@incollection{ScheerZentgraf1982, author = {Scheer, Ulrich and Zentgraf, Hanswalter}, title = {Morphology of nucleolar chromatin in electron microscopic spread preparations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41155}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1982}, abstract = {No abstract available}, language = {en} } @article{FrankeScheer1978, author = {Franke, Werner W. and Scheer, Ulrich}, title = {Morphology of transcriptional units at different states of activity}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41363}, year = {1978}, abstract = {The morphology of two forms of transcription ally active chromatin, the nucleoli and the loops of lampbrush chromosomes, has been examined after fixation in situ or after isolation and dispersion of the material in media of low ionic strengths, using a variety of electron microscopic preparation techniques (e.g. spread preparations with positive or negative staining or without any staining at all, with bright and dark field illumination, with autoradiography, after pretreatment of the chromatin with specific detergents such as Sarkosyl NL-30; transmission and scanning transmission electron microscopy of ultrathin sections). Nucleolar chromatin and chromosomes from oocytes of various amphibia and insects as well as from green algae of the family of the Dasycladaceae were studied in particular detail. The morphology of transcriptional units that are densely packed with lateral ribonucleoprotein fibrils, indicative of great transcriptional activity, was compared with that of chromatin of reduced lateral fibril density, including stages of drug-induced inhibition. The micrographs showed that under conditions which preserve the nucleosomal organization in condensed chromatin studied in parallel, nucleosomes are not recognized in transcriptionally active chromatin. This holds for the transcribed regions as well as for apparently untranscribed (i.e. fibril-free) regions interspersed between ('spacer') and/or adjacent to transcribed genes and for the fibril-free regions within transcriptional units of reduced fibril density. In addition, comparison oflengths of repeating units of isolated rDNA with those observed in spread nucleolar chromatin indicated that this DNA is not foreshortened and packed into nucleosomal structures. Granular particles which were observed, at irregular frequencies and in variable patterns, in some spacer regions, did not result in a proportional shortening of the spacer axis, and were found to be resistant to detergent treatment effective in removing most of the chromatin associated proteins including histones. Thus, these particles behave like RNA polymerases rather than nucleosomes. It is suggested that structural changes from nucleosomal packing to an extended form of DNA are involved in the transcriptional activation of chromatin.}, language = {en} } @article{Linsenmair1961, author = {Linsenmair, Karl Eduard}, title = {Gefangenschafts-Bruterfahrungen mit Rotkehlchen, Schwarzkelchen und Sommergoldh{\"a}hnchen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44675}, year = {1961}, abstract = {No abstract available}, language = {de} } @article{PoethkeHovestadtMitesser2003, author = {Poethke, Hans-Joachim and Hovestadt, Thomas and Mitesser, Oliver}, title = {Local extinction and the evolution of dispersal rates: Causes and correlations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47718}, year = {2003}, abstract = {We present the results of individual-based simulation experiments on the evolution of dispersal rates of organisms living in metapopulations. We find conflicting results regarding the relationship between local extinction rate and evolutionarily stable (ES) dispersal rate depending on which principal mechanism causes extinction: if extinction is caused by environmental catastrophes eradicating local populations, we observe a positive correlation between extinction and ES dispersal rate; if extinction is a consequence of stochastic local dynamics and environmental fluctuations, the correlation becomes ambiguous; and in cases where extinction is caused by dispersal mortality, a negative correlation between local extinction rate and ES dispersal rate emerges. We conclude that extinction rate, which both affects and is affected by dispersal rates, is not an ideal predictor for optimal dispersal rates.}, subject = {Ausbreitung}, language = {en} } @article{Scheer1982, author = {Scheer, Ulrich}, title = {A novel type of chromatin organization in lampbrush chromosomes of Pleurodeles waltlii: visualization of clusters of tandemly repeated, very short transcriptional units}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41087}, year = {1982}, abstract = {A novel chromatin configuration is described in lampbrush chromosomes of Pleurodeles waltlii oocytes which is different from transcriptionally inactive chromatin as weil as from the various forms of transcribed chromatin hitherto described. This novel type of chromatin is not arranged in Christmas tree-Iike configurations of densely packed lateral ribonucleoprotein (RNP) fibriIs but is characterized by a periodic alternating pattern of thick and thin regions which occur in clusters 01 some 10,000 repeats. Each thickened unit with an average length of 45 nm contains two c10sely spaced particles, the putative RNA polymerases, and each thickened unit is separated from the next one by a beaded chromatin spacer with a length of about 80 nm. This chromatin spacer contains on average two particles of approximately 14 nm in diameter, assumed to be nucleosomes. The thickened regions are interpreted to represent short transcriptional units containing approximately 130 base pairs of DNA which are separated from each other by nontranscribed spacers of 240-400 base pairs of DNA. The possibility is discussed that these transcriptional units represent 5S rRNA or tRNA genes.}, language = {en} } @article{BenaventeScheerChaly1989, author = {Benavente, Ricardo and Scheer, Ulrich and Chaly, Nathalie}, title = {Nucleocytoplasmic sorting of macromolecules following mitosis: fate of nuclear constituents after inhibition of pore complex function}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40777}, year = {1989}, abstract = {PtK2 cells in which pore complex-mediated transport is blocked by microinjection early in mitosis of a monoclonal antibody (specific for an Mr 68000 pore complex glycoprotein) or of wheat germ agglutinin (WGA) complete cytokinesis. However, their nuclei remain stably arrested in a telophase-like organization characterized by highly condensed chromatin and the absence of nucleoli, indicating a requirement for pore-mediated transport for the reassembly of interphase nuclei. We have now examined this requirement more closely by monitoring the behavior of individual nuclear macromolecules in microinjected cells using immunofluorescence microscopy and have investigated the effect of microinjecting the antibody or WGA on cellular ultrastructure. The absence of nuclear transport did not affect the sequestration into daughter nuclei of components such as DNA, DNA topoisomerase I and the nucleolar protein fibrillarin that are carried through mitosis on chromosomes. On the other hand, lamins, snRNAs and the p68 pore complex glycoprotein, all cytoplasmic during mitosis, remained largely cytoplasmic in the telophase-arrested cells. Electron microscopy showed the nuclei to be surrounded by a doublelayered membrane with some inserted pore complexes. In addition, however, a variety of membranous structures with associated pore complexes was regularly noted in the cytoplasm, suggesting that chromatin may not be essential for the postmitotic formation of pore complexes. We propose that cellular compartmentalization at telophase is a two-step process. First, a nuclear envelope tightly encloses the condensed chromosomes, excluding non-selectively all macromolecules not associated with the chromosomes. Interphase nuclear organization is then progressively restored by selective pore complex-mediated uptake of nuclear proteins from the cytoplasm.}, subject = {Cytologie}, language = {en} } @article{HigginsSmilinichSaitetal.1994, author = {Higgins, M. J. and Smilinich, N. J. and Sait, S. and Koenig, A. and Pongratz, J. and Gessler, Manfred and Richard III., C. W. and James, M. R. and Sanford, J. P. and Kim, B.-W. and Cattelane, J. and Nowak, N. J. and Winterpacht, A. and Zabel, B. U. and Munroe, D. J. and Bric, E. and Housman, D. E. and Jones, C. and Nakamura, Y. and Gerhard, D. S. and Shows, T. B.}, title = {An Ordered NotI Fragment Map of Human Chromosome Band 11p15}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45766}, year = {1994}, abstract = {An ordered NotI fragment map containing over 60 loci and encompassing approximately 17 Mb has been constructed for human chromosome band llpl5. Forty-two probes, including 11 NotI-linking cosmids, were subregionaUy mapped to llpl5 using a subset of the Jl-deletion hybrids. These and 23 other probes defining loci previously mapped to 11p15 were hybridized to genomic DNA digested with NotI and 5 other infrequently cleaving restriction enzymes and separated by pulsed-field gel electrophoresis. Thirty-nine distinct NotI fragments were detected encompassing approximately 85\% of the estimated length of llp15. The predicted order of the gene loci used is cenMYODI- PTH-CALCA-ST5-RBTNI-HPX-HBB-RRMlTH/ INS!1GF2-H19-CTSD-MUC2-DRD4-HRAS-RNHtel. This map wiu allow higher resolution mapping of new Ilp15 markers, facilitate positional cloning of disease genes, and provide a framework for the physical mapping of llp15 in clone contigs.}, subject = {Genom / Genkartierung / Genanalyse}, language = {en} } @article{TrendelenburgFrankeScheer1977, author = {Trendelenburg, Michael F. and Franke, Werner W. and Scheer, Ulrich}, title = {Frequencies of circular units of nucleolar DNA in oocytes of two insects, Acheta domesticus and Dytiscus marginalis, and changes of nucleolar morphology during oogenesis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41370}, year = {1977}, abstract = {The organization of the extrachromosomal nucleolar material in oocytes of two insect species with different ovary types, the house cricket Acheta domesticus (panoistic ovary) and the water beetle Dytiscus marginalis (meroistic ovary), was studied with light and electron microscopic techniques. Stages early in oogenesis were compared with fully vitellogenic stages (mid-to-Iate diplotene). The arrangement of the nucleolar material undergoes a marked change from a densely aggregated to a dispersed state. The latter was characterized by high transcriptional activity. In spread and positively stained preparations of isolated nucleolar material, a high frequency of small circular units of transcribed rDNA was observed and rings with small numbers (1-5) of pre-rRNA genes were predominant. The observations suggest that the "extra DNA body" observed in early oogenic stages of both species represents a dense aggregate of numerous short circular units of nucleolar chromatin, with morphological subcomponents identifiable in ultrathin sections. These apparently remain in close association with the chromosomal nucleolar organizer(s). The observations further indicate that the individual small nucleolar subunit circles dissociate and are dispersed as actively transcribed rDNA units later in diplotene. The results are discussed in relation to principles of the ultrastructural organization of nucleoli in other cell types as well as in relation to possible mechanisms of gene amplification.}, subject = {Zelldifferenzierung}, language = {en} } @article{WeberOsbornFrankeetal.1977, author = {Weber, Klaus and Osborn, Mary and Franke, Werner W. and Seib, Erinita and Scheer, Ulrich and Herth, Werner}, title = {Identification of microtubular structures in diverse plant and animal cells by immunological cross-reaction revealed in immunofluorescence microscopy using antibodies against tubulin from porcine brain}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41383}, year = {1977}, abstract = {Antibody against tubulin from porcine brain was used to evaluate the immunological cross reactivity of tubulin from a variety of animal and plant cells. Indirect immunofluorescence microscopy revealed microtubule-containing structures including cytoplasmic microtubules, spindle microtubules, cilia and fIagella. Thus tubulin from diverse species of both mammals and plants show immunological cross-reactivity with tubulin from porcine brain. Results obtained by immunofluorescence microscopy are whenever possible compared with previously known ultrastructural results obtained by electron microscopy.}, subject = {Cytologie}, language = {en} } @article{SpringKrohneFrankeetal.1976, author = {Spring, Herbert and Krohne, Georg and Franke, Werner W. and Scheer, Ulrich and Trendelenburg, Michael F.}, title = {Homogeneity and heterogeneity of sizes of transcriptional units and spacer regions in nucleolar genes of Acetabularia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41398}, year = {1976}, abstract = {The arrangement of genes of precursor molecules for ribosomal RNA (pre-rRNA) in primary nuclei from two green algae species, Acetabularia mediterranea and A. major, has been analyzed in an electron microscope study. The pattern of transcriptional units in individual strands of nucleolar chromatin was investigated using spread and positively stained preparations. The rDNA pattern is not uniform but differs in different strands. The predominant type of nucleolar chromatin exhibits a high degree of homogeneity in the sequence of matrix units (intercepts covered with fibrilst hat contain the pre-rRNA) and fibril-free spacer intercepts. Substantial differences, however, are observed between the patterns in different strands. In addition, there is evidence in some strands for intraaxial heterogeneity of both spacer and matrix units. The following major types can be distinguished: type la, ca. 2 micrometer long matrix units, extremely short spacer intercepts in A. mediterranea (ca. 1 micrometer long ones in A. major), completely homogeneous distribution; type Ib, as type la but with intercalated, isolated, significantly shorter and/or longer matrix units; type lIa, matrix unit sizes as in type la, but much longer spacer intercepts, high degree of homogeneity; type Ill, largely heterogeneous arrangements of matrix and spacer units of varying sizes. The matrix unit data are compared with the sizes of pre-rRNA as determined by polyacrylamide gelelectrophoresis under denaturing and non-denaturing conditions. The findings are discussed in relation to recent observations in amphibia and insects and with respect to current concepts of the species-specificity of rDNA arrangements.}, language = {en} } @article{FrankeJaraschHerthetal.1975, author = {Franke, Werner W. and Jarasch, Ernst-Dieter and Herth, Werner and Scheer, Ulrich and Zerban, Heide}, title = {Cytology : general and molecular cytology}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41458}, year = {1975}, abstract = {The present review discusses some general aspects of membrane structure and problems of membrane isolation and membrane biochemistry, with particular focus on the endoplasmic reticulum.}, subject = {Botanik}, language = {en} } @book{KartenbeckZentgrafScheeretal.1971, author = {Kartenbeck, J. and Zentgraf, H. and Scheer, Ulrich and Franke, Werner W.}, title = {The nuclear envelope in freeze-etching}, isbn = {3-540-05538-X}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40534}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1971}, abstract = {No abstract available}, subject = {Anatomie}, language = {en} } @article{KnechtScheer1972, author = {Knecht, Sigrid and Scheer, Ulrich}, title = {Die Liste der Vogelarten von S. Miguel (Azoren) des Gaspar Fructuoso (gestorben 1591)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41402}, year = {1972}, abstract = {No abstract available}, language = {de} } @misc{ReimerRaskaTanetal.1987, author = {Reimer, Georg and Raska, Ivan and Tan, Eng M. and Scheer, Ulrich}, title = {Human autoantibodies: probes for nucleolus structure and function}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41410}, year = {1987}, abstract = {No abstract available}, language = {en} } @phdthesis{Worschech2010, author = {Worschech, Andrea}, title = {Oncolytic Therapy with Vaccinia Virus GLV-1h68 - Comparative Microarray Analysis of Infected Xenografts and Human Tumor Cell Lines -}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45338}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Aim of this thesis was to study the contribution of the hosts immune system during tumor regression. A wild-type rejection model was studied in which tumor regression is mediated through an adaptive, T cell host response (Research article 1). Additionally, the relationship between VACV infection and cancer rejection was assessed by applying organism-specific microarray platforms to infected and non-infected xenografts. It could be shown that tumor rejection in this nude mouse model was orchestrated solely by the hosts innate immune system without help of the adaptive immunity. In a third study the inflammatory baseline status of 75 human cancer cell lines was tested in vitro which was correlated with the susceptibility to VACV and Adenovirus 5 (Ad5) replication of the respective cell line (Manuscript for Research article 3). Although xenografts by themselves lack the ability to signal danger and do not provide sufficient proinflammatory signals to induce acute inflammation, the presence of viral replication in the oncolytic xenograft model provides the "tissue-specific trigger" that activates the immune response and in concordance with the hypothesis, the ICR is activated when chronic inflammation is switched into an acute one. Thus, in conditions in which a switch from a chronic to an acute inflammatory process can be induced by other factors like the immune-stimulation induced by the presence of a virus in the target tissue, adaptive immune responses may not be necessary and immune-mediated rejection can occur without the assistance of T or B cells. However, in the regression study using neu expressing MMC in absence of a stimulus such as a virus and infected cancer cells thereafter, adaptive immunity is needed to provoke the switch into an acute inflammation and initiate tissue rejection. Taken together, this work is supportive of the hypothesis that the mechanisms prompting TSD differ among immune pathologies but the effect phase converges and central molecules can be detected over and over every time TSD occurs. It could be shown that in presence of a trigger such as infection with VACV and functional danger signaling pathways of the infected tumor cells, innate immunity is sufficient to orchestrate rejection of manifested tumors.}, subject = {Tumorimmunologie}, language = {en} } @article{SteinCoulibalyBalimaetal.2020, author = {Stein, Katharina and Coulibaly, Drissa and Balima, Larba Hubert and Goetze, Dethardt and Linsenmair, Karl Eduard and Porembski, Stefan and Stenchly, Kathrin and Theodorou, Panagiotis}, title = {Plant-pollinator networks in savannas of Burkina Faso, West Africa}, series = {Diversity}, volume = {13}, journal = {Diversity}, number = {1}, issn = {1424-2818}, doi = {10.3390/d13010001}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-220157}, year = {2020}, abstract = {West African savannas are severely threatened with intensified land use and increasing degradation. Bees are important for terrestrial biodiversity as they provide native plant species with pollination services. However, little information is available regarding their mutualistic interactions with woody plant species. In the first network study from sub-Saharan West Africa, we investigated the effects of land-use intensity and climatic seasonality on plant-bee communities and their interaction networks. In total, we recorded 5686 interactions between 53 flowering woody plant species and 100 bee species. Bee-species richness and the number of interactions were higher in the low compared to medium and high land-use intensity sites. Bee- and plant-species richness and the number of interactions were higher in the dry compared to the rainy season. Plant-bee visitation networks were not strongly affected by land-use intensity; however, climatic seasonality had a strong effect on network architecture. Null-model corrected connectance and nestedness were higher in the dry compared to the rainy season. In addition, network specialization and null-model corrected modularity were lower in the dry compared to the rainy season. Our results suggest that in our study region, seasonal effects on mutualistic network architecture are more pronounced compared to land-use change effects. Nonetheless, the decrease in bee-species richness and the number of plant-bee interactions with an increase in land-use intensity highlights the importance of savanna conservation for maintaining bee diversity and the concomitant provision of ecosystem services.}, language = {en} } @article{HeisswolfPoethkeObermaier2006, author = {Heisswolf, Annette and Poethke, Hans-Joachim and Obermaier, Elisabeth}, title = {Multitrophic influences on oviposition site selection in a specialized leaf beetle at multiple spatial scales}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47738}, year = {2006}, abstract = {Egg distribution in herbivorous beetles can be affected by bottom-up (host plant), and by top-down factors (parasitoids and predators), as well as by other habitat parameters. The importance of bottom-up and top-down effects may change with spatial scale. In this study, we investigated the influence of host plant factors and habitat structure on egg distribution in the leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae), a monophagous herbivore on Salvia pratensis L. (Lamiales: Lamiaceae), on four spatial scales: individual host plant, microhabitat, macrohabitat, and landscape. At the individual host plant scale we studied the correlation between egg clutch incidence and plant size and quality. On all other scales we analyzed the relationship between the egg clutch incidence of C. canaliculata and host plant percentage cover, host plant density, and the surrounding vegetation structure. Vegetation structure was examined as herbivores might escape egg parasitism by depositing their eggs on sites with vegetation factors unfavorable for host searching parasitoids. The probability that egg clutches of C. canaliculata were present increased with an increasing size, percentage cover, and density of the host plant on three of the four spatial scales: individual host plant, microhabitat, and macrohabitat. There was no correlation between vegetation structure and egg clutch occurrence or parasitism on any spatial scale. A high percentage of egg clutches (38-56\%) was parasitized by Foersterella reptans Nees (Hymenoptera: Tetracampidae), the only egg parasitoid, but there was no relationship between egg parasitism and the spatial distribution of egg clutches of C. canaliculata on any of the spatial scales investigated. However, we also discuss results from a further study, which revealed top-down effects on the larval stage.}, subject = {Eiablage}, language = {en} } @article{HeisswolfObermaierPoethke2005, author = {Heisswolf, Annette and Obermaier, Elisabeth and Poethke, Hans-Joachim}, title = {Selection of large host plants for oviposition by a monophagous leaf beetle: nutritional quality or enemy-free space?}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47728}, year = {2005}, abstract = {1. Oviposition site selection is crucial for the reproductive success of herbivorous insects. According to the preference-performance hypothesis, females should oviposit on host plants that enhance the performance of their offspring. More specifically, the plant vigour hypothesis predicts that females should prefer large and vigorously growing host plants for oviposition and that larvae should perform best on these plants. 2. The present study examined whether females of the monophagous leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) prefer to oviposit on large host plant individuals of the meadow clary and whether large host plants are of higher nutritional quality than small host plants. Subsequently, it was tested whether the female preference correlates with offspring performance and survival. 3. In the field, females preferred large host plant individuals for oviposition and host plant quality, i.e. leaf nitrogen content, was significantly higher in leaves of large than of small host plants. 4. In the laboratory, larval development time was shorter on leaves of large host plant individuals than on small host plant individuals, but this could not be shown in the field. 5. However, a predator-exclusion experiment in the field resulted in a higher survival of larvae on large host plants than on small host plants when all predators had free access to the plants. On caged host plants there was no difference in survival of larvae between plant size categories. 6. It is concluded that females of C. canaliculata select oviposition sites that enhance both performance and survival of their offspring, which meets the predictions of the plant vigour hypothesis.}, subject = {Insekten}, language = {en} } @article{MaschwitzFialaSawetal.1994, author = {Maschwitz, Ulich and Fiala, Brigitte and Saw, L. G. and Norma-Rashid, Yusoff and Idris, Azarae Haji}, title = {Ficus obscura var. borneensis (Moraceae), a new non-specific ant-plant from Malesia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42926}, year = {1994}, abstract = {Ficus obscura var. borneensis is a true myrmecophyte. It spontaneously forms cavities (domatia) in parts of its twigs which open by slits, These occur in the internodes and are usually not swollen. The domatia are inhabited by a variety of non-specific tree-living ants including Crematogaster spp., Cataulacus sp., Tetramorium sp., Cardio condyla sp. and Camponotus sp.. Additionally the plant providL a su~ar-containing secretion from extrafloral nectaries on the lower surfaces of the leaves. Examination of herbarium specimens of 37 other South-east Asian Ficus species did not reveal a single specimen with domatia.}, language = {en} } @phdthesis{Kelber2009, author = {Kelber, Christina}, title = {The olfactory system of leafcutting ants: neuroanatomy and the correlation to social organization}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47769}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {In leaf-cutting ants (genera Atta and Acromyrmex), the worker caste exhibits a pronounced size-polymorphism, and division of labor is largely dependent on worker size (alloethism). Behavioral studies have shown a rich diversity of olfactory-guided behaviors, and the olfactory system seems to be highly developed and very sensitive. To allow fine-tuned behavioral responses to different tasks, adaptations within the olfactory system of different sized workers are expected. In a recent study, two different phenotypes of the antennal lobe of Atta vollenweideri workers were found: MG- and RG-phenotype (with and without a macroglomerulus, MG). The existence of the macroglomerulus is correlated to the body size of workers, with small workers showing the RG-phenotype and large workers showing the MG-phenotype. In the MG, the information about the releaser component of the trail-pheromone is processed. In the first part of my PhD-project, I focus on quantifying behavioral differences between different sized workers in Atta vollenweideri. The study analyzes the trail following behavior; which can be generally performed by all workers. An artificial trail consisting of the releaser component of the trail-pheromone in decreasing concentration was used to test the trail-following performance of individual workers. The trail-following performance of the polymorphic workers is depended of the existence of the MG in the antennal lobe. Workers possessing the MG-phenotype were significantly better in following a decreasing trail then workers showing the RG-phenotype. In the second part I address the question if there are more structural differences, besides the MG, in the olfactory system of different sized workers. Therefore I analyze whether the glomerular numbers are related to worker size. The antennal lobes of small workers contain ~390 glomeruli (low-number; LN-phenotype), and in large workers I found a substantially higher number of ~440 glomeruli (high-number; HN-phenotype). All LN-phenotype workers and some of the small HN-phenotype workers do not possess an MG (LN-RG-phenotype and HN-RG-phenotype) at all, whereas the remaining majority of HN-phenotype workers do possess an MG (HN-MG-phenotype). Mass-stainings of antennal olfactory receptor neurons revealed that the sensory tracts divide the antennal lobe into six clusters of glomeruli (T1-T6). In the T4-cluster ~50 glomeruli are missing in the LN-phenotype workers. Selective staining of single sensilla and their associated receptor neurons showed that T4-glomeruli are innervated by receptor neurons from the main type of olfactory sensilla, the Sensilla trichodea curvata which are also projecting to glomeruli in all other clusters. The other type of olfactory sensilla, the Sensilla basiconica, exclusively innervates T6-glomeruli. Quantitative analyses revealed a correlation between the number of Sensilla basiconica and the volume of T6 glomeruli in different sized workers. The results of both behavioral and neuroanatomical studies in Atta vollenweideri suggest that developmental plasticity of antennal-lobe phenotypes promotes differences in olfactory-guided behavior which may underlie task specialization within ant colonies. The last part of my project focuses on the evolutionary origin of the macroglomerulus and the number of glomeruli in the antennal lobe. I compared the number, volumes and position of the glomeruli of the antennal lobe of 25 different species from all three major Attini groups (lower, higher and leaf-cutting Attini). The antennal lobes of all investigated Attini comprise a high number of glomeruli (257-630). The highest number was found in Apterostigma cf. mayri. This species is at a basal position within the Attini phylogeny, and a high number of glomeruli might have been advantageous in the evolution of the advanced olfactory systems of this Taxa. The macroglomerulus can be found in all investigated leaf-cutting Attini, but in none of the lower and higher Attini species. It is found only in large workers, and is located close to the entrance of the antennal nerve in all investigated species. The results indicate that the presence of a macroglomerulus in large workers of leaf-cutting Attini is a derived overexpression of a trait in the polymorphic leaf-cutting species. It presumably represents an olfactory adaptation to elaborate foraging and mass recruitment systems, and adds to the complexity of division of labor and social organization known for this group.