. Als Allergieparameter wurden Allergen spezifisches IgE im Serum, verschiedene TH1 und TH2 Cytokine in der brochoalveol{\"a}ren Lavage Fl{\"u}ssigkeit und nach in vitro Restimulation in Milzzellen untersucht. Weiterhin wurden Histologien von Lungengewebe angefertigt, um das eosinophile Entz{\"u}ndungsinfiltrat und die Asthma typische Becherzellmetaplasie darzustellen. Weiterhin wurden durch FACS Untersuchungen regulatorische T Zellen nachgewiesen. Es konnte gezeigt werden, dass im Mausmodell die intranasale Applikationsform der SIT die allergischen Symptome effizienter bek{\"a}mpfen konnte, als die beim Menschen etablierte subcutane Applikationsform. Um Mechanismen zu definieren die eine SIT effizienter machen k{\"o}nnten wurde ein IL-4/IL13 Inhibitor (QY) als Adjuvans f{\"u}r die SIT benutzt. F{\"u}r den Zytokininhibitor konnte gezeigt werden, dass bei einer Applikation w{\"a}hrend der allergischen Sensibilisierung die Entstehung einer TH2 Immunantwort und die Ausbildung allergischer Symptome verhindert wird. Die Applikation des Inhibitors zusammen mit einer SIT zeigte jedoch keine zus{\"a}tzlichen signifikanten antiallergischen Effekte im Vergleich zur Durchf{\"u}hrung der SIT als Monotherapie. Diese Ergebnisse deuten m{\"o}glicherweise daraufhin , dass der bekannte Wechsel einer TH2 Immunantwort zu einer TH1 Antwort w{\"a}hrend der SIT nicht der Schl{\"u}sselmechanismus zu einer erfolgreichen Behandlung ist. Insbesondere weil unter der SIT auch in unserem Mausmodell die Induktion von IL-10 sezernierenden CD4+ T regulatorischen Zellen mit der Suppression der allergischen Atemwegsentz{\"u}dnung vergesellschaftet waren, so dass m{\"o}glicherwiese diese Zellen f{\"u}r den Therapieerfolg relevant sind . Um die Rolle regulatorischer T Zellen im Allergiemodell n{\"a}her zu beleuchten wurde im 2. Teil der Arbeit ein monoklonaler superagonistischer anti-CD28 Antik{\"o}rper benutzt, von dem bekannt ist dass T regulatorische Zellen in vivo induziert werden. Es konnte gezeigt werden, dass die Applikation des Antik{\"o}rpers w{\"a}hrend der allergischen Sensibilisierung die Etablierung einer TH2 Immunantwort verst{\"a}rkte. Im Gegensatz dazu wurden durch die therapeutische Applikation des anti CD28 Antik{\"o}rpers in einer etablierten Allergie, IL-10 sezernierende CD4+CD25+ T Zellen induziert, welches mit einer Abschw{\"a}chung der gemessenen Allergieparameter einherging.}, language = {en} } @article{GoetzEylertEisenreichetal.2010, author = {Goetz, Andreas and Eylert, Eva and Eisenreich, Wolfgang and Goebel, Werner}, title = {Carbon Metabolism of Enterobacterial Human Pathogens Growing in Epithelial Colorectal Adenocarcinoma (Caco-2) Cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68555}, year = {2010}, abstract = {Analysis of the genome sequences of the major human bacterial pathogens has provided a large amount of information concerning their metabolic potential. However, our knowledge of the actual metabolic pathways and metabolite fluxes occurring in these pathogens under infection conditions is still limited. In this study, we analysed the intracellular carbon metabolism of enteroinvasive Escherichia coli (EIEC HN280 and EIEC 4608-58) and Salmonella enterica Serovar Typhimurium (Stm 14028) replicating in epithelial colorectal adenocarcinoma cells (Caco-2). To this aim, we supplied [U-13C6]glucose to Caco-2 cells infected with the bacterial strains or mutants thereof impaired in the uptake of glucose, mannose and/or glucose 6-phosphate. The 13C-isotopologue patterns of protein-derived amino acids from the bacteria and the host cells were then determined by mass spectrometry. The data showed that EIEC HN280 growing in the cytosol of the host cells, as well as Stm 14028 replicating in the Salmonella-containing vacuole (SCV) utilised glucose, but not glucose 6-phosphate, other phosphorylated carbohydrates, gluconate or fatty acids as major carbon substrates. EIEC 4608-58 used C3-compound(s) in addition to glucose as carbon source. The labelling patterns reflected strain-dependent carbon flux via glycolysis and/or the Entner-Doudoroff pathway, the pentose phosphate pathway, the TCA cycle and anapleurotic reactions between PEP and oxaloacetate. Mutants of all three strains impaired in the uptake of glucose switched to C3-substrate(s) accompanied by an increased uptake of amino acids (and possibly also other anabolic monomers) from the host cell. Surprisingly, the metabolism of the host cells, as judged by the efficiency of 13C-incorporation into host cell amino acids, was not significantly affected by the infection with either of these intracellular pathogens.}, subject = {Metabolismus}, language = {en} } @article{GoebelKreft1972, author = {Goebel, Werner and Kreft, J{\"u}rgen}, title = {Accumulation of replicative intermediates and catenated forms of the colicinogenic factor E\(_1\) in E. coli during the replication at elevated temperatures}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60625}, year = {1972}, abstract = {No abstract available}, subject = {Biologie}, language = {en} } @article{GoebelKathariouKuhnetal.1988, author = {Goebel, Werner and Kathariou, S. and Kuhn, M. and Sokolovic, Z. and Kreft, J{\"u}rgen and K{\"o}hler, S. and Funke, D. and Chakraborty, T. and Leimeister-W{\"a}chter, M.}, title = {Hemolysin from Listeria-biochemistry, genetics and function in pathogenesis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60563}, year = {1988}, abstract = {No abstract available}, subject = {Biologie}, language = {en} } @article{GoebelChakrabortyKreft1988, author = {Goebel, Werner and Chakraborty, T. and Kreft, J{\"u}rgen}, title = {Bacterial hemolysins as virulence factors}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60553}, year = {1988}, abstract = {No abstract available}, subject = {Biologie}, language = {en} } @article{GoebSchmittBenaventeetal.2010, author = {Goeb, Eva and Schmitt, Johannes and Benavente, Ricardo and Alsheimer, Manfred}, title = {Mammalian Sperm Head Formation Involves Different Polarization of Two Novel LINC Complexes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68449}, year = {2010}, abstract = {Background: LINC complexes are nuclear envelope bridging protein structures formed by interaction of SUN and KASH proteins. They physically connect the nucleus with the peripheral cytoskeleton and are critically involved in a variety of dynamic processes, such as nuclear anchorage, movement and positioning and meiotic chromosome dynamics. Moreover, they are shown to be essential for maintaining nuclear shape. Findings: Based on detailed expression analysis and biochemical approaches, we show here that during mouse sperm development, a terminal cell differentiation process characterized by profound morphogenic restructuring, two novel distinctive LINC complexes are established. They consist either of spermiogenesis-specific Sun3 and Nesprin1 or Sun1g, a novel non-nuclear Sun1 isoform, and Nesprin3. We could find that these two LINC complexes specifically polarize to opposite spermatid poles likely linking to sperm-specific cytoskeletal structures. Although, as shown in co-transfection / immunoprecipitation experiments, SUN proteins appear to arbitrarily interact with various KASH partners, our study demonstrates that they actually are able to confine their binding to form distinct LINC complexes. Conclusions: Formation of the mammalian sperm head involves assembly and different polarization of two novel spermiogenesis-specific LINC complexes. Together, our findings suggest that theses LINC complexes connect the differentiating spermatid nucleus to surrounding cytoskeletal structures to enable its well-directed shaping and elongation, which in turn is a critical parameter for male fertility.}, subject = {Sperma}, language = {en} } @phdthesis{Gnamlin2015, author = {Gnamlin, Prisca}, title = {Use of Tumor Vasculature for Successful Treatment of Carcinomas by Oncolytic Vaccinia Virus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119019}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Tumor-induced angiogenesis is of major interest for oncology research. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor characterized so far. VEGF blockade was shown to be sufficient for angiogenesis inhibition and subsequent tumor regression in several preclinical tumor models. Bevacizumab was the first treatment targeting specifically tumor-induced angiogenesis through VEGF blockade to be approved by the Food and Drugs Administration (FDA) for cancer treatment. However, after very promising results in preclinical evaluations, VEGF blockade did not show the expected success in patients. Some tumors became resistant to VEGF blockade. Several factors have been accounted responsible, the over-expression of other angiogenic factors, the noxious influence of VEFG blockade on normal tissues, the selection of hypoxia resistant neoplastic cells, the recruitment of hematopoietic progenitor cells and finally the transient nature of angiogenesis inhibition by VEGF blockade. The development of blocking agents against other angiogenic factors like placental growth factor (PlGF) and Angiopoietin-2 (Ang-2) allows the development of an anti-angiogenesis strategy adapted to the profile of the tumor. Oncolytic virotherapy uses the natural propensity of viruses to colonize tumors to treat cancer. The recombinant vaccinia virus GLV-1h68 was shown to infect, colonize and lyse several tumor types. Its descendant GLV-1h108, expressing an anti-VEGF antibody, was proved in previous studies to inhibit efficiently tumor induced angiogenesis. Additional VACVs expressing single chain antibodies (scAb) antibodies against PlGF and Ang-2 alone or in combination with anti VEGF scAb were designed. In this study, VACV-mediated anti-angiogenesis treatments have been evaluated in several preclinical tumor models. The efficiency of PlGF blockade, alone or in combination with VEGF, mediated by VACV has been established and confirmed. PlGF inhibition alone or with VEGF reduced tumor burden 5- and 2-folds more efficiently than the control virus, respectively. Ang-2 blockade efficiency for cancer treatment gave controversial results when tested in different laboratories. Here we demonstrated that unlike VEGF, the success of Ang-2 blockade is not only correlated to the strength of the blockade. A particular balance between Ang-2, VEGF and Ang-1 needs to be induced by the treatment to see a regression of the tumor and an improved survival. We saw that Ang-2 inhibition delayed tumor growth up to 3-folds compared to the control virus. These same viruses induced statistically significant tumor growth delays. This study unveiled the need to establish an angiogenic profile of the tumor to be treated as well as the necessity to better understand the synergic effects of VEGF and Ang-2. In addition angiogenesis inhibition by VACV-mediated PlGF and Ang-2 blockade was able to reduce the number of metastases and migrating tumor cells (even more efficiently than VEGF blockade). VACV colonization of tumor cells, in vitro, was limited by VEGF, when the use of the anti-VEGF VACV GLV-1h108 drastically improved the colonization efficiency up to 2-fold, 72 hours post-infection. These in vitro data were confirmed by in vivo analysis of tumors. Fourteen days post-treatment, the anti-VEGF virus GLV-1h108 was colonizing 78.8\% of the tumors when GLV-1h68 colonization rate was 49.6\%. These data confirmed the synergistic effect of VEGF blockade and VACV replication for tumor regression. Three of the tumor cell lines used to assess VACV-mediated angiogenesis inhibition were found, in certain conditions, to mimic either endothelial cell or pericyte functions, and participate directly to the vascular structure. The expression by these tumor cells of e-selectin, p-selectin, ICAM-1 and VCAM-1, normally expressed on activated endothelial cells, corroborates our findings. These proteins play an important role in immune cell recruitment, and there amount vary in presence of VEGF, PlGF and Ang-2, confirming the involvement of angiogenic factors in the immuno-modulatory abilities of tumors. In this study VACV-mediated angiogenesis blockade proved its potential as a therapeutic agent able to treat different tumor types and prevent resistance observed during bevacizumab treatment by acting on different factors. First, the expression of several antibodies by VACV would prevent another angiogenic factor to take over VEGF and stimulate angiogenesis. Then, the ability of VACV to infect tumor cells would prevent them to form blood vessel-like structures to sustain tumor growth, and the localized delivery of the antibody would decrease the risk of adverse effects. Next, the blockade of angiogenic factors would improve VACV replication and decrease the immune-modulatory effect of tumors. Finally the fact that angiogenesis blockade lasts until total regression of the tumor would prevent the recovery of the tumor-associated vasculature and the relapse of patients.}, subject = {Vaccinia-Virus}, language = {en} } @phdthesis{Gloeckner2001, author = {Gl{\"o}ckner, Herma}, title = {Characterization of a new miniaturized hollow-fiber bioreactor for cultivation of cell lines and primary cells to improve cytostatic drug testing in vitro}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-1181317}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {Monolayer or suspension cell cultures are of only limited value as experimental models for human cancer. Therefore, more sophisticated, three-dimensional culture systems like spheroid cultures or histocultures are used, which more closely mimic the tumor in individual patients compared to monolayer or suspension cultures. As tissue culture or tissue engineering requires more sophisticated culture, specialized in vitro techniques may also improve experimental tumor models. In the present work, a new miniaturized hollow-fiber bioreactor system for mammalian cell culture in small volumes (up to 3 ml) is characterized with regard to transport characteristics and growth of leukemic cell lines (chapter 2). Cell and medium compartment are separated by dialysis membranes and oxygenation is accomplished using oxygenation membranes. Due to a transparent housing, cells can be observed by microscopy during culture. The leukemic cell lines CCRF-CEM, HL-60 and REH were cultivated up to densities of 3.5 x 107/ml without medium change or manipulation of the cells. Growth and viability of the cells in the bioreactor were the same or better, and the viable cell count was always higher compared to culture in Transwell{\^a} plates. As shown using CCRF-CEM cells, growth in the bioreactor was strongly influenced and could be controlled by the medium flow rate. As a consequence, consumption of glucose and generation of lactate varied with the flow rate. Influx of low molecular weight substances in the cell compartment could be regulated by variation of the concentration in the medium compartment. Thus, time dependent concentration profiles (e.g. pharmacokinetic profiles of drugs) can be realized as illustrated using glucose as a model compound. Depending on the molecular size cut-off of the membranes used, added growth factors like GM-CSF and IL-3 as well as factors secreted from the cells are retained in the cell compartment for up to one week. Second, a method for monitoring cell proliferation the hollow-fiber bioreactor by use of the Alamar BlueTM dye was developed (chapter 3). Alamar BlueTM is a non-fluorescent compound which yields a fluorescent product after reduction e.g. by living cells. In contrast to the MTT-assay, the Alamar BlueTM-assay does not lead to cell death. However, when not removed from the cells, the Alamar BlueTM dye shows a reversible, time- and concentration-dependent growth inhibition as observed for leukemic cell lines. When applied in the medium compartment of a hollow-fiber bioreactor system, the dye is delivered to the cells across the hollow-fiber membrane, reduced by the cells and released from the cell into the medium compartment back again. Thus, fluorescence intensity can be measured in medium samples reflecting growth of the cells in the cell compartment. This procedure offers several advantages. First, exposure of the cells to the dye can be reduced compared to conventional culture in plates. Second, handling steps are minimized since no sample of the cells needs to be taken for readout. Moreover, for the exchange of medium, a centrifugation step can be avoided and the cells can be cultivated further. Third, the method allows to discriminate between cell densities of 105, 106 and 107 of proliferating HL-60 cells cultivated in the cell compartment of the bioreactor. Measurement of fluorescence in the medium compartment is more sensitive compared to glucose or lactate measurement for cell counts below 106 cells/ml, in particular. In conclusion, the Alamar BlueTM-assay combined with the hollow-fiber bioreactor offers distinct advantages for the non-invasive monitoring of cell viability and proliferation in a closed system. In chapter 4 the use of the hollow-fiber bioreactor as a tool for toxicity testing was investigated, as current models for toxicity as well as efficacy testing of drugs in vitro allow only limited conclusions with regard to the in vivo situation. Examples of the drawbacks of current test systems are the lack of realistic in vitro tumor models and difficulties to model drug pharmacokinetics. The bioreactor proved to be pyrogen free and is steam-sterilizable. Leukemic cell lines like HL-60 and primary cells such as PHA-stimulated lymphocytes can be grown up to high densities of 1-3 x 107 and analyzed during growth in the bioreactor by light-microscopy. The cytostatic drug Ara-C shows a dose-dependent growth inhibition of HL-60 cells and a dose-response curve similar to controls in culture plates. The bioreactor system is highly flexible since several systems can be run in parallel, soluble drugs can be delivered continuously via a perfusion membrane and gaseous compounds via an oxygenation membrane which also allows to control pO2 and pH (via pCO2) during culture in the cell compartment. The modular concept of the bioreactor system allows realization of a variety of different design properties, which may lead to an improved in vitro system for toxicity testing by more closely resembling the in vivo situation. Whereas several distinct advantages of the new system have been demonstrated, more work has to be done to promote in vitro systems in toxicity testing and drug development further and to reduce the need for animal tests.}, subject = {Hohlfaserreaktor}, language = {en} } @phdthesis{Glos2006, author = {Glos, Julian}, title = {Amphibian communities of the dry forest of Western Madagascar : taxonomy, ecology and conservation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-18146}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {In meiner Arbeit habe ich taxonomische, gemeinschafts{\"o}kologische und aut{\"o}kologische Aspekte im westmadagassischen Trockenwald untersucht. Ziel dieser Arbeit war es Antworten auf die Fragen zu geben wie die einzelnen Arten die Habitate in Raum und Zeit nutzen, welchen Einfluss abiotische Parameter, Austrocknungsrisiko der Laichgew{\"a}sser und Mikrohabitat haben und wie Pr{\"a}datoren die Gemeinschaft und das Verhalten einzelner Arten beeinflussen. Somit tr{\"a}gt diese Arbeit dazu bei die grundlegenden Mechanismen zu verstehen, die die Zusammensetzung einer Lebensgemeinschaft bestimmen. Im Einzelnen untersuchte ich hierzu folgende Fragestellungen: Aus welchen Arten bestehen die Anurengemeinschaften des westmadagassischen Trockenwaldes, und wie lassen sich diese Arten morphologisch voneinander abgrenzen? Welche Unterschiede finden sich zwischen den Arten bez{\"u}glich ihres Paarungssystems, ihrer life-history und ihrer Habitatwahl bzw. den Anpassungen an ihr Habitat? Gibt es spezifische Kaulquappengemeinschaften, die sich anhand biotischer und abiotischer Umweltvariablen vorhersagen lassen? Unterscheiden sich die Muster der Vorhersagbarkeit von Gemeinschaften zwischen unterschiedlichen Habitattypen innerhalb eines lokalen r{\"a}umlichen Skalenniveaus? Wie beeinflusst das Vorkommen von Raubfeinden die Verteilung von Kaulquappen und deren Verhalten auf der r{\"a}umlichen Skalenebene einzelner Laichgew{\"a}sser? Anhand welcher Umweltvariablen l{\"a}sst sich die Laichplatzwahl von Anuren in diesem Habitat vorhersagen? Wie lassen sich die Ergebnisse nutzen, um Empfehlungen zum Schutz bedrohter Arten auszusprechen? In dieser Arbeit beschreibe ich eine Froschart wissenschaftlich neu. Diese Art, Scaphiophryne menabensis, ist die seltenste Froschart in ihrem Verbreitungsgebiet, und aus meiner Arbeit resultiert die dringende Empfehlung, sie in ein bestehendes Schutzkonzept f{\"u}r den Kirindy-Wald und seine Umgebung mit einzubeziehen. Weiterhin beschreibe ich wissenschaftlich erstmalig in dieser Arbeit f{\"u}nf Kaulquappenarten und pr{\"a}sentiere Daten zu {\"O}kologie, life-history und Verhalten dieser Arten. Die wissenschaftliche Beschreibung weiterer Frosch- und Kaulquappenarten ist Gegenstand noch andauernder Studien (Scaphiophryne sp., Heterixalus carbonei und H. tricolor; Revision der Kaulquappen von Scaphiophryne). Die Ergebnisse dieser Arbeit stellen damit die Basis f{\"u}r alle weiteren {\"o}kologischen Studien an Fr{\"o}schen und Kaulquappen dieses {\"O}kosystems dar. FAZIT Die Amphibienfauna Madagaskars ist einzigartig, und sie stellt ein aufregendes Feld f{\"u}r {\"o}kologische Fragestellungen dar, sowohl als eigenst{\"a}ndiges System betrachtet als auch als Modell f{\"u}r andere Systeme. Umso mehr verwundert es, dass bislang kaum detaillierte {\"o}kologische Studien an diesem System durchgef{\"u}hrt wurden. Die vorliegende Arbeit schafft zun{\"a}chst mit der taxonomischen Beschreibung der vorkommenden Arten die Basis f{\"u}r {\"o}kologische Fragestellungen und zeigt dann auf den Ebenen sowohl der Gemeinschaft als auch einzelner Arten, wie verschiedene Umweltfaktoren die Verteilung von Anuren in Raum und Zeit beeinflussen. Es zeigt sich, dass sowohl statische Eigenschaften der Gew{\"a}sser als auch dynamische Faktoren wie Raubfeinde oder das Vorhandensein anderer Kaulquappen die Verteilung der Arten auf verschiedenen r{\"a}umlichen Skalenebenen sowie deren Verhalten beeinflussen. Somit tragen die Ergebnisse dieser Arbeit dazu bei, die grundlegenden Mechanismen zu verstehen, die die Zusammensetzung der Lebensgemeinschaften in diesem {\"O}kosystem bestimmen. Nicht zuletzt erm{\"o}glichen diese Erkenntnisse, geeignete, artenorientierte Schutzkonzepte f{\"u}r diese in ihrer Existenz stark bedrohte Anurengemeinschaft zu entwickeln und die Effekte von Habitatzerst{\"o}rung auf diese Gemeinschaft aufzuzeigen.}, subject = {Lurche}, language = {en} } @phdthesis{Glogger2018, author = {Glogger, Marius}, title = {Single-molecule fluorescence microscopy in live \(Trypanosoma\) \(brucei\) and model membranes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169222}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2018}, abstract = {Der eukaryotische Parasit Trypanosoma brucei hat komplexe Strategien entwickelt um der Immunantwort eines Wirtes zu entkommen und eine persistente Infektion innerhalb dessen aufrechtzuerhalten. Ein zentrales Element seiner Verteidigungsstrategie st{\"u}tzt sich auf die Schutzfunktion seines Proteinmantels auf der Zelloberfl{\"a}che. Dieser Mantel besteht aus einer dichten Schicht aus identischen, Glykosylphosphatidylinositol (GPI)-verankerten variablen Oberfl{\"a}chenglykoproteinen (VSG). Der VSG Mantel verhindert die Erkennung der darunterliegenden, invarianten Epitope durch das Immunsystem. Obwohl es notwendig ist die Funktionsweise des VSG Mantels zu verstehen, vor allem um ihn als m{\"o}gliches Angriffsziel gegen den Parasiten zu verwenden, sind seine biophysikalischen Eigenschaften bisher nur unzureichend verstanden. Dies ist vor allem der Tatsache geschuldet, dass die hohe Motilit{\"a}t der Parasiten mikroskopische Studien in lebenden Zellen bisher weitestgehend verhinderten. In der vorliegenden Arbeit wird nun hochmoderne Einzelmolek{\"u}l-Fluoreszenzmikroskopie (EMFM) als M{\"o}glichkeit f{\"u}r mikroskopische Untersuchungen im Forschungsbereich der Trypanosomen vorgestellt. Die Arbeit umfasst Untersuchungen der VSG Dynamik unter definierten Bedingungen k{\"u}nstlicher Membransysteme. Es wurde zuerst der Einfluss der lateralen Proteindichte auf die VSG Diffusion untersucht. Experimente mittels Fluoreszenz- Wiederkehr nach irreversiblem Photobleichen und komplement{\"a}re Einzelmolek{\"u}l- Verfolgungs Experimente offenbarten, dass ein molekularer Diffusionsschwellenwert existiert. {\"U}ber diesem Schwellenwert wurde eine dichteabh{\"a}nige Reduzierung des Diffusionskoeffizienten gemessen. Eine relative Quantifizierung der rekonstituierten VSGs verdeutlichte, dass der Oberfl{\"a}chenmantel der Trypanosomen sehr nahe an diesem Schwellenwert agiert. Der VSG Mantel ist optimiert um eine hohe Proteindichte bei gleichzeitiger hoher Mobilit{\"a}t der VSGs zu gew{\"a}hrleisten. Des Weiteren wurde der Einfluss der VSG N-Glykosylierung auf die Diffusion des Proteins quantitativ untersucht. Die Messungen ergaben, dass die N-Glykosylierung dazu beitr{\"a}gt eine hohe Mobilit{\"a}t bei hohen Proteindichten aufrechtzuerhalten. Eine detaillierte Analyse von VSG Trajektorien offenbarte, dass zwei unterschiedliche Populationen frei diffundierender VSGs in der k{\"u}nstlichen Membran vorlagen. K{\"u}rzlich wurde entdeckt, dass VSGs zwei strukturell unterschiedliche Konformationen annehmen k{\"o}nnen. Die Messungen in der Arbeit stimmen mit diesen Beschreibungen {\"u}berein. Die Ergebnisse der EMFM in k{\"u}nstlichen Membranen wurden durch VSG Einzelmolek{\"u}l- Verfolgungs Experimente auf lebenden Zellen erg{\"a}nzt. Es wurde eine hohe Mobilit{\"a}t und Dynamik einzelner VSGs gemessen, was die allgemein dynamische Natur des VSG Mantels verdeutlicht. Dies f{\"u}hrte zu der Schlussfolgerung, dass der VSG Mantel auf lebenden Trypanosomen ein dichter und dennoch dynamischer Schutzmantel ist. Die F{\"a}higkeit der VSGs ihre Konformation flexibel anzupassen, unterst{\"u}tzt das Erhalten der Fluidit{\"a}t bei variablen Dichten. Diese Eigenschaften des VSG Mantels sind elementar f{\"u}r die Aufrechterhaltung einer presistenden Infektion eines Wirtes. In dieser Arbeit werden des Weiteren verschiedene, auf Hydrogel basierende Einbettungsmethoden vorgestellt. Diese erm{\"o}glichten die Zellimmobilisierung und erlaubten EMFM in lebenden Trypanosomen. Die Hydrogele wiesen eine hohe Zytokompatibilit{\"a}t auf. Die Zellen {\"u}berlebten in den Gelen f{\"u}r eine Stunde nach Beginn der Immobilisierung. Die Hydrogele erf{\"u}llten die Anforderungen der Superresolution Mikroskopie (SRM) da sie eine geringe Autofluoreszenz im Spektralbereich der verwendeten Fluorophore besaßen. Mittels SRM konnte nachgewiesen werden, dass die Hydrogele die Zellen effizient immobilisierten. Als erstes Anwendungsbeispiel der Methode wurde die Organisation der Plasmamembran in lebenden Trypanosomen untersucht. Die Untersuchung eines fluoreszenten Tracers in der inneren Membranschicht ergab, dass dessen Verteilung nicht homogen war. Es wurden spezifische Membrandom{\"a}nen gefunden, in denen das Molek{\"u}l entweder vermehrt oder vermindert auftrat. Dies f{\"u}hrte zu der Schlussfolgerung, dass diese Verteilung durch eine Interaktion des Tracers mit Proteinen des zellul{\"a}ren Zytoskeletts zustande kam. Die in dieser Arbeit pr{\"a}sentierten Ergebnisse zeigen, dass EMFM erfolgreich f{\"u}r verschiedene biologische Untersuchungen im Forschungsfeld der Trypanosomen angewendet werden kann. Dies gilt zum Beispiel f{\"u}r die Untersuchung von der VSG Dynamik in k{\"u}nstlichen Membransystemen, aber auch f{\"u}r Studien in lebenden Zellen unter Verwendung der auf Hydrogelen basierenden Zelleinbettung.}, subject = {Trypanosoma brucei}, language = {en} } @phdthesis{Glaab2020, author = {Glaab, Sabine}, title = {Green classroom at the wildlife park: Aspects of environmental, instructional and conceptual education of primary school children concerning the European wildcat.}, doi = {10.25972/OPUS-16949}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169496}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2020}, abstract = {To foster sustainable environmentally friendly behavior in children it is important to provide an effective form of environmental education. In this context we studied three important factors: Attitude towards nature, environmental knowledge and advanced expert knowledge. Concerning attitude towards nature our first question was: "Is it possible to affect primary school children's environmental values during a one-day visit at a wildlife park?" As a control, the program was also conducted in schools, leading to two different learning settings- wildlife park and school. Regarding environmental knowledge, in our second question we wanted to know, if our modified teaching approach "guided learning at workstations" (G) combining instructional and constructivist elements would lead to good cognitive learning results of primary school children. Additionally, we compared it to a stronger teacher-centered (T) as well as to a stronger student-centered (S) approach. The third question we asked was "Is it possible to convey fascinating expert knowledge on a more advanced subject to primary school children using conceptual change theory?" After gathering primary school children's preconceptions, we defined different groups due to the heterogeneity of their pre-existing conceptions and the change in conceptions. Based on this research we designed a program along with an instrument to measure the impact of the conceptual change teaching method. After years of building a strong cooperation between the section Didactics of Biology at the Julius-Maximilians University W{\"u}rzburg, the nearby schools and the wildlife park "Wild-Park Klaushof" near Bad Kissingen in northern Bavaria it was time to evaluate the environmental education programs prepared and applied by undergraduate university students. As a model species we chose the European wildcat (Felis silvestris silvestris) which represents endangered wildlife in Europe and the need for human interaction for the sake of preserving a species by restoring or recreating the habitat conditions needed while maintaining current infrastructure. Drawing from our own as well as teachers' and university students' experiences, we built, implemented and evaluated a hands-on program following several workstations between the wildcat enclosure and the wildlife park's green classroom. The content of our intervention was presented as a problem-oriented lesson, where children were confronted with the need for human interaction in order to preserve the European wildcat. Not only on a theoretical basis, but very specific to their hometowns they were told where and when nature conservation groups met or where to donate money. 692 Bavarian third grade primary school children in 35 classes participated in the one-day intervention that took place between the months of april, 2014 and november, 2015 in the wildlife park or in their respective classrooms. The ages varied between 8 and 11 years with the mean age being 8.88 ± 0.56 years old. 48.6 \% of them were boys, 51.4 \% were girls. (1) To measure primary school children's environmental attitudes a questionnaire on two major environmental values- preservation and utilization of nature- was administered in a pre, post- and retention test design. It was possible to affect primary school children's environmental preservation values during our one-day program. This result could be found not only at the wildlife park but unexpectedly also in school, where we educated classes for control purposes. We also found this impact consistent in all used teaching approaches and were surprised to see the preservation values change in a way we did not expect from higher tendency towards preservation of nature to a lower one. We presume that children of this age group reflected on the contents of our intervention. This had an influence on their own values towards preservation which led to a more realistic marking behavior in the questionnaire. We therefore conclude that it is possible to affect primary school children's environmental values with a one-day program on environmental content. (2) We were interested in conveying environmental knowledge about the European wildcat; its morphology, ecology and behavior. We designed and applied a knowledge questionnaire also in a pre-, post- and retention test design, to find out, whether different forms of instruction made a difference in learning success of primary school children. We used two approaches with a teacher in the role of a didactic leader- our modified guided approach (G) as well as a stronger teacher-centered one (T) with a higher focus on instruction. The third approach was presented as a strong student-centered learning at workstations (S) without a didactic leader we also called "free learning at workstations". Overall, all children's knowledge scores changed significantly from pre- to post-test and from pre- to retention test, indicating learning success. Differences could only be found between the posttest values of both approaches with a didactic leader (G, T) in comparison to the strong student-centered (S) form. It appears that these primary school children gained knowledge at the out of school learning setting regardless of the used teaching approach. On the subject of short-term differences, we discuss, that the difference in learning success might have been consistent from post to retention test if a consolidation phase had been added in the days following the program as should be common practice after a visit to an out-of- school learning setting but was not part of our intervention. When comparing both approaches with a didactic leader (G, T), we prefer our modified guided learning at workstations (G) since constructivist phases can be implemented without losses concerning learning success. Moreover, the (at least temporary) presence of a teacher in the role of a didactic leader ensures maintained discipline and counteracts off-task behavior. To make sure, different emotional states did not factor in our program, we measured children's situational emotions directly after the morning intervention using a short scale that evaluated interest, wellbeing and boredom. We found, that these emotions remained consistent over both learning settings as well as different forms of instruction. While interest and wellbeing remained constantly high, boredom values remained low. We take this as a sign of high quality designing and conducting the intervention. (3) In the afternoon of the one-day intervention, children were given the opportunity to investigate the wildcat further, this time using the conceptual change theory in combination with a more complex and fascinating content: cats' vision in dusk and dawn. Children were confronted with their preconceptions which had been sampled prior to the study and turned into three distinctive topics reflected in a special questionnaire. In a pre-, post and retention test design we included the most common alternative conceptions, the scientifically correct conceptions as well as other preconceptions. We gathered a high heterogeneity of preconceptions and defined three groups based on conceptual change literature: "Conceptual change", "Synthetic Models" and "Conceptual Growth". In addition to these we identified two more groups after our data analysis: "Knowledge" and "Non-addressed Concepts". We found that instruction according to the conceptual change theory did not work with primary school children in our intervention. The conceptual change from the addressed alternative conceptions as well as from other preconceptions towards the scientifically correct conceptions was successfully achieved only on occasion. In our case and depending on the topic only one third to one fourth of the children actually held the addressed conception while the rest was not targeted by the instruction. Moreover, we conclude children holding other conceptions were rather confused than educated by the confrontation. We assume that children of this age group may be overchallenged by the conceptual change method.}, subject = {Biologie}, language = {en} } @phdthesis{Gjorgjevikj2014, author = {Gjorgjevikj, Maja}, title = {IL-4 analogues with site-specific chemical modification as screening tools for foldamers}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-113531}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {The cytokine Interleukin-4 (IL-4) plays a crucial role in the pathophysiology and progression of asthma and other atopic diseases. Its activities are signaled into the cells upon binding to and signaling through a shared receptor complex composed of the subunits IL-4Rα and common γc. Another cytokine, Interleukin-13 shares many functions with IL-4. This can be explained by the fact that both, IL-4 and IL-13, can signal via a shared receptor complex comprising the IL-4R and the IL-13R1 subunit. Therefore, the IL-4Rα receptor subunit has become a highly promising drug target, since it mediates IL-4 and IL-13 responses and blocking IL-4Rα will abrogate IL-4 as well as IL-13 effector functions. Currently, an IL-4 based mutein (Pitrakinra), acting as a dual IL-4/IL-13 receptor antagonist is in clinical development. This work describes the generation and production of biologically active IL-4 muteins, which contain a single additional engineered cysteine. The introduction of a free thiol group allows site-specific chemical modification. The muteins were expressed in E. coli in insoluble form, refolded and purified. The thiol group of the mutein was protected as mixed disulfide with the tripeptide glutathione. A first attempt to chemically reduce the engineered cysteine residue failed, because the three native disulfide bonds of IL-4 exhibit a similar reactivity and chemical reduction of the native disulfide resulted in full deactivation and precipitation of the IL-4 protein. Therefore, an enzymatic approach was developed which specifically reduces the mixed disulfide bonds with an attached glutathion moiety and thus leaves the native structurally essential disulfide bonds unaltered. For optimization, four different IL-4 cysteine muteins with four cysteine residues introduced at positions close to the IL-4Rα binding site were tested and their reduction rates by glutaredoxin was determined. The enzymatic reduction occured at different rates for all four muteins indicating that accessibility is an important influence and must be determined individually for each mutant protein. After optimization of the pH value and particularly the reaction time, all muteins could be prepared with the engineered thiol group being released in reasonable yield. The proteins exhibiting the free thiol group were then modified by N-ethylmaleimide (NEM) or maleimido-PEG. The effects of these modifications at different positions on binding to IL-4R were measured employing SPR biosensor technology. In the second project of this study, foldamers, which represent a new class of stable, compactly folded biomolecules and can specifically interact with proteins and nucleic acids, were examined to identify their potential as new drugs to interfere with IL-4 activities. Fragment-based drug discovery offers great promise for providing new starting points for drug discovery and facilitates the lead optimization. As foldamers equipped with a thiol-group for tethering could not to be produced; only the effect of foldamers present in a synthesized foldamer library on the binding to IL-4R could be tested. Two libraries containing different foldamers based on aromatic amide were synthesized by Michael Grotz and Dr. Michael Deligny and tested in our lab for their capability to disrupt the ligand-receptor interaction of IL-4 and its receptor IL-4Rα [ECD] using surface plasmon resonance technology. None of the studied foldamers could specifically inhibit the IL-4/IL-4Rα interaction. Some foldamers showed non-specific binding. The study presented here shows the design and production of a potentially new type of IL-4 antagonists, which employ site-specific chemical modification to exert their antagonistic function.}, subject = {Il 4}, language = {en} } @article{GilmoreCruzRodzLeimeisterWaechteretal.1989, author = {Gilmore, Michael S. and Cruz-Rodz, Armando L. and Leimeister-W{\"a}chter, Michaela and Kreft, J{\"u}rgen and Goebel, Werner}, title = {A Bacillus cereus cytolytic determinant, cereolysin AB, which comprises the phospholipase C and sphingomyelinase genes: nucleotide sequence and genetic linkage}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60588}, year = {1989}, abstract = {A cloned cytolytic determinant from the genome of Bacillus cereus GP-4 has been characterized at the molecular Ievel. Nucleotide sequence determination revealed the presence of two open reading frames. 8oth open reading frames were found by deletion and complementation analysis to be necessary for expression of the hemolytic phenotype by Bacillus subtilis and Escherichia coli hosts. The 5' open reading frame was found to be nearly identical to a recently reported phospholipase C gene derived from a mutant B. cereus strain which overexpresses the respective protein, and it conferred a lecithinase-positive phenotype to the B. subtilis host. The 3' open reading frame encoded a sphingomyelinase. The two tandemly encoded activities, phospholipase C and sphingomyelinase, constitute a biologically functional cytolytic determinant of B. cereus termed cereolysin AB.}, subject = {Biologie}, language = {en} } @article{GesslerThomasCouillinetal.1989, author = {Gessler, Manfred and Thomas, G. H. and Couillin, P. and Junien, C. and McGillivray, B. C. and Hayden, M. and Jaschek, G. and Bruns, G. A.