}, subject = {Gehirn}, language = {en} } @article{HeisswolfReichmannPoethkeetal.2009, author = {Heisswolf, Annette and Reichmann, Stefanie and Poethke, Hans-Joachim and Schr{\"o}der, Boris and Obermaier, Elisabeth}, title = {Habitat quality matters for the distribution of an endangered leaf beetle and its egg parasitoid in a fragmented landscape}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47740}, year = {2009}, abstract = {Fragmentation, deterioration, and loss of habitat patches threaten the survival of many insect species. Depending on their trophic level, species may be differently affected by these factors. However, studies investigating more than one trophic level on a landscape scale are still rare. In the present study we analyzed the effects of habitat size, isolation, and quality for the occurrence and population density of the endangered leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) and its egg parasitoid, the hymenopteran wasp Foersterella reptans Nees (Hymenoptera: Tetracampidae). C. canaliculata is strictly monophagous on meadow sage (Salvia pratensis), while F. reptans can also parasitize other hosts. Both size and isolation of habitat patches strongly determined the occurrence of the beetle. However, population density increased to a much greater extent with increasing host plant density ( = habitat quality) than with habitat size. The occurrence probability of the egg parasitoid increased with increasing population density of C. canaliculata. In conclusion, although maintaining large, well-connected patches with high host plant density is surely the major conservation goal for the specialized herbivore C. canaliculata, also small patches with high host plant densities can support viable populations and should thus be conserved. The less specialized parasitoid F. reptans is more likely to be found on patches with high beetle density, while patch size and isolation seem to be less important.}, subject = {Fragmentierung}, language = {en} } @article{WeisingFiala1992, author = {Weising, Kurt and Fiala, Brigitte}, title = {Botanische Eindr{\"u}cke vom Bako-Nationalpark / Sarawak}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42947}, year = {1992}, abstract = {No abstract available}, language = {de} } @article{MaschwitzFialaLeeetal.1989, author = {Maschwitz, Ulich and Fiala, Brigitte and Lee, Ying Fah and Chey, Vun Khen and Tan, Fui Lian}, title = {New and little-known myrmecophytic associations from Bornean rain forests}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42957}, year = {1989}, abstract = {The woody climber Millettia niuewenhuisii (Fabaceae) and the shrub Myrmeconauclea strigosa (Rubiaceae) in Sabah, Borneo are associated with ants. The hollow stems of Millettia nieuwenhuisii are regularly inhabited by an aggressive Cladomyrma sp., which keeps pseudococcids inside the stem. On Myrmeconauclea strigosa the ants live in hollow internodal swellings near the end of the branches. In this plant many different ant species use the nesting space in an opportunistic manner.}, language = {en} } @article{FialaMaschwitzPongetal.1989, author = {Fiala, Brigitte and Maschwitz, Ulrich and Pong, Tho, Yow and Helbig, Andreas J.}, title = {Studies of a South East Asian ant-plant association : protection of Macaranga trees by Crematogaster borneensis}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42857}, year = {1989}, abstract = {In the humid tropics of SE Asia there are some 14 myrmecophytic species of the pioneer tree genus Macaranga (Euphorbiaceae). In Peninsular Malaysia a close association exists between the trees and the small, non-stinging myrmicine Crema togas ter borneensis. These ants feed mainly on food bodies provided by the plants and have their colonies inside the hollow intemodes. In a ten months field study we were able to demonstrate for four Macaranga species (M. triloba, M. hypoleuca, M. hosei, M. hulletti) that host plants also benefit considerably from ant-occupation. Ants do not contribute to the nutrient demands of their host plant, they do, however, protect it against herbivores and plant competition. Cleaning behaviour of the ants results in the removal of potential herbivores already in their earliest developmental stages. Strong aggressiveness and a mass recruiting system enable the ants to defend the host plant against many herbivorous insects. This results in a significant decrease in leaf damage due to herbivores on ant-occupied compared to ant-free myrmecophytes as well as compared to non-myrmecophytic Macaranga species. Most important is the ants' defense of the host plant against plant competitors, especially vines, which are abundant in the well-lit pioneer habitats where Macaranga grows. Ants bite off any foreign plant part coming into contact with their host plant. Both ant-free myrmecophytes and non-myrmecophytic Macaranga species had a significantly higher incidence of vine growth than specimens with active ant colonies. This may be a factor of considerable importance allowing Macaranga plants to grow at sites of strongest competition.}, language = {en} } @article{WeisingFialaRamlochetal.1990, author = {Weising, K. and Fiala, Brigitte and Ramloch, K. and Kahl, K. and Epplen, J. T.}, title = {Olingonucleotide fingerprinting in angiosperms}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42884}, year = {1990}, abstract = {No abstract available}, language = {en} } @article{MaschwitzFialaLinsenmair1994, author = {Maschwitz, Ulrich and Fiala, Brigitte and Linsenmair, Karl Eduard}, title = {Clerodendrum fistulosum (Verbenanceae), an unspecific myrmecophyte from Borneo with spontaneously opening domatia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31013}, year = {1994}, abstract = {Clerodendrumjistulosum Becc. is a true myrmecophyte as it offers nesting space for ants in hollow intemodes. In contrast to previous reports our investigations proved that these domatia open by themselves, thus providing cavities for a variety of different ant species. In Sarawak, Malaysia, we did not find an obligate relationship between C. jistulosum and a specific ant-partner. For comparison, studies on herbarium material of other Clerodendrum species were carried out a further species, C. deflexum from the Malay Peninsula and Sumatra presumably also is myrmecophytic.}, language = {en} } @article{Linsenmair1964, author = {Linsenmair, Karl Eduard}, title = {Ritter und T{\"u}rmchen: aus dem Leben der Reiterkrabbe}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44643}, year = {1964}, abstract = {No abstract available}, language = {de} } @article{ThielckeLinsenmair1963, author = {Thielcke, Gerhard and Linsenmair, Karl Eduard}, title = {Zur geographischen Variation des Gesanges des Zilpzalps, Phylloscopus collybita, in Mittel- und S{\"u}dwesteuropa mit einem Vergleich des Gesanges de Fitis, Phylloscopus trochilus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44657}, year = {1963}, abstract = {No abstract available}, language = {de} } @article{LinsenmairJander1963, author = {Linsenmair, Karl Eduard and Jander, R.}, title = {Das "Entspannungsschwimmen" von Velia und Stenus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-44663}, year = {1963}, abstract = {No abstract available}, language = {de} } @article{CavalettoFaccoliMarinietal.2020, author = {Cavaletto, Giacomo and Faccoli, Massimo and Marini, Lorenzo and Spaethe, Johannes and Magnani, Gianluca and Rassati, Davide}, title = {Effect of trap color on captures of bark- and wood-boring beetles (Coleoptera; Buprestidae and Scolytinae) and associated predators}, series = {Insects}, volume = {11}, journal = {Insects}, number = {11}, issn = {2075-4450}, doi = {10.3390/insects11110749}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216325}, year = {2020}, abstract = {Traps baited with attractive lures are increasingly used at entry-points and surrounding natural areas to intercept exotic wood-boring beetles accidentally introduced via international trade. Several trapping variables can affect the efficacy of this activity, including trap color. In this study, we tested whether species richness and abundance of jewel beetles (Buprestidae), bark and ambrosia beetles (Scolytinae), and their common predators (i.e., checkered beetles, Cleridae) can be modified using trap colors different to those currently used for surveillance of jewel beetles and bark and ambrosia beetles (i.e., green or black). We show that green and black traps are generally efficient, but also that many flower-visiting or dark-metallic colored jewel beetles and certain bark beetles are more attracted by other colors. In addition, we show that checkered beetles have color preferences similar to those of their Scolytinae preys, which limits using trap color to minimize their inadvertent removal. Overall, this study confirmed that understanding the color perception mechanisms in wood-boring beetles can lead to important improvements in trapping techniques and thereby increase the efficacy of surveillance programs.}, language = {en} } @phdthesis{Roeschert2021, author = {R{\"o}schert, Isabelle}, title = {Aurora-A prevents transcription-replication conflicts in MYCN-amplified neuroblastoma}, doi = {10.25972/OPUS-24303}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-243037}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Neuroblastoma is the most abundant, solid, extracranial tumor in early childhood and the leading cause of cancer-related childhood deaths worldwide. Patients with high-risk neuroblastoma often show MYCN-amplification and elevated levels of Aurora-A. They have a low overall survival and despite multimodal therapy options a poor therapeutic prognosis. MYCN-amplified neuroblastoma cells depend on Aurora-A functionality. Aurora-A stabilizes MYCN and prevents it from proteasomal degradation by competing with the E3 ligase SCFFBXW7. Interaction between Aurora-A and MYCN can be observed only in S phase of the cell cycle and activation of Aurora-A can be induced by MYCN in vitro. These findings suggest the existence of a profound interconnection between Aurora-A and MYCN in S phase. Nevertheless, the details remain elusive and were investigated in this study. Fractionation experiments show that Aurora-A is recruited to chromatin in S phase in a MYCN-dependent manner. Albeit being unphosphorylated on the activating T288 residue, Aurora-A kinase activity was still present in S phase and several putative, novel targets were identified by phosphoproteomic analysis. Particularly, eight phosphosites dependent on MYCN-activated Aurora-A were identified. Additionally, phosphorylation of serine 10 on histone 3 was verified as a target of this complex in S phase. ChIP-sequencing experiments reveal that Aurora-A regulates transcription elongation as well as histone H3.3 variant incorporation in S phase. 4sU-sequencing as well as immunoblotting demonstrated that Aurora-A activity impacts splicing. PLA measurements between the transcription and replication machinery revealed that Aurora-A prevents the formation of transcription-replication conflicts, which activate of kinase ATR. Aurora-A inhibitors are already used to treat neuroblastoma but display dose-limiting toxicity. To further improve Aurora-A based therapies, we investigated whether low doses of Aurora-A inhibitor combined with ATR inhibitor could increase the efficacy of the treatment albeit reducing toxicity. The study shows that the combination of both drugs leads to a reduction in cell growth as well as an increase in apoptosis in MYCN-amplified neuroblastoma cells, which is not observable in MYCN non-amplified neuroblastoma cells. This new approach was also tested by a collaboration partner in vivo resulting in a decrease in tumor burden, an increase in overall survival and a cure of 25\% of TH-MYCN mice. These findings indicate indeed a therapeutic window for targeting MYCN-amplified neuroblastoma.}, subject = {Neuroblastom}, language = {en} } @article{ThoelkenThammErbacheretal.2019, author = {Th{\"o}lken, Clemens and Thamm, Markus and Erbacher, Christoph and Lechner, Marcus}, title = {Sequence and structural properties of circular RNAs in the brain of nurse and forager honeybees (Apis mellifera)}, series = {BMC Genomics}, volume = {20}, journal = {BMC Genomics}, doi = {10.1186/s12864-018-5402-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241302}, year = {2019}, abstract = {Background The honeybee (Apis mellifera) represents a model organism for social insects displaying behavioral plasticity. This is reflected by an age-dependent task allocation. The most protruding tasks are performed by young nurse bees and older forager bees that take care of the brood inside the hive and collect food from outside the hive, respectively. The molecular mechanism leading to the transition from nurse bees to foragers is currently under intense research. Circular RNAs, however, were not considered in this context so far. As of today, this group of non-coding RNAs was only known to exist in two other insects, Drosophila melanogaster and Bombyx mori. Here we complement the state of circular RNA research with the first characterization in a social insect. Results We identified numerous circular RNAs in the brain of A. mellifera nurse bees and forager bees using RNA-Seq with exonuclease enrichment. Presence and circularity were verified for the most abundant representatives. Back-splicing in honeybee occurs further towards the end of transcripts and in transcripts with a high number of exons. The occurrence of circularized exons is correlated with length and CpG-content of their flanking introns. The latter coincides with increased DNA-methylation in the respective loci. For two prominent circular RNAs the abundance in worker bee brains was quantified in TaqMan assays. In line with previous findings of circular RNAs in Drosophila, circAmrsmep2 accumulates with increasing age of the insect. In contrast, the levels of circAmrad appear age-independent and correlate with the bee's task. Its parental gene is related to amnesia-resistant memory. Conclusions We provide the first characterization of circRNAs in a social insect. Many of the RNAs identified here show homologies to circular RNAs found in Drosophila and Bombyx, indicating that circular RNAs are a common feature among insects. We find that exon circularization is correlated to DNA-methylation at the flanking introns. The levels of circAmrad suggest a task-dependent abundance that is decoupled from age. Moreover, a GO term analysis shows an enrichment of task-related functions. We conclude that circular RNAs could be relevant for task allocation in honeybee and should be investigated further in this context.}, language = {en} } @phdthesis{Helmerich2023, author = {Helmerich, Dominic Andreas}, title = {Einfl{\"u}sse der Photophysik und Photochemie von Cyaninfarbstoffen auf die Lokalisationsmikroskopie}, doi = {10.25972/OPUS-24716}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-247161}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {In den letzten Jahren haben sich hochaufl{\"o}sende Fluoreszenzmikroskopiemethoden, basierend auf der Lokalisation einzelner Fluorophore, zu einem leistungsstarken Werkzeug etabliert, um Fluoreszenzbilder weit unterhalb der Aufl{\"o}sungsgrenze zu generieren. Hiermit k{\"o}nnen r{\"a}umliche Aufl{\"o}sungen von ~ 20 nm erzielt werden, was weit unterhalb der Beugungsgrenze liegt. Dabei haben zahlreiche Optimierungen und Entwicklungen neuer Methoden in der Einzelmolek{\"u}l-Lokalisationsmikroskopie die Genauigkeit der orstspezifischen Bestimmung einzelner Fluorophore auf bis zu ~ 1 - 3 nm erh{\"o}ht. Eine Aufl{\"o}sung im molekularen Bereich, weit unterhalb von ~ 10 nm bleibt allerdings herausfordernd, da die Lokalisationsgenauigkeit nur ein Kriterium hierf{\"u}r ist. Allerdings wurde sich in den letzten Jahren {\"u}berwiegend auf die Verbesserung dieses Parameters konzentriert. Weitere Kriterien f{\"u}r die fluoreszenzmikroskopische Aufl{\"o}sung sind dabei unter anderem die Markierungsdichte und die Kopplungseffizienz der Zielstruktur, sowie der Kopplungsfehler (Abstand zur Zielstruktur nach Farbstoffkopplung), die sich herausfordernd f{\"u}r eine molekulare Aufl{\"o}sung darstellen. Auch wenn die Kopplungseffizienz und -dichte hoch und der Kopplungsfehler gering ist, steigt bei Interfluorophordistanzen < 5nm, abh{\"a}ngig von den Farbstoffen, die Wahrscheinlichkeit von starken und schwachen Farbstoffwechselwirkungen und damit von Energie{\"u}bertragungsprozessen zwischen den Farbstoffen, stark an. Daneben sollten Farbstoffe, abh{\"a}nging von der Lokalisationsmikroskopiemethode, spezifische Kriterien, wie beispielsweise die Photoschaltbarkeit bei dSTORM, erf{\"u}llen, was dazu f{\"u}hrt, dass diese Methoden h{\"a}ufig nur auf einzelne Farbstoffe beschr{\"a}nkt sind. In dieser Arbeit konnte mithilfe von definierten DNA-Origami Konstrukten gezeigt werden, dass das Blinkverhalten von Cyaninfarbstoffen unter dSTORM-Bedingungen einer Abstandsabh{\"a}ngigkeit aufgrund von spezifischen Energie{\"u}bertragungsprozessen folgt, womit Farbstoffabst{\"a}nde im sub-10 nm Bereich charakterisiert werden konnten. Dar{\"u}ber hinaus konnte diese Abstandsabh{\"a}ngigkeit an biologischen Proben gezeigt werden. Hierbei konnten verschiedene zellul{\"a}re Rezeptoren effizient und mit geringem Abstandsfehler zur Zielstruktur mit Cyaninfarbstoffen gekoppelt werden. Diese abstandsabh{\"a}nigen Prozesse und damit Charakterisierungen k{\"o}nnten dabei nicht nur spezifisch f{\"u}r die h{\"a}ufig unter dSTORM-Bedingungen verwendeten Cyaninfarbstoffen g{\"u}ltig sein, sondern auch auf andere Farbstoffklassen, die einen Auszustand zeigen, {\"u}bertragbar sein. Dar{\"u}ber hinaus konnte gezeigt werden, dass hochaufl{\"o}sende dSTORM Aufnahmen unabh{\"a}ngig vom Farbstoffkopplungsgrad der Antik{\"o}rpern sind, welche h{\"a}ufig f{\"u}r Standardf{\"a}rbungen von zellul{\"a}ren Strukturen verwendet werden. Dabei konnte durch Photonenkoinzidenzmessungen dargelegt werden, dass aufgrund komplexer Farbstoffwechselwirkungen im Mittel nur ein Farbstoff aktiv ist, wobei h{\"o}here Kopplungsgrade ein komplexes Blinkverhalten zu Beginn der Messung zeigen. Durch die undefinierten Farbstoffabst{\"a}nde an Antik{\"o}rpern konnte hier kein eindeutiger Energie{\"u}bertragungsmechanismus entschl{\"u}sselt werden. Dennoch konnte gezeigt werden, dass Farbstoffaggregate bzw. H-Dimere unter dSTORM-Bedingungen destabilisiert werden. Durch die zuvor erw{\"a}hnten DNA-Origami Konstrukte definierter Interfluorophordistanzen konnten Energie{\"u}bertragungsmechanismen entschl{\"u}sselt werden, die auch f{\"u}r die Antik{\"o}rper diverser Kopplungsgrade g{\"u}ltig sind. Des Weiteren konnten, ausgel{\"o}st durch komplexe Energie{\"u}bertragungsprozesse h{\"o}herer Kopplungsgrade am Antik{\"o}rper, Mehrfarbenaufnahmen zellul{\"a}rer Strukturen generiert werden, die {\"u}ber die spezifische Fluoreszenzlebenszeit separiert werden konnten. Dies stellt hier eine weitere M{\"o}glichkeit dar, unter einfachen Bedingungen, schnelle Mehrfarbenaufnahmen zellul{\"a}rer Strukturen zu generieren. Durch die Verwendung des selben Farbstoffes unterschiedlicher Kopplungsgrade kann hier nur mit einer Anregungswellenl{\"a}nge und frei von chromatischer Aberration gearbeitet werden. Neben den photophysikalischen Untersuchungen der Cyaninfarbstoffe Cy5 und Alexa Fluor 647 wurden diese ebenso photochemisch n{\"a}her betrachtet. Dabei konnte ein neuartiger chemischer Mechanismus entschl{\"u}sselt werden. Dieser Mechanismus f{\"u}hrt, ausgel{\"o}st durch Singulett-Sauerstoff (1O2), zu einer Photozerschneidung des konjugierten Doppelbindungssystems um zwei Kohlenstoffatome, was zu strukturellen und spektroskopischen Ver{\"a}nderungen dieser Farbstoffe f{\"u}hrt. Auf Grundlage dieses Mechanismus konnte eine neue DNA-PAINT Methode entwickelt werden, die zu einer Beschleunigung der Aufnahmezeit f{\"u}hrt.}, subject = {Einzelmolek{\"u}lmikroskopie}, language = {de} } @phdthesis{Aydinli2021, author = {Aydinli, Muharrem}, title = {Software unterst{\"u}tzte Analyse von regulatorischen Elementen in Promotoren mittels AIModules}, doi = {10.25972/OPUS-24802}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248025}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Die Regulation der Genexpression steht am Anfang vieler zellbiologischer Prozesse wie beispielsweise dem Zellwachstum oder der Differenzierung. Gene werden an Promotoren transkribiert, wobei ein Promotor selbst aus vielen logischen Einheiten aufgebaut ist, den Transkriptionsfaktorbindestellen (TFBSs). Diese k{\"o}nnen sehr nah beieinander liegen, aber auch weit entfernt voneinander sein. Sie werden spezifisch von Transkriptionsfaktoren (TFs) gebunden, die die Transkritptionsrate z.B. verst{\"a}rken (Enhancer) oder schw{\"a}chen (Silencer) k{\"o}nnen. Zwei oder mehr dieser TFBSs mit bestimmtem Abstand werden als "Module" zusammengefasst, die {\"u}ber Spezies hinweg konserviert sein k{\"o}nnen. Typischerweise findet man Module in Zellen mit einem Zellkern. Spezies mit gemeinsamen Modulen k{\"o}nnen ein Hinweis auf die gemeinsame phylogenetische Abstammung darstellen, aber auch gemeinsame Funktionsmechanismen von TFs {\"u}ber Gene hinweg aufdecken. Heutzutage sind verschiedene Anwendungen verf{\"u}gbar, mit denen nach TFBSs in DNA gesucht werden kann. Zum Zeitpunkt des Verfassens dieser Arbeit sind aber nur zwei kommerzielle Produkte bekannt, die nicht nur TFBSs, sondern auch Module erkennen. Deshalb stellen wir hier die freie und quelloffene L{\"o}sung "AIModules" vor, die diese L{\"u}cke f{\"u}llt und einen Webservice zur Verf{\"u}gung stellt, der es erlaubt nach TFBSs sowie nach Modulen auf DNA- und auf RNA-Abschnitten zu suchen. F{\"u}r die Motivesuche werden entweder Matrizen aus der Jaspar Datenbank oder Matrizen vom Anwender verwendet. Dar{\"u}berhinaus zeigen wir, dass unser Tool f{\"u}r die TF Suche nur Sekunden ben{\"o}tigt, wohingegen conTraV3 mindestens eine Stunde f{\"u}r dieselbe Analyse braucht. Zus{\"a}tzlich kann der Anwender bei unserem Tool den Grad der Konserviertheit f{\"u}r TFs mit angeben und wir zeigen, dass wir mit unserer L{\"o}sung, die die Jaspar Datenbank heranzieht, mehr Module finden, als ein kommerziell verf{\"u}gbares Produkt. Weiterhin kann mit unserer L{\"o}sung auch auf RNA-Sequenzen nach regulatorischen Motiven gesucht werden, wenn der Anwender die daf{\"u}r n{\"o}tigen Matrizen liefert. Wir zeigen dies am Beispiel von Polyadenylierungsstellen. Zusammenfassend stellen wir ein Werkzeug vor, das erstens frei und quelloffen ist und zweitens entweder auf Servern ver{\"o}ffentlicht werden kann oder On-Site auf einem Notebook l{\"a}uft. Unser Tool erlaubt es Promotoren zu analysieren und nach konservierten Modulen sowie TFBSs in Genfamilien sowie nach regulatorischen Elementen in mRNA wie z.B. Polyadenylierungsstellen oder andere regulatorische Elemente wie beispielsweise Enhancern oder Silencern in genomischer DNA zu suchen.}, subject = {Genregulation}, language = {de} } @phdthesis{Boegelein2021, author = {B{\"o}gelein, Anna}, title = {Einfluss systemischer Therapeutika auf die CXCR4-Expression von Myelomzellen}, doi = {10.25972/OPUS-24174}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241746}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2021}, abstract = {Im Zuge der Bem{\"u}hungen um neue, tumorspezifische Therapieans{\"a}tze f{\"u}r die Myelomerkrankung hat sich der C-X-C-Chemokinrezeptor 4 (CXCR4) aufgrund seiner zentralen Rolle in der Tumorgenese als vielversprechender Angriffspunkt hervorgetan. Im Sinne eines theranostischen Konzepts wird der Rezeptor mithilfe eines radioaktiv markierten Liganden quantifiziert und anschließend von rezeptorspezifischen Radiotherapeutika als Zielstruktur genutzt. Die CXCR4-Expression ist allerdings ein h{\"o}chst dynamischer Prozess mit großer inter- und intraindividueller Heterogenit{\"a}t, der u.a. durch eine begleitende Chemotherapie beeinflusst werden kann. Ob sich therapieinduzierte Ver{\"a}nderungen der Rezeptorexpression gezielt nutzen lassen, um die CXCR4-Expression zu optimieren und so die Effektivit{\"a}t der CXCR4-gerichteten Strategien zu steigern, wurde bislang nicht untersucht. Vor diesem Hintergrund wurden in der vorliegenden Arbeit verschiedene, in der Myelomtherapie etablierte Substanzen sowohl einzeln als auch in Kombination hinsichtlich ihres Einflusses auf die CXCR4-Expression von MM-Zelllinien und prim{\"a}ren MM-Zellen unter in vitro Bedingungen analysiert. In den durchgef{\"u}hrten Experimenten zeigte sich eine hohe Variabilit{\"a}t der CXCR4-Expression der MM-Zellen nach Therapieinduktion, die sich als substanz-, dosis- und zeitabh{\"a}ngig herausstellte. Die Ergebnisse best{\"a}tigten das große Potenzial der therapieinduzierten Modulation der CXCR4-Expression. Im weiteren Verlauf sind translationale Forschungsans{\"a}tze gerechtfertigt, die die {\"U}bertragbarkeit der in vitro gewonnenen Ergebnisse auf die komplexen Vorg{\"a}nge im lebenden Organismus {\"u}berpr{\"u}fen. Langfristiges Ziel ist der Entwurf eines patientenzentrierten, multimodalen Therapiekonzepts, welches das CXCR4-gerichtete theranostische Konzept mit einer individuell angepassten, medikament{\"o}sen MM-Therapie kombiniert.}, subject = {Plasmozytom}, language = {de} } @phdthesis{Kortmann2022, author = {Kortmann, Mareike}, title = {Biodiversity and recreation - Optimizing tourism and forest management in forests affected by bark beetles}, doi = {10.25972/OPUS-24031}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-240317}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Forests are multi-functional system, which have to fulfil different objectives at the same time. The main functions include the production of wood, storage of carbon, the promotion of biological diversity and the provision of recreational space. Yet, global forests are affected by large and intense natural disturbances, like bark beetle infestations. While natural disturbances threaten wood production and are perceived as 'catastrophe' diminishing recreational value, biodiversity can benefit from the disturbance-induced changes in forest structures. This trade-off poses a dilemma to managers of bark beetle affected stands, particularly in protected areas designated to both nature conservation and recreation. Forest landscapes need a sustainable management concept aligning these different objectives. In order to support this goal with scientific knowledge, the aim of this work is to analyse ecological and social effects along a gradient of different disturbance severities. In this context, I studied the effects of a disturbance severity gradient on the diversity of different taxonomic groups including vascular plants, mosses, lichens, fungi, arthropods and birds in five national parks in Central Europe. To analyse the recreational value of the landscape I conducted visitor surveys in the same study areas in which the biodiversity surveys were performed. To analyse possible psychological or demographic effects on preferences for certain disturbance intensities, an additional online survey was carried out.}, subject = {Borkenk{\"a}fer}, language = {en} } @phdthesis{Kuhlemann2022, author = {Kuhlemann, Alexander}, title = {Bioorthogonal labeling of neuronal proteins using super-resolution fluorescence microscopy}, doi = {10.25972/OPUS-24373}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-243731}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {The synaptic cleft is of central importance for synaptic transmission, neuronal plasticity and memory and thus well studied in neurobiology. To target proteins of interest with high specificity and strong signal to noise conventional immunohistochemistry relies on the use of fluorescently labeled antibodies. However, investigations on synaptic receptors remain challenging due to the defined size of the synaptic cleft of ~20 nm between opposing pre- and postsynaptic membranes. At this limited space, antibodies bear unwanted side effects such as crosslinking, accessibility issues and a considerable linkage error between fluorophore and target of ~10 nm. With recent single molecule localization microscopy (SMLM) methods enabling localization precisions of a few nanometers, the demand for labeling approaches with minimal linkage error and reliable recognition of the target molecules rises. Within the scope of this work, different labeling techniques for super-resolution fluorescence microscopy were utilized allowing site-specific labeling of a single amino acid in synaptic proteins like kainate receptors (KARs), transmembrane α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor regulatory proteins (TARPs), γ-aminobutyric acid type A receptors (GABA-ARs) and neuroligin 2 (NL2). The method exploits the incorporation of unnatural amino acids (uAAs) in the protein of interest using genetic code expansion (GCE) via amber suppression technology and subsequent labeling with tetrazine functionalized fluorophores. Implementing this technique, hard-to-target proteins such as KARs, TARPs and GABA-ARs could be labeled successfully, which could only be imaged insufficiently with conventional labeling approaches. Furthermore, functional studies involving electrophysiological characterization, as well as FRAP and FRET experiments validated that incorporation of uAAs maintains the native character of the targeted proteins. Next, the method was transferred into primary hippocampal neurons and in combination with super-resolution microscopy it was possible to resolve the nanoscale organization of γ2 and γ8 TARPs. Cluster analysis of dSTORM localization data verified synaptic accumulation of γ2, while γ8 was homogenously distributed along the neuron. Additionally, GCE and bioorthogonal labeling allowed visualization of clickable GABA-A receptors located at postsynaptic compartments in dissociated hippocampal neurons. Moreover, saturation experiments and FRET imaging of clickable multimeric receptors revealed successful binding of multiple tetrazine functionalized fluorophores to uAA-modified dimeric GABA-AR α2 subunits in close proximity (~5 nm). Further utilization of tetrazine-dyes via super-resolution microscopy methods such as dSTORM and click-ExM will provide insights to subunit arrangement in receptors in the future. This work investigated the nanoscale organization of synaptic proteins with minimal linkage error enabling new insights into receptor assembly, trafficking and recycling, as well as protein-protein interactions at synapses. Ultimately, bioorthogonal labeling can help to understand pathologies such as the limbic encephalitis associated with GABA-AR autoantibodies and is already in application for cancer therapies.}, subject = {microscopy}, language = {en} } @phdthesis{Boetzl2022, author = {B{\"o}tzl, Fabian Alexander}, title = {The influence of crop management and adjacent agri-environmental scheme type on natural pest control in differently structured landscapes}, doi = {10.25972/OPUS-24140}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-241400}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2022}, abstract = {Summary Chapters I \& II: General Introduction \& General Methods Agriculture is confronted with a rampant loss of biodiversity potentially eroding ecosystem service potentials and adding up to other stressors like climate change or the consequences of land-use change and intensive management. To counter this 'biodiversity crisis', agri-environment schemes (AES) have been introduced as part of ecological intensification efforts. These AES combine special management regimes with the establishment of tailored habitats to create refuges for biodiversity in agricultural landscapes and thus ensure biodiversity mediated ecosystem services such as pest control. However, little is known about how well different AES habitats fulfil this purpose and whether they benefit ecosystem services in adjacent crop fields. Here I investigated how effective different AES habitats are for restoring biodiversity in different agricultural landscapes (Chapter V) and whether they benefit natural pest control in adjacent oilseed rape (Chapter VI) and winter cereal fields (Chapter VII). I recorded biodiversity and pest control potentials using a variety of different methods (Chapters II, V, VI \& VII). Moreover, I validated the methodology I used to assess predator assemblages and predation rates (Chapters III \& IV). Chapter III: How to record ground dwelling predators? Testing methodology is critical as it ensures scientific standards and trustworthy results. Pitfall traps are widely used to record ground dwelling predators, but little is known about how different trap types affect catches. I compared different types of pitfall traps that had been used in previous studies in respect to resulting carabid beetle assemblages. While barrier traps collected more species and deliver more complete species inventories, conventional simple pitfall traps provide reliable results with comparatively little handling effort. Placing several simple pitfall traps in the field can compensate the difference while still saving handling effort.   Chapter IV: How to record predation rates? A plethora of methods has been proposed and used for recording predation rates, but these have rarely been validated before use. I assessed whether a novel approach to record predation, the use of sentinel prey cards with glued on aphids, delivers realistic results. I compared different sampling efforts and showed that obtained predation rates were similar and could be linked to predator (carabid beetle) densities and body-sizes (a proxy often used for food intake rates). Thus, the method delivers reliable and meaningful predation rates. Chapter V: Do AES habitats benefit multi-taxa biodiversity? The main goal of AES is the conservation of biodiversity in agricultural landscapes. I investigated how effectively AES habitats with different temporal continuity fulfil this goal in differently structured landscapes. The different AES habitats investigated had variable effects on local biodiversity. Temporal continuity of AES habitats was the most important predictor with older, more temporally continuous habitats harbouring higher overall biodiversity and different species assemblages in most taxonomic groups than younger AES habitats. Results however varied among taxonomic groups and natural enemies were equally supported by younger habitats. Semi-natural habitats in the surrounding landscape and AES habitat size were of minor importance for local biodiversity and had limited effects. This stresses that newly established AES habitats alone cannot restore farmland biodiversity. Both AES habitats as well as more continuous semi-natural habitats synergistically increase overall biodiversity in agricultural landscapes. Chapter VI: The effects of AES habitats on predators in adjacent oilseed rape fields Apart from biodiversity conservation, ensuring ecosystem service delivery in agricultural landscapes is a crucial goal of AES. I therefore investigated the effects of adjacent AES habitats on ground dwelling predator assemblages in oilseed rape fields. I found clear distance decay effects from the field edges into the field centres on both richness and densities of ground dwelling predators. Direct effects of adjacent AES habitats on assemblages in oilseed rape fields however were limited and only visible in functional traits of carabid beetle assemblages. Adjacent AES habitats doubled the proportion of predatory carabid beetles indicating a beneficial role for pest control. My results show that pest control potentials are largest close to the field edges and beneficial effects are comparably short ranged. Chapter VII: The effects of AES habitats on pest control in adjacent cereal fields Whether distance functions and potential effects of AES habitats are universal across crops is unknown. Therefore, I assessed distance functions of predators, pests, predation rates and yields after crop rotation in winter cereals using the same study design as in the previous year. Resulting distance functions were not uniform and differed from those found in oilseed rape in the previous year, indicating that the interactions between certain adjacent habitats vary with habitat and crop types. Distance functions of cereal-leaf beetles (important cereal pests) and parasitoid wasps were moreover modulated by semi-natural habitat proportion in the surrounding landscapes. Field edges buffered assemblage changes in carabid beetle assemblages over crop rotation confirming their important function as refuges for natural enemies. My results emphasize the beneficial role of field edges for pest control potentials. These findings back the calls for smaller field sizes and more diverse, more heterogeneously structured agricultural landscapes. Chapter VIII: General Discussion Countering biodiversity loss and ensuring ecosystem service provision in agricultural landscapes is intricate and requires strategic planning and restructuring of these landscapes. I showed that agricultural landscapes could benefit maximally from (i) a mixture of AES habitats and semi-natural habitats to support high levels of overall biodiversity and from (ii) smaller continuously managed agricultural areas (i.e. smaller field sizes or the insertion of AES elements within large fields) to maximize natural pest control potentials in crop fields. I propose a mosaic of younger AES habitats and semi-natural habitats to support ecosystem service providers and increase edge density for ecosystem service spillover into adjacent crops. The optimal extent and density of this network as well as the location in which AES and semi-natural habitats interact most beneficially with adjacent crops need further investigation. My results provide a further step towards more sustainable agricultural landscapes that simultaneously allow biodiversity to persist and maintain agricultural production under the framework of ecological intensification.}, subject = {{\"O}kologie}, language = {en} } @article{ScheinerLimMeixneretal.2021, author = {Scheiner, Ricarda and Lim, Kayun and Meixner, Marina D. and Gabel, Martin S.}, title = {Comparing the appetitive learning performance of six European honeybee subspecies in a common apiary}, series = {Insects}, volume = {12}, journal = {Insects}, number = {9}, issn = {2075-4450}, doi = {10.3390/insects12090768}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245180}, year = {2021}, abstract = {The Western honeybee (Apis mellifera L.) is one of the most widespread insects with numerous subspecies in its native range. How far adaptation to local habitats has affected the cognitive skills of the different subspecies is an intriguing question that we investigate in this study. Naturally mated queens of the following five subspecies from different parts of Europe were transferred to Southern Germany: A. m. iberiensis from Portugal, A. m. mellifera from Belgium, A. m. macedonica from Greece, A. m. ligustica from Italy, and A. m. ruttneri from Malta. We also included the local subspecies A. m. carnica in our study. New colonies were built up in a common apiary where the respective queens were introduced. Worker offspring from the different subspecies were compared in classical olfactory learning performance using the proboscis extension response. Prior to conditioning, we measured individual sucrose responsiveness to investigate whether possible differences in learning performances were due to differential responsiveness to the sugar water reward. Most subspecies did not differ in their appetitive learning performance. However, foragers of the Iberian honeybee, A. m. iberiensis, performed significantly more poorly, despite having a similar sucrose responsiveness. We discuss possible causes for the poor performance of the Iberian honeybees, which may have been shaped by adaptation to the local habitat.}, language = {en} } @article{BassetCizekCuenoudetal.2015, author = {Basset, Yves and Cizek, Lukas and Cu{\´e}noud, Philippe and Didham, Raphael K. and Novotny, Vojtech and {\O}degaard, Frode and Roslin, Tomas and Tishechkin, Alexey K. and Schmidl, J{\"u}rgen and Winchester, Neville N. and Roubik, David W. and Aberlenc, Henri-Pierre and Bail, Johannes and Barrios, Hector and Bridle, Jonathan R. and Casta{\~n}o-Meneses, Gabriela and Corbara, Bruno and Curletti, Gianfranco and da Rocha, Wesley Duarte and De Bakker, Domir and Delabie, Jacques H. C. and Dejean, Alain and Fagan, Laura L. and Floren, Andreas and Kitching, Roger L. and Medianero, Enrique and de Oliveira, Evandro Gama and Orivel, Jerome and Pollet, Marc and Rapp, Mathieu and Ribeiro, Servio P. and Roisin, Yves and Schmidt, Jesper B. and S{\o}rensen, Line and Lewinsohn, Thomas M. and Leponce, Maurice}, title = {Arthropod Distribution in a Tropical Rainforest: Tackling a Four Dimensional Puzzle}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {12}, doi = {10.1371/journal.pone.0144110}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136393}, pages = {e0144110}, year = {2015}, abstract = {Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents a first step towards scrutinizing the global distribution of biodiversity on Earth. To date most studies have focused on narrow taxonomic groups or lack a design that allows partitioning of the components of diversity. Here, we consider an exceptionally large dataset (113,952 individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama, where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting the soil, litter, understory, lower and upper canopy habitats, replicated across seasons in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance, observed and estimated species richness, additive decomposition of species richness, multiplicative partitioning of species diversity, variation in species composition, species turnover and guild structure as components of diversity. At the scale of our study (2km of distance, 40m in height and 400 days), the effects related to the vertical and seasonal dimensions were most important. Most adult arthropods were collected from the soil/litter or the upper canopy and species richness was highest in the canopy. We compared the distribution of arthropods and trees within our study system. Effects related to the seasonal dimension were stronger for arthropods than for trees. We conclude that: (1) models of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods; (2) it is imperative that estimates of global biodiversity derived from mass collecting of arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning observed here; and (3) given the high species turnover observed between seasons, global climate change may have severe consequences for rainforest arthropods.}, language = {en} } @article{AgostonLiHaslingeretal.2012, author = {Agoston, Zsuzsa and Li, Naixin and Haslinger, Anja and Wizenmann, Andrea and Schulte, Dorothea}, title = {Genetic and physical interaction of Meis2, Pax3 and Pax7 during dorsal midbrain development}, series = {BMC Developmental Biology}, volume = {12}, journal = {BMC Developmental Biology}, number = {10}, doi = {10.1186/1471-213X-12-10}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132626}, year = {2012}, abstract = {Background: During early stages of brain development, secreted molecules, components of intracellular signaling pathways and transcriptional regulators act in positive and negative feed-back or feed-forward loops at the mid-hindbrain boundary. These genetic interactions are of central importance for the specification and subsequent development of the adjacent mid-and hindbrain. Much less, however, is known about the regulatory relationship and functional interaction of molecules that are expressed in the tectal anlage after tectal fate specification has taken place and tectal development has commenced. Results: Here, we provide experimental evidence for reciprocal regulation and subsequent cooperation of the paired-type transcription factors Pax3, Pax7 and the TALE-homeodomain protein Meis2 in the tectal anlage. Using in ovo electroporation of the mesencephalic vesicle of chick embryos we show that (i) Pax3 and Pax7 mutually regulate each other's expression in the mesencephalic vesicle, (ii) Meis2 acts downstream of Pax3/7 and requires balanced expression levels of both proteins, and (iii) Meis2 physically interacts with Pax3 and Pax7. These results extend our previous observation that Meis2 cooperates with Otx2 in tectal development to include Pax3 and Pax7 as Meis2 interacting proteins in the tectal anlage. Conclusion: The results described here suggest a model in which interdependent regulatory loops involving Pax3 and Pax7 in the dorsal mesencephalic vesicle modulate Meis2 expression. Physical interaction with Meis2 may then confer tectal specificity to a wide range of otherwise broadly expressed transcriptional regulators, including Otx2, Pax3 and Pax7.}, language = {en} } @phdthesis{Hoecherl2015, author = {H{\"o}cherl, Nicole}, title = {Nesting behaviour of the paper wasp Polistes dominula - with special focus on thermoregulatory mechanisms}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132681}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Wasps of the genus Polistes comprise over 200 species and are nearly cosmopolitan. They show a lack of physiological caste differentiation and are therefore considered as primitively eusocial. Furthermore, paper wasps are placed between the solitary living Eumenidae and the highly social organized Vespinae. Hence, they are often called a "key genus" for understanding the evolution of sociality. Particularly, Polistes dominula, with its small easy manageable nests and its frequent occurrence and wide distribution range is often the subject of studies. In Europe, the invasion of this species into northern regions is on the rise. Since little was known about the nesting behaviour of P. dominula in Central Europe, the basic principles about nesting were investigated in W{\"u}rzburg, Germany (latitude 49°) by conducting a comprehensive field-study spanning three consecutive years. Furthermore, the thermoregulation of individual wasps in their natural habitat had not yet been investigated in detail. Therefore, their ability to respond to external hazards with elevated thorax temperatures was tested. In addition, different types of nest thermoregulation were investigated using modern methods such as infrared thermography and temperature data logger. In the present work, the investigation of basic nesting principles revealed that foundress groups (1-4 foundresses) and nests are smaller and that the nesting season is shorter in the W{\"u}rzburg area than in other regions. The mean size of newly founded nests was 83 cells and the average nesting season was around 4.6 months. The queens neither preferred single (54\%) nor multiple founding (46\%) in this study. The major benefit of multiple founding is an increased rate of survival. During the three years of observation, only 47\% of single-foundress colonies survived, whereas 100\% of colonies that were built by more than two queens, survived. However, an influence of the number of foundresses on the productivity of colonies in terms of number of cells and pupae per nest has not shown up. However, the length of the nesting season as well as the nest sizes varied strongly depending on the climatic conditions of the preceding winter during the three consecutive years. In order to investigate the thermoregulatory mechanisms of individual adult P. dominula wasps, I presented artificial threats by applying smoke or carbon dioxide simulating fire and predator attacks, respectively, and monitored the thorax temperature of wasps on the nest using infrared thermography. The results clearly revealed that P. dominula workers recognized smoke and CO2 and reacted almost instantaneously and simultaneously with an increase of their thorax temperature. The maximal thorax temperature was reached about 65 s after the application of both stressors, but subsequently the wasps showed a different behaviour pattern. They responded to a longer application of smoke with moving to the exit and fled, whereas in case of CO2 the wasps started flying and circling the nest without trying to escape. No rise of the thorax temperature was detectable after an air blast was applied or in wasps resting on the nest. Additionally, the thorax temperatures of queens were investigated during dominance battles. I found that the thorax temperature of the dominant queens rose up to 5°C compared to that of subordinate queens that attacked the former. The study of active mechanisms for nest thermoregulation revealed no brood incubation or clustering behaviour of P. dominula. Furthermore, I found out that wing fanning for cooling the nest was almost undetectable (4 documented cases). However, I could convincingly record that water evaporation is most effective for nest cooling. By the direct comparison of active (with brood and adults) and non-active (without brood and adults) nests, the start of cooling by water evaporation was detected above maximum outside temperatures of 25°C or at nest temperatures above 35°C. The powerful role of water in nest cooling was manifested by an average decrease of temperature of a single cell of about 8°C and a mean duration of 7 min until the cell reached again its initial temperature. The investigation of passive thermoregulatory mechanisms revealed that the nest site choice as well as nest orientation appears to be essential for P. dominula wasps. Furthermore, I was able to show that the architecture of the nests plays an important role. Based on the presented results, it can be assumed that the vertical orientation of cells helps maintaining the warmth of nests during the night, whereas the pedicel assists in cooling the nest during the day.}, subject = {Franz{\"o}sische Feldwespe}, language = {en} } @phdthesis{ContarAdolfi2017, author = {Contar Adolfi, Mateus}, title = {Sex determination and meiosis in medaka: The role of retinoic acid}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136335}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {Sex determination (SD) is a complex and diverse developmental process that leads to the decision whether the bipotential gonad anlage will become a testis or an ovary. This mechanism is regulated by gene cascades, networks and/or chromosomal systems, and can be influenced by fluctuations of extrinsic factors like temperature, exposure to hormones and pollution. Within vertebrates, the group of fish show the widest variety of sex determination mechanism. This whole diversity of processes and mechanisms converges to the formation of two different gametes, the eggs and the sperm, the first bigger and static, and the second smaller and motile. Meiosis is crucial for the formation of both types of gametes, and the timing of meiosis entry is one of the first recognizable differences between male and female in vertebrates. The germ cells go into meiosis first in female than in male, and in mammals, this event has been shown to be regulated by retinoic acid (RA). This small polar molecule induces in the germ cells the expression of the pre-meiotic marker Stra8 (stimulated by retinoic acid gene 8), which is necessary for meiosis initiation. Interestingly, genome analyzes have shown that the majority of fish (including medaka) lack the stra8 gene, adding a question mark to the role of RA in meiosis induction in this group. Since a role of RA in entry of meiosis and sexual development of fish is still far from being understood, I investigated in medaka (Oryzias latipes) a possible signaling function of RA during the SD period in embryos and in reproductively active gonads of adults. I generated a transgenic medaka line that reports responsiveness to RA in vivo. With this tool, I compared RA responsiveness with the expression of the main gene involved in the synthesis of RA. My results show that there is a de-correlation between the action of RA with its source. In adults, expression of the RA metabolizing enzymes show sexually dimorphic RA levels, with aldh1a2 levels being higher in testis, and cyp26a1 stronger in female gonad. In ovary, the responsiveness is restricted to the early meiotic oocytes. In testis, RA is acting directly in the pre-meiotic cells, but also in Sertoli and Leydig cells. Treatment experiments on testis organ culture showed that RA pathway activation leads to a decrease in meiosis markers expression levels. During the development, RA responsiveness in the germ cells was observed in both sexes much earlier than the first female meiosis entry. Treatments with RA-synthesis inhibitor show a decrease in meiosis markers expression levels only after the sex differentiation period in female. Expression analyzes of embryos treated with exogenous RA showed induction of dmrt1a at the gonad levels and an increase of amh levels. Both genes are not only involved in male formation, but also in the regulation of germ cell proliferation and differentiation. RA is important in meiosis induction and gametogenesis in adult medaka. However, there is no evidence for a similar role of RA in initiating the first meiosis in female germ cells at the SD stage. Moreover, contrary to common expectation, RA seems to induce sex related genes that are involved indirectly in meiosis inhibition. In this thesis, I showed for the first time that RA can be involved in both induction and inhibition of meiosis entry, depending on the sex and the developmental stage in a stra8-independent model organism.}, subject = {Japank{\"a}rpfling}, language = {en} } @phdthesis{Hackl2016, author = {Hackl, Thomas}, title = {A draft genome for the Venus flytrap, Dionaea muscipula : Evaluation of assembly strategies for a complex Genome - Development of novel approaches and bioinformatics solutions}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133149}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {The Venus flytrap, \textit{Dionaea muscipula}, with its carnivorous life-style and its highly specialized snap-traps has fascinated biologist since the days of Charles Darwin. The goal of the \textit{D. muscipula} genome project is to gain comprehensive insights into the genomic landscape of this remarkable plant. The genome of the diploid Venus flytrap with an estimated size between 2.6 Gbp to 3.0 Gbp is comparatively large and comprises more than 70 \% of repetitive regions. Sequencing and assembly of genomes of this scale are even with state-of-the-art technology and software challenging. Initial sequencing and assembly of the genome was performed by the BGI (Beijing Genomics Institute) in 2011 resulting in a 3.7 Gbp draft assembly. I started my work with thorough assessment of the delivered assembly and data. My analysis showed that the BGI assembly is highly fragmented and at the same time artificially inflated due to overassembly of repetitive sequences. Furthermore, it only comprises about on third of the expected genes in full-length, rendering it inadequate for downstream analysis. In the following I sought to optimize the sequencing and assembly strategy to obtain an assembly of higher completeness and contiguity by improving data quality and assembly procedure and by developing tailored bioinformatics tools. Issues with technical biases and high levels of heterogeneity in the original data set were solved by sequencing additional short read libraries from high quality non-polymorphic DNA samples. To address contiguity and heterozygosity I examined numerous alternative assembly software packages and strategies and eventually identified ALLPATHS-LG as the most suited program for assembling the data at hand. Moreover, by utilizing digital normalization to reduce repetitive reads, I was able to substantially reduce computational demands while at the same time significantly increasing contiguity of the assembly. To improve repeat resolution and scaffolding, I started to explore the novel PacBio long read sequencing technology. Raw PacBio reads exhibit high error rates of 15 \% impeding their use for assembly. To overcome this issue, I developed the PacBio hybrid correction pipeline proovread (Hackl et al., 2014). proovread uses high coverage Illumina read data in an iterative mapping-based consensus procedure to identify and remove errors present in raw PacBio reads. In terms of sensitivity and accuracy, proovread outperforms existing software. In contrast to other correction programs, which are incapable of handling data sets of the size of D. muscipula project, proovread's flexible design allows for the efficient distribution of work load on high-performance computing clusters, thus enabling the correction of the Venus flytrap PacBio data set. Next to the assembly process itself, also the assessment of the large de novo draft assemblies, particularly with respect to coverage by available sequencing data, is difficult. While typical evaluation procedures rely on computationally extensive mapping approaches, I developed and implemented a set of tools that utilize k-mer coverage and derived values to efficiently compute coverage landscapes of large-scale assemblies and in addition allow for automated visualization of the of the obtained information in comprehensive plots. Using the developed tools to analyze preliminary assemblies and by combining my findings regarding optimizations of the assembly process, I was ultimately able to generate a high quality draft assembly for D. muscipula. I further refined the assembly by removal of redundant contigs resulting from separate assembly of heterozygous regions and additional scaffolding and gapclosing using corrected PacBio data. The final draft assembly comprises 86 × 10 3 scaffolds and has a total size of 1.45 Gbp. The difference to the estimated genomes size is well explained by collapsed repeats. At the same time, the assembly exhibits high fractions full-length gene models, corroborating the interpretation that the obtained draft assembly provides a complete and comprehensive reference for further exploration of the fascinating biology of the Venus flytrap.