}, title = {A deletion map of the WAGR region on chromosome II}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59255}, year = {1989}, abstract = {The WAGR (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) region has been assigned to chromosome 11p13 on the basis of overlapping constitutional deletions found in affected individuals. We have utilized 31 DNA probes which map to the WAGR deletion region, together with six reference loci and 13 WAGR-related deletions, to subdivide this area into 16 intervals. Specific intervals have been correlated with phenotypic features, leading to the identification of individual subregions for the aniridia and Wilms tumor loci. Delineation, by specific probes, of multiple intervals above and below the critical region and of five intervals within the overlap area provides a framework map for molecular characterization of WAGR gene loci and of deletion boundary regions.}, subject = {Biochemie}, language = {en} } @techreport{GesslerSimolaBruns1989, author = {Gessler, Manfred and Simola, Kalle O. and Bruns, Gail A. P.}, title = {Cloning of breakpoints of a chromosome translocation identifies the AN2 locus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30177}, year = {1989}, abstract = {Chromosome translocations involving llpl3 have been associated with familial aniridia in two kindreds highlighting the chromosomal localization of the AN2 locus. This locus is also part of the WAGR complex (Wilros tumor, aniridia, genitourinary abnormalities, and mental retardation). In one kindred, the translocation is associated with a deletion, and probes for this region were used to identify and clone the breakpoints of the translocation in the second kindred. Comparison of phage restriction maps exclude the presence of any sizable deletion in this case. Sequences at the chromosome 11 breakpoint are conserved in multiple species, suggesting that the translocation falls within the AN2 gene.}, language = {en} } @article{GesslerPoustkaCaveneeetal.1990, author = {Gessler, Manfred and Poustka, Annemarie and Cavenee, Webster and Neve, Rachael L. and Orkin, Stuart H. and Bruns, Gail A.}, title = {Homozygous deletion in Wilms tumours of a zinc-finger gene identified by chromosome jumping}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30122}, year = {1990}, abstract = {No abstract available}, language = {en} } @article{GesslerKoenigBruns1992, author = {Gessler, Manfred and K{\"o}nig, A. and Bruns, G. A. P.}, title = {The genomic organization and expression of the WT1 gene}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59195}, year = {1992}, abstract = {The Wilms tumor gene WTl, a proposed tumor suppressor gene, has been identifled based on its location within a homozygous deletion found in tumor tissue. The gene encodes a putative transcription factor containing a Cys/His zinc finger domain. The critical homozygous deletions, however, are rarely seen, suggesting that in many cases the gene may be inactivated by more subtle alterations. To facilitate the seareh for smaller deletions and point mutations we have established the genomic organization of the WTl gene and have determined the sequence of all 10 exons and flanking intron DNA. The pattern of alternative splicing in two regions has been characterized in detail. These results will form the basis for future studies of mutant alleles at this locus.}, subject = {Biochemie}, language = {en} } @article{GesslerKoenigArdenetal.1994, author = {Gessler, Manfred and K{\"o}nig, A. and Arden, K. and Grundy, P. and Orkin, S. H. and Sallan, S. and Peters, C. and Ruyle, S. and Mandell, J. and Li, F. and Cavenee, W. and Bruns, G. A.}, title = {Infrequent mutation of the WT1 gene in 77 Wilms' Tumors}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34308}, year = {1994}, abstract = {Homozygous deletions in Wilms' tumor DNA have been a key step in the identification and isolation of the WTI gene. Several additional loci are also postulated to contribute to Wilms' tumor formation. To assess the frequency of WTI alterations we have analyzed the WTI locus in a panel of 77 Wilms' tumors. Eight tumors showed evidence for large deletions of several hundred or thousand kilobasepairs of DNA, some of which were also cytogenetically detected. Additional intragenic mutations were detected using more sensitive SSCP analyses to scan all 10 WTI exons. Most of these result in premature stop codons or missense mutations that inactivate the remaining WTI allele. The overall frequency of WTI alterations detected with these methods is less than 15\%. While some mutations may not be detectable with the methods employed, our results suggest that direct alterations of the WTI gene are present in only a small fraction of Wilms' tumors. Thus, mutations at other Wilms' tumor loci or disturbance of interactions between these genes likely play an important role in Wilms' tumor development.}, language = {en} } @article{GesslerKonigMooreetal.1993, author = {Gessler, Manfred and Konig, Anja and Moore, Jay and Qualman, Steven and Arden, Karen and Cavenee, Webster and Bruns, Gail}, title = {Homozygous inactivation of WTI in a Wilms' tumor associated with the WAGR syndrome}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59146}, year = {1993}, abstract = {Wilms' tumor is a childhood nephroblastoma that is postulated to arise through the inactivation of a tumor suppressor gene by a two-hit mechanism. A candidate II p 13 Wilms' tumor gene, WTI, has been cloned and shown to encode a zinc finger protein. Patients with the WAGR syndrome (Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation) have a high risk of developing Wilms' tumor and they carry constitutional deletions of one chromosome II allele encompassing the WTI gene. Analysis of the remaining WTI allele in a Wilms' tumor from a WAGR patient revealed the deletion of a single nucleotide in exon 7. This mutation likely played a key role in tumor formation, as it prevents translation of the DNA-binding zinc finger domain that is essential for the function of the WTI polypeptide as a transcriptional regulator.}, subject = {Biochemie}, language = {en} } @article{GesslerHameisterHenryetal.1990, author = {Gessler, Manfred and Hameister, H. and Henry, I. and Junien, C. and Braun, T. and Arnold, H. H.}, title = {The human MyoD1 (MYF3) gene maps on the short arm of chromosome 11 but is not associated with the WAGR locus or the region for the Beckwith-Wiedemann syndrome}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59221}, year = {1990}, abstract = {The human gene encoding the myogenic determination factor myf3 (mouse MyoD1) has been mapped to the short arm of chromosome 11. Analysis of several somatic cell hybrids containing various derivatives with deletions or translocations revealed that the human MyoD (MYF3) gene is not associated with the WAGR locus at chromosomal band 11pl3 nor with the loss of the heterozygosity region at 11p15.5 related to the Beckwith-Wiedemann syndrome. Subregional mapping by in situ hybridization with an myf3 specific probe shows that the gene resides at the chromosomal band llp14, possibly at llp14.3.}, subject = {Biochemie}, language = {en} } @article{GesslerGrupeGrzeschiketal.1992, author = {Gessler, Manfred and Grupe, Andrew and Grzeschik, Karl-Heinz and Pongs, Olaf}, title = {The potassium channel gene HK1 maps to human chromosome 11p14.1, close to the FSHB gene}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59184}, year = {1992}, abstract = {Transiently activating (A-type) potassium (K) channels are important regulators of action potential and action potential firing frequencies. HK1 designates the firsthuman cDNA that is highly homologous to the rat RCK4 cDNA that codes for an A-type K-channel. The HK1 channel is expressed in heart. By somatic cell hybrid analysis, the HK1 gene has been assigned to human chromosome 11p13-pl4, the WAGR deletion region (Wilms tumor, aniridia, genito-urinary abnormalities and mental retardation). Subsequent pulsed field gel (PFG) analysis and comparison with the well-established PFG map of this region localized the gene to 11p14, 200-600 kb telomeric to the FSHB gene.}, subject = {Biochemie}, language = {en} } @article{GesslerBruns1988, author = {Gessler, Manfred and Bruns, Gail A. P.}, title = {Molecular mapping and cloning of the breakpoints of a chromosome 11p14.1-p13 deletion associated with the AGR syndrome}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59264}, year = {1988}, abstract = {Chromosome 11p13 is frequently rearranged in individuals with the WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) or parts of this syndrome. To map the cytogenetic aberrations molecularly, we screened DNA from cell Unes with known WAGR-related chromosome abnormalities for rearrangements with pulsed fleld gel (PFG) analysis using probes deleted from one chromosome 11 homolog of a WAGR patient. The first alteration was detected in a cell line from an individual with aniridia, genitourinary anomalies, mental retardation, and a deletion described as 11p14.1-p13. We have located one breakpoint close to probe HU11-164B and we have cloned both breakpoint sites as well as the junctional fragment. The breakpoints subdivide current intervals on the genetic map, and the probes for both sides will serve as important additional markers for a long-range restriction map of this region. Further characterization and sequencing of the breakpoints may yield insight into the mechanisms by which these deletions occur.}, subject = {Biochemie}, language = {en} } @misc{GesslerBruns1993, author = {Gessler, Manfred and Bruns, Gail A.}, title = {Sequence of the WT1 upstream region including the Wit-1 gene}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30193}, year = {1993}, abstract = {No abstract available}, language = {en} } @article{GesslerBruns1989, author = {Gessler, Manfred and Bruns, G. A. P.}, title = {A physical map around the WAGR complex on the short arm of chromosome 11}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59246}, year = {1989}, abstract = {A long-range restriction map of part of the short arm of ehromosome 11 including the WAGR region has been constructed using pulsed-field gel electrophoresis and a number of infrequently cutting restriction enzymes. A total of 15.4 Mbp has been mapped in detall, extending from proximal 11p14 to the distal part of 11p12. The map localizes 35 different DNA probes and reveals at least nine areas with features eharaeteristle of BTF islands, some of which may be candidates for the different loci underlying the phenotype of the WAGR syndrome. This map will furthermore allow screening of DNA from individuals with WAGR-related phenotypes and from Wilms tumors for associated chromosomal rearrangements.}, subject = {Biochemie}, language = {en} } @article{GesslerBarnekow1984, author = {Gessler, Manfred and Barnekow, Angelika}, title = {Differential expression of the cellular oncogenes c-src and c-yes in embryonal and adult chicken tissues}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59289}, year = {1984}, abstract = {The cellular onc-genes c-src and c-yes are expressed very differently during chicken embryonic development. The c-src mRNA and its translational product are detectable at high levels in brain extracts of chicken embryos and adult chickens, whereas muscle extracts show an age-dependent decrease in the amounts of c-src-specific mRNA and pp60c-src kinase activity. In contrast, the Ievels of c-yes mRNA in brain, heart, and muscle are relatively low in early embryonic stages and increase later on to values comparable to those found for liver, while in adult animals the pattern of c-yes expression is similar to that of the c-src gene. From the close correlation between the Ievels of pp60c-src, its enzymatic activity, and its corresponding mRNA at a given stage of development and in given tissues, it appears that the expression of pp60c-src is primarily controlled at the level of transcription. It is suggested that because of the different patterns of expression, the two cellular oncogenes, c-src and c-yes, play different roles in cell proliferation during early embryonic stages as weil as in ensuing differentiation processes.}, subject = {Biochemie}, language = {en} } @article{GeorgievChaoCastroetal.2020, author = {Georgiev, Kostadin B. and Chao, Anne and Castro, Jorge and Chen, Yan-Han and Choi, Chang-Yong and Fontaine, Joseph B. and Hutto, Richard L. and Lee, Eun-Jae and M{\"u}ller, J{\"o}rg and Rost, Josep and Żmihorski, Michal and Thorn, Simon}, title = {Salvage logging changes the taxonomic, phylogenetic and functional successional trajectories of forest bird communities}, series = {Journal of Applied Ecology}, volume = {57}, journal = {Journal of Applied Ecology}, number = {6}, doi = {10.1111/1365-2664.13599}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-214887}, pages = {1103 -- 1112}, year = {2020}, abstract = {Salvage logging following natural disturbances may alter the natural successional trajectories of biological communities by affecting the occurrences of species, functional groups and evolutionary lineages. However, few studies have examined whether dissimilarities between bird communities of salvaged and unsalvaged forests are more pronounced for rare species, functional groups and evolutionary lineages than for their more common counterparts. We compiled data on breeding bird assemblages from nine study areas in North America, Europe and Asia, covering a 17-year period following wildfire or windstorm disturbances and subsequent salvage logging. We tested whether dissimilarities based on non-shared species, functional groups and evolutionary lineages (a) decreased or increased over time and (b) the responses of rare, common and dominant species varied, by using a unified statistical framework based on Hill numbers and null models. We found that dissimilarities between bird communities caused by salvage logging persisted over time for rare, common and dominant species, evolutionary lineages and for rare functional groups. Dissimilarities of common and dominant functional groups increased 14 years post disturbance. Salvage logging led to significantly larger dissimilarities than expected by chance. Functional dissimilarities between salvaged and unsalvaged sites were lower compared to taxonomic and phylogenetic dissimilarities. In general, dissimilarities were highest for rare, followed by common and dominant species. Synthesis and applications. Our research demonstrates that salvage logging did not decrease dissimilarities of bird communities over time and taxonomic, functional and phylogenetic dissimilarities persisted for over a decade. We recommend resource managers and decision makers to reserve portions of disturbed forest to enable unmanaged post-disturbance succession of bird communities, particularly to conserve rare species found in unsalvaged disturbed forests.}, language = {en} } @phdthesis{Georgiev2021, author = {Georgiev, Kostadin}, title = {Sustainable management of naturally disturbed forests}, doi = {10.25972/OPUS-24285}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242854}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Owing to climate change, natural forest disturbances and consecutive salvage logging are drastically increasing worldwide, consequently increasing the importance of understanding how these disturbances would affect biodiversity conservation and provision of ecosystem services. In chapter II, I used long-term water monitoring data and mid-term data on α-diversity of twelve species groups to quantify the effects of natural disturbances (windthrow and bark beetle) and salvage logging on concentrations of nitrate and dissolved organic carbon (DOC) in streamwater and α-diversity. I found that natural disturbances led to a temporal increase of nitrate concentrations in streamwater, but these concentrations remained within the health limits recommended by the World Health Organization for drinking water. Salvage logging did not exert any additional impact on nitrate and DOC concentrations, and hence did not affect streamwater quality. Thus, neither natural forest disturbances in watersheds nor associated salvage logging have a harmful effect on the quality of the streamwater used for drinking water. Natural disturbances increased the α-diversity in eight out of twelve species groups. Salvage logging additionally increased the α-diversity of five species groups related to open habitats, but decreased the biodiversity of three deadwood-dependent species groups. In chapter III, I investigated whether salvage logging following natural disturbances (wildfire and windthrow) altered the natural successional trajectories of bird communities. I compiled data on breeding bird assemblages from nine study areas in North America, Europe and Asia, over a period of 17 years and tested whether bird community dissimilarities changed over time for taxonomic, functional and phylogenetic diversity when rare, common and dominant species were weighted differently. I found that salvage logging led to significantly larger dissimilarities than expected by chance and that these dissimilarities persisted over time for rare, common and dominant species, evolutionary lineages, and for rare functional groups. Dissimilarities were highest for rare, followed by common and dominant species. In chapter IV, I investigated how β-diversity of 13 taxonomic groups would differ in intact, undisturbed forests, disturbed, unlogged forests and salvage-logged forests 11 years after a windthrow and salvage logging. The study suggests that both windthrow and salvage logging drive changes in between-treatment β-diversity, whereas windthrow alone seems to drive changes in within-treatment β-diversity. Over a decade after the windthrow at the studied site, the effect of subsequent salvage logging on within-treatment β-diversity was no longer detectable but the effect on between-treatment β-diversity persisted, with more prominent changes in saproxylic groups and rare species than in non-saproxylic groups or common and dominant species. Based on these results, I suggest that salvage logging needs to be carefully weighed against its long-lasting impact on communities of rare species. Also, setting aside patches of naturally disturbed areas is a valuable management alternative as these patches would enable post-disturbance succession of bird communities in unmanaged patches and would promote the conservation of deadwood-dependent species, without posing health risks to drinking water sources.}, subject = {species richness}, language = {en} } @phdthesis{Geissinger2010, author = {Geissinger, Ulrike}, title = {Vaccinia Virus-mediated MR Imaging of Tumors in Mice: Overexpression of Iron-binding Proteins in Colonized Xenografts}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-48099}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Vaccinia virus plays an important role in human medicine and molecular biology ever since the 18th century after E. Jenner discovered its value as a vaccination virus against smallpox. After the successful eradication of smallpox, vaccinia virus, apart from its use as a vaccine carrier, is today mainly used as a viral vector in molecular biology and increasingly in cancer therapy. The capability to specifically target and destroy cancer cells makes it a perfect agent for oncolytic virotherapy. Furthermore, the virus can easily be modified by inserting genes encoding therapeutic or diagnostic proteins to be expressed within the tumor. The emphasis in this study was the diagnosis of tumors using different vaccinia virus strains. Viruses with metal-accumulating capabilities for tumor detection via MRI technology were generated and tested for their usefulness in cell culture and in vivo. The virus strains GLV-1h131, GLV-1h132, and GLV-1h133 carry the gene encoding the two subunits of the iron storage protein ferritin under the control of three different promoters. GLV-1h110, GLV-1h111, and GLV-1h112 encode the bacterial iron storage protein bacterioferritin, whereas GLV-1h113 encodes the codon-optimized version of bacterioferritin for more efficient expression in human cells. GLV-1h22 contains the transferrin receptor gene, which plays an important role in iron uptake, and GLV-1h114 and GLV-1h115 contain the murine transferrin receptor gene. For possibly better iron uptake the virus strains GLV-1h154, GLV-1h155, GLV-1h156, and GLV-1h157 were generated, each with a version of a ferritin gene and a transferrin receptor gene. GLV-1h154 carries the genes that encode bacterioferritin and human transferrin receptor, GLV-1h155 the human ferritin H-chain gene and the human transferrin receptor gene. GLV-1h156 and GLV-1h157 infected cells both express the mouse transferrin receptor and bacterioferritin or human ferritin H-chain, respectively. The virus strains GLV-1h186 and GLV-1h187 were generated to contain a mutated form of the ferritin light chain, which was shown to result in iron overload and the wildtype light chain gene, respectively. The gene encoding the Divalent Metal Transporter 1, which is a major protein in the uptake of iron, was inserted in the virus strain GLV-1h102. The virus strain GLV-1h184 contains the magA gene of the magnetotactic bacterium Magnetospirillum magnetotacticum, which produces magnetic nanoparticles for orientation in the earth's magnetic field. Initially the infection and replication capability of all the virus strains were analyzed and compared to that of the parental virus strain GLV-1h68, revealing that all the viruses were able to infect cells of the human cancer cell lines A549 and GI-101A. All constructs exhibited a course of infection comparable to that of GLV-1h68. Next, to investigate the expression of the foreign proteins in GI-101A and A549 cells with protein analytical methods, SDS-gelelectrophoresis, Western blots and ELISAs were performed. The proteins, which were expressed under the control of the strong promoters, could be detected using these methods. To be able to successfully detect the protein expression of MagA and DMT1, which were expressed under the control of the weak promoter, the more sensitive method RT-PCR was used to at least confirm the transcription of the inserted genes. The determination of the iron content in infected GI-101A and A549 cells showed that infection with all used virus strains led to iron accumulation in comparison to uninfected cells, even infection with the parental virus strain GLV-1h68. The synthetic phytochelatin EC20 was also shown to enhance the accumulation of different heavy metals in bacterial cultures. In vivo experiments with A549 tumor-bearing athymic nude mice revealed that 24 days post infection virus particles were found mainly in the tumor. The virus-mediated expression of recombinant proteins in the tumors was detected successfully by Western blot. Iron accumulation in tumor lysates was investigated by using the ferrozine assay and led to the result that GLV-1h68-infected tumors had the highest iron content. Histological stainings confirmed the finding that iron accumulation was not a direct result of the insertion of genes encoding iron-accumulating proteins in the virus genome. Furthermore virus-injected tumorous mice were analyzed using MRI technology. Two different measurements were performed, the first scan being done with a seven Tesla small animal scanner seven days post infection whereas the second scan was performed using a three Tesla human scanner 21 days after virus injection. Tumors of mice injected with the virus strains GLV-1h113 and GLV-1h184 were shown to exhibit shortened T2 and T2* relaxation times, which indicates enhanced iron accumulation. In conclusion, the experiments in this study suggest that the bacterioferritin-encoding virus strain GLV-1h113 and the magA-encoding virus strain GLV-1h184 are promising candidates to be used for cancer imaging after further analyzation and optimization.}, subject = {Vaccinia-Virus}, language = {en} } @article{GeisingerRodriguezCasuriagaBenavente2021, author = {Geisinger, Adriana and Rodr{\´i}guez-Casuriaga, Rosana and Benavente, Ricardo}, title = {Transcriptomics of Meiosis in the Male Mouse}, series = {Frontiers in Cell and Developmental Biology}, volume = {9}, journal = {Frontiers in Cell and Developmental Biology}, issn = {2296-634X}, doi = {10.3389/fcell.2021.626020}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231032}, year = {2021}, abstract = {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.}, language = {en} } @article{GeiseLinsenmair1988, author = {Geise, W. and Linsenmair, Karl Eduard}, title = {Adaptations of the reed frog Hyperbolius viridiflavus to its arid environment. IV. Ecological significance of water economy with comments on thermoregulation and energy allocation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30570}, year = {1988}, abstract = {No abstract available}, language = {en} } @article{GeigerKerstingSchlegeletal.2022, author = {Geiger, Nina and Kersting, Louise and Schlegel, Jan and Stelz, Linda and F{\"a}hr, Sofie and Diesendorf, Viktoria and Roll, Valeria and Sostmann, Marie and K{\"o}nig, Eva-Maria and Reinhard, Sebastian and Brenner, Daniela and Schneider-Schaulies, Sibylle and Sauer, Markus and Seibel, J{\"u}rgen and Bodem, Jochen}, title = {The acid ceramidase is a SARS-CoV-2 host factor}, series = {Cells}, volume = {11}, journal = {Cells}, number = {16}, issn = {2073-4409}, doi = {10.3390/cells11162532}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286105}, year = {2022}, abstract = {SARS-CoV-2 variants such as the delta or omicron variants, with higher transmission rates, accelerated the global COVID-19 pandemic. Thus, novel therapeutic strategies need to be deployed. The inhibition of acid sphingomyelinase (ASM), interfering with viral entry by fluoxetine was reported. Here, we described the acid ceramidase as an additional target of fluoxetine. To discover these effects, we synthesized an ASM-independent fluoxetine derivative, AKS466. High-resolution SARS-CoV-2-RNA FISH and RTqPCR analyses demonstrate that AKS466 down-regulates viral gene expression. It is shown that SARS-CoV-2 deacidifies the lysosomal pH using the ORF3 protein. However, treatment with AKS488 or fluoxetine lowers the lysosomal pH. Our biochemical results show that AKS466 localizes to the endo-lysosomal replication compartments of infected cells, and demonstrate the enrichment of the viral genomic, minus-stranded RNA and mRNAs there. Both fluoxetine and AKS466 inhibit the acid ceramidase activity, cause endo-lysosomal ceramide elevation, and interfere with viral replication. Furthermore, Ceranib-2, a specific acid ceramidase inhibitor, reduces SARS-CoV-2 replication and, most importantly, the exogenous supplementation of C6-ceramide interferes with viral replication. These results support the hypotheses that the acid ceramidase is a SARS-CoV-2 host factor.}, language = {en} } @article{GebertSteffan‐DewenterKronbachetal.2022, author = {Gebert, Friederike and Steffan-Dewenter, Ingolf and Kronbach, Patrick and Peters, Marcell K.}, title = {The role of diversity, body size and climate in dung removal: A correlative and experimental approach}, series = {Journal of Animal Ecology}, volume = {91}, journal = {Journal of Animal Ecology}, number = {11}, doi = {10.1111/1365-2656.13798}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-293907}, pages = {2181 -- 2191}, year = {2022}, abstract = {The mechanisms by which climatic changes influence ecosystem functions, that is, by a direct climatic control of ecosystem processes or by modifying richness and trait compositions of species communities, remain unresolved. This study is a contribution to this discourse by elucidating the linkages between climate, land use, biodiversity, body size and ecosystem functions. We disentangled direct climatic from biodiversity-mediated effects by using dung removal by dung beetles as a model system and by combining correlative field data and exclosure experiments along an extensive elevational gradient on Mt. Kilimanjaro, Tanzania. Dung removal declined with increasing elevation, being associated with a strong reduction in the richness and body size traits of dung beetle communities. Climate influenced dung removal rates by modifying biodiversity rather than by direct effects. The biodiversity-ecosystem effect was driven by a change in the mean body size of dung beetles. Dung removal rates were strongly reduced when large dung beetles were experimentally excluded. This study underscores that climate influences ecosystem functions mainly by modifying biodiversity and underpins the important role of body size for dung removal.}, language = {en} } @article{GebertSteffanDewenterMorettoetal.2019, author = {Gebert, Friederike and Steffan-Dewenter, Ingolf and Moretto, Philippe and Peters, Marcell K.}, title = {Climate rather than dung resources predict dung beetle abundance and diversity along elevational and land use gradients on Mt. Kilimanjaro}, series = {Journal of Biogeography}, volume = {47}, journal = {Journal of Biogeography}, number = {2}, doi = {10.1111/jbi.13710}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204701}, pages = {371 -- 381}, year = {2019}, abstract = {Aim: While elevational gradients in species richness constitute some of the best depicted patterns in ecology, there is a large uncertainty concerning the role of food resource availability for the establishment of diversity gradients in insects. Here, we analysed the importance of climate, area, land use and food resources for determining diversity gradients of dung beetles along extensive elevation and land use gradients on Mt. Kilimanjaro, Tanzania. Location: Mt. Kilimanjaro, Tanzania. Taxon: Scarabaeidae (Coleoptera). Methods: Dung beetles were recorded with baited pitfall traps at 66 study plots along a 3.6 km elevational gradient. In order to quantify food resources for the dung beetle community in form of mammal defecation rates, we assessed mammalian diversity and biomass with camera traps. Using a multi-model inference framework and path analysis, we tested the direct and indirect links between climate, area, land use and mammal defecation rates on the species richness and abundance of dung beetles. Results: We found that the species richness of dung beetles declined exponentially with increasing elevation. Human land use diminished the species richness of functional groups exhibiting complex behaviour but did not have a significant influence on total species richness. Path analysis suggested that climate, in particular temperature and to a lesser degree precipitation, were the most important predictors of dung beetle species richness while mammal defecation rate was not supported as a predictor variable. Main conclusions: Along broad climatic gradients, dung beetle diversity is mainly limited by climatic factors rather than by food resources. Our study points to a predominant role of temperature-driven processes for the maintenance and origination of species diversity of ectothermic organisms, which will consequently be subject to ongoing climatic changes.}, language = {en} } @phdthesis{Gebert2022, author = {Gebert, Friederike}, title = {Mammals and dung beetles along elevational and land use gradients on Mount Kilimanjaro: diversity, traits and ecosystem services}, doi = {10.25972/OPUS-19195}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-191950}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Despite belonging to the best described patterns in ecology, the mechanisms driving biodiversity along broad-scale climatic gradients, like the latitudinal gradient in diversity, remain poorly understood. Because of their high biodiversity, restricted spatial ranges, the continuous change in abiotic factors with altitude and their worldwide occurrence, mountains constitute ideal study systems to elucidate the predictors of global biodiversity patterns. However, mountain ecosystems are increasingly threatened by human land use and climate change. Since the consequences of such alterations on mountainous biodiversity and related ecosystem services are hardly known, research along elevational gradients is also of utmost importance from a conservation point of view. In addition to classical biodiversity research focusing on taxonomy, the significance of studying functional traits and their prominence in biodiversity ecosystem functioning (BEF) relationships is increasingly acknowledged. In this dissertation, I explore the patterns and drivers of mammal and dung beetle diversity along elevational and land use gradients on Mt. Kilimanjaro, Tanzania. Furthermore, I investigate the predictors of dung decomposition by dung beetles under different extinction scenarios. Mammals are not only charismatic, they also fulfil important roles in ecosystems. They provide important ecosystem services such as seed dispersal and nutrient cycling by turning over high amounts of biomass. In chapter II, I show that mammal diversity and community biomass both exhibited a unimodal distribution with elevation on Mt.Kilimanjaro and were mainly impacted by primary productivity, a measure of the total food abundance, and the protection status of study plots. Due to their large size and endothermy, mammals, in contrast to most arthopods, are theoretically predicted to be limited by food availability. My results are in concordance with this prediction. The significantly higher diversity and biomass in the Kilimanjaro National Park and in other conservation areas underscore the important role of habitat protection is vital for the conservation of large mammal biodiversity on tropical mountains. Dung beetles are dependent on mammals since they rely upon mammalian dung as a food and nesting resource. Dung beetles are also important ecosystem service providers: they play an important role in nutrient cycling, bioturbation, secondary seed dispersal and parasite suppression. In chapter III, I show that dung beetle diversity declined with elevation while dung beetle abundance followed a hump-shaped pattern along the elevational gradient. In contrast to mammals, dung beetle diversity was primarily predicted by temperature. Despite my attempt to accurately quantifiy mammalian dung resources by calculating mammalian defecation rates, I did not find an influence of dung resource availability on dung beetle richness. Instead, higher temperature translated into higher dung beetle diversity. Apart from being important ecosystem service providers, dung beetles are also model organisms for BEF studies since they rely on a resource which can be quantified easily. In chapter IV, I explore dung decomposition by dung beetles along the elevational gradient by means of an exclosure experiment in the presence of the whole dung beetle community, in the absence of large dung beetles and without any dung beetles. I show that dung decomposition was the highest when the dung could be decomposed by the whole dung beetle community, while dung decomposition was significantly reduced in the sole presence of small dung beetles and the lowest in the absence of dung beetles. Furthermore, I demonstrate that the drivers of dung decomposition were depend on the intactness of the dung beetle community. While body size was the most important driver in the presence of the whole dung beetle community, species richness gained in importance when large dung beetles were excluded. In the most perturbed state of the system with no dung beetles present, temperature was the sole driver of dung decomposition. In conclusion, abiotic drivers become more important predictors of ecosystem services the more the study system is disturbed. In this dissertation, I exemplify that the drivers of diversity along broad-scale climatic gradients on Mt. Kilimanjaro depend on the thermoregulatory strategy of organisms. While mammal diversity was mainly impacted by food/energy resources, dung beetle diversity was mainly limited by temperature. I also demonstrate the importance of protected areas for the preservation of large mammal biodiversity. Furthermore, I show that large dung beetles were disproportionately important for dung decomposition as dung decomposition significantly decreased when large dung beetles were excluded. As regards land use, I did not detect an overall effect on dung beetle and mammal diversity nor on dung beetle-mediated dung decomposition. However, for the most specialised mammal trophic guilds and dung beetle functional groups, negative land use effects were already visible. Even though the current moderate levels of land use on Mt. Kilimanjaro can sustain high levels of biodiversity, the pressure of the human population on Mt. Kilimanjaro is increasing and further land use intensification poses a great threat to biodiversity. In synergy wih land use, climate change is jeopardizing current patterns and levels of biodiversity with the potential to displace communities, which may have unpredictable consequences for ecosystem service provisioning in the future.}, subject = {Kilimandscharo}, language = {en} } @article{GaubatzEsterlechnerReichertetal.2013, author = {Gaubatz, Stefan and Esterlechner, Jasmina and Reichert, Nina and Iltzsche, Fabian and Krause, Michael and Finkernagel, Florian}, title = {LIN9, a Subunit of the DREAM Complex, Regulates Mitotic Gene Expression and Proliferation of Embryonic Stem Cells}, series = {PLoS ONE}, journal = {PLoS ONE}, doi = {10.1371/journal.pone.0062882}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96922}, year = {2013}, abstract = {The DREAM complex plays an important role in regulation of gene expression during the cell cycle. We have previously shown that the DREAM subunit LIN9 is required for early embryonic development and for the maintenance of the inner cell mass in vitro. In this study we examined the effect of knocking down LIN9 on ESCs. We demonstrate that depletion of LIN9 alters the cell cycle distribution of ESCs and results in an accumulation of cells in G2 and M and in an increase of polyploid cells. Genome-wide expression studies showed that the depletion of LIN9 results in downregulation of mitotic genes and in upregulation of differentiation-specific genes. ChIP-on chip experiments showed that mitotic genes are direct targets of LIN9 while lineage specific markers are regulated indirectly. Importantly, depletion of LIN9 does not alter the expression of pluripotency markers SOX2, OCT4 and Nanog and LIN9 depleted ESCs retain alkaline phosphatase activity. We conclude that LIN9 is essential for proliferation and genome stability of ESCs by activating genes with important functions in mitosis and cytokinesis.}, language = {en} } @article{GattoSchulzeNielsen2016, author = {Gatto, Francesco and Schulze, Almut and Nielsen, Jens}, title = {Systematic Analysis Reveals that Cancer Mutations Converge on Deregulated Metabolism of Arachidonate and Xenobiotics}, series = {Cell Reports}, volume = {16}, journal = {Cell Reports}, number = {3}, doi = {10.1016/j.celrep.2016.06.038}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164814}, pages = {878-895}, year = {2016}, abstract = {Mutations are the basis of the clonal evolution of most cancers. Nevertheless, a systematic analysis of whether mutations are selected in cancer because they lead to the deregulation of specific biological processes independent of the type of cancer is still lacking. In this study, we correlated the genome and transcriptome of 1,082 tumors. We found that nine commonly mutated genes correlated with substantial changes in gene expression, which primarily converged on metabolism. Further network analyses circumscribed the convergence to a network of reactions, termed AraX, that involves the glutathione- and oxygen-mediated metabolism of arachidonic acid and xenobiotics. In an independent cohort of 4,462 samples, all nine mutated genes were consistently correlated with the deregulation of AraX. Among all of the metabolic pathways, AraX deregulation represented the strongest predictor of patient survival. These findings suggest that oncogenic mutations drive a selection process that converges on the deregulation of the AraX network.}, language = {en} } @article{GassenBrechtefeldSchandryetal.2012, author = {Gassen, Alwine and Brechtefeld, Doris and Schandry, Niklas and Arteaga-Salas, J. Manuel and Israel, Lars and Imhof, Axel and Janzen, Christian J.}, title = {DOT1A-dependent H3K76 methylation is required for replication regulation in Trypanosoma brucei}, series = {Nucleic Acids Research}, volume = {40}, journal = {Nucleic Acids Research}, number = {20}, doi = {10.1093/nar/gks801}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131449}, pages = {10302 - 10311}, year = {2012}, abstract = {Cell-cycle progression requires careful regulation to ensure accurate propagation of genetic material to the daughter cells. Although many cell-cycle regulators are evolutionarily conserved in the protozoan parasite Trypanosoma brucei, novel regulatory mechanisms seem to have evolved. Here, we analyse the function of the histone methyltransferase DOT1A during cell-cycle progression. Over-expression of DOT1A generates a population of cells with aneuploid nuclei as well as enucleated cells. Detailed analysis shows that DOT1A over-expression causes continuous replication of the nuclear DNA. In contrast, depletion of DOT1A by RNAi abolishes replication but does not prevent karyokinesis. As histone H3K76 methylation has never been associated with replication control in eukaryotes before, we have discovered a novel function of DOT1 enzymes, which might not be unique to trypanosomes.}, language = {en} } @article{GaritanoTrojaolaSanchoGoetzetal.2021, author = {Garitano-Trojaola, Andoni and Sancho, Ana and G{\"o}tz, Ralph and Eiring, Patrick and Walz, Susanne and Jetani, Hardikkumar and Gil-Pulido, Jesus and Da Via, Matteo Claudio and Teufel, Eva and Rhodes, Nadine and Haertle, Larissa and Arellano-Viera, Estibaliz and Tibes, Raoul and Rosenwald, Andreas and Rasche, Leo and Hudecek, Michael and Sauer, Markus and Groll, J{\"u}rgen and Einsele, Hermann and Kraus, Sabrina and Kort{\"u}m, Martin K.}, title = {Actin cytoskeleton deregulation confers midostaurin resistance in FLT3-mutant acute myeloid leukemia}, series = {Communications Biology}, volume = {4}, journal = {Communications Biology}, number = {1}, doi = {10.1038/s42003-021-02215-w}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260709}, year = {2021}, abstract = {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.