}, subject = {Venusfliegenfalle}, language = {en} } @article{DossoYeoKonateetal.2012, author = {Dosso, Kanvaly and Yeo, Kolo and Konate, Souleymane and Linsenmair, Karl Eduard}, title = {Importance of protected areas for biodiversity conservation in central Cote d'Ivoire: Comparison of termite assemblages between two neighboring areas under differing levels of disturbance}, series = {Journal of Insect Science}, volume = {12}, journal = {Journal of Insect Science}, number = {131}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133218}, year = {2012}, abstract = {To highlight human impact on biodiversity in the Lamto region, termites were studied with regard to their use as bio-indicators of habitat change in the tropics. Using a standardized method, termites were sampled in the three most common habitat types, i.e., in semi-deciduous forest, savanna woodland, and annually burned savanna, all inside Lamto Reserve and its surrounding rural domain. Termite species richness fell from 25 species in the Lamto forest to 13 species in the rural area, involving strong modification in the species composition (species turnover = 59 \%). In contrast, no significant change in diversity was found between the Lamto savannas and the rural ones. In addition, the relative abundance of termites showed a significantly greater decline in the rural domain, even in the species Ancistrotermes cavithorax (Sjostedt) (Isoptera: Termitidae), which is known to be ecologically especially versatile. Overall, the findings of this study suggest further investigation around Lamto Reserve on the impact of human activities on biodiversity, focusing on forest conversion to land uses (e.g. agricultural and silvicultural systems).}, language = {en} } @phdthesis{MontalbandelBarrio2015, author = {Montalb{\´a}n del Barrio, Itsaso}, title = {Immunosuppressive role of adenosine produced by ectonucleotidases CD39 and CD73 in ovarian cancer, tumor associated macrophages and the host immune system}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133268}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Eierstockkrebs ist der Tumor mit der schlechtesten Heilungsprognose unter allen gyn{\"a}kologischen Malignomen. Allein in Deutschland verursacht er {\"u}ber 6000 Tote pro Jahr. Patienten mit Ovarialkarzinom zeigen erst in einem sehr fortgeschrittenen Stadium charakteristische Symptome. Die einzig m{\"o}glichen Behandlungsmethoden sind dann die operative Tumorentfernung und die Verabreichung von platinbasierter Chemotherapien sowie von Anthrazyklinen. Da die aktuelle 5-Jahres-{\"U}berlebensrate lediglich 20-40\% betr{\"a}gt, besteht ein dringender Bedarf an neuen therapeutischen Optionen. Seit herausgefunden wurde, dass immunologische Parameter das {\"U}berleben der Patienten beeinflussen, ist Immuntherapie zu einer der vielversprechendsten Behandlungsarten des Eierstockkrebs geworden. Das Ziel unserer Forschung ist die {\"U}berwindung der Immunevasion des Tumors durch ein Verhindern der immun-unterdr{\"u}ckenden Mechanismen des Tumors. Im Speziellen befasst sich diese Arbeit mit dem Einfluss von Adenosin, das durch die Ectonukleotidasen CD39 und CD73 in der Mikroumgebung des Tumors gebildet wird. Die CD39- und CD73-Expression der Zellen f{\"u}hrt zu Immunosuppression da diese Ectonukleotidasen immun-stimulierendes, extrazellul{\"a}res ATP in immunsuppressives Adenosin umwandeln. Dies wurde zuerst als Effektormechanismus f{\"u}r regulatorische T-Zellen beschrieben, kann aber auch im Tumormikromilieu von Bedeutung sein. Mit dem Wissen, dass Tumorzellen von Eierstockkrebs-Patientinnen große Mengen der ATP-unterdr{\"u}ckenden Ectonukleotidasen CD39 und CD73 bilden, analysierten wir die adenosinvermittelte Unterdr{\"u}ckendung von Immunantwortenin der Mikroumgebung der Tumorzellen. Im Vergleich zu regulatorischen T Zellen konnten wir bei Eierstockkrebs-Zelllinien und bei aus Aszites gewonnenen Krebszellen eine 30- bis 60-fache Adenosinproduktion messen. Um diesen mutmaßlichen Immunevasions-Mechanismus zu best{\"a}tigen, untersuchten wir seine Auswirkungen auf mehrere Immunzellenpopulationen. CSFE-basierte Experimente zeigten zum Beispiel eine Hemmung der CD4+ T-Zell-Proliferation durch Adenosin, welches von Eierstockkrebs-Zellen produziert wurde. In diesem Zusammenhang haben wir auch eine in-vitro Methode entwickelt, mit der wir die Beeinflussung von Makrophagen durch Eierstockkrebszellen analysieren und modulieren konnten. Neben seiner suppressiven Wirkung {\"u}bt Adenosin auch chemotaktische Effekte auf menschliche Monozyten aus und lockt wahrscheinlich myeloide Vorl{\"a}uferzellen zum Tumorgewebe. Anschließend differenzieren sich menschliche Monozyten in einer von Eierstockkrebszellen geformten Mikroumgebung zu M2 Makrophagen oder tumor-assoziierten Makrophagen (TAMs), die ihrerseits erhebliche Mengen der Adenosin-produzierenden Ectonukleotidasen CD39 und CD73 bilden. W{\"a}hrend wir die Regulierung der Ectonukleotidasen-Expression untersuchten, entdeckten wir auch, dass klinisch genutzte Techniken zur Behandlung von Eierstockkrebs (zum Beispiel die Anwendung von Doxorubicin oder Bestrahlung) in vitro das CD73- und CD39-Level von Eierstockkrebs- und Immunzellen beeinflussen. In dieser Studie zeigen wir, wie dieser behandlungsbedingte Wechsel des ATP/Adenosine-Verh{\"a}ltnisses die Effektorfunktion verschiedener Immunzellen moduliert. Dar{\"u}ber hinaus untersuchen wir den potentiellen Vorteil von klinisch verf{\"u}gbaren, niedermolekularen Inhibitoren f{\"u}r CD39 und CD73, die die Immunsuppression in der Mikroumgebung des Tumors partiell aufheben k{\"o}nnten, und die vor allem in Kombination mit g{\"a}ngigen Behandlungsschemata von großem Interesse sein k{\"o}nnten.}, subject = {Eierstockkrebs}, language = {en} } @article{HoennemannSanzMorenoWolfetal.2012, author = {H{\"o}nnemann, Jan and Sanz-Moreno, Adrian and Wolf, Elmar and Eilers, Martin and Els{\"a}sser, Hans-Peter}, title = {Miz1 Is a Critical Repressor of cdkn1a during Skin Tumorigenesis}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {4}, doi = {10.1371/journal.pone.0034885}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133285}, pages = {e34885}, year = {2012}, abstract = {The transcription factor Miz1 forms repressive DNA-binding complexes with the Myc, Gfi-1 and Bcl-6 oncoproteins. Known target genes of these complexes encode the cyclin-dependent kinase inhibitors (CKIs) cdkn2b (p15\(^{Ink4}\)), cdkn1a (p21\(^{Cip1}\)), and cdkn1c (p57\(^{Kip2}\)). Whether Miz1-mediated repression is important for control of cell proliferation in vivo and for tumor formation is unknown. Here we show that deletion of the Miz1 POZ domain, which is critical for Miz1 function, restrains the development of skin tumors in a model of chemically-induced, Ras-dependent tumorigenesis. While the stem cell compartment appears unaffected, interfollicular keratinocytes lacking functional Miz1 exhibit a reduced proliferation and an accelerated differentiation of the epidermis in response to the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Tumorigenesis, proliferation and normal differentiation are restored in animals lacking cdkn1a, but not in those lacking cdkn2b. Our data demonstrate that Miz1-mediated attenuation of cell cycle arrest pathways via repression of cdkn1a has a critical role during tumorigenesis in the skin.}, language = {en} } @phdthesis{AppeltMenzel2016, author = {Appelt-Menzel, Antje}, title = {Etablierung und Qualifizierung eines humanen Blut-Hirn-Schranken-Modells unter Verwendung von induziert pluripotenten und multipotenten Stammzellen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134646}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {Die Blut-Hirn-Schranke (BHS) stellt eine der dichtesten und wichtigsten Barrieren zwischen Blutzirkulation und Zentralnervensystem (ZNS) dar. Sie besteht aus spezialisierten Endothelzellen, welche die zerebralen Kapillaren auskleiden und durch sehr dichte Tight Junctions (TJs) miteinander verbunden sind. Weitere Komponenten der dynamischen Blut-Hirn-Schrankenbarriere stellen Perizyten, Astrozyten, Neurone und Mikrogliazellen dar, welche zusammen mit der extrazellul{\"a}ren Matrix der Basalmembran der Gehirnkapillaren und den zuvor genannten Endothelzellen ein komplexes regulatorisches System, die so genannte neurovaskul{\"a}re Einheit bilden (Hawkins und Davis 2005). Die Hauptfunktionen der BHS lassen sich in drei Untergruppen untergliedern, die physikalische, metabolische und Transport-Barriere (Neuhaus und Noe 2010). Haupts{\"a}chlich dient die BHS der Aufrechterhaltung der Hom{\"o}ostase des ZNS und dem Schutz vor neurotoxischen Substanzen sowie Pathogenen, wie Bakterien und Viren. Zudem ist sie auch f{\"u}r die Versorgung der Neuronen mit N{\"a}hrstoffen und regulierenden Substanzen sowie den Efflux von Stoffwechselendprodukten des ZNS zur{\"u}ck ins Blut verantwortlich. F{\"u}r die Entwicklung von Medikamenten zur Behandlung von neurodegenerativen Erkrankungen, wie Morbus Alzheimer, Morbus Parkinson und Multiple Sklerose oder Gehirntumoren, stellt die Dichtigkeit der BHS gegen{\"u}ber Substanzen und die hohe metabolische Aktivit{\"a}t der Endothelzellen aber ein großes Problem dar. Viele Medikamente sind nicht in der Lage in ausreichender Konzentration die BHS zu {\"u}berwinden, um an ihren Wirkort zu gelangen oder werden vor dem Transport metabolisiert und die Wirksamkeit dadurch eingeschr{\"a}nkt. Weiterhin spielen auch Defekte der BHS eine entscheidende Rolle in der Beeinflussung der Pathogenese vieler ZNS-Erkrankungen. Aufgrund des hohen Bedarfs an geeigneten Testsystemen in der Grundlagen- sowie pr{\"a}klinischen Forschung f{\"u}r Medikamentenentwicklung und Infektionsstudien wurden eine Vielzahl unterschiedlicher BHS-Modelle entwickelt. Neben in silico-, azellul{\"a}ren in vitro- und in vivo-Modellen sind auch zahlreiche zellbasierte Modelle der BHS entwickelt worden. Standardisierte Modelle auf Basis immortalisierter Zelllinien jedoch weisen nur eine inhomogene TJ-Expression auf und verf{\"u}gen meist {\"u}ber eine geringe Barriereintegrit{\"a}t, erfasst {\"u}ber transendotheliale elektrische Widerst{\"a}nde (TEER) unter 150 · cm2 (Deli et al. 2005). Im Vergleich dazu wurden in Tierexperimenten TEER-Werte von mehr als 1500 · cm2 an der BHS gemessen (Butt et al. 1990; Crone und Olesen 1982). Die Verf{\"u}gbarkeit humaner prim{\"a}rer BHS-Zellen ist sehr limitiert und ihr Einsatz nicht nur im Hinblick auf ethische Aspekte bedenklich. Humane Gehirnzellen k{\"o}nnen z. B. aus Biopsie- oder Autopsiematerial von Patienten mit Epilepsie oder Gehirntumoren isoliert werden. Allerdings besteht hier das Risiko, dass die isolierten Zellen krankheitsbedingt ver{\"a}ndert sind, was die Eigenschaften der BHS-Modelle erheblich beeinflussen kann. Eine Alternative, die diese Probleme umgeht, ist die Verwendung von humanen induziert pluripotenten Stammzellen (hiPSCs), um standardisierte humane BHS-Modelle unter reproduzierbaren Bedingungen bereitzustellen. Im Rahmen dieser Arbeit ist es gelungen, hiPSCs in vitro nach etablierten und standardisierten Methoden in Endothelzellen der BHS, neurale Stammzellen (hiPS-NSCs) sowie Astrozyten (hiPS-A) zu differenzieren (Lippmann et al. 2012; Lippmann et al. 2014; Wilson et al. 2015; Yan et al. 2013;Reinhardt et al. 2013) und zum Aufbau der Modelle einzusetzen. Die Endothelzellen wurden mit Hilfe protein- und genbasierter Nachweismethoden auf das Vorhandensein von endothelzellspezifischen TJ-Markern sowie spezifischen Transportern untersucht und funktionell charakterisiert. Die Kryokonservierung der hiPS-EC-Progenitoren, die im Rahmen der vorliegenden Arbeit entwickelt wurde, erm{\"o}glicht eine gr{\"o}ßere r{\"a}umliche und zeitliche Flexibilit{\"a}t beim Arbeiten mit den stammzellbasierten Modellen sowie das Anlegen standardisierter Zellbanken. Weiterhin wurden multipotente NSCs aus fetalen Gehirnbiopsien isoliert (fNSCs) und als Kontrollkulturen zu den hiPS-NSCs f{\"u}r den Aufbau von BHS-Modellen eingesetzt. Mit dem Ziel die in vivo-BHS bestm{\"o}glich zu imitieren und die Modelleigenschaften zu optimieren, wurde ein Set aus zehn unterschiedlichen BHS-Modellen basierend auf prim{\"a}ren Zellen, hiPSCs und fNSCs analysiert. Der Aufbau der BHS-Modelle erfolgte unter Verwendung von Transwellsystemen. Durch die systematische Untersuchung des Einflusses der unterschiedlichen Zelltypen der neurovaskul{\"a}ren Einheit auf die Barriereintegrit{\"a}t und Genexpression des BHS-Endothels, konnten die Quadrupel-Kulturen mit Perizyten, Astrozyten und hiPS-NSCs als die Kultur mit den physiologischsten Eigenschaften identifiziert werden. Auf Grund der signifikant erh{\"o}hten TEER-Werte von bis zu 2500 · cm2 und einer um mindestens 1,5-fachen Steigerung der Genexpression BHSrelevanter Transporter und TJ-Molek{\"u}le gegen{\"u}ber den Monokulturen, wurden diese Modelle f{\"u}r weiterf{\"u}hrende Studien ausgew{\"a}hlt. Das Vorhandensein eines komplexen, in vivo-{\"a}hnlichen TJ-Netzwerkes, bestehend aus Occludin, Claudin 1, 3, 4 und 5, konnte mittels quantitativer Realtime-PCR, Western Blot sowie ultrastruktureller Analyse in der Gefrierbruch- und Raster-Elektronenmikroskopie nachgewiesen werden. Neben der Begrenzung der parazellul{\"a}ren Permeabilit{\"a}t, welche {\"u}ber die geringe Permeation von FITC-Dextran (4 kDa und 40 kDa), Fluoreszein und Lucifer Yellow nachgewiesen wurde, stellt die BHS ebenfalls eine Barriere f{\"u}r den transzellul{\"a}ren Transport von Substanzen dar. Eine Beurteilung der Modelle hinsichtlich der Qualifikation f{\"u}r die Nutzung im Wirkstoffscreening wurde mit Hilfe von Transportversuchen unter dem Einsatz von BHS-relevanten Referenzsubstanzen durchgef{\"u}hrt. Die Klassifikation der Testsubstanzen erfolgte analog ihrer Permeationsgeschwindigkeiten: Diazepam und Koffein gelten als schnell transportierte Wirkstoffe, Ibuprofen, Celecoxib und Diclofenac werden mit einer mittleren Geschwindigkeit {\"u}ber die BHS transportiert und Loratadin sowie Rhodamin 123 sind langsam permeierende Substanzen. Innerhalb der Versuche mit den Quadrupelkulturen wurde diese Reihenfolge best{\"a}tigt, lediglich f{\"u}r Koffein wurde ein signifikant niedrigerer Permeationskoeffizient verglichen mit der Monokultur erzielt. Der Einsatz der hiPSC-Technologie erm{\"o}glicht es zudem, aus einer Stammzelllinie große Mengen an humanen somatischen Zelltypen zu generieren und f{\"u}r gezielte Anwendungen bereitzustellen. Es konnte im Rahmen dieser Arbeit gezeigt werden, dass mit Hilfe eines eigens f{\"u}r diese Zwecke konstruierten R{\"u}hrreaktorsystems eine reproduzierbare Expansion der hiPSCs unter definierten Bedingungen erm{\"o}glicht wurde. Basierend auf dieser Grundlage ist nun ein Hochdurchsatz-Screening von Medikamenten denkbar. Die in dieser Arbeit pr{\"a}sentierten Daten belegen die Etablierung eines stammzellbasierten in vitro- Quadrupelmodels der humanen BHS, welches {\"u}ber in vivo-{\"a}hnliche Eigenschaften verf{\"u}gt. Die Anforderungen, die an humane BHS-Modelle gestellt werden, wie die Reproduzierbarkeit der Ergebnisse, eine angemessene Charakterisierung, welche die Untersuchung der Permeabilit{\"a}t von Referenzsubstanzen einschließt, die Analyse der Expression von BHS-relevanten Transportermolek{\"u}len sowie die solide und physiologische Morphologie der Zellen, wurden erf{\"u}llt. Das etablierte BHS-Modell kann in der Pharmaindustrie f{\"u}r die Entwicklung von Medikamenten eingesetzt werden. Ausreichend qualifizierte Modelle k{\"o}nnen hier in der pr{\"a}klinischen Forschung genutzt werden, um Toxizit{\"a}ts- und Transportstudien an neu entwickelten Substanzen durchzuf{\"u}hren und eine bessere in vitro-in vivo-Korrelation der Ergebnisse zu erm{\"o}glichen oder Mechanismen zu entwickeln, um die BHS-Barriere gezielt zu {\"u}berwinden.}, subject = {Blut-Hirn-Schranke}, language = {de} } @article{SangesScheuermannZahedietal.2012, author = {Sanges, C. and Scheuermann, C. and Zahedi, R. P. and Sickmann, A. and Lamberti, A. and Migliaccio, N. and Baljuls, A. and Marra, M. and Zappavigna, S. and Rapp, U. and Abbruzzese, A. and Caraglia, M. and Arcari, P.}, title = {Raf kinases mediate the phosphorylation of eukaryotic translation elongation factor 1A and regulate its stability in eukaryotic cells}, series = {Cell Death \& Disease}, volume = {3}, journal = {Cell Death \& Disease}, number = {e276}, doi = {10.1038/cddis.2012.16}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134673}, year = {2012}, abstract = {We identified eukaryotic translation elongation factor 1A (eEF1A) Raf-mediated phosphorylation sites and defined their role in the regulation of eEF1A half-life and of apoptosis of human cancer cells. Mass spectrometry identified in vitro S21 and T88 as phosphorylation sites mediated by B-Raf but not C-Raf on eEF1A1 whereas S21 was phosphorylated on eEF1A2 by both B-and C-Raf. Interestingly, S21 belongs to the first eEF1A GTP/GDP-binding consensus sequence. Phosphorylation of S21 was strongly enhanced when both eEF1A isoforms were preincubated prior the assay with C-Raf, suggesting that the eEF1A isoforms can heterodimerize thus increasing the accessibility of S21 to the phosphate. Overexpression of eEF1A1 in COS 7 cells confirmed the phosphorylation of T88 also in vivo. Compared with wt, in COS 7 cells overexpressed phosphodeficient (A) and phospho-mimicking (D) mutants of eEF1A1 (S21A/D and T88A/D) and of eEF1A2 (S21A/D), resulted less stable and more rapidly proteasome degraded. Transfection of S21 A/D eEF1A mutants in H1355 cells increased apoptosis in comparison with the wt isoforms. It indicates that the blockage of S21 interferes with or even supports C-Raf induced apoptosis rather than cell survival. Raf-mediated regulation of this site could be a crucial mechanism involved in the functional switching of eEF1A between its role in protein biosynthesis and its participation in other cellular processes.}, language = {en} } @article{LandoEndesfelderBergeretal.2012, author = {Lando, David and Endesfelder, Ulrike and Berger, Harald and Subramanian, Lakxmi and Dunne, Paul D. and McColl, James and Klenerman, David and Carr, Antony M. and Sauer, Markus and Allshire, Robin C. and Heilemann, Mike and Laue, Ernest D.}, title = {Quantitative single-molecule microscopy reveals that CENP-A\(^{Cnp1}\) deposition occurs during G2 in fission yeast}, series = {Open Biology}, volume = {2}, journal = {Open Biology}, number = {120078}, doi = {10.1098/rsob.120078}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134682}, year = {2012}, abstract = {The inheritance of the histone H3 variant CENP-A in nucleosomes at centromeres following DNA replication is mediated by an epigenetic mechanism. To understand the process of epigenetic inheritance, or propagation of histones and histone variants, as nucleosomes are disassembled and reassembled in living eukaryotic cells, we have explored the feasibility of exploiting photo-activated localization microscopy (PALM). PALM of single molecules in living cells has the potential to reveal new concepts in cell biology, providing insights into stochastic variation in cellular states. However, thus far, its use has been limited to studies in bacteria or to processes occurring near the surface of eukaryotic cells. With PALM, one literally observes and 'counts' individual molecules in cells one-by-one and this allows the recording of images with a resolution higher than that determined by the diffraction of light (the so-called super-resolution microscopy). Here, we investigate the use of different fluorophores and develop procedures to count the centromere-specific histone H3 variant CENP-A\(^{Cnp1}\) with single-molecule sensitivity in fission yeast (Schizosaccharomyces pombe). The results obtained are validated by and compared with ChIP-seq analyses. Using this approach, CENP-A\(^{Cnp1}\) levels at fission yeast (S. pombe) centromeres were followed as they change during the cell cycle. Our measurements show that CENP-A(Cnp1) is deposited solely during the G2 phase of the cell cycle.}, language = {en} } @phdthesis{Herweg2018, author = {Herweg, Jo-Ana}, title = {Die Simkania-Vakuole: Die Rolle von ER, retro-/anterograden Protein- und Lipidtransport}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136844}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2018}, abstract = {Simkania negevensis (Sn) is a Chlamydia-like obligate intracellular bacterium which replicates within a membrane bound vacuole, termed SCV (Simkania-containing vacuole). The SCV is a unique compartment closely associated with ER-membranes, consequently ER-stress is blocked by the bacteria. SCV morphology is similar among epithelial cells (HeLa229, A549, HEp-2) and macrophages (THP1). The SCV represents the first intracellular interface between the host and pathogen which serves as a replication niche. Identifying human and bacterial factors associated with ER-SCV-membranes should contribute towards the understanding of SCV composition and formation as well as interactions with ER or transports. Comparative studies of the SCV should indicate similarities to the chlamydial inclusion since some host cell factors are already known for Chlamydia. In this thesis, a purification protocol has been established that is applicable to HeLa229 and THP1 ER-SCV-membranes and has been further utilized for proteome and lipidome analyses. 302 bacterial and 1178 human proteins composing ER-SCV-membranes and 885 bacterial proteins composing purified Sn have been identified by using label-free mass spectrometry measurements. Among the human factors of non or Sn infected ER-(SCV-) membranes we found 51 enriched or depleted proteins in addition to 57 transport associated ones that indicated infection induced differences among intracellular protein transport. Contrary regulation of retrograde and anterograde transported proteins could be confirmed by using RNA interference and inhibitor tests, whereby Clathrin-associated and COPI vesicles seem to play a central role. Application of Retro-inhibitors, which interfered with retrograde transport processes between endosome to Golgi or early to late endosomes, as well as Bafilomycin A1 (retrograde, late endosomes and lysosomes) and Brefeldin A (anterograde, ER and Golgi) exerted a strong influence on SCV formation, morphology and intracellular lipid transport. By using label-free mass spectrometry measurements and thin layer chromatography we could determine differences in lipid levels within Sn infected cells, ER-SCV-membranes and purified Sn in comparison to uninfected cells. In addition to lipid enrichment or depletion in whole-cell extracts and ER-SCV-membranes, we identified two infection-specific lipids, cholesterol-ß-Dglucoside and PE 30:0. Further, high-throughput RNA interference tests indicated a dependence of Sn infections on endosome to Golgi and Clathrin-associated vesicle transports. Taken together, we were able to identify initial potential SCV-associated proteins and lipids that were connected to bacterial infection. Furthermore, SCV formation and Sn infectiousness depends on retrograde transport processes and therefore also on acquisition of nutrients, such as lipids.}, subject = {Simkania}, language = {de} } @phdthesis{Imes2016, author = {Imes, Dennis}, title = {Aufkl{\"a}rung der molekularen Struktur und Funktion des R-Typ Anionenkanals QUAC1 in Schließzellen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136860}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {Zum Gasaustausch mit Ihrer Umgebung besitzen h{\"o}here Pflanzen stomat{\"a}re Komplexe. Die Turgor-getrieben Atmungs{\"o}ffnungen in der Epidermis der Bl{\"a}tter werden von zwei Schließzellen ums{\"a}umt. Um bei Trockenheit einen exzessiven Verlust von Wasser zu verhindern, synthetisieren/importieren Schließzellen das Stresshormon ABA (Abszisins{\"a}ure), das {\"u}ber eine schnelle ABA-Signalkaskade plasmamembrangebundene Ionenkan{\"a}le steuert. Dabei wird der Stomaschluss durch die Aktivit{\"a}t von R-(rapid) und S-(slow)Typ Anionenkan{\"a}len initiiert. Obwohl die R- und S-Typ Anionenstr{\"o}me in Schließzellen seit Jahrzehnten bekannt waren, konnte erst k{\"u}rzlich das Gen identifiziert werden, das f{\"u}r den S-Typ Anionenkanal (SLAC1, Slow activating Anion Channel 1) kodiert. Daraufhin wurde schnell der Zusammenhang zwischen dem Stresshormon ABA, der ABA-Signalkette und der Aktivit{\"a}t des SLAC1 Anionenkanals im heterologen Expressionssystem der X. laevis Oozyten als auch in Schließzellprotoplasten aufgekl{\"a}rt. Es konnte gezeigt werden, dass ABA durch einen zytosolischen Rezeptor/Phosphatasekomplex (RCAR1/ABI1) erkannt wird und die Aktivit{\"a}t von kalziumabh{\"a}ngigen Kinasen (CPK-Familie) sowie kalziumunabh{\"a}ngigen Kinasen der SnRK2-Familie (OST1) steuert. In Anwesenheit von ABA phosphorylieren diese Kinasen SLAC1 und sorgen so f{\"u}r die Aktivierung von Anionenstr{\"o}men und damit f{\"u}r die Initiierung des Stomaschlusses. Die genetische Herkunft der ABA-induzierten R-Typ Str{\"o}me in Schließzellen war zu Beginn der vorliegenden Arbeit noch nicht bekannt. R-Typ Str{\"o}me zeichnen sich durch eine strikte Spannungsabh{\"a}ngigkeit und sehr schnellen Aktivierungs- sowie Deaktivierungskinetiken aus. Die Charakterisierung von Verlustmutanten des Schließzell-exprimierten Gens ALMT12 (Aluminium-aktivierter Malattransporter 12) konnte in Zusammenarbeit mit der Arbeitsgruppe Martinoia (Z{\"u}rich) erste Hinweise auf die Beteiligung dieses Gens an der Stomabewegung demonstrieren. Anschließende Patch-Clamp Untersuchungen an Schließzellprotoplasten aus Wildtyppflanzen und ALMT12-Verlustmutanten zeigten, dass ALMT12 f{\"u}r die Malat-aktivierte R-Typ Anionenstromkomponente verantwortlich ist. Deshalb wurde der Anionenkanal QUAC1 (Quickly activating Anion Channel 1) benannt - in Anlehnung an die Benennung des Anionenkanals SLAC1. Mit der Identifizierung von QUAC1 in planta war es nun meine Aufgabe, die elektrischen Eigenschaften von ALMT12/QUAC1 und dessen Aktivit{\"a}tskontrolle durch die ABA-Signalkaskade im heterologen Expressionssystem der Xenopus Oozyten zu untersuchen. Protein-Protein Interaktionsstudien mit der Hilfe der Bimolekularen Fluoreszenz-Technik, sowie die Beobachtung von markant erh{\"o}hten QUAC1 Anionenstr{\"o}men in Anwesenheit der SnRK2 Kinase OST1 und den Calcium-abh{\"a}ngigen Kinasen CPK2 und CPK20, ließen den Schluss zu, dass QUAC1, ebenso wie SLAC1, unter der Kontrolle des schnellen ABA-Signalwegs steht. Eine zus{\"a}tzliche Expression des negativen Regulators ABI1 unterdr{\"u}ckte die aktivierenden Eigenschaften der QUAC1-aktivierenden Kinasen, was die Hypothese der Koregulation von S- und R-Typ Anionenkan{\"a}len durch die gleiche ABA-Signalkaskade weiter unterst{\"u}tzt. Zur weiteren Aufkl{\"a}rung der elektrischen Eigenschaften von QUAC1 wurden tiefgreifende elektrophysiologische Untersuchungen mit der Zwei-Elektroden-Spannungsklemmen Technik durchgef{\"u}hrt. Durch die Wahl von geschickten Spannungsprotokollen konnte sowohl die schnelle Aktivierungskinetik als auch die schnelle Deaktivierungskinetik von QUAC1 bestimmt und quantifiziert werden. Diese Stromantworten waren sehr {\"a}hnlich zu den R-Typ Str{\"o}men, die man von Patch-Clamp Untersuchungen an Schließzellprotoplasten kannte, was ein weiteres Indiz daf{\"u}r war, dass es sich bei QUAC1 tats{\"a}chlich um eine Komponente des R-Typ Kanals aus Schließzellen handelt. Weiterf{\"u}hrende Untersuchungen bez{\"u}glich der Spannungsabh{\"a}ngigkeit und der Selektivit{\"a}t von QUAC1 charakterisierten das Protein als einen Depolarisations-aktivierten Anionenkanal mit einer starken Pr{\"a}ferenz f{\"u}r Dicarbons{\"a}uren wie Malat und Fumarat. Zudem konnte auch eine Leitf{\"a}higkeit f{\"u}r Sulfat und Chlorid nachgewiesen werden. Interessanterweise erwies sich Malat nicht nur als ein permeierendes Ion, sondern auch als ein regulierendes Ion, welches das spannungsabh{\"a}ngige Schalten von QUAC1 maßgeblich beeinflusst. Extrazellul{\"a}res Malat verschob die Offenwahrscheinlichkeit von QUAC1 sehr stark zu negativeren Membranspannungen, so dass der Anionenkanal bereits bei typischen Ruhespannungen von Schließzellen (ca. -150 mV) aktiviert werden konnte. Eine Beladung von QUAC1-exprimierender Oozyten mit Malat bewirkte zum einen h{\"o}here Anioneneffluxstr{\"o}me, aber auch eine Verschiebung der spannungsabh{\"a}ngigen Offenwahrscheinlichkeit zu negativeren Membranpotentialen. Struktur-Funktionsanalysen sollten die umstrittene Topologie von ALMT-{\"a}hnlichen Proteinen beleuchten und die molekulare Herkunft der Phosphorylierungsaktivierung aufzeigen, sowie die Malatabh{\"a}ngigkeit und die starke Spannungsabh{\"a}ngigkeit von QUAC1 aufkl{\"a}ren. Es zeigte sich jedoch schnell, dass Punktmutationen und Deletionen im C-Terminus von QUAC1 sehr h{\"a}ufig zu nicht-funktionellen Mutanten f{\"u}hrten. Diese Tatsache weist darauf hin, dass es sich um einen hoch-strukturierten und funktionell sehr wichtigen Bereich des Anionenkanals handelt. Auch die Topologie des Anionenkanalproteins wird in der Literatur kontrovers diskutiert. Sowohl die Lage des N- und C-Terminus (extrazellul{\"a}r oder intrazellul{\"a}r), als auch die Anzahl der membrandurchspannenden Dom{\"a}nen war nicht abschließend gekl{\"a}rt. Deshalb wurde in einem Fluoreszenz-basiertem Ansatz die Lage der Termini bestimmt. Im Rahmen meiner Arbeit konnte somit eindeutig gezeigt werden, dass sich beide Termini im Zytosol der Zelle befinden. Auf Grundlage von Modellen aus der Literatur und meiner Topologiebestimmungen konnte schließlich ein erweitertes Modell zur Struktur von QUAC1 entwickelt werden. Dieses Modell kann in Zukunft als Ausgangspunkt f{\"u}r weiterf{\"u}hrende Struktur-Funktionsanalysen dienen. Diese Arbeit hat somit gezeigt, dass das Gen QUAC1 tats{\"a}chlich eine Komponente der R-Typ Str{\"o}me in Schließzellen kodiert. Ebenso wie SLAC1 steht der Malat-induzierte Anionenkanal QUAC1 unter der Kontrolle der schnellen ABA-Signalkaskade. In Zukunft bleibt zu kl{\"a}ren, welche weiteren Gene f{\"u}r die R-Typ Kanalproteine in Schließzellen kodieren und welche strukturelle Grundlage f{\"u}r die besonderen Eigenschaften von QUAC1 hinsichtlich seiner schnellen Kinetiken, seiner Selektivit{\"a}t und Aktivierbarkeit durch Malat.