}, language = {en} } @article{GarciaMartinezBrunkAvalosetal.2015, author = {Garc{\´i}a-Mart{\´i}nez, Jorge and Brunk, Michael and Avalos, Javier and Terpitz, Ulrich}, title = {The CarO rhodopsin of the fungus Fusarium fujikuroi is a light-driven proton pump that retards spore germination}, series = {Scientific Reports}, volume = {5}, journal = {Scientific Reports}, number = {7798}, doi = {10.1038/srep07798}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149049}, year = {2015}, abstract = {Rhodopsins are membrane-embedded photoreceptors found in all major taxonomic kingdoms using retinal as their chromophore. They play well-known functions in different biological systems, but their roles in fungi remain unknown. The filamentous fungus Fusarium fujikuroi contains two putative rhodopsins, CarO and OpsA. The gene carO is light-regulated, and the predicted polypeptide contains all conserved residues required for proton pumping. We aimed to elucidate the expression and cellular location of the fungal rhodopsin CarO, its presumed proton-pumping activity and the possible effect of such function on F. fujikuroi growth. In electrophysiology experiments we confirmed that CarO is a green-light driven proton pump. Visualization of fluorescent CarO-YFP expressed in F. fujikuroi under control of its native promoter revealed higher accumulation in spores (conidia) produced by light-exposed mycelia. Germination analyses of conidia from carO\(^{-}\) mutant and carO\(^{+}\) control strains showed a faster development of light-exposed carO-germlings. In conclusion, CarO is an active proton pump, abundant in light-formed conidia, whose activity slows down early hyphal development under light. Interestingly, CarO-related rhodopsins are typically found in plant-associated fungi, where green light dominates the phyllosphere. Our data provide the first reliable clue on a possible biological role of a fungal rhodopsin.}, language = {en} } @article{GarciaMatosShenetal.2014, author = {Garcia, Tzintzuni I. and Matos, Isa and Shen, Yingjia and Pabuwal, Vagmita and Coelho, Maria Manuela and Wakamatsu, Yuko and Schartl, Manfred and Walter, Ronald B.}, title = {Novel Method for Analysis of Allele Specific Expression in Triploid Oryzias latipes Reveals Consistent Pattern of Allele Exclusion}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {6}, issn = {1932-6203}, doi = {10.1371/journal.pone.0100250}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116000}, pages = {e100250}, year = {2014}, abstract = {Assessing allele-specific gene expression (ASE) on a large scale continues to be a technically challenging problem. Certain biological phenomena, such as X chromosome inactivation and parental imprinting, affect ASE most drastically by completely shutting down the expression of a whole set of alleles. Other more subtle effects on ASE are likely to be much more complex and dependent on the genetic environment and are perhaps more important to understand since they may be responsible for a significant amount of biological diversity. Tools to assess ASE in a diploid biological system are becoming more reliable. Non-diploid systems are, however, not uncommon. In humans full or partial polyploid states are regularly found in both healthy (meiotic cells, polynucleated cell types) and diseased tissues (trisomies, non-disjunction events, cancerous tissues). In this work we have studied ASE in the medaka fish model system. We have developed a method for determining ASE in polyploid organisms from RNAseq data and we have implemented this method in a software tool set. As a biological model system we have used nuclear transplantation to experimentally produce artificial triploid medaka composed of three different haplomes. We measured ASE in RNA isolated from the livers of two adult, triploid medaka fish that showed a high degree of similarity. The majority of genes examined (82\%) shared expression more or less evenly among the three alleles in both triploids. The rest of the genes (18\%) displayed a wide range of ASE levels. Interestingly the majority of genes (78\%) displayed generally consistent ASE levels in both triploid individuals. A large contingent of these genes had the same allele entirely suppressed in both triploids. When viewed in a chromosomal context, it is revealed that these genes are from large sections of 4 chromosomes and may be indicative of some broad scale suppression of gene expression.}, language = {en} } @article{GaoNagpalSchneideretal.2015, author = {Gao, Shiqiang and Nagpal, Jatin and Schneider, Martin W. and Kozjak-Pavlovic, Vera and Nagel, Georg and Gottschalk, Alexander}, title = {Optogenetic manipulation of cGMP in cells and animals by the tightly light-regulated guanylyl-cyclase opsin CyclOp}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, number = {8046}, doi = {10.1038/ncomms9046}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148197}, year = {2015}, abstract = {Cyclic GMP (cGMP) signalling regulates multiple biological functions through activation of protein kinase G and cyclic nucleotide-gated (CNG) channels. In sensory neurons, cGMP permits signal modulation, amplification and encoding, before depolarization. Here we implement a guanylyl cyclase rhodopsin from Blastocladiella emersonii as a new optogenetic tool (BeCyclOp), enabling rapid light-triggered cGMP increase in heterologous cells (Xenopus oocytes, HEK293T cells) and in Caenorhabditis elegans. Among five different fungal CyclOps, exhibiting unusual eight transmembrane topologies and cytosolic N-termini, BeCyclOp is the superior optogenetic tool (light/dark activity ratio: 5,000; no cAMP production; turnover (20 °C) ~17 cGMPs\(^{-1}\)). Via co-expressed CNG channels (OLF in oocytes, TAX-2/4 in C. elegans muscle), BeCyclOp photoactivation induces a rapid conductance increase and depolarization at very low light intensities. In O\(_2\)/CO\(_2\) sensory neurons of C. elegans, BeCyclOp activation evokes behavioural responses consistent with their normal sensory function. BeCyclOp therefore enables precise and rapid optogenetic manipulation of cGMP levels in cells and animals.}, language = {en} } @article{GanuzaRedlichUhleretal.2022, author = {Ganuza, Cristina and Redlich, Sarah and Uhler, Johannes and Tobisch, Cynthia and Rojas-Botero, Sandra and Peters, Marcell K. and Zhang, Jie and Benjamin, Caryl S. and Englmeier, Jana and Ewald, J{\"o}rg and Fricke, Ute and Haensel, Maria and Kollmann, Johannes and Riebl, Rebekka and Uphus, Lars and M{\"u}ller, J{\"o}rg and Steffan-Dewenter, Ingolf}, title = {Interactive effects of climate and land use on pollinator diversity differ among taxa and scales}, series = {Science Advances}, volume = {8}, journal = {Science Advances}, number = {18}, doi = {10.1126/sciadv.abm9359}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301303}, year = {2022}, abstract = {Changes in climate and land use are major threats to pollinating insects, an essential functional group. Here, we unravel the largely unknown interactive effects of both threats on seven pollinator taxa using a multiscale space-for-time approach across large climate and land-use gradients in a temperate region. Pollinator community composition, regional gamma diversity, and community dissimilarity (beta diversity) of pollinator taxa were shaped by climate-land-use interactions, while local alpha diversity was solely explained by their additive effects. Pollinator diversity increased with reduced land-use intensity (forest < grassland < arable land < urban) and high flowering-plant diversity at different spatial scales, and higher temperatures homogenized pollinator communities across regions. Our study reveals declines in pollinator diversity with land-use intensity at multiple spatial scales and regional community homogenization in warmer and drier climates. Management options at several scales are highlighted to mitigate impacts of climate change on pollinators and their ecosystem services.}, language = {en} } @article{GalluzziBravoSanPedroVitaleetal.2015, author = {Galluzzi, L. and Bravo-San Pedro, J. M. and Vitale, I. and Aaronson, S. A. and Abrams, J. M. and Adam, D. and Alnemri, E. S. and Altucci, L. and Andrews, D. and Annicchiarico-Petruzelli, M. and Baehrecke, E. H. and Bazan, N. G. and Bertrand, M. J. and Bianchi, K. and Blagosklonny, M. V. and Blomgren, K. and Borner, C. and Bredesen, D. E. and Brenner, C. and Campanella, M. and Candi, E. and Cecconi, F. and Chan, F. K. and Chandel, N. S. and Cheng, E. H. and Chipuk, J. E. and Cidlowski, J. A. and Ciechanover, A. and Dawson, T. M. and Dawson, V. L. and De Laurenzi, V. and De Maria, R. and Debatin, K. M. and Di Daniele, N. and Dixit, V. M. and Dynlacht, B. D. and El-Deiry, W. S. and Fimia, G. M. and Flavell, R. A. and Fulda, S. and Garrido, C. and Gougeon, M. L. and Green, D. R. and Gronemeyer, H. and Hajnoczky, G. and Hardwick, J. M. and Hengartner, M. O. and Ichijo, H. and Joseph, B. and Jost, P. J. and Kaufmann, T. and Kepp, O. and Klionsky, D. J. and Knight, R. A. and Kumar, S. and Lemasters, J. J. and Levine, B. and Linkermann, A. and Lipton, S. A. and Lockshin, R. A. and L{\´o}pez-Ot{\´i}n, C. and Lugli, E. and Madeo, F. and Malorni, W. and Marine, J. C. and Martin, S. J. and Martinou, J. C. and Medema, J. P. and Meier, P. and Melino, S. and Mizushima, N. and Moll, U. and Mu{\~n}oz-Pinedo, C. and Nu{\~n}ez, G. and Oberst, A. and Panaretakis, T. and Penninger, J. M. and Peter, M. E. and Piacentini, M. and Pinton, P. and Prehn, J. H. and Puthalakath, H. and Rabinovich, G. A. and Ravichandran, K. S. and Rizzuto, R. and Rodrigues, C. M. and Rubinsztein, D. C. and Rudel, T. and Shi, Y. and Simon, H. U. and Stockwell, B. R. and Szabadkai, G. and Tait, S. W. and Tang, H. L. and Tavernarakis, N. and Tsujimoto, Y. and Vanden Berghe, T. and Vandenabeele, P. and Villunger, A. and Wagner, E. F. and Walczak, H. and White, E. and Wood, W. G. and Yuan, J. and Zakeri, Z. and Zhivotovsky, B. and Melino, G. and Kroemer, G.}, title = {Essential versus accessory aspects of cell death: recommendations of the NCCD 2015}, series = {Cell Death and Differentiation}, volume = {22}, journal = {Cell Death and Differentiation}, doi = {10.1038/cdd.2014.137}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121207}, pages = {58-73}, year = {2015}, abstract = {Cells exposed to extreme physicochemical or mechanical stimuli die in an uncontrollable manner, as a result of their immediate structural breakdown. Such an unavoidable variant of cellular demise is generally referred to as 'accidental cell death' (ACD). In most settings, however, cell death is initiated by a genetically encoded apparatus, correlating with the fact that its course can be altered by pharmacologic or genetic interventions. 'Regulated cell death' (RCD) can occur as part of physiologic programs or can be activated once adaptive responses to perturbations of the extracellular or intracellular microenvironment fail. The biochemical phenomena that accompany RCD may be harnessed to classify it into a few subtypes, which often (but not always) exhibit stereotyped morphologic features. Nonetheless, efficiently inhibiting the processes that are commonly thought to cause RCD, such as the activation of executioner caspases in the course of apoptosis, does not exert true cytoprotective effects in the mammalian system, but simply alters the kinetics of cellular demise as it shifts its morphologic and biochemical correlates. Conversely, bona fide cytoprotection can be achieved by inhibiting the transduction of lethal signals in the early phases of the process, when adaptive responses are still operational. Thus, the mechanisms that truly execute RCD may be less understood, less inhibitable and perhaps more homogeneous than previously thought. Here, the Nomenclature Committee on Cell Death formulates a set of recommendations to help scientists and researchers to discriminate between essential and accessory aspects of cell death.}, language = {en} } @article{GabelliniSebald1986, author = {Gabellini, N. and Sebald, Walter}, title = {Nucleotide sequence and transcription of the fbc operon from Rhodopseudomonas sphaeroides. Evaluation of the deduced amino acid sequences of the FeS protein, cytochrome b and cytochrome c\(_1\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62615}, year = {1986}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{GabelliniHarnischMcCarthyetal.1985, author = {Gabellini, N. and Harnisch, U. and McCarthy, J. E. and Hauska, G. and Sebald, Walter}, title = {Cloning and expression of the fbc operon encoding the FeS protein, cytochrome b and cytochrome c\(_1\) from the Rhodopseudomonas sphaeroides b/c\(_1\) complex}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62642}, year = {1985}, abstract = {The gene for the FeS protein of the Rhodopseudomonas sphaeroides b/c1 complex was identified by means of crosshybridization with a segment of the gene encoding the corresponding FeS protein of Neurospora crassa. Plasmids (pRSF1-14) containing the cross-hybridizing region, covering in total 13.5 kb of chromosomal DNA, were expressed in vitro in a homologous system. One RSF plasmid directed the synthesis of all three main polypeptides of the R. sphaeroides blc1 complex: the FeS protein, cytochrome b and cytochrome c1• The FeS protein and cytochrome c1 were apparently synthesized as precursor fonns. None of the pRSF plasmids directed the synthesis of the 10-kd polypeptide found in b/c1 complex preparations. Partial sequencing of the cloned region was performed. Several sites of strong homology between R. sphaeroides and eukaryotic polypeptides of the b/c1 complex were identified. The genes encode the three b/c1 polypeptides in the order: (5') FeS protein, cytochrome b, cytochrome c1• The three genes are transcribed to give a polycistronic mRNA of 2.9 kb. This transcriptional unit has been designated the jbc operon; its coding capacity corresponds to the size of the polycistronic mRNA assuming that only the genes for the FeS protein (jbcF), cytochrome b (jbcß) and cytochrome c1 (jbcC) are present. This could indicate that these three subunits constitute the minimal catalytic unit of the b/c1 complex from photosynthetic membranes.}, subject = {Biochemie}, language = {en} } @phdthesis{Gabel2024, author = {Gabel, Martin Sebastian}, title = {Behavioural resistance to \(Varroa\) \(destructor\) in the Western honeybee \(Apis\) \(mellifera\) - Mechanisms leading to decreased mite reproduction}, doi = {10.25972/OPUS-36053}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-360536}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2024}, abstract = {The Western Honeybee (Apis mellifera) is among the most versatile species in the world. Its adaptability is rooted in thousands of the differently specialized individuals acting jointly together. Thus, bees that are able to handle a certain task or condition well can back up other individuals less capable to do so on the colony level. Vice versa, the latter individuals might perform better in other situations. This evolutionary recipe for success ensures the survival of colonies despite challenging habitat conditions. In this context, the ectoparasitic mite Varroa destructor reflects the most pronounced biotic challenge to honeybees worldwide. Without proper treatment, infested colonies rapidly dwindle and ultimately die. Nevertheless, resistance behaviours against this parasite have evolved in some populations through natural selection, enabling colonies to survive untreated. In this, different behaviours appear to be adapted to the respective habitat conditions and may complement each other. Yet, the why and how of this behavioural response to the mite remains largely unknown. My thesis focuses on the biological background of Varroa-resistance traits in honeybees and presents important findings for the comprehension of this complex host-parasite interaction. Based on this, I draw implications for both, applied bee breeding and scientific investigations in the field of Varroa-resistance. Specifically, I focus on two traits commonly found in resistant and, to a lower degree, also mite-susceptible colonies: decreased mite reproduction and the uncapping and subsequent recapping of sealed brood cells. Examining failures in the reproductive success of mites as a primary mechanism of Varroa-resistance, I was able to link them to specific bee behaviours and external factors. Since mite reproduction and the brood rearing of bees are inevitably connected, I first investigated the effects of brood interruption on the reproductive success of mites. Brood interruption decreased the reproductive success of mites both immediately and in the long term. By examining the causes of reproductive failure, I could show that this was mainly due to an increased share of infertile mites. Furthermore, I proved that interruption in brood rearing significantly increased the expression of recapping behaviour. These findings consequently showed a dynamic modulation of mite reproduction and recapping, as well as a direct effect of brood interruption on both traits. To further elucidate the plasticity in the expression of both traits, I studied mite reproduction, recapping behaviour and infestation levels over the course of three years. The resulting extensive dataset unveiled a significant seasonal variation in mite reproduction and recapping. In addition, I show that recapping decreases the reproductive success of mites by increasing delayed developing female offspring and cells lacking male offspring. By establishing a novel picture-based brood investigation method, I could furthermore show that both the removal of brood cells and recapping activity specifically target brood ages in which mite offspring would be expected. Recapping, however, did not cause infertility of mites. Considering the findings of my first study, this points towards complementary mechanisms. This underlines the importance of increased recapping behaviour and decreased mite reproduction as resistance traits, while at the same time emphasising the challenges of reliable data acquisition. To pave the way for a practical application of these findings in breeding, we then investigated the heritability (i.e., the share of genotypic variation on the observed phenotypic variation) of the accounted traits. By elaborating comparable test protocols and compiling data from over 4,000 colonies, we could, for the first time, demonstrate that recapping of infested cells and decreased reproductive success of mites are heritable (and thus selectable) traits in managed honeybee populations. My thesis proves the importance of recapping and decreased mite reproduction as resistance traits and therefore valuable goals for breeding efforts. In this regard, I shed light on the underlying mechanisms of both traits, and present clear evidence for their interaction and heritability.}, subject = {Varroa destructor}, language = {en} } @phdthesis{Gaballa2024, author = {Gaballa, Abdallah Hatem Hassan Hosny Ahmed}, title = {PAF1c drives MYC-mediated immune evasion in pancreatic ductal adenocarcinoma}, doi = {10.25972/OPUS-36045}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-360459}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2024}, abstract = {The expression of the MYC proto-oncogene is elevated in a large proportion of patients with pancreatic ductal adenocarcinoma (PDAC). Previous findings in PDAC have shown that this increased MYC expression mediates immune evasion and promotes S-phase progression. How these functions are mediated and whether a downstream factor of MYC mediates these functions has remained elusive. Recent studies identifying the MYC interactome revealed a complex network of interaction partners, highlighting the need to identify the oncogenic pathway of MYC in an unbiased manner. In this work, we have shown that MYC ensures genomic stability during S-phase and prevents transcription-replication conflicts. Depletion of MYC and inhibition of ATR kinase showed a synergistic effect to induce DNA damage. A targeted siRNA screen targeting downstream factors of MYC revealed that PAF1c is required for DNA repair and S-phase progression. Recruitment of PAF1c to RNAPII was shown to be MYC dependent. PAF1c was shown to be largely dispensable for cell proliferation and regulation of MYC target genes. Depletion of CTR9, a subunit of PAF1c, caused strong tumor regression in a pancreatic ductal adenocarcinoma model, with long-term survival in a subset of mice. This effect was not due to induction of DNA damage, but to restoration of tumor immune surveillance. Depletion of PAF1c resulted in the release of RNAPII with transcription elongation factors, including SPT6, from the bodies of long genes, promoting full-length transcription of short genes. This resulted in the downregulation of long DNA repair genes and the concomitant upregulation of short genes, including MHC class I genes. These data demonstrate that a balance between long and short gene transcription is essential for tumor progression and that interference with PAF1c levels shifts this balance toward a tumor-suppressive transcriptional program. It also directly links MYC-mediated S-phase progression to immune evasion. Unlike MYC, PAF1c has a stable, known folded structure; therefore, the development of a small molecule targeting PAF1c may disrupt the immune evasive function of MYC while sparing its physiological functions in cellular growth.}, subject = {Myc}, language = {en} } @article{FoersterBeisserGrohmeetal.2012, author = {F{\"o}rster, Frank and Beisser, Daniela and Grohme, Markus A. and Liang, Chunguang and Mali, Brahim and Siegl, Alexander Matthias and Engelmann, Julia C. and Shkumatov, Alexander V. and Schokraie, Elham and M{\"u}ller, Tobias and Schn{\"o}lzer, Martina and Schill, Ralph O. and Frohme, Marcus and Dandekar, Thomas}, title = {Transcriptome analysis in tardigrade species reveals specific molecular pathways for stress adaptations}, series = {Bioinformatics and biology insights}, volume = {6}, journal = {Bioinformatics and biology insights}, doi = {10.4137/BBI.S9150}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123089}, pages = {69-96}, year = {2012}, abstract = {Tardigrades have unique stress-adaptations that allow them to survive extremes of cold, heat, radiation and vacuum. To study this, encoded protein clusters and pathways from an ongoing transcriptome study on the tardigrade \(Milnesium\) \(tardigradum\) were analyzed using bioinformatics tools and compared to expressed sequence tags (ESTs) from \(Hypsibius\) \(dujardini\), revealing major pathways involved in resistance against extreme environmental conditions. ESTs are available on the Tardigrade Workbench along with software and databank updates. Our analysis reveals that RNA stability motifs for \(M.\) \(tardigradum\) are different from typical motifs known from higher animals. \(M.\) \(tardigradum\) and \(H.\) \(dujardini\) protein clusters and conserved domains imply metabolic storage pathways for glycogen, glycolipids and specific secondary metabolism as well as stress response pathways (including heat shock proteins, bmh2, and specific repair pathways). Redox-, DNA-, stress- and protein protection pathways complement specific repair capabilities to achieve the strong robustness of \(M.\) \(tardigradum\). These pathways are partly conserved in other animals and their manipulation could boost stress adaptation even in human cells. However, the unique combination of resistance and repair pathways make tardigrades and \(M.\) \(tardigradum\) in particular so highly stress resistant.}, language = {en} } @phdthesis{Foerster2010, author = {F{\"o}rster, Frank}, title = {Making the most of phylogeny: Unique adaptations in tardigrades and 216374 internal transcribed spacer 2 structures}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-51466}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {The phylum Tardigrada consists of about 1000 described species to date. The animals live in habitats within marine, freshwater and terrestrial ecosystems allover the world. Tardigrades are polyextremophiles. They are capable to resist extreme temperature, pressure or radiation. In the event of desiccation, tardigrades enter a so-called tun stage. The reason for their great tolerance capabilities against extreme environmental conditions is not discovered yet. Our Funcrypta project aims at finding answers to the question what mechanisms underlie these adaption capabilities particularly with regard to the species Milnesium tardigradum. The first part of this thesis describes the establishment of expressed sequence tags (ESTs) libraries for different stages of M. tardigradum. From proteomics data we bioinformatically identified 144 proteins with a known function and additionally 36 proteins which seemed to be specific for M. tardigradum. The generation of a comprehensive web-based database allows us to merge the proteome and transcriptome data. Therefore we created an annotation pipeline for the functional annotation of the protein and nucleotide sequences. Additionally, we clustered the obtained proteome dataset and identified some tardigrade-specific proteins (TSPs) which did not show homology to known proteins. Moreover, we examined the heat shock proteins of M. tardigradum and their different expression levels depending on the actual state of the animals. In further bioinformatical analyses of the whole data set, we discovered promising proteins and pathways which are described to be correlated with the stress tolerance, e.g. late embryogenesis abundant (LEA) proteins. Besides, we compared the tardigrades with nematodes, rotifers, yeast and man to identify shared and tardigrade specific stress pathways. An analysis of the 50 and 30 untranslated regions (UTRs) demonstrates a strong usage of stabilising motifs like the 15-lipoxygenase differentiation control element (15-LOX-DICE) but also reveals a lack of other common UTR motifs normally used, e.g. AU rich elements. The second part of this thesis focuses on the relatedness between several cryptic species within the tardigrade genus Paramacrobiotus. Therefore for the first time, we used the sequence-structure information of the internal transcribed spacer 2 (ITS2) as a phylogenetic marker in tardigrades. This allowed the description of three new species which were indistinguishable using morphological characters or common molecular markers like the 18S ribosomal ribonucleic acid (rRNA) or the Cytochrome c oxidase subunit I (COI). In a large in silico simulation study we also succeeded to show the benefit for the phylogenetic tree reconstruction by adding structure information to the ITS2 sequence. Next to the genus Paramacrobiotus we used the ITS2 to corroborate a monophyletic DO-group (Sphaeropleales) within the Chlorophyceae. Additionally we redesigned another comprehensive database—the ITS2 database resulting in a doubled number of sequence-structure pairs of the ITS2. In conclusion, this thesis shows the first insights (6 first author publications and 4 coauthor publications) into the reasons for the enormous adaption capabilities of tardigrades and offers a solution to the debate on the phylogenetic relatedness within the tardigrade genus Paramacrobiotus.}, subject = {Phylogenie}, language = {en} } @article{FoernzlerWittbrodtSchartl1991, author = {F{\"o}rnzler, Dorothee and Wittbrodt, Joachim and Schartl, M.anfred}, title = {Analysis of an esterase linked to a locus involved in the regulation of the melanoma oncogene and isolation of polymorphic marker sequences in Xiphophorus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61726}, year = {1991}, abstract = {Melanoma formation in Xiphophorus hybrids is mediated by a growth factor receptor tyrosine kinase oncogene encoded by the Tu locus. In the wild-type parental fish no tumors occur due to the activity of a locus that regulates the activity of the melanoma oncogene. Molecu/ar identification of this regulatory locus (R) requires a precise physical map of the chromosomal region. Therefore we studied esterase isozymes in Xiphophorus, two of which have been previously reported to be linked to locus R. We confinn that ES 1 is a distant marker for R ( approx. 30cM), and contrary to earlier studies, we show that this isozyme is present in all species of the genus and at similar activity Ievels in all organs tested. ES4, which has also been reported to be linked to R, was found to be a misclassification of liver ES1. In an attempt to identify markersthat bridge the large distance between ESl and R, we have generated DNA probes which are highly polymorphic. They will be useful in finding Iandmarks on a physical map of the R-containing chromosomal region.}, subject = {Physiologische Chemie}, language = {en} } @phdthesis{Foeger2000, author = {F{\"o}ger, Niko}, title = {Costimulatory function of CD44}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-1186}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2000}, abstract = {T cell activation is supposed to require two signals via engagement of the TCR and a costimulatory molecule. However, the signaling cascade of costimulatory molecules has remained elusive. Here, I provide evidence that CD44 supports proliferation as well as apoptosis mainly, if not exclusively, by enhancing signal transduction via the TCR/CD3 complex. Blockade of CD44 interferes with mounting of an immune response. This has been demonstrated by the significantly decreased IL-2 production of a T helper line, when stimulated in the presence of a competing CD44 receptor globulin. To evaluate the underlying mechanism, CD44 was cross-linked by an immobilized antibody (IM7). Cross-linking of CD44 induces proliferation of peripheral T cells and apoptosis of thymocytes and a T helper line in the presence of subthreshold levels of anti-CD3. CD44-induced proliferation was accompanied by an upregulation of the activation markers CD25 and CD69 and an increased cytokine production. TCR-mediated apoptosis was accompanied by an upregulation of CD95 ligand and CD95 receptor, which could be greatly enhanced by costimulation via CD44. On the level of signal transduction, coligation of CD44 with CD3 resulted in a strong and sustained increase of early tyrosine phosphorylation events and upregulated downstream signal transduction pathways, such as the ras/ERK and the JNK signaling cascades. These pleiotropic effects of CD44 are due to its involvement in the most proximal events in TCR signaling, as demonstrated by a strong increase in the phosphorylation of the TCR z-chain and ZAP-70. Notably, cross-linking of CD44 was binding-site dependent and was only effective when supporting colocalization of the TCR/CD3 complex and CD44. Cross-linking of CD44 via immobilized IM7 also induced profound changes in cell morphology, characterized by strong adhesion, spreading and development of surface extensions, which were dependent on a functional tubulin and actin cytoskeleton. These cytoskeletal rearrangements were mediated by rac1, a small GTPase of the rho subfamily, and src-family kinases, two of which, fyn and lck, were found to be associated with CD44. By cross-linkage of CD44 these kinases were redistributed into so called lipid rafts. It is supposed that for T cell activation a relocation of the TCR/CD3 complex into the same membrane microdomains is required. The data are interpreted in the sense that the costimulatory function of CD44 relies on its cooperativity with the TCR. Most likely by recruitment of phosphokinases CD44 significantly lowers the threshold for the initiation of signaling via the TCR. The requirement for immobilized anti-CD44, the necessity for neighbouring anti-CD3 and the dependence on the binding site of CD44 strongly suggest that the costimulatory mechanism involves cytoskeletal rearrangements, which facilitate recruitment and redirection of src-family protein kinases in glycolipid enriched membrane microdomains.}, subject = {Antigen CD44}, language = {en} } @article{FussOtherHeinzeetal.2021, author = {Fuss, Carmina Teresa and Other, Katharina and Heinze, Britta and Landwehr, Laura-Sophie and Wiegering, Armin and Kalogirou, Charis and Hahner, Stefanie and Fassnacht, Martin}, title = {Expression of the chemokine receptor CCR7 in the normal adrenal gland and adrenal tumors and its correlation with clinical outcome in adrenocortical carcinoma}, series = {Cancers}, volume = {13}, journal = {Cancers}, number = {22}, issn = {2072-6694}, doi = {10.3390/cancers13225693}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-250112}, year = {2021}, abstract = {Background: The chemokine receptor CCR7 is crucial for an intact immune function, but its expression is also associated with clinical outcome in several malignancies. No data exist on the expression of CCR7 in adrenocortical tumors. Methods: CCR7 expression was investigated by qRT-PCR and immunohistochemistry in 4 normal adrenal glands, 59 adrenocortical adenomas, and 181 adrenocortical carcinoma (ACC) samples. Results: CCR7 is highly expressed in the outer adrenocortical zones and medulla. Aldosterone-producing adenomas showed lower CCR7 protein levels (H-score 1.3 ± 1.0) compared to non-functioning (2.4 ± 0.5) and cortisol-producing adenomas (2.3 ± 0.6), whereas protein expression was variable in ACC (1.8 ± 0.8). In ACC, CCR7 protein expression was significantly higher in lymph node metastases (2.5 ± 0.5) compared to primary tumors (1.8±0.8) or distant metastases (2.0 ± 0.4; p < 0.01). mRNA levels of CCR7 were not significantly different between ACCs, normal adrenals, and adrenocortical adenomas. In contrast to other tumor entities, neither CCR7 protein nor mRNA expression significantly impacted patients' survival. Conclusion: We show that CCR7 is expressed on mRNA and protein level across normal adrenals, benign adrenocortical tumors, as well as ACCs. Given that CCR7 did not influence survival in ACC, it is probably not involved in tumor progression, but it could play a role in adrenocortical homeostasis.}, language = {en} } @article{FujiwaraHermannLuiblKatsuraetal.2018, author = {Fujiwara, Yuri and Hermann-Luibl, Christiane and Katsura, Maki and Sekiguchi, Manabu and Ida, Takanori and Helfrich-F{\"o}rster, Charlotte and Yoshii, Taishi}, title = {The CCHamide1 Neuropeptide Expressed in the Anterior Dorsal Neuron 1 Conveys a Circadian Signal to the Ventral Lateral Neurons in Drosophila melanogaster}, series = {Frontiers in Physiology}, volume = {09}, journal = {Frontiers in Physiology}, issn = {1664-042X}, doi = {10.3389/fphys.2018.01276}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-195940}, year = {2018}, abstract = {The fruit fly Drosophila melanogaster possesses approximately 150 brain clock neurons that control circadian behavioral rhythms. Even though individual clock neurons have self-sustaining oscillators, they interact and synchronize with each other through a network. However, little is known regarding the factors responsible for these network interactions. In this study, we investigated the role of CCHamide1 (CCHa1), a neuropeptide expressed in the anterior dorsal neuron 1 (DN1a), in intercellular communication of the clock neurons. We observed that CCHa1 connects the DN1a clock neurons to the ventral lateral clock neurons (LNv) via the CCHa1 receptor, which is a homolog of the gastrin-releasing peptide receptor playing a role in circadian intercellular communications in mammals. CCHa1 knockout or knockdown flies have a generally low activity level with a special reduction of morning activity. In addition, they exhibit advanced morning activity under light-dark cycles and delayed activity under constant dark conditions, which correlates with an advance/delay of PAR domain Protein 1 (PDP1) oscillations in the small-LNv (s-LNv) neurons that control morning activity. The terminals of the s-LNv neurons show rather high levels of Pigment-dispersing factor (PDF) in the evening, when PDF is low in control flies, suggesting that the knockdown of CCHa1 leads to increased PDF release; PDF signals the other clock neurons and evidently increases the amplitude of their PDP1 cycling. A previous study showed that high-amplitude PDP1 cycling increases the siesta of the flies, and indeed, CCHa1 knockout or knockdown flies exhibit a longer siesta than control flies. The DN1a neurons are known to be receptive to PDF signaling from the s-LNv neurons; thus, our results suggest that the DN1a and s-LNv clock neurons are reciprocally coupled via the neuropeptides CCHa1 and PDF, and this interaction fine-tunes the timing of activity and sleep.}, language = {en} } @phdthesis{Fuchs2017, author = {Fuchs, Benjamin Felix}, title = {Effects of timing and herbivory on a grass-endophyte association and its trophic interactions}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-141465}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {I.) Plant associated microorganisms can affect the plant`s interaction with herbivores and higher trophic levels. For instance, endophytic fungi infecting aerial plant parts of grass species produce bioactive alkaloids that can negatively affect species from higher trophic levels, indicating a defensive mutualism between the grass and the endophyte. However, beneficial insects can also be negatively affected by the endophyte, which might question the mutualistic effect of endophytic fungi. On the other hand, grass-endophytes are affected by environmental conditions and species interactions. Grazing can increase endophyte frequencies in natural habitats. Furthermore, endophyte mediated effects on herbivores are most pronounced during warm summers following rainy springs. In this study, we investigated whether endophyte derived alkaloids cascade up a food chain (chapter II) and whether their concentrations depend on plant age and season (chapter III). Further we analysed, whether altered herbivore phenology affects the endophytic fungus (chapter IV) and whether endophyte derived alkaloid production is induced by different herbivore species (chapter V). II.) In our first experimental study we analysed whether grass-endophyte derived alkaloids decreased the performance of two ladybird species feeding on aphids exclusively reared on endophyte infected grass (6 weeks young grass). Further, we screened species from three trophic levels (grass, herbivores and aphid predators) for their alkaloid content using two year old infected grass as diet for herbivores. We established an UPLC-MS method to detect and quantify the amount of the endophyte derived alkaloids peramine and lolitrem B extracted from the organic plant and insect material. Performance parameters of ladybirds revealed little differences between ladybirds fed on aphids reared on endophyte infected and non-infected grass, which probably resulted from low alkaloid concentrations in the young (6-weeks old) endophyte infected grass used in this part of the study. Alkaloid quantification of the two year old endophyte infected grass, herbivores and aphid predators revealed similar concentrations between grass and aphids, while aphid predators contained approximately half of that amount which still exceeded the bioactive threshold. We conclude that alkaloids produced by grass-endophytes cascade up the food chain and are responsible for fitness disadvantages of higher trophic levels. III.) In the second study we investigated the impact of plant age and seasonal timing on grass-endophyte growth and alkaloid production. Plants were sown in April of 2013 and sampled monthly over 30 consecutive months. Endophyte growth was quantified with real-time PCR (qPCR) and alkaloid concentrations with UPLC-MS. We showed that alkaloid concentrations and fungal growth followed a seasonal rhythmicity and that alkaloid concentrations increased with plant age. Alkaloid concentrations peak during summer, when also herbivore abundances are high. Consequently, we conclude that plant age and season contribute to the toxicity of endophytes on grass herbivores IV.) In the third study we simulated earlier spring arrival of aphids by enhancing aphid abundance on endophyte infected and endophyte-free grass in spring and analysed responses across three trophic levels. Enhanced aphid abundance in spring caused higher aphid abundances during the study period. Predators stayed unaffected by increased herbivore abundances; however they did level aphid numbers within two weeks after arrival on the plants, independent of aphid abundance. Grass-endophyte showed a time delayed growth, two weeks after aphid abundance peak and after predators already controlled aphid infestations on the plants. We conclude that phenology shifts of herbivorous insects can affect multi-trophic interactions leading to desynchronizations between phenologies of interacting species and mismatches in food-webs. V.) In the fourth study we analysed whether herbivores induce endophyte growth and alkaloid production and whether different types of herbivores induce specific alkaloid production. We applied three different herbivore treatments on endophyte infected grass over 18 weeks. Locust herbivory increased the insect deterring alkaloid peramine and clipping of plants (simulation of grazing livestock) increased the vertebrate toxic alkaloid lolitrem B. Aphid herbivory did not affect endophyte derived alkaloid concentrations. Endophyte responses to herbivory were species specific which indicates a primarily plant protecting role of alkaloid synthesis in endophyte infected plants and a close chemical crosstalk between interacting species. VI.) In summary, we showed that endophyte derived alkaloids affect higher trophic levels and that alkaloid concentrations in the plant depend on prevalent herbivore species, plant age and seasonal timing. Our results indicate a close chemical crosstalk between the host plant and the endophytic fungus which is susceptible to environmental changes altering the endophyte`s alkaloid production in plants. We gained insights into the grass-endophyte symbiosis in ecological contexts and conclude that several factors determine the herbivore toxic potential of endophytic fungi and thereby their plant mutualistic or parasitic character. Future studies should investigate the mechanisms behind the herbivore induced alkaloid concentration increase, shown in this thesis, especially whether plant signals mediate the endophyte response. Furthermore it would be interesting to study the induction of indirect endophyte mediated defence and how it affects multi-trophic level interactions.