}, subject = {Ackerschmalwand}, language = {de} } @phdthesis{Pasch2016, author = {Pasch, Elisabeth}, title = {The role of SUN4 and related proteins in sperm head formation and fertility}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139092}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {Spermiogenesis describes the differentiation of haploid germ cells into motile, fertilization-competent spermatozoa. During this fundamental transition the species-specific sperm head is formed, which necessitates profound nuclear restructuring coincident with the assembly of sperm-specific structures and chromatin compaction. In the case of the mouse, it is characterized by reshaping of the early round spermatid nucleus into an elongated sickle-shaped sperm head. This tremendous shape change requires the transduction of cytoskeletal forces onto the nuclear envelope (NE) or even further into the nuclear interior. LINC (linkers of nucleoskeleton and cytoskeleton) complexes might be involved in this process, due to their general function in bridging the NE and thereby physically connecting the nucleus to the peripheral cytoskeleton. LINC complexes consist of inner nuclear membrane integral SUN-domain proteins and outer nuclear membrane KASH-domain counterparts. SUN- and KASH-domain proteins are directly connected to each other within the perinuclear space, and are thus capable of transferring forces across the NE. To date, these protein complexes are known for their essential functions in nuclear migration, anchoring and positioning of the nucleus, and even for chromosome movements and the maintenance of cell polarity and nuclear shape. In this study LINC complexes were investigated with regard to their potential role in sperm head formation, in order to gain further insight into the processes occurring during spermiogenesis. To this end, the behavior and function of the testis-specific SUN4 protein was studied. The SUN-domain protein SUN4, which had received limited characterization prior to this work, was found to be exclusively expressed in haploid stages during germ cell development. In these cell stages, it specifically localized to the posterior NE at regions decorated by the manchette, a spermatid-specific structure which was previously shown to be involved in nuclear shaping. Mice deficient for SUN4 exhibited severely disorganized manchette residues and gravely misshapen sperm heads. These defects resulted in a globozoospermia-like phenotype and male mice infertility. Therefore, SUN4 was not only found to be mandatory for the correct assembly and anchorage of the manchette, but also for the correct localization of SUN3 and Nesprin1, as well as of other NE components. Interaction studies revealed that SUN4 had the potential to interact with SUN3, Nesprin1, and itself, and as such is likely to build functional LINC complexes that anchor the manchette and transfer cytoskeletal forces onto the nucleus. Taken together, the severe impact of SUN4 deficiency on the nucleocytoplasmic junction during sperm development provided direct evidence for a crucial role of SUN4 and other LINC complex components in mammalian sperm head formation and fertility.}, subject = {Maus}, language = {en} } @phdthesis{Bertho2016, author = {Bertho, Sylvain}, title = {Biochemical and molecular characterization of an original master sex determining gene in Salmonids}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139130}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {Sexual development is a fundamental and versatile process that shapes animal morphology, physiology and behavior. The underlying developmental process is composed of the sex determination and the sex differentiation. Sex determination mechanisms are extremely labile among taxa. The initial triggers of the sex determination process are often genetics called sex determining genes. These genes are expressed in the bipotential gonad and tilt the balance to a developmental program allowing the differentiation of either a testis or an ovary. Fish represent a large and fascinating vertebrate group to study both sex determination and sex differentiation mechanisms. To date, among the known sex determining genes, three gene families namely sox, dmrt and TGF-β factors govern this developmental program. As exception to this rule, sdY "sexually dimorphic on the Y" does not belong to one of these families as it comes from the duplication / evolution of an ancestor gene related to immunity, i.e., the interferon related factor 9, irf9. sdY is the master sex determining gene in salmonids, a group of fishes that include species such as rainbow trout and Atlantic salmon. The present study was aimed to firstly characterize the features of SdY protein. Results indicate that SdY is predominantly localized in the cytoplasm tested in various fish and mammalian cell lines and confirmed by different methods. Predictive in silico analysis revealed that SdY is composed of a β-sandwich core surrounded by three α-helices as well specific characteristics conferring a putative protein-protein interaction site. Secondly, the study was aimed to understand how SdY could trigger testicular differentiation. SdY is a truncated divergent version of Irf9 that has a conserved protein-protein domain but lost the DNA interaction domain of its ancestor gene. It was then hypothesized that SdY could initiate testicular differentiation by protein-protein interactions. To evaluate this we first conducted a yeast-two-hybrid screen that revealed a high proportion of transcription factors including fox proteins. Using various biochemical and cellular methods we confirm an interaction between SdY and Foxl2, a major transcription factor involved in ovarian differentiation and identity maintenance. Interestingly, the interaction of SdY with Foxl2 leads to nuclear translocation of SdY from the cytoplasm. Furthermore, this SdY translocation mechanism was found to be specific to fish Foxl2 and to a lesser extend Foxl3 and not other Fox proteins or mammalian FoxL2. In addition, we found that this interaction allows the stabilization of SdY and prevents its degradation. Finally, to better decipher SdY action we used as a model a mutated version of SdY that was identified in XY females of Chinook salmon natural population. Results show that this mutation induces a local conformation defect obviously leading to a misfolded protein and a quick degradation. Moreover, the mutated version compromised the interaction with Foxl2 defining a minimal threshold to induce testicular differentiation. Altogether results from my thesis propose that SdY would trigger testicular differentiation in salmonids by preventing Foxl2 to promote ovarian differentiation. Further research should be now carried out on how this interaction of SdY and Foxl2 acts in-vivo.}, subject = {Lachsartige }, language = {en} } @phdthesis{Costea2016, author = {Costea, Paul Igor}, title = {Stratification and variation of the human gut microbiota}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139649}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {The microbial communities that live inside the human gastrointestinal tract -the human gut microbiome- are important for host health and wellbeing. Characterizing this new "organ", made up of as many cells as the human body itself, has recently become possible through technological advances. Metagenomics, the high-throughput sequencing of DNA directly from microbial communities, enables us to take genomic snapshots of thousands of microbes living together in this complex ecosystem, without the need for isolating and growing them. Quantifying the composition of the human gut microbiome allows us to investigate its properties and connect it to host physiology and disease. The wealth of such connections was unexpected and is probably still underestimated. Due to the fact that most of our dietary as well as medicinal intake affects the microbiome and that the microbiome itself interacts with our immune system through a multitude of pathways, many mechanisms have been proposed to explain the observed correlations, though most have yet to be understood in depth. An obvious prerequisite to characterizing the microbiome and its interactions with the host is the accurate quantification of its composition, i.e. determining which microbes are present and in what numbers they occur. Historically, standard practices have existed for sample handling, DNA extraction and data analysis for many years. However, these were generally developed for single microbe cultures and it is not always feasible to implement them in large scale metagenomic studies. Partly because of this and partly because of the excitement that new technology brings about, the first metagenomic studies each took the liberty to define their own approach and protocols. From early meta-analysis of these studies it became clear that the differences in sample handling, as well as differences in computational approaches, made comparisons across studies very difficult. This restricts our ability to cross-validate findings of individual studies and to pool samples from larger cohorts. To address the pressing need for standardization, we undertook an extensive comparison of 21 different DNA extraction methods as well as a series of other sample manipulations that affect quantification. We developed a number of criteria for determining the measurement quality in the absence of a mock community and used these to propose best practices for sampling, DNA extraction and library preparation. If these were to be accepted as standards in the field, it would greatly improve comparability across studies, which would dramatically increase the power of our inferences and our ability to draw general conclusions about the microbiome. Most metagenomics studies involve comparisons between microbial communities, for example between fecal samples from cases and controls. A multitude of approaches have been proposed to calculate community dissimilarities (beta diversity) and they are often combined with various preprocessing techniques. Direct metagenomics quantification usually counts sequencing reads mapped to specific taxonomic units, which can be species, genera, etc. Due to technology-inherent differences in sampling depth, normalizing counts is necessary, for instance by dividing each count by the sum of all counts in a sample (i.e. total sum scaling), or by subsampling. To derive a single value for community (dis-)similarity, multiple distance measures have been proposed. Although it is theoretically difficult to benchmark these approaches, we developed a biologically motivated framework in which distance measures can be evaluated. This highlights the importance of data transformations and their impact on the measured distances. Building on our experience with accurate abundance estimation and data preprocessing techniques, we can now try and understand some of the basic properties of microbial communities. In 2011, it was proposed that the space of genus level variation of the human gut microbial community is structured into three basic types, termed enterotypes. These were described in a multi-country cohort, so as to be independent of geography, age and other host properties. Operationally defined through a clustering approach, they are "densely populated areas in a multidimensional space of community composition"(source) and were proposed as a general stratifier for the human population. Later studies that applied this concept to other datasets raised concerns about the optimum number of clusters and robustness of the clustering approach. This heralded a long standing debate about the existence of structure and the best ways to determine and capture it. Here, we reconsider the concept of enterotypes, in the context of the vastly increased amounts of available data. We propose a refined framework in which the different types should be thought of as weak attractors in compositional space and we try to implement an approach to determining which attractor a sample is closest to. To this end, we train a classifier on a reference dataset to assign membership to new samples. This way, enterotypes assignment is no longer dataset dependent and effects due to biased sampling are minimized. Using a model in which we assume the existence of three enterotypes characterized by the same driver genera, as originally postulated, we show the relevance of this stratification and propose it to be used in a clinical setting as a potential marker for disease development. Moreover, we believe that these attractors underline different rules of community assembly and we recommend they be accounted for when analyzing gut microbiome samples. While enterotypes describe structure in the community at genus level, metagenomic sequencing can in principle achieve single-nucleotide resolution, allowing us to identify single nucleotide polymorphisms (SNPs) and other genomic variants in the gut microbiome. Analysis methodology for this level of resolution has only recently been developed and little exploration has been done to date. Assessing SNPs in a large, multinational cohort, we discovered that the landscape of genomic variation seems highly structured even beyond species resolution, indicating that clearly distinguishable subspecies are prevalent among gut microbes. In several cases, these subspecies exhibit geo-stratification, with some subspecies only found in the Chinese population. Generally however, they present only minor dispersion limitations and are seen across most of our study populations. Within one individual, one subspecies is commonly found to dominate and only rarely are several subspecies observed to co-occur in the same ecosystem. Analysis of longitudinal data indicates that the dominant subspecies remains stable over periods of more than three years. When interrogating their functional properties we find many differences, with specific ones appearing relevant to the host. For example, we identify a subspecies of E. rectale that is lacking the flagellum operon and find its presence to be significantly associated with lower body mass index and lower insulin resistance of their hosts; it also correlates with higher microbial community diversity. These associations could not be seen at the species level (where multiple subspecies are convoluted), which illustrates the importance of this increased resolution for a more comprehensive understanding of microbial interactions within the microbiome and with the host. Taken together, our results provide a rigorous basis for performing comparative metagenomics of the human gut, encompassing recommendations for both experimental sample processing and computational analysis. We furthermore refine the concept of community stratification into enterotypes, develop a reference-based approach for enterotype assignment and provide compelling evidence for their relevance. Lastly, by harnessing the full resolution of metagenomics, we discover a highly structured genomic variation landscape below the microbial species level and identify common subspecies of the human gut microbiome. By developing these high-precision metagenomics analysis tools, we thus hope to contribute to a greatly improved understanding of the properties and dynamics of the human gut microbiome.}, subject = {Mensch}, language = {en} } @phdthesis{Danner2017, author = {Danner, Nadja}, title = {Honey bee foraging in agricultural landscapes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139322}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {1. Today honey bee colonies face a wide range of challenges in modern agricultural landscapes which entails the need for a comprehensive investigation of honey bees in a landscape context and the assessment of environmental risks. Within this dissertation the pollen foraging of honey bee colonies is studied in different agricultural landscapes to gain insight into the use of pollen resources and the influence of landscape structure across the season. General suggestions for landscape management to support honey bees and other pollinators are derived. 2. Decoding of waggle dances and a subsequent spatial foraging analysis are used as methods in Chapters 4 and 5 to study honey bee colonies in agricultural landscapes. The recently developed metabarcoding of mixed pollen samples was applied for the first time in honey bee foraging ecology and allowed for a detailed analysis of pollen, that was trapped from honey bees in front hive entrances (Chapter 6). 3. Pollen identification through molecular sequencing and DNA barcoding has been proposed as an alternative approach to light microscopy, which still is a tedious and error-prone task. In this study we assessed mixed pollen probes through next-generation sequencing and developed a bioinformatic workflow to analyse these high-throughput data with a newly created reference database. To evaluate the feasibility, we compared results from classical identification based on light microscopy from the same samples with our sequencing results. Abundance estimations from sequencing data were significantly correlated with counted abundances through light microscopy. Next-generation sequencing thus presents a useful and efficient workflow to identify pollen at the genus and species level without requiring specialized palynological expert knowledge. 4. During maize flowering, four observation hives were placed in and rotated between 11 landscapes covering a gradient in maize acreage. A higher foraging frequency on maize fields compared to other landuse types showed that maize is an intensively used pollen resource for honey bee colonies. Mean foraging distances were significantly shorter for maize pollen than for other pollen origins, indicating that effort is put into collecting a diverse pollen diet. The percentage of maize pollen foragers did not increase with maize acreage in the landscape and was not reduced by grassland area as an alternative pollen resource. Our findings allow estimating the distance-related exposure risk of honey bee colonies to pollen from surrounding maize fields treated with systemic insecticides. 5. It is unknown how an increasing area of mass-flowering crops like oilseed rape (OSR) or a decrease of semi-natural habitats (SNH) change the temporal and spatial availability of pollen resources for honey bee colonies, and thus foraging distances and frequency in different habitat types. Sixteen observation hives were placed in and rotated between 16 agricultural landscapes with independent gradients of OSR and SNH area within 2 km to analyze foraging distances and frequencies. SNH and OSR reduced foraging distance at different spatial scales and depending on season, with possible benefits for the performance of honey bee colonies. Frequency of pollen foragers per habitat type was equally high for SNH, grassland and OSR fields, but lower for other crops and forest. In landscapes with a small proportion of SNH a significantly higher density of pollen foragers on SNH was observed, indicating the limitation of pollen resources in simple agricultural landscapes and the importance of SNH. 6. Quantity and diversity of collected pollen can influence the growth and health of honey bee colonies, but little is known about the influence of landscape structure on pollen diet. In a field experiment we rotated 16 honey bee colonies across 16 agricultural landscapes (see also Chapter 5), used traps to get samples of collected pollen and observed the intra-colonial dance communication to gain information about foraging distances. Neither the amount of collected pollen nor pollen diversity were related to landscape diversity. The revealed increase of foraging distances with decreasing landscape diversity suggests that honey bees compensate for a lower landscape diversity by increasing their pollen foraging range in order to maintain pollen amount and diversity. 7. Our results show the importance of diverse pollen resources for honey bee colonies in agricultural landscapes. Beside the risk of exposure to pesticides honey bees face the risk of nutritional deficiency with implications for their health. By modifying landscape composition and therefore availability of resources we are able to contribute to the wellbeing of honey bees. Agri-environmental schemes aiming to support pollinators should focus on possible spatial and temporal gaps in pollen availability and diversity in agricultural landscapes.}, subject = {Apis mellifera}, language = {en} } @article{HendriksmaHaertelSteffanDewenter2011, author = {Hendriksma, Harmen P. and H{\"a}rtel, Stephan and Steffan-Dewenter, Ingolf}, title = {Testing Pollen of Single and Stacked Insect-Resistant Bt-Maize on In vitro Reared Honey Bee Larvae}, series = {PLoS One}, volume = {6}, journal = {PLoS One}, number = {12}, doi = {10.1371/journal.pone.0028174}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137803}, pages = {e28174}, year = {2011}, abstract = {The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.}, language = {en} } @phdthesis{Zimnol2017, author = {Zimnol, Anna}, title = {Relevance of angiotensin II type 1a receptor and NADPH oxidase for the formation of angiotensin II-mediated DNA damage}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137469}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {Das Renin-Angiotensin-Aldosteron-System (RAAS) reguliert den Blutdruck sowie den Elektrolyt- und Wasserhaushalt. Das aktive Peptid, Angiotensin II (AngII), f{\"u}hrt dabei zur Vasokonstriktion und in h{\"o}heren Konzentrationen zu Bluthochdruck. Hypertensive Patienten haben ein erh{\"o}htes Risiko an Krebs zu erkranken, vor allem an Nierenkrebs. Wir konnten bereits in vivo zeigen, dass AngII in der Lage ist, den Blutdruck zu steigern und dosisabh{\"a}ngig zu DNA-Sch{\"a}den {\"u}ber den Angiotensin II Typ 1-Rezeptor (AT1R) f{\"u}hrt. Ein stimuliertes RAAS kann ferner {\"u}ber die Aktivierung der NADPH-Oxidase, einer Hauptquelle der Generierung reaktiver Sauerstoffspezies (ROS) in der Zelle, zu oxidativem Stress f{\"u}hren. Zielsetzung dieser Arbeit war es zum einen, mit Hilfe von AT1a-Rezeptor-defizienten M{\"a}usen in vivo zu pr{\"u}fen, ob die Bildung von ROS, sowie die Bildung von DNA-Sch{\"a}den in der Niere und im Herzen unabh{\"a}ngig von einem erh{\"o}hten Blutdruck auftreten. Zum anderen sollte, ebenfalls in vivo, untersucht werden, ob eine oder beide von zwei untersuchten Isoformen der NADPH-Oxidase (Nox) f{\"u}r die Ausl{\"o}sung oxidativen Stresses in der Niere verantwortlich ist. Zun{\"a}chst wurden f{\"u}r den Versuch zur {\"U}berpr{\"u}fung der Abh{\"a}ngigkeit AngII-induzierter DNA-Sch{\"a}den vom Blutdruck m{\"a}nnliche C57BL/6-M{\"a}use und AT1a-Knockout (KO)-M{\"a}use mit osmotischen Minipumpen ausgestattet, die AngII in einer Konzentrationen von 600 ng/kg min {\"u}ber einen Zeitraum von 28 Tagen abgaben. Zus{\"a}tzlich wurde eine Gruppe von AngII-behandelten Wildtyp (WT)-M{\"a}usen mit dem AT1-Rezeptor-Blocker Candesartan (Cand) behandelt. W{\"a}hrend des Versuchszeitraumes fanden regelm{\"a}ßige, nicht-invasive Blutdruckmessungen an den wachen M{\"a}usen statt. In WT-M{\"a}usen induzierte AngII Bluthochdruck, verursachte erh{\"o}hte Albumin-Level im Urin und f{\"u}hrte zur Bildung von ROS in Niere und im Herzen. Außerdem traten in dieser Gruppe DNA-Sch{\"a}den in Form von Einzel- und Doppelstrangbr{\"u}chen auf. All diese Reaktionen auf AngII konnten jedoch durch gleichzeitige Behandlung mit Cand verhindert werden. AT1a-KO-M{\"a}use hatten, verglichen mit WT-Kontrollm{\"a}usen, einen signifikant niedrigeren Blutdruck und normale Albumin-Level im Urin. In AT1a-KO-M{\"a}usen, die mit AngII behandelt wurden, konnte kein Anstieg des systolischen Blutdrucks sowie kein Einfluss auf die Nierenfunktion gefunden werden. Jedoch f{\"u}hrte AngII in dieser Gruppe zu einer Steigerung von ROS in der Niere und im Herzen. Zus{\"a}tzlich wurden genomische Sch{\"a}den, vor allem in Form von Doppelstrangbr{\"u}chen signifikant in dieser Gruppe induziert. Auch wenn AT1a-KO-Tiere, unabh{\"a}ngig von einer AngII-Infusion, keine eingeschr{\"a}nkte Nierenfunktion zeigten, so wiesen sie erhebliche histopathologische Sch{\"a}den im Hinblick auf die Glomeruli und das Tubulussystem auf. Diese Art von Sch{\"a}den deuten auf eine besondere Bedeutung des AT1aR im Hinblick auf die embryonale Entwicklung der Niere hin. Zusammenfassend beweisen die Ergebnisse dieses Experiments eindeutig, dass eine AngII-induzierte ROS-Produktion und die Induktion von DNA-Sch{\"a}den unabh{\"a}ngig von einem erh{\"o}hten Blutdruck auftreten. Da in der AngII-behandelten AT1a-KO-Gruppe eine signifikant h{\"o}here Expression des AT1b-Rezeptors zu finden war und die Blockade von beiden Rezeptorsubtypen mit Cand zu einer Verhinderung der sch{\"a}dlichen Effekte durch AngII f{\"u}hrte, scheint der AT1bR im Falle einer AT1aR-Defizienz f{\"u}r die Entstehung der Sch{\"a}den zust{\"a}ndig zu sein. Ziel des zweiten Experimentes war es, den Beitrag der Nox2 und Nox4 zum oxidativen DNA-Schaden in vivo zu untersuchen. Hierf{\"u}r wurden m{\"a}nnliche C57BL/6-M{\"a}use und Nox2- oder Nox4-defiziente M{\"a}use mit osmotischen Minipumpen ausgestattet, die AngII in einer Konzentration von 600 ng/kg min {\"u}ber einen Zeitraum von 28 Tagen abgaben. Im WT-Stamm und in beiden Nox-defizienten St{\"a}mmen induzierte AngII Bluthochdruck, verursachte erh{\"o}hte Albumin-Level im Urin und f{\"u}hrte zur Bildung von ROS in der Niere. Außerdem waren in allen AngII-behandelten Gruppen genomische Sch{\"a}den, vor allem in Form von Doppelstrangbr{\"u}chen, erh{\"o}ht. Auch in Abwesenheit von AngII wiesen Nox2- und Nox4-defiziente M{\"a}use mehr Doppelstrangbr{\"u}che im Vergleich zu WT-Kontrollm{\"a}usen auf. Interessanterweise kompensieren allerdings weder Nox2 noch Nox4 das Fehlen der jeweils anderen Isoform auf RNA-Basis. Aufgrund dieser Ergebnisse schließen wir, dass bislang keine Isoform alleine f{\"u}r die Generierung von oxidativen DNA-Sch{\"a}den in der Niere verantwortlich gemacht werden kann und dass eine Beteiligung einer weiteren Nox-Isoform sehr wahrscheinlich ist. M{\"o}glicherweise k{\"o}nnten aber auch andere ROS-generierende Enzyme, wie Xanthinoxidase oder Stickoxidsynthase involviert sein. Da genomische Sch{\"a}den in Nieren von Nox2- und Nox4-defizienten M{\"a}usen in Abwesenheit von AngII gegen{\"u}ber den Sch{\"a}den in WT-Kontrollm{\"a}usen erh{\"o}ht waren, k{\"o}nnten die beiden Isoformen auch eine sch{\"u}tzende Funktion im Bereich von Nierenkrankheiten {\"u}bernehmen. Da dies aber bislang nur f{\"u}r Nox4 beschrieben ist, ist es wahrscheinlicher, dass das Fehlen von einer der beiden Isoformen eher einen Einfluss auf die Embryonalentwicklung hat. Um dies jedoch abschließend zu kl{\"a}ren w{\"a}re es sinnvoll mit induzierbaren Knockout-Modellen zu arbeiten, bei denen m{\"o}gliche entwicklungsbedingte Effekte minimiert werden k{\"o}nnen.}, subject = {Angiotensin II}, language = {de} } @article{StejskalStreinzerDyeretal.2015, author = {Stejskal, Kerstin and Streinzer, Martin and Dyer, Adrian and Paulus, Hannes F. and Spaethe, Johannes}, title = {Functional Significance of Labellum Pattern Variation in a Sexually Deceptive Orchid (Ophrys heldreichii): Evidence of Individual Signature Learning Effects}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {11}, doi = {10.1371/journal.pone.0142971}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137582}, pages = {e0142971}, year = {2015}, abstract = {Mimicking female insects to attract male pollinators is an important strategy in sexually deceptive orchids of the genus Ophrys, and some species possess flowers with conspicuous labellum patterns. The function of the variation of the patterns remains unresolved, with suggestions that these enhance pollinator communication. We investigated the possible function of the labellum pattern in Ophrys heldreichii, an orchid species in which the conspicuous and complex labellum pattern contrasts with a dark background. The orchid is pollinated exclusively by males of the solitary bee, Eucera berlandi. Comparisons of labellum patterns revealed that patterns within inflorescences are more similar than those of other conspecific plants. Field observations showed that the males approach at a great speed and directly land on flowers, but after an unsuccessful copulation attempt, bees hover close and visually scan the labellum pattern for up to a minute. Learning experiments conducted with honeybees as an accessible model of bee vision demonstrated that labellum patterns of different plants can be reliably learnt; in contrast, patterns of flowers from the same inflorescence could not be discriminated. These results support the hypothesis that variable labellum patterns in O. heldreichii are involved in flower-pollinator communication which would likely help these plants to avoid geitonogamy.