}, language = {en} } @phdthesis{Froese2008, author = {Froese, Alexander}, title = {The Popeye domain containing gene 2 (Popdc2): Generation and functional characterization of a null mutant in mice and promoter analysis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-26473}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2008}, abstract = {In the present study a knockout mouse model of the Popeye domain containing gene 2 (Popdc2) was generated and functionally characterized. The Popdc2 null mutants were viable with an apparent normal life span. ß-galactosidase staining to visualize the expression of the Popdc2-LacZ transgene revealed the presence of the Popdc2 in heart, bladder, smooth and skeletal muscles. In the heart LacZ was found to be present in cardiac myocytes with elevated levels in the myocytes of the cardiac conduction system. Holter ECGs records of the heart function of the 8 months (but not in 3 and 6 months) old mutant and WT littermates revealed a pronounced sinus bradycardia in the mutant mice in response to three different stress regimens: isoproterenol infusion, mental stress and a physical exercise. Histological examination of the Popdc2 null mutants SAN revealed structural alterations as was detected by HCN4 staining. Moreover, volume measurements using 3-D reconstructions of serial sections stained with HCN4 antibody revealed a volume reduction of about 30\% in the mutant SAN. Taken together data presented in this study suggest that the Popdc2 KO mouse line may serve as an animal model of human sick sinus syndrome. In the second part of this thesis the Popdc2 gene promoter was analyzed. Three transcription factors binding sites were predicted in the promoter region and characterized.}, subject = {Herz}, language = {en} } @article{FriedrichRahmannWeigeletal.2010, author = {Friedrich, Torben and Rahmann, Sven and Weigel, Wilfried and Rabsch, Wolfgang and Fruth, Angelika and Ron, Eliora and Gunzer, Florian and Dandekar, Thomas and Hacker, Joerg and Mueller, Tobias and Dobrindt, Ulrich}, title = {High-throughput microarray technology in diagnostics of enterobacteria based on genome-wide probe selection and regression analysis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67936}, year = {2010}, abstract = {The Enterobacteriaceae comprise a large number of clinically relevant species with several individual subspecies. Overlapping virulence-associated gene pools and the high overall genome plasticity often interferes with correct enterobacterial strain typing and risk assessment. Array technology offers a fast, reproducible and standardisable means for bacterial typing and thus provides many advantages for bacterial diagnostics, risk assessment and surveillance. The development of highly discriminative broad-range microbial diagnostic microarrays remains a challenge, because of marked genome plasticity of many bacterial pathogens. Results: We developed a DNA microarray for strain typing and detection of major antimicrobial resistance genes of clinically relevant enterobacteria. For this purpose, we applied a global genome-wide probe selection strategy on 32 available complete enterobacterial genomes combined with a regression model for pathogen classification. The discriminative power of the probe set was further tested in silico on 15 additional complete enterobacterial genome sequences. DNA microarrays based on the selected probes were used to type 92 clinical enterobacterial isolates. Phenotypic tests confirmed the array-based typing results and corroborate that the selected probes allowed correct typing and prediction of major antibiotic resistances of clinically relevant Enterobacteriaceae, including the subspecies level, e.g. the reliable distinction of different E. coli pathotypes. Conclusions: Our results demonstrate that the global probe selection approach based on longest common factor statistics as well as the design of a DNA microarray with a restricted set of discriminative probes enables robust discrimination of different enterobacterial variants and represents a proof of concept that can be adopted for diagnostics of a wide range of microbial pathogens. Our approach circumvents misclassifications arising from the application of virulence markers, which are highly affected by horizontal gene transfer. Moreover, a broad range of pathogens have been covered by an efficient probe set size enabling the design of high-throughput diagnostics.}, subject = {Mikroarray}, language = {en} } @phdthesis{Friedrich2009, author = {Friedrich, Torben}, title = {New statistical Methods of Genome-Scale Data Analysis in Life Science - Applications to enterobacterial Diagnostics, Meta-Analysis of Arabidopsis thaliana Gene Expression and functional Sequence Annotation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39858}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {Recent progresses and developments in molecular biology provide a wealth of new but insufficiently characterised data. This fund comprises amongst others biological data of genomic DNA, protein sequences, 3-dimensional protein structures as well as profiles of gene expression. In the present work, this information is used to develop new methods for the characterisation and classification of organisms and whole groups of organisms as well as to enhance the automated gain and transfer of information. The first two presented approaches (chapters 4 und 5) focus on the medically and scientifically important enterobacteria. Its impact in medicine and molecular biology is founded in versatile mechanisms of infection, their fundamental function as a commensal inhabitant of the intestinal tract and their use as model organisms as they are easy to cultivate. Despite many studies on single pathogroups with clinical distinguishable pathologies, the genotypic factors that contribute to their diversity are still partially unknown. The comprehensive genome comparison described in Chapter 4 was conducted with numerous enterobacterial strains, which cover nearly the whole range of clinically relevant diversity. The genome comparison constitutes the basis of a characterisation of the enterobacterial gene pool, of a reconstruction of evolutionary processes and of comprehensive analysis of specific protein families in enterobacterial subgroups. Correspondence analysis, which is applied for the first time in this context, yields qualitative statements to bacterial subgroups and the respective, exclusively present protein families. Specific protein families were identified for the three major subgroups of enterobacteria namely the genera Yersinia and Salmonella as well as to the group of Shigella and E. coli by applying statistical tests. In conclusion, the genome comparison-based methods provide new starting points to infer specific genotypic traits of bacterial groups from the transfer of functional annotation. Due to the high medical importance of enterobacterial isolates their classification according to pathogenicity has been in focus of many studies. The microarray technology offers a fast, reproducible and standardisable means of bacterial typing and has been proved in bacterial diagnostics, risk assessment and surveillance. The design of the diagnostic microarray of enterobacteria described in chapter 5 is based on the availability of numerous enterobacterial genome sequences. A novel probe selection strategy based on the highly efficient algorithm of string search, which considers both coding and non-coding regions of genomic DNA, enhances pathogroup detection. This principle reduces the risk of incorrect typing due to restrictions to virulence-associated capture probes. Additional capture probes extend the spectrum of applications of the microarray to simultaneous diagnostic or surveillance of antimicrobial resistance. Comprehensive test hybridisations largely confirm the reliability of the selected capture probes and its ability to robustly classify enterobacterial strains according to pathogenicity. Moreover, the tests constitute the basis of the training of a regression model for the classification of pathogroups and hybridised amounts of DNA. The regression model features a continuous learning capacity leading to an enhancement of the prediction accuracy in the process of its application. A fraction of the capture probes represents intergenic DNA and hence confirms the relevance of the underlying strategy. Interestingly, a large part of the capture probes represents poorly annotated genes suggesting the existence of yet unconsidered factors with importance to the formation of respective virulence phenotypes. Another major field of microarray applications is gene expression analysis. The size of gene expression databases rapidly increased in recent years. Although they provide a wealth of expression data, it remains challenging to integrate results from different studies. In chapter 6 the methodology of an unsupervised meta-analysis of genome-wide A. thaliana gene expression data sets is presented, which yields novel insights in function and regulation of genes. The application of kernel-based principal component analysis in combination with hierarchical clustering identified three major groups of contrasts each sharing overlapping expression profiles. Genes associated with two groups are known to play important roles in Indol-3 acetic acid (IAA) mediated plant growth and development as well as in pathogen defence. Yet uncharacterised serine-threonine kinases could be assigned to novel functions in pathogen defence by meta-analysis. In general, hidden interrelation between genes regulated under different conditions could be unravelled by the described approach. HMMs are applied to the functional characterisation of proteins or the detection of genes in genome sequences. Although HMMs are technically mature and widely applied in computational biology, I demonstrate the methodical optimisation with respect to the modelling accuracy on biological data with various distributions of sequence lengths. The subunits of these models, the states, are associated with a certain holding time being the link to length distributions of represented sequences. An adaptation of simple HMM topologies to bell-shaped length distributions described in chapter 7 was achieved by serial chain-linking of single states, while residing in the class of conventional HMMs. The impact of an optimisation of HMM topologies was underlined by performance evaluations with differently adjusted HMM topologies. In summary, a general methodology was introduced to improve the modelling behaviour of HMMs by topological optimisation with maximum likelihood and a fast and easily implementable moment estimator. Chapter 8 describes the application of HMMs to the prediction of interaction sites in protein domains. As previously demonstrated, these sites are not trivial to predict because of varying degree in conservation of their location and type within the domain family. The prediction of interaction sites in protein domains is achieved by a newly defined HMM topology, which incorporates both sequence and structure information. Posterior decoding is applied to the prediction of interaction sites providing additional information of the probability of an interaction for all sequence positions. The implementation of interaction profile HMMs (ipHMMs) is based on the well established profile HMMs and inherits its known efficiency and sensitivity. The large-scale prediction of interaction sites by ipHMMs explained protein dysfunctions caused by mutations that are associated to inheritable diseases like different types of cancer or muscular dystrophy. As already demonstrated by profile HMMs, the ipHMMs are suitable for large-scale applications. Overall, the HMM-based method enhances the prediction quality of interaction sites and improves the understanding of the molecular background of inheritable diseases. With respect to current and future requirements I provide large-scale solutions for the characterisation of biological data in this work. All described methods feature a highly portable character, which allows for the transfer to related topics or organisms, respectively. Special emphasis was put on the knowledge transfer facilitated by a steadily increasing wealth of biological information. The applied and developed statistical methods largely provide learning capacities and hence benefit from the gain of knowledge resulting in increased prediction accuracies and reliability.}, subject = {Genomik}, language = {en} } @article{FriedenreichSchartl1990, author = {Friedenreich, Hildegard and Schartl, Manfred}, title = {Transient expression directed by homologous and heterologous promoter and enhancer sequences in fish cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61774}, year = {1990}, abstract = {ln order to construct fish specific expression vectors for studies on gene regulation in vitro and in vivo a variety of heterologous enhancers and promoters from mammals and from viruses of higher vertebrate cells were tested for expression of the bacterial chloramphenicol acetyl transferase reporter gene in three teleost fish cell lines. Several viral enhancers were found to be constitutively active at high Ieveis. The human metallothionein promoter showed inducible expression in the presence of heavy metal Ions. A fish sequence was isolated that can be used as a homologous constitutively active promoter for expression of foreign genes. Using the human growth hormone gene with an active promoter in fish cells for transient expression insufficient splicing and Iack of translation were observed, pointing to limitations in the use of heterologous genes in gene transfer experiments. On the contrary, some heterologous promoters and enhancers functioned in fish c as weil as in their cell type of origin, indicating t at corresponding transcription factors are sufficient conserved between fish and human over a period of 900 million years of Independent evolution.}, subject = {Physiologische Chemie}, language = {en} } @article{FrickeSteffanDewenterZhangetal.2022, author = {Fricke, Ute and Steffan-Dewenter, Ingolf and Zhang, Jie and Tobisch, Cynthia and Rojas-Botero, Sandra and Benjamin, Caryl S. and Englmeier, Jana and Ganuza, Cristina and Haensel, Maria and Riebl, Rebekka and Uhler, Johannes and Uphus, Lars and Ewald, J{\"o}rg and Kollmann, Johannes and Redlich, Sarah}, title = {Landscape diversity and local temperature, but not climate, affect arthropod predation among habitat types}, series = {PLoS ONE}, volume = {17}, journal = {PLoS ONE}, number = {4}, doi = {10.1371/journal.pone.0264881}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301292}, year = {2022}, abstract = {Arthropod predators are important for ecosystem functioning by providing top-down regulation of insect herbivores. As predator communities and activity are influenced by biotic and abiotic factors on different spatial scales, the strength of top-down regulation ('arthropod predation') is also likely to vary. Understanding the combined effects of potential drivers on arthropod predation is urgently needed with regard to anthropogenic climate and land-use change. In a large-scale study, we recorded arthropod predation rates using artificial caterpillars on 113 plots of open herbaceous vegetation embedded in contrasting habitat types (forest, grassland, arable field, settlement) along climate and land-use gradients in Bavaria, Germany. As potential drivers we included habitat characteristics (habitat type, plant species richness, local mean temperature and mean relative humidity during artificial caterpillar exposure), landscape diversity (0.5-3.0-km, six scales), climate (multi-annual mean temperature, 'MAT') and interactive effects of habitat type with other drivers. We observed no substantial differences in arthropod predation rates between the studied habitat types, related to plant species richness and across the Bavarian-wide climatic gradient, but predation was limited when local mean temperatures were low and tended to decrease towards higher relative humidity. Arthropod predation rates increased towards more diverse landscapes at a 2-km scale. Interactive effects of habitat type with local weather conditions, plant species richness, landscape diversity and MAT were not observed. We conclude that landscape diversity favours high arthropod predation rates in open herbaceous vegetation independent of the dominant habitat in the vicinity. This finding may be harnessed to improve top-down control of herbivores, e.g. agricultural pests, but further research is needed for more specific recommendations on landscape management. The absence of MAT effects suggests that high predation rates may occur independent of moderate increases of MAT in the near future.}, language = {en} } @article{FrickeRedlichZhangetal.2022, author = {Fricke, Ute and Redlich, Sarah and Zhang, Jie and Tobisch, Cynthia and Rojas-Botero, Sandra and Benjamin, Caryl S. and Englmeier, Jana and Ganuza, Cristina and Riebl, Rebekka and Uhler, Johannes and Uphus, Lars and Ewald, J{\"o}rg and Kollmann, Johannes and Steffan-Dewenter, Ingolf}, title = {Plant richness, land use and temperature differently shape invertebrate leaf-chewing herbivory on plant functional groups}, series = {Oecologia}, volume = {199}, journal = {Oecologia}, number = {2}, doi = {10.1007/s00442-022-05199-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325079}, pages = {407-417}, year = {2022}, abstract = {Higher temperatures can increase metabolic rates and carbon demands of invertebrate herbivores, which may shift leaf-chewing herbivory among plant functional groups differing in C:N (carbon:nitrogen) ratios. Biotic factors influencing herbivore species richness may modulate these temperature effects. Yet, systematic studies comparing leaf-chewing herbivory among plant functional groups in different habitats and landscapes along temperature gradients are lacking. This study was conducted on 80 plots covering large gradients of temperature, plant richness and land use in Bavaria, Germany. We investigated proportional leaf area loss by chewing invertebrates ('herbivory') in three plant functional groups on open herbaceous vegetation. As potential drivers, we considered local mean temperature (range 8.4-18.8 °C), multi-annual mean temperature (range 6.5-10.0 °C), local plant richness (species and family level, ranges 10-51 species, 5-25 families), adjacent habitat type (forest, grassland, arable field, settlement), proportion of grassland and landscape diversity (0.2-3 km scale). We observed differential responses of leaf-chewing herbivory among plant functional groups in response to plant richness (family level only) and habitat type, but not to grassland proportion, landscape diversity and temperature—except for multi-annual mean temperature influencing herbivory on grassland plots. Three-way interactions of plant functional group, temperature and predictors of plant richness or land use did not substantially impact herbivory. We conclude that abiotic and biotic factors can assert different effects on leaf-chewing herbivory among plant functional groups. At present, effects of plant richness and habitat type outweigh effects of temperature and landscape-scale land use on herbivory among legumes, forbs and grasses.