}, language = {en} } @phdthesis{Eck2016, author = {Eck, Saskia}, title = {The impact of thermogenetic depolarizations of specific clock neurons on Drosophila melanogaster's circadian clock}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137118}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {The rotation of the earth around its own axis determines periodically changing environmental conditions, like alterations in light and temperature. For the purpose of adapting all organisms' behavior, physiology and metabolism to recurring changes, endogenous clocks have evolved, which allow the organisms to anticipate environmental changes. In chronobiology, the scientific field dealing with the investigation of the underlying mechanisms of the endogenous clock, the fruit fly Drosophila melanogaster serves as a beneficial model organism. The fruit fly's circadian clock exhibits a rather simple anatomical organization, but nevertheless constitutes homologies to the mammalian system. Thus also in this PhD-thesis the fruit fly was used to decipher general features of the circadian clock's interneuronal communication. Drosophila melanogaster's circadian clock consists of about 150 clock neurons, which are located in the central nervous system of the fly. These clock neurons can be subdivided regarding to their anatomical position in the brain into the dorsal neurons (DN1s, DN2s, DN3s), as well as into the lateral neurons (LPNs, LNds, s-LNvs, l-LNvs). Functionally these clock neuron clusters can be classified as Morning- and Evening oscillators (M- and E- oscillators), driving different parts of the fly's locomotor activity in light-dark conditions (LD). The Morning-oscillators are represented by the s-LNvs and are known to be the main pacemakers, driving the pace of the clock in constant conditions (constant darkness; DD). The group of Evening-oscillators consists of the LNds, the DN1s and the 5th s-LNv and is important for the proper timing of the evening activity in LD. All of these clock neurons are not functionally independent, but form complex neuronal connections, which are highly plastic in their response to different environmental stimuli (Zeitgebers), like light or temperature. Even though a lot is known about the function and the importance of some clock neuron clusters, the exact interplay between the neurons is not fully known yet. To investigate the mechanisms, which are involved in communication processes among different clock neurons, we depolarized specific clock cells in a temporally and cell-type restricted manner using dTrpA1, a thermosensitive cation channel, which allows the depolarization of neurons by application of temperature pulses (TP) above 29°C to the intact and freely moving fly. Using different clock specific GAL4-driver lines and applying TPs at different time points within the circadian cycle in DD enabled us with the help of phase shift experiments to draw conclusions on the properties of the endogenous clock. The obtained phase shifts in locomotor behavior elicited by specific clock neuronal activation were plotted as phase response curves (PRCs). The depolarization of all clock neurons shifted the phase of activity the strongest, especially in the delay zone of the PRC. The exclusive depolarization of the M oscillators together with the l-LNvs (PDF+ neurons: s-LNvs \& l-LNvs) caused shifts in the delay and in the advance zone as well, however the advances were severely enhanced in their temporal occurrence ranging into the subjective day. We concluded that light might have inhibitory effects on the PDF+ cells in that particular part of the PRC, as typical light PRCs do not exhibit that kind of distinctive advances. By completely excluding light in the PRC-experiments of this PhD-thesis, this photic inhibitory input to the PDF+ neurons is missing, probably causing the broadened advance zone. These findings suggest the existence of an inhibitory light-input pathway to the PDF+ cells from the photoreceptive organs (Hofbauer-Buchner eyelet, photoreceptor cells of compound eyes, ocelli) or from other clock neurons, which might inhibit phase advances during the subjective day. To get an impression of the molecular state of the clock in the delay and advance zone, staining experiments against Period (PER), one of the most important core clock components, and against the neuropeptide Pigment Dispersing Factor (PDF) were performed. The cycling of PER levels mirrored the behavioral phase shifts in experimental flies, whereas the controls were widely unaffected. As just those neurons, which had been depolarized, exhibited immediate shifted PER oscillations, this effect has to be rapidly regulated in a cell-autonomous manner. However, the molecular link between clock neuron depolarization and shifts in the molecular clock's cycling is still missing. This issue was addressed by CREB (cAMP responsive element binding protein) quantification in the large ventrolateral neurons (l-LNvs), as these neurons responded unexpectedly and strongest to the artificial depolarization exhibiting a huge increase in PER levels. It had been previously suggested that CREB is involved in circadian rhythms by binding to regulatory sequences of the period gene (Belvin et al., 1999), thus activating its transcription. We were able to show, that CREB levels in the l-LNvs are under circadian regulation, as they exhibit higher CREB levels at the end of the subjective night relative to the end of the subjective day. That effect was further reinforced by artificial depolarization, independently of the time point of depolarization. Furthermore the data indicate that rises in CREB levels are coinciding with the time point of increases of PER levels in the l-LNvs, suggesting CREB being the molecular link between the neuronal electrical state and the molecular clock. Taking together, the results indicate that a temporal depolarization using dTrpA1 is able to significantly phase shift the clock on the behavioral and protein level. An artificial depolarization at the beginning of the subjective night caused phase delays, whereas a depolarization at the end of the subjective night resulted in advances. The activation of all clock neurons caused a PRC that roughly resembled a light-PRC. However, the depolarization of the PDF+ neurons led to a PRC exhibiting a shape that did not resemble that of a light-mediated PRC, indicating the complex processing ability of excitatory and inhibitory input by the circadian clock. Even though this experimental approach is highly artificial, just the exclusion of light-inputs enabled us to draw novel conclusions on the network communication and its light input pathways.}, subject = {Chronobiologie}, language = {en} } @article{ParthoChenBrauckhoffetal.2011, author = {Partho, Halder and Chen, Yi-chun and Brauckhoff, Janine and Hofbauer, Alois and Dabauvalle, Marie-Christine and Lewandrowski, Urs and Winkler, Christiane and Sickmann, Albert and Buchner, Erich}, title = {Identification of Eps15 as Antigen Recognized by the Monoclonal Antibodies aa2 and ab52 of the Wuerzburg Hybridoma Library against Drosophila Brain}, series = {PLoS One}, volume = {6}, journal = {PLoS One}, number = {12}, doi = {10.1371/journal.pone.0029352}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137957}, pages = {e29352}, year = {2011}, abstract = {The Wuerzburg Hybridoma Library against the Drosophila brain represents a collection of around 200 monoclonal antibodies that bind to specific structures in the Drosophila brain. Here we describe the immunohistochemical staining patterns, the Western blot signals of one- and two-dimensional electrophoretic separation, and the mass spectrometric characterization of the target protein candidates recognized by the monoclonal antibodies aa2 and ab52 from the library. Analysis of a mutant of a candidate gene identified the Drosophila homolog of the Epidermal growth factor receptor Pathway Substrate clone 15 (Eps15) as the antigen for these two antibodies.}, language = {en} } @article{BijuSchwarzLinkeetal.2011, author = {Biju, Joseph and Schwarz, Roland and Linke, Burkhard and Blom, Jochen and Becker, Anke and Claus, Heike and Goesmann, Alexander and Frosch, Matthias and M{\"u}ller, Tobias and Vogel, Ulrich and Schoen, Christoph}, title = {Virulence Evolution of the Human Pathogen Neisseria meningitidis by Recombination in the Core and Accessory Genome}, series = {PLoS One}, volume = {6}, journal = {PLoS One}, number = {4}, doi = {10.1371/journal.pone.0018441}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137960}, pages = {e18441}, year = {2011}, abstract = {Background Neisseria meningitidis is a naturally transformable, facultative pathogen colonizing the human nasopharynx. Here, we analyze on a genome-wide level the impact of recombination on gene-complement diversity and virulence evolution in N. meningitidis. We combined comparative genome hybridization using microarrays (mCGH) and multilocus sequence typing (MLST) of 29 meningococcal isolates with computational comparison of a subset of seven meningococcal genome sequences. Principal Findings We found that lateral gene transfer of minimal mobile elements as well as prophages are major forces shaping meningococcal population structure. Extensive gene content comparison revealed novel associations of virulence with genetic elements besides the recently discovered meningococcal disease associated (MDA) island. In particular, we identified an association of virulence with a recently described canonical genomic island termed IHT-E and a differential distribution of genes encoding RTX toxin- and two-partner secretion systems among hyperinvasive and non-hyperinvasive lineages. By computationally screening also the core genome for signs of recombination, we provided evidence that about 40\% of the meningococcal core genes are affected by recombination primarily within metabolic genes as well as genes involved in DNA replication and repair. By comparison with the results of previous mCGH studies, our data indicated that genetic structuring as revealed by mCGH is stable over time and highly similar for isolates from different geographic origins. Conclusions Recombination comprising lateral transfer of entire genes as well as homologous intragenic recombination has a profound impact on meningococcal population structure and genome composition. Our data support the hypothesis that meningococcal virulence is polygenic in nature and that differences in metabolism might contribute to virulence.}, language = {en} } @article{KuhnGrippFliederetal.2015, author = {Kuhn, Joachim and Gripp, Tatjana and Flieder, Tobias and Dittrich, Marcus and Hendig, Doris and Busse, Jessica and Knabbe, Cornelius and Birschmann, Ingvild}, title = {UPLC-MRM Mass Spectrometry Method for Measurement of the Coagulation Inhibitors Dabigatran and Rivaroxaban in Human Plasma and Its Comparison with Functional Assays}, series = {PLOS ONE}, volume = {10}, journal = {PLOS ONE}, number = {12}, doi = {10.1371/journal.pone.0145478}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136023}, pages = {e0145478}, year = {2015}, abstract = {Introduction The fast, precise, and accurate measurement of the new generation of oral anticoagulants such as dabigatran and rivaroxaban in patients' plasma my provide important information in different clinical circumstances such as in the case of suspicion of overdose, when patients switch from existing oral anticoagulant, in patients with hepatic or renal impairment, by concomitant use of interaction drugs, or to assess anticoagulant concentration in patients' blood before major surgery. Methods Here, we describe a quick and precise method to measure the coagulation inhibitors dabigatran and rivaroxaban using ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry in multiple reactions monitoring (MRM) mode (UPLC-MRM MS). Internal standards (ISs) were added to the sample and after protein precipitation; the sample was separated on a reverse phase column. After ionization of the analytes the ions were detected using electrospray ionization-tandem mass spectrometry. Run time was 2.5 minutes per injection. Ion suppression was characterized by means of post-column infusion. Results The calibration curves of dabigatran and rivaroxaban were linear over the working range between 0.8 and 800 mu g/L (r > 0.99). Limits of detection (LOD) in the plasma matrix were 0.21 mu g/L for dabigatran and 0.34 mu g/L for rivaroxaban, and lower limits of quantification (LLOQ) in the plasma matrix were 0.46 mu g/L for dabigatran and 0.54 mu g/L for rivaroxaban. The intraassay coefficients of variation (CVs) for dabigatran and rivaroxaban were < 4\% and 6\%; respectively, the interassay CVs were < 6\% for dabigatran and < 9\% for rivaroxaban. Inaccuracy was < 5\% for both substances. The mean recovery was 104.5\% (range 83.8-113.0\%) for dabigatran and 87.0\%(range 73.6-105.4\%) for rivaroxaban. No significant ion suppressions were detected at the elution times of dabigatran or rivaroxaban. Both coagulation inhibitors were stable in citrate plasma at -20 degrees C, 4 degrees C and even at RT for at least one week. A method comparison between our UPLC-MRM MS method, the commercially available automated Direct Thrombin Inhibitor assay (DTI assay) for dabigatran measurement from CoaChrom Diagnostica, as well as the automated anti-Xa assay for rivaroxaban measurement from Chromogenix both performed by ACL-TOP showed a high degree of correlation. However, UPLC-MRM MS measurement of dabigatran and rivaroxaban has a much better selectivity than classical functional assays measuring activities of various coagulation factors which are susceptible to interference by other coagulant drugs. Conclusions Overall, we developed and validated a sensitive and specific UPLC-MRM MS assay for the quick and specific measurement of dabigatran and rivaroxaban in human plasma.}, language = {en} } @article{SinghKingstonGuptaetal.2015, author = {Singh, Amit K. and Kingston, Joseph J. and Gupta, Shishir K. and Batra, Harsh V.}, title = {Recombinant Bivalent Fusion Protein rVE Induces CD4+ and CD8+ T-Cell Mediated Memory Immune Response for Protection Against Yersinia enterocolitica Infection}, series = {Frontiers in Microbiology}, volume = {6}, journal = {Frontiers in Microbiology}, number = {1407}, doi = {10.3389/fmicb.2015.01407}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136114}, year = {2015}, abstract = {Studies investigating the correlates of immune protection against Yersinia infection have established that both humoral and cell mediated immune responses are required for the comprehensive protection. In our previous study, we established that the bivalent fusion protein (rVE) comprising immunologically active regions of Y pestis LcrV (100-270 aa) and YopE (50-213 aa) proteins conferred complete passive and active protection against lethal Y enterocolitica 8081 challenge. In the present study, cohort of BALB/c mice immunized with rVE or its component proteins rV, rE were assessed for cell mediated immune responses and memory immune protection against Y enterocolitica 8081 rVE immunization resulted in extensive proliferation of both CD4 and CD8 T cell subsets; significantly high antibody titer with balanced IgG1: IgG2a/IgG2b isotypes (1:1 ratio) and up regulation of both Th1 (INF-\(\alpha\), IFN-\(\gamma\), IL 2, and IL 12) and Th2 (IL 4) cytokines. On the other hand, rV immunization resulted in Th2 biased IgG response (11:1 ratio) and proliferation of CD4+ T-cell; rE group of mice exhibited considerably lower serum antibody titer with predominant Th1 response (1:3 ratio) and CD8+ T-cell proliferation. Comprehensive protection with superior survival (100\%) was observed among rVE immunized mice when compared to the significantly lower survival rates among rE (37.5\%) and rV (25\%) groups when IP challenged with Y enterocolitica 8081 after 120 days of immunization. Findings in this and our earlier studies define the bivalent fusion protein rVE as a potent candidate vaccine molecule with the capability to concurrently stimulate humoral and cell mediated immune responses and a proof of concept for developing efficient subunit vaccines against Gram negative facultative intracellular bacterial pathogens.}, language = {en} } @article{KatjaLopezTillichetal.2011, author = {Katja, Schulze and L{\´o}pez, Diana A. and Tillich, Ulrich M. and Frohme, Marcus}, title = {A simple viability analysis for unicellular cyanobacteria using a new autofluorescence assay, automated microscopy, and ImageJ}, series = {BMC Biotechnology}, volume = {11}, journal = {BMC Biotechnology}, number = {118}, doi = {10.1186/1472-6750-11-118}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137735}, year = {2011}, abstract = {Background Currently established methods to identify viable and non-viable cells of cyanobacteria are either time-consuming (eg. plating) or preparation-intensive (eg. fluorescent staining). In this paper we present a new and fast viability assay for unicellular cyanobacteria, which uses red chlorophyll fluorescence and an unspecific green autofluorescence for the differentiation of viable and non-viable cells without the need of sample preparation. Results The viability assay for unicellular cyanobacteria using red and green autofluorescence was established and validated for the model organism Synechocystis sp. PCC 6803. Both autofluorescence signals could be observed simultaneously allowing a direct classification of viable and non-viable cells. The results were confirmed by plating/colony count, absorption spectra and chlorophyll measurements. The use of an automated fluorescence microscope and a novel ImageJ based image analysis plugin allow a semi-automated analysis. Conclusions The new method simplifies the process of viability analysis and allows a quick and accurate analysis. Furthermore results indicate that a combination of the new assay with absorption spectra or chlorophyll concentration measurements allows the estimation of the vitality of cells.}, language = {en} } @article{StaigerCadotKooteretal.2012, author = {Staiger, Christine and Cadot, Sidney and Kooter, Raul and Dittrich, Marcus and M{\"u}ller, Tobias and Klau, Gunnar W. and Wessels, Lodewyk F. A.}, title = {A Critical Evaluation of Network and Pathway-Based Classifiers for Outcome Prediction in Breast Cancer}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {4}, doi = {10.1371/journal.pone.0034796}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131323}, pages = {e34796}, year = {2012}, abstract = {Recently, several classifiers that combine primary tumor data, like gene expression data, and secondary data sources, such as protein-protein interaction networks, have been proposed for predicting outcome in breast cancer. In these approaches, new composite features are typically constructed by aggregating the expression levels of several genes. The secondary data sources are employed to guide this aggregation. Although many studies claim that these approaches improve classification performance over single genes classifiers, the gain in performance is difficult to assess. This stems mainly from the fact that different breast cancer data sets and validation procedures are employed to assess the performance. Here we address these issues by employing a large cohort of six breast cancer data sets as benchmark set and by performing an unbiased evaluation of the classification accuracies of the different approaches. Contrary to previous claims, we find that composite feature classifiers do not outperform simple single genes classifiers. We investigate the effect of (1) the number of selected features; (2) the specific gene set from which features are selected; (3) the size of the training set and (4) the heterogeneity of the data set on the performance of composite feature and single genes classifiers. Strikingly, we find that randomization of secondary data sources, which destroys all biological information in these sources, does not result in a deterioration in performance of composite feature classifiers. Finally, we show that when a proper correction for gene set size is performed, the stability of single genes sets is similar to the stability of composite feature sets. Based on these results there is currently no reason to prefer prognostic classifiers based on composite features over single genes classifiers for predicting outcome in breast cancer.}, language = {en} } @article{RuczyńskiBartoń2012, author = {Ruczyński, Ireneusz and Bartoń, Kamil A.}, title = {Modelling Sensory Limitation: The Role of Tree Selection, Memory and Information Transfer in Bats' Roost Searching Strategies}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0044897}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133963}, pages = {e44897}, year = {2012}, abstract = {Sensory limitation plays an important role in the evolution of animal behaviour. Animals have to find objects of interest (e.g. food, shelters, predators). When sensory abilities are strongly limited, animals adjust their behaviour to maximize chances for success. Bats are nocturnal, live in complex environments, are capable of flight and must confront numerous perceptual challenges (e.g. limited sensory range, interfering clutter echoes). This makes them an excellent model for studying the role of compensating behaviours to decrease costs of finding resources. Cavity roosting bats are especially interesting because the availability of tree cavities is often limited, and their quality is vital for bats during the breeding season. From a bat's sensory point of view, cavities are difficult to detect and finding them requires time and energy. However, tree cavities are also long lasting, allowing information transfer among conspecifics. Here, we use a simple simulation model to explore the benefits of tree selection, memory and eavesdropping (compensation behaviours) to searches for tree cavities by bats with short and long perception range. Our model suggests that memory and correct discrimination of tree suitability are the basic strategies decreasing the cost of roost finding, whereas perceptual range plays a minor role in this process. Additionally, eavesdropping constitutes a buffer that reduces the costs of finding new resources (such as roosts), especially when they occur in low density. We conclude that natural selection may promote different strategies of roost finding in relation to habitat conditions and cognitive skills of animals.}, language = {en} } @article{OndruschKreft2011, author = {Ondrusch, Nicolai and Kreft, J{\"u}rgen}, title = {Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in \(Listeria\) \(monocytogenes\)}, series = {PLoS ONE}, volume = {6}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0016151}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134050}, pages = {e16151}, year = {2011}, abstract = {Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat.}, language = {en} } @article{EndesfelderMalkuschFlottmannetal.2011, author = {Endesfelder, Ulrike and Malkusch, Sebastian and Flottmann, Benjamin and Mondry, Justine and Liguzinski, Piotr and Verveer, Peter J. and Heilemann, Mike}, title = {Chemically Induced Photoswitching of Fluorescent Probes - A General Concept for Super-Resolution Microscopy}, series = {Molecules}, volume = {16}, journal = {Molecules}, number = {4}, doi = {10.3390/molecules16043106}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134080}, pages = {3106-3118}, year = {2011}, abstract = {We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.}, language = {en} } @article{TuChenLimetal.2012, author = {Tu, Xiaolin and Chen, Jianquan and Lim, Joohyun and Karner, Courtney M. and Lee, Seung-Yon and Heisig, Julia and Wiese, Cornelia and Surendran, Kameswaran and Kopan, Raphael and Gessler, Manfred and Long, Fanxin}, title = {Physiological Notch Signaling Maintains Bone Homeostasis via RBPjk and Hey Upstream of NFATc1}, series = {PLoS Genetics}, volume = {8}, journal = {PLoS Genetics}, number = {3}, doi = {10.1371/journal.pgen.1002577}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133490}, pages = {e1002577}, year = {2012}, abstract = {Notch signaling between neighboring cells controls many cell fate decisions in metazoans both during embryogenesis and in postnatal life. Previously, we uncovered a critical role for physiological Notch signaling in suppressing osteoblast differentiation in vivo. However, the contribution of individual Notch receptors and the downstream signaling mechanism have not been elucidated. Here we report that removal of Notch2, but not Notch1, from the embryonic limb mesenchyme markedly increased trabecular bone mass in adolescent mice. Deletion of the transcription factor RBPjk, a mediator of all canonical Notch signaling, in the mesenchymal progenitors but not the more mature osteoblast-lineage cells, caused a dramatic high-bone-mass phenotype characterized by increased osteoblast numbers, diminished bone marrow mesenchymal progenitor pool, and rapid age-dependent bone loss. Moreover, mice deficient in Hey1 and HeyL, two target genes of Notch-RBPjk signaling, exhibited high bone mass. Interestingly, Hey1 bound to and suppressed the NFATc1 promoter, and RBPjk deletion increased NFATc1 expression in bone. Finally, pharmacological inhibition of NFAT alleviated the high-bone-mass phenotype caused by RBPjk deletion. Thus, Notch-RBPjk signaling functions in part through Hey1-mediated inhibition of NFATc1 to suppress osteoblastogenesis, contributing to bone homeostasis in vivo.}, language = {en} } @article{EckhardtAndersMuranyietal.2011, author = {Eckhardt, Manon and Anders, Maria and Muranyi, Walter and Heilemann, Mike and Krijnse-Locker, Jacomine and M{\"u}ller, Barbara}, title = {A SNAP-Tagged Derivative of HIV-1-A Versatile Tool to Study Virus-Cell Interactions}, series = {PLoS ONE}, volume = {6}, journal = {PLoS ONE}, number = {7}, doi = {10.1371/journal.pone.0022007}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133534}, pages = {e22007}, year = {2011}, abstract = {Fluorescently labeled human immunodeficiency virus (HIV) derivatives, combined with the use of advanced fluorescence microscopy techniques, allow the direct visualization of dynamic events and individual steps in the viral life cycle. HIV proteins tagged with fluorescent proteins (FPs) have been successfully used for live-cell imaging analyses of HIV-cell interactions. However, FPs display limitations with respect to their physicochemical properties, and their maturation kinetics. Furthermore, several independent FP-tagged constructs have to be cloned and characterized in order to obtain spectral variations suitable for multi-color imaging setups. In contrast, the so-called SNAP-tag represents a genetically encoded non-fluorescent tag which mediates specific covalent coupling to fluorescent substrate molecules in a self-labeling reaction. Fusion of the SNAP-tag to the protein of interest allows specific labeling of the fusion protein with a variety of synthetic dyes, thereby offering enhanced flexibility for fluorescence imaging approaches. Here we describe the construction and characterization of the HIV derivative HIV(SNAP), which carries the SNAP-tag as an additional domain within the viral structural polyprotein Gag. Introduction of the tag close to the C-terminus of the matrix domain of Gag did not interfere with particle assembly, release or proteolytic virus maturation. The modified virions were infectious and could be propagated in tissue culture, albeit with reduced replication capacity. Insertion of the SNAP domain within Gag allowed specific staining of the viral polyprotein in the context of virus producing cells using a SNAP reactive dye as well as the visualization of individual virions and viral budding sites by stochastic optical reconstruction microscopy. Thus, HIV(SNAP) represents a versatile tool which expands the possibilities for the analysis of HIV-cell interactions using live cell imaging and sub-diffraction fluorescence microscopy.}, language = {en} } @article{PillaiHeidemannKumaretal.2011, author = {Pillai, Deepu R. and Heidemann, Robin M. and Kumar, Praveen and Shanbhag, Nagesh and Lanz, Titus and Dittmar, Michael S. and Sandner, Beatrice and Beier, Christoph P. and Weidner, Norbert and Greenlee, Mark W. and Schuierer, Gerhard and Bogdahn, Ulrich and Schlachetzki, Felix}, title = {Comprehensive Small Animal Imaging Strategies on a Clinical 3 T Dedicated Head MR-Scanner; Adapted Methods and Sequence Protocols in CNS Pathologies}, series = {PLoS ONE}, volume = {6}, journal = {PLoS ONE}, number = {2}, doi = {10.1371/journal.pone.0016091}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134193}, pages = {e16091}, year = {2011}, abstract = {Background: Small animal models of human diseases are an indispensable aspect of pre-clinical research. Being dynamic, most pathologies demand extensive longitudinal monitoring to understand disease mechanisms, drug efficacy and side effects. These considerations often demand the concomitant development of monitoring systems with sufficient temporal and spatial resolution. Methodology and Results: This study attempts to configure and optimize a clinical 3 Tesla magnetic resonance scanner to facilitate imaging of small animal central nervous system pathologies. The hardware of the scanner was complemented by a custom-built, 4-channel phased array coil system. Extensive modification of standard sequence protocols was carried out based on tissue relaxometric calculations. Proton density differences between the gray and white matter of the rodent spinal cord along with transverse relaxation due to magnetic susceptibility differences at the cortex and striatum of both rats and mice demonstrated statistically significant differences. The employed parallel imaging reconstruction algorithms had distinct properties dependent on the sequence type and in the presence of the contrast agent. The attempt to morphologically phenotype a normal healthy rat brain in multiple planes delineated a number of anatomical regions, and all the clinically relevant sequels following acute cerebral ischemia could be adequately characterized. Changes in blood-brain-barrier permeability following ischemia-reperfusion were also apparent at a later time. Typical characteristics of intracerebral haemorrhage at acute and chronic stages were also visualized up to one month. Two models of rodent spinal cord injury were adequately characterized and closely mimicked the results of histological studies. In the employed rodent animal handling system a mouse model of glioblastoma was also studied with unequivocal results. Conclusions: The implemented customizations including extensive sequence protocol modifications resulted in images of high diagnostic quality. These results prove that lack of dedicated animal scanners shouldn't discourage conventional small animal imaging studies.}, 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{RoesslerBrill2013, author = {R{\"o}ssler, Wolfgang and Brill, Martin F.}, title = {Parallel processing in the honeybee olfactory pathway: structure, function, and evolution}, series = {Journal of Comparative Physiology A}, volume = {199}, journal = {Journal of Comparative Physiology A}, doi = {10.1007/s00359-013-0821-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132548}, pages = {981-996}, year = {2013}, abstract = {Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.}, language = {en} } @article{ElKeredySchleyerKoenigetal.2012, author = {El-Keredy, Amira and Schleyer, Michael and K{\"o}nig, Christian and Ekim, Aslihan and Gerber, Bertram}, title = {Behavioural Analyses of Quinine Processing in Choice, Feeding and Learning of Larval Drosophila}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0040525}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130811}, pages = {e40525}, year = {2012}, abstract = {Gustatory stimuli can support both immediate reflexive behaviour, such as choice and feeding, and can drive internal reinforcement in associative learning. For larval Drosophila, we here provide a first systematic behavioural analysis of these functions with respect to quinine as a study case of a substance which humans report as "tasting bitter". We describe the dose-effect functions for these different kinds of behaviour and find that a half-maximal effect of quinine to suppress feeding needs substantially higher quinine concentrations (2.0 mM) than is the case for internal reinforcement (0.6 mM). Interestingly, in previous studies (Niewalda et al. 2008, Schipanski et al 2008) we had found the reverse for sodium chloride and fructose/sucrose, such that dose-effect functions for those tastants were shifted towards lower concentrations for feeding as compared to reinforcement, arguing that the differences in dose-effect function between these behaviours do not reflect artefacts of the types of assay used. The current results regarding quinine thus provide a starting point to investigate how the gustatory system is organized on the cellular and/or molecular level to result in different behavioural tuning curves towards a bitter tastant.}, language = {en} } @article{ZoephelReiherRexeretal.2012, author = {Zoephel, Judith and Reiher, Wencke and Rexer, Karl-Heinz and Kahnt, J{\"o}rg and Wegener, Christian}, title = {Peptidomics of the Agriculturally Damaging Larval Stage of the Cabbage Root Fly Delia radicum (Diptera: Anthomyiidae)}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0041543}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131727}, pages = {e41543}, year = {2012}, abstract = {The larvae of the cabbage root fly induce serious damage to cultivated crops of the family Brassicaceae. We here report the biochemical characterisation of neuropeptides from the central nervous system and neurohemal organs, as well as regulatory peptides from enteroendocrine midgut cells of the cabbage maggot. By LC-MALDI-TOF/TOF and chemical labelling with 4-sulfophenyl isothiocyanate, 38 peptides could be identified, representing major insect peptide families: allatostatin A, allatostatin C, FMRFamide-like peptides, kinin, CAPA peptides, pyrokinins, sNPF, myosuppressin, corazonin, SIFamide, sulfakinins, tachykinins, NPLP1-peptides, adipokinetic hormone and CCHamide 1. We also report a new peptide (Yamide) which appears to be homolog to an amidated eclosion hormone-associated peptide in several Drosophila species. Immunocytochemical characterisation of the distribution of several classes of peptide-immunoreactive neurons and enteroendocrine cells shows a very similar but not identical peptide distribution to Drosophila. Since peptides regulate many vital physiological and behavioural processes such as moulting or feeding, our data may initiate the pharmacological testing and development of new specific peptide-based protection methods against the cabbage root fly and its larva.}, language = {en} } @article{SchneiderTautzGruenewaldetal.2012, author = {Schneider, Christof W. and Tautz, J{\"u}rgen and Gr{\"u}newald, Bernd and Fuchs, Stefan}, title = {RFID Tracking of Sublethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {1}, doi = {10.1371/journal.pone.0030023}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131753}, pages = {e30023}, year = {2012}, abstract = {The development of insecticides requires valid risk assessment procedures to avoid causing harm to beneficial insects and especially to pollinators such as the honeybee Apis mellifera. In addition to testing according to current guidelines designed to detect bee mortality, tests are needed to determine possible sublethal effects interfering with the animal's vitality and behavioral performance. Several methods have been used to detect sublethal effects of different insecticides under laboratory conditions using olfactory conditioning. Furthermore, studies have been conducted on the influence insecticides have on foraging activity and homing ability which require time-consuming visual observation. We tested an experimental design using the radiofrequency identification (RFID) method to monitor the influence of sublethal doses of insecticides on individual honeybee foragers on an automated basis. With electronic readers positioned at the hive entrance and at an artificial food source, we obtained quantifiable data on honeybee foraging behavior. This enabled us to efficiently retrieve detailed information on flight parameters. We compared several groups of bees, fed simultaneously with different dosages of a tested substance. With this experimental approach we monitored the acute effects of sublethal doses of the neonicotinoids imidacloprid (0.15-6 ng/bee) and clothianidin (0.05-2 ng/bee) under field-like circumstances. At field-relevant doses for nectar and pollen no adverse effects were observed for either substance. Both substances led to a significant reduction of foraging activity and to longer foraging flights at doses of >= 0.5 ng/bee (clothianidin) and >= 1.5 ng/bee (imidacloprid) during the first three hours after treatment. This study demonstrates that the RFID-method is an effective way to record short-term alterations in foraging activity after insecticides have been administered once, orally, to individual bees. We contribute further information on the understanding of how honeybees are affected by sublethal doses of insecticides.}, language = {en} } @article{NaseemDandekar2012, author = {Naseem, Muhammad and Dandekar, Thomas}, title = {The Role of Auxin-Cytokinin Antagonism in Plant-Pathogen Interactions}, series = {PLOS Pathogens}, volume = {8}, journal = {PLOS Pathogens}, number = {11}, doi = {10.1371/journal.ppat.1003026}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131901}, pages = {e1003026}, year = {2012}, abstract = {No abstract available.}, language = {en} } @article{KesslerHertelJungkunstetal.2012, author = {Kessler, Michael and Hertel, Dietrich and Jungkunst, Hermann F. and Kluge, J{\"u}rgen and Abrahamczyk, Stefan and Bos, Merijn and Buchori, Damayanti and Gerold, Gerhard and Gradstein, S. Robbert and K{\"o}hler, Stefan and Leuschner, Christoph and Moser, Gerald and Pitopang, Ramadhanil and Saleh, Shahabuddin and Schulze, Christian H. and Sporn, Simone G. and Steffan-Dewenter, Ingolf and Tjitrosoedirdjo, Sri S. and Tscharntke, Teja}, title = {Can Joint Carbon and Biodiversity Management in Tropical Agroforestry Landscapes Be Optimized?}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {10}, doi = {10.1371/journal.pone.0047192}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132016}, pages = {e47192}, year = {2012}, abstract = {Managing ecosystems for carbon storage may also benefit biodiversity conservation, but such a potential 'win-win' scenario has not yet been assessed for tropical agroforestry landscapes. We measured above-and below-ground carbon stocks as well as the species richness of four groups of plants and eight of animals on 14 representative plots in Sulawesi, Indonesia, ranging from natural rainforest to cacao agroforests that have replaced former natural forest. The conversion of natural forests with carbon stocks of 227-362 Mg C ha\(^{-1}\) to agroforests with 82-211 Mg C ha\(^{-1}\) showed no relationships to overall biodiversity but led to a significant loss of forest-related species richness. We conclude that the conservation of the forest-related biodiversity, and to a lesser degree of carbon stocks, mainly depends on the preservation of natural forest habitats. In the three most carbon-rich agroforestry systems, carbon stocks were about 60\% of those of natural forest, suggesting that 1.6 ha of optimally managed agroforest can contribute to the conservation of carbon stocks as much as 1 ha of natural forest. However, agroforestry systems had comparatively low biodiversity, and we found no evidence for a tight link between carbon storage and biodiversity. Yet, potential win-win agroforestry management solutions include combining high shade-tree quality which favours biodiversity with cacao-yield adapted shade levels.}, language = {en} } @article{HolzschuhDormannTscharntkeetal.2013, author = {Holzschuh, Andrea and Dormann, Carsten F. and Tscharntke, Teja and Steffan-Dewenter, Ingolf}, title = {Mass-flowering crops enhance wild bee abundance}, series = {Oecologia}, volume = {172}, journal = {Oecologia}, number = {2}, doi = {10.1007/s00442-012-2515-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132149}, pages = {477-484}, year = {2013}, abstract = {Although agricultural habitats can provide enormous amounts of food resources for pollinator species, links between agricultural and (semi-)natural habitats through dispersal and foraging movements have hardly been studied. In 67 study sites, we assessed the interactions between mass-flowering oilseed rape fields and semi-natural grasslands at different spatial scales, and their effects on the number of brood cells of a solitary cavity-nesting bee. The probability that the bee Osmia bicornis colonized trap nests in oilseed rape fields increased from 12 to 59 \% when grassland was nearby, compared to fields isolated from grassland. In grasslands, the number of brood cells of O. bicornis in trap nests was 55 \% higher when adjacent to oilseed rape compared to isolated grasslands. The percentage of oilseed rape pollen in the larval food was higher in oilseed rape fields and grasslands adjacent to oilseed rape than in isolated grasslands. In both oilseed rape fields and grasslands, the number of brood cells was positively correlated with the percentage of oilseed rape pollen in the larval food. We show that mass-flowering agricultural habitats—even when they are intensively managed—can strongly enhance the abundance of a solitary bee species nesting in nearby semi-natural habitats. Our results suggest that positive effects of agricultural habitats have been underestimated and might be very common (at least) for generalist species in landscapes consisting of a mixture of agricultural and semi-natural habitats. These effects might also have—so far overlooked—implications for interspecific competition and mutualistic interactions in semi-natural habitats.}, language = {en} } @article{RinawatiSteinLindner2013, author = {Rinawati, Fitria and Stein, Katharina and Lindner, Andr{\´e}}, title = {Climate change impacts on biodiversity-the setting of a lingering global crisis}, series = {Diversity}, volume = {5}, journal = {Diversity}, number = {1}, doi = {10.3390/d50100114}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131866}, pages = {114-123}, year = {2013}, abstract = {Climate change has created potential major threats to global biodiversity. The multiple components of climate change are projected to affect all pillars of biodiversity, from genes over species to biome level. Of particular concerns are "tipping points" where the exceedance of ecosystem thresholds will possibly lead to irreversible shifts of ecosystems and their functioning. As biodiversity underlies all goods and services provided by ecosystems that are crucial for human survival and wellbeing, this paper presents potential effects of climate change on biodiversity, its plausible impacts on human society as well as the setting in addressing a global crisis. Species affected by climate change may respond in three ways: change, move or die. Local species extinctions or a rapidly affected ecosystem as a whole respectively might move toward its particular "tipping point", thereby probably depriving its services to human society and ending up in a global crisis. Urgent and appropriate actions within various scenarios of climate change impacts on biodiversity, especially in tropical regions, are needed to be considered. Foremost a multisectoral approach on biodiversity issues with broader policies, stringent strategies and programs at international, national and local levels is essential to meet the challenges of climate change impacts on biodiversity.}, language = {en} } @phdthesis{Kunz2017, author = {Kunz, Meik}, title = {Systembiologische Analysen von Interaktionen: Zytokinine (Pflanzenpathogene), 3D-Zellkulturen (Krebstherapie) und Drugtargets}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134911}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2017}, abstract = {Der Einsatz von computergest{\"u}tzten Analysen hat sich zu einem festen Bestandteil der biowissenschaftlichen Forschung etabliert. Im Rahmen dieser vorliegenden Arbeit wurden systembiologische Untersuchungen auf verschiedene biologische Themengebiete und Organismen angewendet. In diesem Zusammenhang liefert die Arbeit einen innovativen und interdisziplin{\"a}ren methodischen Ansatz. Die grundlegende Frage lautet: Wie verstehe und beschreibe ich Signalwege und wie kann ich sie beeinflussen? Der Ansatz verkn{\"u}pft verschiedene biologische Datens{\"a}tze und Datenebenen miteinander, beginnend vom Genom und Interaktionskontext {\"u}ber semiquantitative Simulationen hin zu neuen Interventionen und Experimenten, welche therapeutisch und biotechnologisch genutzt werden k{\"o}nnen. Die Analysen k{\"o}nnen auf diese Weise - zu einem besseren Verst{\"a}ndnis experimenteller Daten und biologischer Fragestellungen beitragen und erm{\"o}glichen ein systematisches Verst{\"a}ndnis der zugrunde liegenden Signalwege und Netzwerkeffekte (z.B. in Pflanzen). - Dar{\"u}ber hinaus erm{\"o}glichen sie die Identifizierung wichtiger funktioneller Hubproteine und die Entwicklung neuer therapeutischer Strategien f{\"u}r weitere experimentelle Testungen (z.B. Tumormodelle), - stellen zudem einen hilfreichen Schritt auf dem Weg zur personalisierten Medizin (z.B. lncRNAs und Tumormodelle) und Medikamentenentwicklung (z.B. Datenbank DrumPID) dar. (i) Als Grundlage wurde hierzu eine integrierte systembiologische Methode entwickelt, welche experimentelle Daten (z.B. Transkriptomdaten) hinsichtlich ihrer biologischen Funktionen untersucht und die Identifizierung relevanter funktioneller Cluster und Hubproteine erm{\"o}glicht. In einem ersten Teil wurden Analysen zum pflanzlichen Immunsystem durchgef{\"u}hrt. Mithilfe der entwickelten Methode wurden Genexpressionsdatens{\"a}tze von A. thaliana, die mit dem Pathogen Pst DC3000 infiziert wurden, untersucht, um den Einfluss verschiedener Virulenzfaktoren auf das Interaktom der Wirtspflanze zu untersuchen und neue Modulatoren einer CK-vermittelten Immunabwehr zu finden. In diesem Zusammenhang konnte gezeigt werden, dass die von Pst DC3000 sekretierten Abwehrstoffe wichtige pflanzliche Hormonsignalwege f{\"u}r die Immunabwehr in A. thaliana beeinflussen. Die Ergebnisse zeigen zudem, dass sich der Einfluss auf das Netzwerkverhalten der Effektorproteine und COR-Phytotoxine von dem der PAMPs unterscheidet, sich jedoch auch eine Regulierung gemeinsamer Signalwege und eine {\"U}berlappung der beiden Phasen der Immunantwort (PTI und ETI) in A. thaliana finden lassen. Die komplexe Immunantwort auf eine Infektion spiegelt sich zudem in einer h{\"o}heren Anzahl an funktionellen Clustern und Hubproteinen in Pst DC3000 gegen{\"u}ber den beiden untersuchten Mutanten wider, wobei sich f{\"u}r Pst DC3000 insbesondere ein stark vernetztes immunrelevantes Cluster um den JA-Signalweg zeigt. Weiterhin wurden anhand der entwickelten Methode wichtige Hubproteine f{\"u}r die Immunabwehr identifiziert. Als bedeutende Vertreter sind AHK2 und AAR14 zu nennen, welche Teil des Zweikomponentensystems der Signal{\"u}bertragung von CK sind und hierbei wichtige Modulatoren f{\"u}r eine CK-vermittelte Immunabwehr darstellen. (ii) Im zweiten Teil der Arbeit schließen sich Untersuchungen an einem in vitro-Experiment einer 2D- und 3D-Zellkultur einer HSP90-Behandlung in einem Lungentumormodell an. In diesem Zusammenhang wurden mithilfe der entwickelten Methode Unterschiede zwischen den beiden Zellkultursystemen gefunden, die das unterschiedliche Behandlungsansprechen erkl{\"a}ren, und f{\"u}r die beiden KRAS-mutierten Zelllinien A549 und H441 des 3D-Testsystems neue prognostische und therapeutische Kandidaten identifiziert. Hierbei haben die durchgef{\"u}hrten Analysen zwei funktionelle Cluster von Protein-Interaktionen um p53 und die STAT-Familie gefunden, welche eine Verbindung zu HSP90 haben und die entsprechenden Behandlungsunterschiede nach einer HSP90-Inhibierung zwischen den beiden Zellkultursystemen erkl{\"a}ren k{\"o}nnen. Unter Ber{\"u}cksichtigung des zelllinien-spezifischen Mutationshintergrunds wurde eine prognostische Markersignatur und daraus abgeleitet HIF1A f{\"u}r die H441-Zelllinie und AMPK f{\"u}r die A549-Zelllinie als neue therapeutische Targets gefunden, wobei die anschließend durchgef{\"u}hrten in silico-Simulationen einen potentiellen therapeutischen Effekt aufzeigen konnten. Weiterhin wurden wichtige experimentelle Readout-Parameter in ein in silico-Lungentumormodell integriert, wobei unter Einbeziehung des Mutationshintergrunds f{\"u}r die verwendeten Zelllinien die HSP90-Behandlung des 3D-Testsystems computergest{\"u}tzt abgebildet werden konnte. Im weiteren Verlauf wurden im in silico-Lungentumormodell Resistenzmechanismen nach einer Gefitinib-Behandlung mit bekanntem Mutationsstatus f{\"u}r die Zelllinien HCC827 und A549 untersucht und daraus folgend neue Therapieans{\"a}tze abgeleitet, die von potentieller klinischer Bedeutung sein k{\"o}nnen. Die durchgef{\"u}hrten in silico-Simulationen f{\"u}r HCC827 konnten hierbei zeigen, dass eine EGFR- und c-MET-Koaktivierung zu einer Gefitinib-Resistenz f{\"u}hren kann, wohingegen bei den A549 eine Komutation von KRAS und IGF-1R zu einem geringen Behandlungsansprechen beitr{\"a}gt. Die Simulationen lassen zudem erkennen, dass eine direkte Inhibierung der an der Resistenzentwicklung beteiligten Rezeptoren c-MET und IGF-1R in beiden F{\"a}llen nicht die bestm{\"o}gliche Therapiestrategie darstellt. In beiden Zelllinien konnte gezeigt werden, dass eine kombinierte Inhibierung von PI3K und MEK den bestm{\"o}glichen therapeutischen Effekt liefert, was demnach einen vielversprechenden Therapieansatz bei Gefitinib-resistenten Lungentumorpatienten darstellt. In einem weiteren Schritt wurde das therapeutische Potential der miRNA-21 im in silico-Modell f{\"u}r die HCC827-Zelllinie untersucht. Die durchgef{\"u}hrten Simulationen zeigen, dass eine miRNA-21-{\"U}berexpression zu einer Resistenzentwickung nach Gefitinib-Behandlung beitragen kann, wobei eine Inhibierung der miRNA-21 diesen Effekt umkehren kann. Die Ergebnisse lassen zudem erkennen, dass eine PTEN-Aktivierung als potentieller Marker einer erfolgreichen therapeutischen Inhibierung der miRNA-21 fungieren kann, wohingegen eine reduzierte miRNA-21-Expression als m{\"o}glicher Marker f{\"u}r eine erfolgreiche Gefitinib-Behandlung dienen kann. (iii) Im dritten Teil der Arbeit wurden systematisch RNA- und Protein-Interaktionen untersucht. Hierzu wurden integrierte systembiologische Analysen an neu identifizierten und funktionell bislang unbekannten lncRNAs durchgef{\"u}hrt. Die Analysen f{\"u}r die infolge einer Herzhypertrophie hochregulierte lncRNA Chast haben umfassend gezeigt, dass diese Proteine und Transkriptionsfaktoren regulieren und binden kann, welche die Signal{\"u}bertragung und Genexpression regulieren, aber auch eine Verbindung zum kardiovaskul{\"a}ren System und stressinduzierter Herzhypertrophie besitzt. Anhand der Ergebnisse l{\"a}sst sich schlussfolgern, dass Chast direkt und indirekt (a) Proteine binden und die Translation beeinflussen kann, zudem eine Chromatin-modifizierende Funktion besitzt und so die Transkription, z.B. f{\"u}r herz- und stress-assoziierte Gene, reguliert, und/oder (b) in einem negativen Feedbackloop seine eigene Transkription reguliert. Obwohl lncRNAs meist eine geringe Konservierung aufweisen, konnten die durchgef{\"u}hrten Analysen f{\"u}r Chast eine Sequenz-Struktur-Konservierung in S{\"a}ugetieren aufzeigen. Weiterhin haben die Untersuchungen an zwei hypoxie-induzierten lncRNAs in Endothelzellen gezeigt, dass die lncRNA MIR503HG eine hohe Sequenz-Struktur-Konservierung in S{\"a}ugetieren besitzt, wohingegen die LINC00323-003 eine geringe Konservierung aufzeigt. Dies untermauert die Tatsache, dass lncRNAs h{\"a}ufig eine geringe Konservierung aufweisen, was Untersuchungen in Modellorganismen hinsichtlich einer therapeutischen Nutzung schwierig machen. Da sich zahlreiche Untersuchungen auf Interaktionen und Signalwege konzentriert haben, wurde abschließend eine Datenbank entwickelt, welche Analysen von Protein-Interaktionen und Signalwegen nachhaltig voranbringt. Die entwickelte DrumPID-Datenbank stellt insbesondere die Interaktion zwischen einem Medikament und seinem Target in den Fokus und erm{\"o}glicht Analysen einzelner Interaktionen und beteiligter Signalwege, bietet zus{\"a}tzlich aber auch verschiedene Links zu anderen Datenbanken f{\"u}r individuelle weiterf{\"u}hrende Analysen. DrumPID erm{\"o}glicht ein geeignetes Medikament u. a. f{\"u}r ein vorgegebenes Zielprotein zu finden und dessen Wirkmechanismus und Interaktionskontext zu untersuchen, was zu einem besseren experimentellen Verst{\"a}ndnis beitragen kann. Zudem erlaubt DrumPID eine potentielle chemische Leitstruktur f{\"u}r ein Zielprotein zu entwickeln, was z.B. spezifisch ein parasitisches Protein inhibiert, ohne dabei einen toxischen Effekt im Menschen zu haben. Zahlreiche weitere Pharmakabeispiele belegen, dass DrumPID f{\"u}r den t{\"a}glichen wissenschaftlichen Gebrauch auf dem Gebiet der Analyse von Protein-Pharmaka-Interaktionen und der Medikamentenentwicklung geeignet ist. Die beschriebenen Ergebnisse der Promotionsarbeit wurden in f{\"u}nf Originalarbeiten, zwei {\"U}bersichtsartikeln und einem Buchteil, u. a. in Science Translational Medicine, ver{\"o}ffentlicht, sechs dieser Publikationen erfolgten im Rahmen von Erstautorschaften.}, subject = {Systembiologie}, language = {de} } @article{VieiraJonesDanonetal.2012, author = {Vieira, Jacqueline and Jones, Alex R. and Danon, Antoine and Sakuma, Michiyo and Hoang, Nathalie and Robles, David and Tait, Shirley and Heyes, Derren J. and Picot, Marie and Yoshii, Taishi and Helfrich-F{\"o}rster, Charlotte and Soubigou, Guillaume and Coppee, Jean-Yves and Klarsfeld, Andr{\´e} and Rouyer, Francois and Scrutton, Nigel S. and Ahmad, Margaret}, title = {Human Cryptochrome-1 Confers Light Independent Biological Activity in Transgenic Drosophila Correlated with Flavin Radical Stability}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {3}, doi = {10.1371/journal.pone.0031867}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134513}, pages = {e31867}, year = {2012}, abstract = {Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome - 1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism.}, language = {en} } @article{HeddergottKruegerBabuetal.2012, author = {Heddergott, Niko and Kr{\"u}ger, Timothy and Babu, Sujin B. and Wei, Ai and Stellamanns, Erik and Uppaluri, Sravanti and Pfohl, Thomas and Stark, Holger and Engstler, Markus}, title = {Trypanosome Motion Represents an Adaptation to the Crowded Environment of the Vertebrate Bloodstream}, series = {PLoS Pathogens}, volume = {8}, journal = {PLoS Pathogens}, number = {11}, doi = {10.1371/journal.ppat.1003023}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134595}, pages = {e1003023}, year = {2012}, abstract = {Blood is a remarkable habitat: it is highly viscous, contains a dense packaging of cells and perpetually flows at velocities varying over three orders of magnitude. Only few pathogens endure the harsh physical conditions within the vertebrate bloodstream and prosper despite being constantly attacked by host antibodies. African trypanosomes are strictly extracellular blood parasites, which evade the immune response through a system of antigenic variation and incessant motility. How the flagellates actually swim in blood remains to be elucidated. Here, we show that the mode and dynamics of trypanosome locomotion are a trait of life within a crowded environment. Using high-speed fluorescence microscopy and ordered micro-pillar arrays we show that the parasites mode of motility is adapted to the density of cells in blood. Trypanosomes are pulled forward by the planar beat of the single flagellum. Hydrodynamic flow across the asymmetrically shaped cell body translates into its rotational movement. Importantly, the presence of particles with the shape, size and spacing of blood cells is required and sufficient for trypanosomes to reach maximum forward velocity. If the density of obstacles, however, is further increased to resemble collagen networks or tissue spaces, the parasites reverse their flagellar beat and consequently swim backwards, in this way avoiding getting trapped. In the absence of obstacles, this flagellar beat reversal occurs randomly resulting in irregular waveforms and apparent cell tumbling. Thus, the swimming behavior of trypanosomes is a surprising example of micro-adaptation to life at low Reynolds numbers. For a precise physical interpretation, we compare our high-resolution microscopic data to results from a simulation technique that combines the method of multi-particle collision dynamics with a triangulated surface model. The simulation produces a rotating cell body and a helical swimming path, providing a functioning simulation method for a microorganism with a complex swimming strategy.}, language = {en} } @article{NanguneriFlottmannHorstmannetal.2012, author = {Nanguneri, Siddharth and Flottmann, Benjamin and Horstmann, Heinz and Heilemann, Mike and Kuner, Thomas}, title = {Three-Dimensional, Tomographic Super-Resolution Fluorescence Imaging of Serially Sectioned Thick Samples}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {5}, doi = {10.1371/journal.pone.0038098}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134434}, pages = {e38098}, year = {2012}, abstract = {Three-dimensional fluorescence imaging of thick tissue samples with near-molecular resolution remains a fundamental challenge in the life sciences. To tackle this, we developed tomoSTORM, an approach combining single-molecule localization-based super-resolution microscopy with array tomography of structurally intact brain tissue. Consecutive sections organized in a ribbon were serially imaged with a lateral resolution of 28 nm and an axial resolution of 40 nm in tissue volumes of up to 50 \(\mu\)mx50\(\mu\)mx2.5\(\mu\)m. Using targeted expression of membrane bound (m)GFP and immunohistochemistry at the calyx of Held, a model synapse for central glutamatergic neurotransmission, we delineated the course of the membrane and fine-structure of mitochondria. This method allows multiplexed super-resolution imaging in large tissue volumes with a resolution three orders of magnitude better than confocal microscopy.}, language = {en} } @article{SchokraieWarnkenHotzWagenblattetal.2012, author = {Schokraie, Elham and Warnken, Uwe and Hotz-Wagenblatt, Agnes and Grohme, Markus A. and Hengherr, Steffen and F{\"o}rster, Frank and Schill, Ralph O. and Frohme, Marcus and Dandekar, Thomas and Schn{\"o}lzer, Martina}, title = {Comparative proteome analysis of Milnesium tardigradum in early embryonic state versus adults in active and anhydrobiotic state}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0045682}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134447}, pages = {e45682}, year = {2012}, abstract = {Tardigrades have fascinated researchers for more than 300 years because of their extraordinary capability to undergo cryptobiosis and survive extreme environmental conditions. However, the survival mechanisms of tardigrades are still poorly understood mainly due to the absence of detailed knowledge about the proteome and genome of these organisms. Our study was intended to provide a basis for the functional characterization of expressed proteins in different states of tardigrades. High-throughput, high-accuracy proteomics in combination with a newly developed tardigrade specific protein database resulted in the identification of more than 3000 proteins in three different states: early embryonic state and adult animals in active and anhydrobiotic state. This comprehensive proteome resource includes protein families such as chaperones, antioxidants, ribosomal proteins, cytoskeletal proteins, transporters, protein channels, nutrient reservoirs, and developmental proteins. A comparative analysis of protein families in the different states was performed by calculating the exponentially modified protein abundance index which classifies proteins in major and minor components. This is the first step to analyzing the proteins involved in early embryonic development, and furthermore proteins which might play an important role in the transition into the anhydrobiotic state.