}, language = {en} } @article{FrickeRedlichZhangetal.2023, author = {Fricke, Ute and Redlich, Sarah and Zhang, Jie and Benjamin, Caryl S. and Englmeier, Jana and Ganuza, Cristina and Haensel, Maria and Riebl, Rebekka and Rojas-Botero, Sandra and Tobisch, Cynthia and Uhler, Johannes and Uphus, Lars and Steffan-Dewenter, Ingolf}, title = {Earlier flowering of winter oilseed rape compensates for higher pest pressure in warmer climates}, series = {Journal of Applied Ecology}, volume = {60}, journal = {Journal of Applied Ecology}, number = {2}, doi = {10.1111/1365-2664.14335}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312562}, pages = {365 -- 375}, year = {2023}, abstract = {Global warming can increase insect pest pressure by enhancing reproductive rates. Whether this translates into yield losses depends on phenological synchronisation of pests with their host plants and natural enemies. Simultaneously, landscape composition may mitigate climate effects by shaping the resource availability for pests and their antagonists. Here, we study the combined effects of temperature and landscape composition on pest abundances, larval parasitism, crop damage and yield, while also considering crop phenology, to identify strategies for sustainable management of oilseed rape (OSR) pests under warming climates. In all, 29 winter OSR crop fields were investigated in different climates (defined by multi-annual mean temperature, MAT) and landscape contexts in Bavaria, Germany. We measured abundances of adult pollen beetles and stem weevil larvae, pollen beetle larval parasitism, bud loss, stem damage and seed yield, and calculated the flowering date from growth stage observations. Landscape parameters (proportion of non-crop and OSR area, change in OSR area relative to the previous year) were calculated at six spatial scales (0.6-5 km). Pollen beetle abundance increased with MAT but to different degrees depending on the landscape context, that is, increased less strongly when OSR proportions were high (1-km scale), interannually constant (5-km scale) or both. In contrast, stem weevil abundance and stem damage did not respond to landscape composition nor MAT. Pollen beetle larval parasitism was overall low, but occasionally exceeded 30\% under both low and high MAT and with reduced OSR area (0.6-km scale). Despite high pollen beetle abundance in warm climates, yields were high when OSR flowered early. Thereby, higher temperatures favoured early flowering. Only among late-flowering OSR crop fields yield was higher in cooler than warmer climates. Bud loss responded analogously. Landscape composition did not substantially affect bud loss and yield. Synthesis and applications: Earlier flowering of winter OSR compensates for higher pollen beetle abundance in warmer climates, while interannual continuity of OSR area prevents high pollen beetle abundance in the first place. Thus, regional coordination of crop rotation and crop management promoting early flowering may contribute to sustainable pest management in OSR under current and future climatic conditions.}, language = {en} } @phdthesis{Fricke2022, author = {Fricke, Ute}, title = {Herbivory, predation and pest control in the context of climate and land use}, doi = {10.25972/OPUS-28732}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287328}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Chapter 1 - General introduction Anthropogenic land-use and climate change are the major drivers of the global biodiversity loss. Yet, biodiversity is essential for human well-being, as we depend on the availability of potable water, sufficient food and further benefits obtained from nature. Each species makes a somewhat unique contribution to these ecosystem services. Furthermore, species tolerate environmental stressors, such as climate change, differently. Thus, biodiversity is both the "engine" and the "insurance" for human well-being in a changing climate. Here, I investigate the effects of temperature and land use on herbivory (Chapter 2), predation (Chapter 3) and pest control (Chapter 4), and at the same time identify features of habitats (e.g. plant richness, proximity to different habitat types) and landscapes (e.g. landscape diversity, proportion of oilseed rape area) as potential management targets in an adaptation strategy to climate change. Finally, I discuss the similarities and differences between factors influencing herbivory, predation and pest control, while placing the observations in the context of climate change as a multifaceted phenomenon, and highlighting starting points for sustainable insect pest management (Chapter 5). Chapter 2 - Plant richness, land use and temperature differently shape invertebrate leaf-chewing herbivory on major plant functional groups Invertebrate herbivores are temperature-sensitive. Rising temperatures increase their metabolic rates and thus their demand for carbon-rich relative to protein-rich resources, which can lead to changes in the diets of generalist herbivores. Here, we quantified leaf-area loss to chewing invertebrates among three plant functional groups (legumes, non-leguminous forbs and grasses), which largely differ in C:N (carbon:nitrogen) ratio. This reseach was conducted along spatial temperature and land-use gradients in open herbaceous vegetation adjacent to different habitat types (forest, grassland, arable field, settlement). Herbivory largely differed among plant functional groups and was higher on legumes than forbs and grasses, except in open areas in forests. There, herbivory was similar among plant functional groups and on legumes lower than in grasslands. Also the presence of many plant families lowered herbivory on legumes. This suggests that open areas in forests and diverse vegetation provide certain protection against leaf damage to some plant families (e.g. legumes). This could be used as part of a conservation strategy for protected species. Overall, the effects of the dominant habitat type in the vicinity and diverse vegetation outweighed those of temperature and large-scale land use (e.g. grassland proportion, landscape diversity) on herbivory of legumes, forbs and grasses at the present time. Chapter 3 - Landscape diversity and local temperature, but not climate, affect arthropod predation among habitat types Herbivorous insects underlie top-down regulation by arthropod predators. Thereby, predation rates depend on predator community composition and behaviour, which is shaped by temperature, plant richness and land use. How the interaction of these factors affects the regulatory performance of predators was unknown. Therefore, we assessed arthropod predation rates on artificial caterpillars along temperature, and land-use gradients. On plots with low local mean temperature (≤ 7°C) often not a single caterpillar was attacked, which may be due to the temperature-dependent inactivity of arthropods. However, multi-annual mean temperature, plant richness and the dominant habitat type in the vicinity did not substantially affect arthropod predation rates. Highest arthropod predation rates were observed in diverse landscapes (2-km scale) independently of the locally dominanting habitat type. As landscape diversity, but not multi-annual mean temperature, affected arthropod predation rates, the diversification of landscapes may also support top-down regulation of herbivores independent of moderate increases of multi-annual mean temperature in the near future. Chapter 4 - Pest control and yield of winter oilseed rape depend on spatiotemporal crop-cover dynamics and flowering onset: implications for global warming Winter oilseed rape is an important oilseed crop in Europe, yet its seed yield is diminished through pests such as the pollen beetle and stem weevils. Damage from pollen beetles depends on pest abundances, but also on the timing of infestation relative to crop development as the bud stage is particularly vulnerable. The development of both oilseed rape and pollen beetles is temperature-dependent, while temperature effects on pest abundances are yet unknown, which brings opportunities and dangers to oilseed rape cropping under increased temperatures. We obtained measures of winter oilseed rape (flowering time, seed yield) and two of its major pests (pollen beetle, stem weevils) for the first time along both land-use and temperature gradients. Infestation with stem weevils was not influenced by any temperature or land-use aspect considered, and natural pest regulation of pollen beetles in terms of parasitism rates of pollen beetle larvae was low (< 30\%), except on three out of 29 plots. Nonetheless, we could identify conditions favouring low pollen beetle abundances per plant and high seed yields. Low pollen beetle densities were favoured by a constant oilseed rape area relative to the preceding year (5-km scale), whereas a strong reduction in area (> 40\%) caused high pest densities (concentration effect). This occurred more frequently in warmer regions, due to drought around sowing, which contributed to increased pollen beetle numbers in those regions. Yet, in warmer regions, oilseed rape flowered early, which possibly led to partial escape from pollen beetle infestation in the most vulnerable bud stage. This is also suggested by higher seed yields of early flowering oilseed rape fields, but not per se at higher temperatures. Thus, early flowering (e.g. cultivar selection) and the interannual coordination of oilseed rape area offer opportunities for environmental-friendly pollen beetle management. Chapter 5 - General discussion Anthropogenic land-use and climate change are major threats to biodiversity, and consequently to ecosystem functions, although I could show that ecosystem functions such as herbivory and predation barely responded to temperature along a spatial gradient at present time. Yet, it is important to keep several points in mind: (i) The high rate of climate warming likely reduces the time that species will have to adapt to temperature in the future; (ii) Beyond mean temperatures, many aspects of climate will change; (iii) The compensation of biodiversity loss through functional redundancy in arthropod communities may be depleted at some point; (iv) Measures of ecosystem functions are limited by methodological filters, so that changes may be captured incompletely. Although much uncertainty of the effects of climate and land-use change on ecosystem functions remains, actions to halt biodiversity loss and to interfere with natural processes in an environmentally friendly way, e.g. reduction of herbivory on crops, are urgently needed. With this thesis, I contribute options to the environment-friendly regulation of herbivory, which are at least to some extent climate resilient, and at the same time make a contribution to halt biodiversity loss. Yet, more research and a transformation process is needed to make human action more sustainable. In terms of crop protection, this means that the most common method of treating pests with fast-acting pesticides is not necessarily the most sustainable. To realize sustainable strategies, collective efforts will be needed targeted at crop damage prevention through reducing pest populations and densities in the medium to long term. The sooner we transform human action from environmentally damaging to biodiversity promoting, the higher is our insurance asset that secures human well-being under a changing climate.}, subject = {{\"O}kologie}, language = {en} } @article{FraunholzSinha2012, author = {Fraunholz, Martin and Sinha, Bhanu}, title = {Intracellular staphylococcus aureus: Live-in and let die}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {2}, journal = {Frontiers in Cellular and Infection Microbiology}, number = {43}, doi = {10.3389/fcimb.2012.00043}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123374}, year = {2012}, abstract = {Staphylococcus aureus uses a plethora of virulence factors to accommodate a diversity of niches in its human host. Aside from the classical manifestations of S. aureus-induced diseases, the pathogen also invades and survives within mammalian host cells. The survival strategies of the pathogen are as diverse as strains or host cell types used. S. aureus is able to replicate in the phagosome or freely in the cytoplasm of its host cells. It escapes the phagosome of professional and non-professional phagocytes, subverts autophagy, induces cell death mechanisms such as apoptosis and pyronecrosis, and even can induce anti-apoptotic programs in phagocytes. The focus of this review is to present a guide to recent research outlining the variety of intracellular fates of S. aureus.}, language = {en} } @phdthesis{Fraune2014, author = {Fraune, Johanna}, title = {The evolutionary history of the mammalian synaptonemal complex}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-100043}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2014}, abstract = {Der Synaptonemalkomplex (SC) ist eine hochkonservierte Proteinstruktur. Er weist eine dreiteili-ge, leiter{\"a}hnliche Organisation auf und ist f{\"u}r die stabile Paarung der homologen Chromosomen w{\"a}hrend der Prophase der ersten meiotischen Teilung verantwortlich, die auch als Synpase be-zeichnet wird. Fehler w{\"a}hrend der Synpase f{\"u}hren zu Aneuploidie oder Apoptose der sich entwi-ckelnden Keimzellen. Seit 1956 ist der SC Gegenstand intensiver Forschung. Seine Existenz wurde in zahlreichen Orga-nismen von der Hefe bis zum Menschen beschrieben. Seine Struktur aus zwei parallel verlaufen-den Lateralelementen (LE), die durch eine Vielzahl von sogenannten Transversalfilamenten (TF) verbunden werden und dem Zentralen Element (CE) in der Mitte des SC ist dabei offensichtlich {\"u}ber die Millionen von Jahren der Evolution erhalten geblieben. Einzelne Proteinkomponenten des SC wurden jedoch nur in wenigen Modelorganismen charakterisiert, darunter Saccharomyces cerevisiae, Arabidopsis thaliana, Drosophila melanogaster, Ceanorhabditis elegans und Mus mus-culus. Unerwarteter Weise gelang es bei dieser Charakterisierung nicht, eine evolution{\"a}re Ver-wandtschaft, d.h. eine Homologie zwischen den Proteinsequenzen der verschiedenen SCs nach-zuweisen. Diese Tatsache sprach gegen die grunds{\"a}tzliche Annahme, dass der SC in der Evolution nur einmal entstanden sei. Diese Arbeit hat sich nun der Aufgabe gewidmet, die Diskrepanz zwischen der hochkonservierten Struktur des SC und seiner augenscheinlich nicht-homologen Proteinzusammensetzung zu l{\"o}sen. Dabei beschr{\"a}nkt sie sich auf die Analyse des Tierreichs. Es ist die erste Studie zur Evolution des SC in Metazoa und demonstriert die Monophylie der S{\"a}uger SC Proteinkomponenten im Tierreich. Die Arbeit zeigt, dass mindestens vier von sieben SC Proteinen der Maus sp{\"a}testens im letzten gemeinsamen Vorfahren der Gewebetiere (Eumetazoa) enstanden sind und auch damals Teil ei-nes urspr{\"u}nglichen SC waren, wie er heute in dem Nesseltier Hydra zu finden ist. Dieser SC weist die typische Struktur auf und besitzt bereits alle notwendigen Komponenten, um die drei Dom{\"a}-nen - LE, TF und CE - zu assemblieren. Dar{\"u}ber hinaus ergaben die einzelnen Phylogenien der verschiedenen SC Proteine der Maus, dass der SC eine sehr dynamische Evolutionsgeschichte durchlaufen hat. Zus{\"a}tzliche Proteine wurden w{\"a}hrend der Entstehung der Bilateria und der Wir-beltiere in den SC integriert, w{\"a}hrend andere urspr{\"u}ngliche Komponenten m{\"o}glicherweise Gen-Duplikationen erfuhren bzw. besonders in der Linie der H{\"a}utungstiere verloren gingen oder sich stark ver{\"a}nderten. Es wird die These aufgestellt, dass die auf den ersten Blick nicht-homologen SC Proteine der Fruchtfliege und des Fadenwurms tats{\"a}chlich doch von den urspr{\"u}nglichen Prote-inenkomponenten abstammen, sich aber aufgrund der rasanten Evolution der Arthropoden und der Nematoden bis zu deren Unkenntlichkeit diversifizierten. Zus{\"a}tzlich stellt die Arbeit Hydra als alternatives wirbelloses Modellsystem f{\"u}r die Meiose- und SC-Forschung zu den {\"u}blichen Modellen D. melanogaster und C. elegans vor. Die k{\"u}rzlich gewon-nenen Erkenntnisse {\"u}ber den Hydra SC sowie der Einsatz der Standard-Methoden in diesem Orga-nismus werden in dem abschließenden Kapitel zusammengefasst und diskutiert.}, subject = {Synaptinemal-Komplex}, language = {en} } @phdthesis{Franzke2023, author = {Franzke, Myriam}, title = {Keep on track : The use of visual cues for orientation in monarch butterflies}, doi = {10.25972/OPUS-28470}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-284709}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {The monarch butterfly (Danaus plexippus) performs one of the most astonishing behaviors in the animal kingdom: every fall millions of these butterflies leave their breeding grounds in North Amerika and migrate more than 4.000 km southwards until they reach their overwintering habitat in Central Mexico. To maintain their migratory direction over this enormous distance, the butterflies use a time-compensated sun compass. Beside this, skylight polarization, the Earth's magnetic field and specific mountain ranges seem to guide the butterflies as well the south. In contrast to this fascinating orientation ability, the behavior of the butterflies in their non-migratory state received less attention. Although they do not travel long distances, they still need to orient themselves to find food, mating partners or get away from competitors. The aim of the present doctoral thesis was to investigate use of visual cues for orientation in migrating as well as non-migrating monarch butterflies. For this, field experiments investigating the migration of the butterflies in Texas (USA) were combined with experiments testing the orientation performance of non-migratory butterflies in Germany. In the first project, I recorded the heading directions of tethered butterflies during their annual fall migration. In an outdoor flight simulator, the butterflies maintained a southwards direction as long as they had a view of the sun's position. Relocating the position of the sun by 180° using a mirror, revealed that the sun is the animals' main orientation reference. Furthermore, I demonstrated that when the sun is blocked and a green light stimulus (simulated sun) is introduced, the animals interpreted this stimulus as the 'real' sun. However, this cue was not sufficient to set the migratory direction when simulated as the only visual cue in indoor experiments. When I presented the butterflies a linear polarization pattern additionally to the simulated sun, the animals headed in the correct southerly direction showing that multiple skylight cues are required to guide the butterflies during their migration. In the second project, I, furthermore, demonstrated that non-migrating butterflies are able to maintain a constant direction with respect to a simulated sun. Interestingly, they ignored the spectral component of the stimulus and relied on the intensity instead. When a panoramic skyline was presented as the only orientation reference, the butterflies maintained their direction only for short time windows probably trying to stabilize their flight based on optic-flow information. Next, I investigated whether the butterflies combine celestial with local cues by simulating a sun stimulus together with a panoramic skyline. Under this conditions, the animals' directedness was increased demonstrating that they combine multiple visual cues for spatial orientation. Following up on the observation that a sun stimulus resulted in a different behavior than the panoramic skyline, I investigated in my third project which orientation strategies the butterflies use by presenting different simulated cues to them. While a bright stripe on a dark background elicited a strong attraction of the butterflies steering in the direction of the stimulus, the inverted version of the stimulus was used for flight stabilization. In contrast to this, the butterflies maintained arbitrary directions with a high directedness with respect to a simulated sun. In an ambiguous scenery with two identical stimuli (two bright stripes, two dark stripes, or two sun stimuli) set 180° apart, a constant flight course was only achieved when two sun stimuli were displayed suggesting an involvement of the animals' internal compass. In contrast, the butterflies used two dark stripes for flight stabilization and were alternatingly attracted by two bright stripes. This shows that monarch butterflies use stimulus-dependent orientation strategies and gives the first evidence for different neuronal pathways controlling the output behavior.}, subject = {Monarchfalter}, language = {en} } @inproceedings{FrankeZentgrafScheer1978, author = {Franke, Werner W. and Zentgraf, Hanswalter and Scheer, Ulrich}, title = {Supranucleosomal and non-nucleosomal chromatin configurations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39447}, year = {1978}, abstract = {A significant contribution to the understanding of chromatin organization was the d iscovery of the nucleosome as a globular repeating unit of the package of DNA (Hewish and Burgoyne, 1973; Woodcock, 1973; Kornberg, 1974; Olins and Olins, 1974; for review see Oudet et al., 1978 a) . In accord with the original definition and in ag reement with most workers in this field of research we identify a nucleosome as a spheric alor slightly oblate gr anular particle 10-13 nm in diameter, containing about 200 base pairs of DNA and two of each of the four his tones H2a, H2b, H3 and H4. It is this structure in which the bulk of the nuclear chroma tin is organized in most eukaryotic cells, with the exception of the dinofl age llates (Rae and Steele, 1977; dinofl agellate DNA, however, c an be packed into nucleosoma l structures in vitro by addition of the appropriate amounts of histones;the same reference). Although it seems clear from the work reported that condensed and transcriptiona lly inactive chroma tin is contained in nucleosomes as the principle for first order p acking of DNA there are two important questions onto which we are focusing in the present study: ( i ) What is the higher order of p a cking present in - and perhaps typical-of - the condensed sta te of chromatin, and (ii) what is the specific form of arrangement of transcriptionally a ctive chromatin?}, language = {en} }