}, language = {en} } @phdthesis{Koenig2016, author = {K{\"o}nig, Sebastian}, title = {Spatially selective visual attention in Drosophila melanogaster}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134452}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {Finding the right behavior at the right time is one of the major tasks of brains. In a natural scenery there is often an abundance of stimuli present and the brain has to separate the relevant from the irrelevant ones. Selective visual attention (SVA) is a property of higher visual systems that achieves this separation, as it allows to '[…] focus on one source of sensory input to the exclusion of others' (Luck and Mangun, 1996). There are probably several forms of SVA depending upon the criteria used for the separation, such as salience, color, location in space, novelty, or motion. Many studies have investigated SVA in humans and non-human primates. However, complex functions like attention were initially not expected to be already implemented in the brains of simple organisms like Drosophila. After a first demonstration of selective attention in the fly (Wolf and Heisenberg, 1980), it took some time until other studies included attentional mechanisms in their argumentation to explain certain behaviors of Drosophila. However, their definition and characterization of attention differed and often was ambiguous. Here, one particular form, spatially selective visual attention in the fly Drosophila is investigated. It has been shown earlier that the fly spontaneously may restrict its behavioral responses in stationary flight to the visual stimuli on one side of the visual field. On the basis of experiments of Sareen et al., (2011) it has been conjectured that the fly has a focus of attention (FoA) and that the fly responds to the visual stimuli within this area of the visual field. Whether the FoA is the adequate concept for this spatial property of SVA in the fly needs to be further discussed and is a subject also of the present study. At this stage, the concept will be used in the description of the new results expanding the characterization of SVA. This study continued the investigation of SVA during tethered flight with variable but controlled visual input and an automated primary data evaluation. This standardized paradigm allowed for analysis of wild-type behavior as well as for a comparison of several mutant and pharmacologically manipulated strains to the wild-type. Some properties of human SVA like the occurrence of externally as well as internally caused shifts of attention were found in Drosophila and it could be shown, that SVA in the fly can be externally guided and has an attention span. Additionally, a neurotransmitter and proteins, which play a significant role in SVA were discovered. Based on this, the genetic tools available for Drosophila provided the means to a first examination of cells and circuits involved in SVA. Finally, the free walk behavior of flies that had been shown to have compromised SVA was characterized. The results suggested that the observed phenotypes of SVA were not behavior specific. Covert shifts of the FoA were investigated. The FoA can be externally guided by visual cues to one or the other side of the visual field and even after the cue has disappeared it remains there for <4s. An intriguing finding of this study is the fact, that the quality of the cue determines whether it is attractive or repellent. For example a cue can be changed from being repellent (negative) to being attractive (positive) by changing its oscillation amplitude from 4° to 2°. Testing the effectiveness of cues in the upper and lower visual field separately, revealed that the perception of a cue by the fly is not exclusively based on a sum of its specifications. Because positive cueing did not have an after-effect in each of the two half-fields alone, but did so if the cue was shown in both, the fly seems to evaluate the cue for each combination of parameters specifically. Whether this evaluation of the cue changed on a trial-to-trial basis or if the cue in some cases failed to shift the FoA can at this point not be determined. Looking at the responses of the fly to the displacement of a black vertical stripe showed that they can be categorized as no responses, syn-directional responses (following the direction of motion of the stripe) and anti-directional responses (in the opposite direction of the motion of the stripe). The yaw-torque patterns of the latter bared similarities with spontaneous body saccades and they most likely represented escape attempts of the fly. Syn-directional responses, however, were genuine object responses, distinguishable by a longer latency until they were elicited and a larger amplitude. These properties as well as the distribution of response polarities were not influenced by the presence or absence of a cue. When two stripes were displaced simultaneously in opposite directions the rate of no responses increased in comparison to the displacement of a single stripe. If one of the stripes was cued, both, the responses towards and away from the side of cue resembled the syn-directional responses. Significant progress was made with the elucidation of the neuronal underpinnings of SVA. Ablation of the mushroom bodies (MB) demonstrated their requirement for SVA. Furthermore, it was shown that dopamine signaling has to be balanced between too much and too little. Either inhibiting the synthesis of dopamine or its re-uptake at the synapse via the dDAT impaired the flies' susceptibility to cueing. Using the Gal4/UAS system, cell specific expression or knockdown of the dDAT was used to scrutinize the role of MB sub-compartments in SVA. The αβ-lobes turned out to be necessary and sufficient to maintain SVA. The Gal4-line c708a labels only a subset of Kenyon cells (KC) within the αβ-lobes, αβposterior. These cells stand out, because of (A) the mesh-like arrangement of their fibers within the lobes and (B) the fact that unlike the other KCs they bypass the calyx and thereby the main source of olfactory input to the MBs, forming connections only in the posterior accessory calyx (Tanaka et al., 2008). This structure receives no or only marginal olfactory input, suggesting for it a role in tasks other than olfaction. This study shows their requirement in a visual task by demonstrating that they are necessary to uphold SVA. Restoring dDAT function in these approximately only 90 cells was probably insufficient to lower the dopamine concentration at the relevant synapses and hence a rescue failed. Alternatively, the processes mediating SVA at the αβ-lobes might require an interplay between all of their KCs. In conclusion, the results provide an initial point for future research to fully understand the localization of and circuitry required for SVA in the brain. In the experiments described so far, attention has been externally guided. However, flies are also able to internally shift their FoA without any cues from the outside world. In a set of 60 consecutive simultaneous displacements of two stripes, they were more likely to produce a response with the same polarity as the preceding one than a random polarity selection predicted. This suggested a dwelling of the FoA on one side of the visual field. Assuming that each response was influenced by the previous one in a way that the probability to repeat the response polarity was increased by a certain factor (dwelling factor, df), a random selection of response type including a df was computed. Implementation of the df removed the difference between observed probability of polarity repetition and the one suggested by random selection. When the interval between displacements was iteratively increased to 5s, no significant df could be detected anymore for pauses longer than 4s. In conclusion, Drosophila has an attention span of approximately 4s. Flies with a mutation in the radish gene expressed no after-effect of cueing and had a shortened attention span of about 1s. The dDAT inhibitor methylphenidate is able to rescue the first, but does not affect the latter phenotype. Probably, radish is differently involved in the two mechanisms. This study showed, that endogenous (covert) shifts of spatially selective visual attention in the fly Drosophila can be internally and externally guided. The variables determining the quality of a cue turned out to be multifaceted and a more systematic approach is needed for a better understanding of what property or feature of the cue changes the way it is evaluated by the fly. A first step has been made to demonstrate that SVA is a fundamental process and compromising it can influence the characteristics of other behaviors like walking. The existence of an attention span, the dependence of SVA on dopamine as well as the susceptibility to pharmacological manipulations, which in humans are used to treat respective diseases, point towards striking similarities between SVA in humans and Drosophila.}, subject = {Taufliege}, language = {en} } @phdthesis{Heidinger2015, author = {Heidinger, Ina M. M.}, title = {Beyond metapopulation theory: Determinants of the dispersal capacity of bush crickets and grasshoppers}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135068}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2015}, abstract = {Habitat fragmentation and destruction due to anthropogenic land use are the major causes of the increasing extinction risk of many species and have a detrimental impact on animal populations in numerous ways. The long-term survival and stability of spatially structured populations in fragmented landscapes largely depends on the colonisation of habitat patches and the exchange of individuals and genes between patches. The degree of inter-patch dispersal, in turn, depends on the dispersal ability of a species (i.e. the combination of physiological and morphological factors that facilitate dispersal) and the landscape structure (i.e. the nature of the landscape matrix or the spatial configuration of habitat patches). As fragmentation of landscapes is increasing and the number of species is continuously declining, a thorough understanding of the causes and consequences of dispersal is essential for managing natural populations and developing effective conservation strategies. In the context of animal dispersal, movement behaviour is intensively investigated with capture-mark-recapture studies. For the analysis of such experiments, the influence of marking technique, handling and translocation of marked animals on movement pattern is of crucial importance since it may mask the effects of the main research question. Chapter 2 of this thesis presents a capture-mark-recapture study investigating the effect of translocation on the movement behaviour of the blue-winged grasshopper Oedipoda caerulescens. Transferring individuals of this grasshopper species to suitable but unfamilliar sites has a significant influence on their movement behaviour. Translocated individuals moved longer distances, showed smaller daily turning angles, and thus their movements were more directed than those of resident individuals. The effect of translocation was most pronounced on the first day of the experiment, but may persist for longer. On average, daily moved distances of translocated individuals were about 50 \% longer than that of resident individuals because they have been transferred to an unfamiliar habitat patch. Depending on experiment duration, this leads to considerable differences in net displacement between translocated and resident individuals. In summary, the results presented in chapter 2 clearly point out that translocation effects should not be disregarded in future studies on arthropod movement, respectively dispersal. Studies not controlling for possible translocation effects may result in false predictions of dispersal behaviour, habitat detection capability or habitat preferences. Beside direct field observations via capture-mark-recapture methods, genetic markers can be used to investigate animal dispersal. Chapter 3 presents data on the genetic structure of populations of Metrioptera bicolor, a wing-dimorphic bush cricket, in a spatially structured landscape with patches of suitable habitat distributed within a diverse matrix of different habitat types. Using microsatellite markers, the effects of geographic distance and different matrix types on the genetic differentiation among 24 local populations was assessed. The results of this study clearly indicate that for M. bicolor the isolation of local populations severely depends on the type of surrounding matrix. The presence of forest and a river running through the study area was positively correlated with the extent of genetic differentiation between populations. This indicates that both matrix types severely impede gene flow and the exchange of individuals between local populations of this bush cricket. In addition, for a subsample of populations which were separated only by arable land or settlements, a significant positive correlation between pairwise genetic and geographic distances exists. For the complete data set, this correlation could not be found. This is most probably due to the adverse effect of forest and river on gene flow which dominates the effect of geographic distance in the limited set of patches investigated in this study. The analyses in chapter 3 clearly emphasize the differential resistance of different habitat types on dispersal and the importance of a more detailed view on matrix 'quality' in metapopulation studies. Studies that focus on the specific dispersal resistance of different matrix types may provide much more detailed information on the dispersal capacity of species than a mere analysis of isolation by distance. Such information is needed to improve landscape oriented models for species conservation. In addition to direct effects on realised dispersal (see chapter 3), landscape structure on its own is known to act as an evolutionary selection agent because it determines the costs and benefits of dispersal. Both morphological and behavioural traits of individuals and the degree to which a certain genotype responds to environmental variation have heritable components, and are therefore expected to be able to respond to selection pressures. Chapter 4 analyses the influence of patch size, patch connectivity (isolation of populations) and sand dynamics (stability of habitat) on thorax- and wing length as proxies for dispersal ability of O. caerulescens in coastal grey dunes. This study revealed clear and sex-specific effects of landscape dynamics and patch configuration on dispersal-related morphology. Males of this grasshopper species were smaller and had shorter wings if patches were larger and less connected. In addition, both sexes were larger in habitat patches with high sand dynamics compared to those in patches with lower dynamics. The investments in wing length were only larger in connected populations when sand dynamics were low, indicating that both landscape and patch-related environmental factors are of importance. These results are congruent with theoretical predictions on the evolution of dispersal in metapopulations. They add to the evidence that dispersal-related morphology varies and is selected upon in recently structured populations even at small spatial scales. Dispersal involves different individual fitness costs like increased predation risk, energy expenditure, costs of developing dispersal-related traits, failure to find new suitable habitat as well as reproductive costs. Therefore, the decision to disperse should not be random but depend on the developmental stage or the physiological condition of an individual just as on actual environmental conditions (context-dependent dispersal, e.g. sex- and wing morph-biased dispersal). Biased dispersal is often investigated by comparing the morphology, physiology and behaviour of females and males or sedentary and dispersive individuals. Studies of biased dispersal in terms of capture-mark-recapture experiments, investigating real dispersal and not routine movements, and genetic proofs of biased dispersal are still rare for certain taxa, especially for orthopterans. However, information on biased dispersal is of great importance as for example, undetected biased dispersal may lead to false conclusions from genetic data. In chapter 5 of this thesis, a combined approach of morphological and genetic analyses was used to investigate biased dispersal of M. bicolor. The presented results not only show that macropterous individuals are predestined for dispersal due to their morphology, the genetic data also indicate that macropters are more dispersive than micropters. Furthermore, even within the group of macropterous individuals, males are supposed to be more dispersive than females. To get an idea of the flight ability of M. bicolor, the morphological data were compared with that of Locusta migratoria and Schistocerca gregaria, which are proved to be very good flyers. Based on the morphological data presented here, one can assume a good flight ability for macropters of M. bicolor, although flying individuals of this species are seldom observed in natural populations.}, subject = {Heuschrecken <{\"U}berfamilie>}, language = {en} } @article{SchmittKellerNourkamiTutdibietal.2011, author = {Schmitt, Jana and Keller, Andreas and Nourkami-Tutdibi, Nasenien and Heisel, Sabrina and Habel, Nunja and Leidinger, Petra and Ludwig, Nicole and Gessler, Manfred and Graf, Norbert and Berthold, Frank and Lenhof, Hans-Peter and Meese, Eckart}, title = {Autoantibody Signature Differentiates Wilms Tumor Patients from Neuroblastoma Patients}, series = {PLoS ONE}, volume = {6}, journal = {PLoS ONE}, number = {12}, doi = {10.1371/journal.pone.0028951}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133794}, pages = {e28951}, year = {2011}, abstract = {Several studies report autoantibody signatures in cancer. The majority of these studies analyzed adult tumors and compared the seroreactivity pattern of tumor patients with the pattern in healthy controls. Here, we compared the autoimmune response in patients with neuroblastoma and patients with Wilms tumor representing two different childhood tumors. We were able to differentiate untreated neuroblastoma patients from untreated Wilms tumor patients with an accuracy of 86.8\%, a sensitivity of 87.0\% and a specificity of 86.7\%. The separation of treated neuroblastoma patients from treated Wilms tumor patients' yielded comparable results with an accuracy of 83.8\%. We furthermore identified the antigens that contribute most to the differentiation between both tumor types. The analysis of these antigens revealed that neuroblastoma was considerably more immunogenic than Wilms tumor. The reported antigens have not been found to be relevant for comparative analyses between other tumors and controls. In summary, neuroblastoma appears as a highly immunogenic tumor as demonstrated by the extended number of antigens that separate this tumor from Wilms tumor.}, 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{HarringtonScelsiHarteletal.2012, author = {Harrington, John M. and Scelsi, Chris and Hartel, Andreas and Jones, Nicola G. and Engstler, Markus and Capewell, Paul and MacLeod, Annette and Hajduk, Stephen}, title = {Novel African Trypanocidal Agents: Membrane Rigidifying Peptides}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0044384}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135179}, pages = {e44384}, year = {2012}, abstract = {The bloodstream developmental forms of pathogenic African trypanosomes are uniquely susceptible to killing by small hydrophobic peptides. Trypanocidal activity is conferred by peptide hydrophobicity and charge distribution and results from increased rigidity of the plasma membrane. Structural analysis of lipid-associated peptide suggests a mechanism of phospholipid clamping in which an internal hydrophobic bulge anchors the peptide in the membrane and positively charged moieties at the termini coordinate phosphates of the polar lipid headgroups. This mechanism reveals a necessary phenotype in bloodstream form African trypanosomes, high membrane fluidity, and we suggest that targeting the plasma membrane lipid bilayer as a whole may be a novel strategy for the development of new pharmaceutical agents. Additionally, the peptides we have described may be valuable tools for probing the biosynthetic machinery responsible for the unique composition and characteristics of African trypanosome plasma membranes.}, language = {en} } @article{RoierLeitnerIwashkiwetal.2012, author = {Roier, Sandro and Leitner, Deborah R. and Iwashkiw, Jeremy and Schild-Pr{\"u}fert, Kristina and Feldman, Mario F. and Krohne, Georg and Reidl, Joachim and Schild, Stefan}, title = {Intranasal Immunization with Nontypeable Haemophilus influenzae Outer Membrane Vesicles Induces Cross-Protective Immunity in Mice}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {8}, doi = {10.1371/journal.pone.0042664}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-135201}, pages = {e42664}, year = {2012}, abstract = {Haemophilus influenzae is a Gram-negative human-restricted bacterium that can act as a commensal and a pathogen of the respiratory tract. Especially nontypeable H. influenzae (NTHi) is a major threat to public health and is responsible for several infectious diseases in humans, such as pneumonia, sinusitis, and otitis media. Additionally, NTHi strains are highly associated with exacerbations in patients suffering from chronic obstructive pulmonary disease. Currently, there is no licensed vaccine against NTHi commercially available. Thus, this study investigated the utilization of outer membrane vesicles (OMVs) as a potential vaccine candidate against NTHi infections. We analyzed the immunogenic and protective properties of OMVs derived from various NTHi strains by means of nasopharyngeal immunization and colonization studies with BALB/c mice. The results presented herein demonstrate that an intranasal immunization with NTHi OMVs results in a robust and complex humoral and mucosal immune response. Immunoprecipitation revealed the most important immunogenic proteins, such as the heme utilization protein, protective surface antigen D15, heme binding protein A, and the outer membrane proteins P1, P2, P5 and P6. The induced immune response conferred not only protection against colonization with a homologous NTHi strain, which served as an OMV donor for the immunization mixtures, but also against a heterologous NTHi strain, whose OMVs were not part of the immunization mixtures. These findings indicate that OMVs derived from NTHi strains have a high potential to act as a vaccine against NTHi infections.}, language = {en} } @article{AsoHerbOguetaetal.2012, author = {Aso, Yoshinori and Herb, Andrea and Ogueta, Maite and Siwanowicz, Igor and Templier, Thomas and Friedrich, Anja B. and Ito, Kei and Scholz, Henrike and Tanimoto, Hiromu}, title = {Three Dopamine Pathways Induce Aversive Odor Memories with Different Stability}, series = {PLoS Genetics}, volume = {8}, journal = {PLoS Genetics}, number = {7}, doi = {10.1371/journal.pgen.1002768}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130631}, pages = {e1002768}, year = {2012}, abstract = {Animals acquire predictive values of sensory stimuli through reinforcement. In the brain of Drosophila melanogaster, activation of two types of dopamine neurons in the PAM and PPL1 clusters has been shown to induce aversive odor memory. Here, we identified the third cell type and characterized aversive memories induced by these dopamine neurons. These three dopamine pathways all project to the mushroom body but terminate in the spatially segregated subdomains. To understand the functional difference of these dopamine pathways in electric shock reinforcement, we blocked each one of them during memory acquisition. We found that all three pathways partially contribute to electric shock memory. Notably, the memories mediated by these neurons differed in temporal stability. Furthermore, combinatorial activation of two of these pathways revealed significant interaction of individual memory components rather than their simple summation. These results cast light on a cellular mechanism by which a noxious event induces different dopamine signals to a single brain structure to synthesize an aversive memory.}, language = {en} } @article{BugaScholzKumaretal.2012, author = {Buga, Ana-Maria and Scholz, Claus J{\"u}rgen and Kumar, Senthil and Herndon, James G. and Alexandru, Dragos and Cojocaru, Gabriel Radu and Dandekar, Thomas and Popa-Wagner, Aurel}, title = {Identification of New Therapeutic Targets by Genome-Wide Analysis of Gene Expression in the Ipsilateral Cortex of Aged Rats after Stroke}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {12}, doi = {10.1371/journal.pone.0050985}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130657}, pages = {e50985}, year = {2012}, abstract = {Background: Because most human stroke victims are elderly, studies of experimental stroke in the aged rather than the young rat model may be optimal for identifying clinically relevant cellular responses, as well for pinpointing beneficial interventions. Methodology/Principal Findings: We employed the Affymetrix platform to analyze the whole-gene transcriptome following temporary ligation of the middle cerebral artery in aged and young rats. The correspondence, heat map, and dendrogram analyses independently suggest a differential, age-group-specific behaviour of major gene clusters after stroke. Overall, the pattern of gene expression strongly suggests that the response of the aged rat brain is qualitatively rather than quantitatively different from the young, i.e. the total number of regulated genes is comparable in the two age groups, but the aged rats had great difficulty in mounting a timely response to stroke. Our study indicates that four genes related to neuropathic syndrome, stress, anxiety disorders and depression (Acvr1c, Cort, Htr2b and Pnoc) may have impaired response to stroke in aged rats. New therapeutic options in aged rats may also include Calcrl, Cyp11b1, Prcp, Cebpa, Cfd, Gpnmb, Fcgr2b, Fcgr3a, Tnfrsf26, Adam 17 and Mmp14. An unexpected target is the enzyme 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1 in aged rats, a key enzyme in the cholesterol synthesis pathway. Post-stroke axonal growth was compromised in both age groups. Conclusion/Significance: We suggest that a multi-stage, multimodal treatment in aged animals may be more likely to produce positive results. Such a therapeutic approach should be focused on tissue restoration but should also address other aspects of patient post-stroke therapy such as neuropathic syndrome, stress, anxiety disorders, depression, neurotransmission and blood pressure.}, language = {en} } @article{WeisseHeddergottHeydtetal.2012, author = {Weiße, Sebastian and Heddergott, Niko and Heydt, Matthias and Pfl{\"a}sterer, Daniel and Maier, Timo and Haraszti, Tamas and Grunze, Michael and Engstler, Markus and Rosenhahn, Axel}, title = {A Quantitative 3D Motility Analysis of Trypanosoma brucei by Use of Digital In-line Holographic Microscopy}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {5}, doi = {10.1371/journal.pone.0037296}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130666}, pages = {e37296}, year = {2012}, abstract = {We present a quantitative 3D analysis of the motility of the blood parasite Trypanosoma brucei. Digital in-line holographic microscopy has been used to track single cells with high temporal and spatial accuracy to obtain quantitative data on their behavior. Comparing bloodstream form and insect form trypanosomes as well as mutant and wildtype cells under varying external conditions we were able to derive a general two-state-run-and-tumble-model for trypanosome motility. Differences in the motility of distinct strains indicate that adaption of the trypanosomes to their natural environments involves a change in their mode of swimming.}, language = {en} } @phdthesis{Beck2016, author = {Beck, Katherina}, title = {Einfluss von RSK auf die Aktivit{\"a}t von ERK, den axonalen Transport und die synaptische Funktion in Motoneuronen von \(Drosophila\) \(melanogaster\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130717}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2016}, abstract = {In dieser Arbeit sollte die Funktion von RSK in Motoneuronen von Drosophila untersucht werden. Mutationen im RSK2-Gen verursachen das Coffin-Lowry-Syndrom (CLS), das durch mentale Retardierung charakterisiert ist. RSK2 ist haupts{\"a}chlich in Regionen des Gehirns exprimiert, in denen Lernen und Ged{\"a}chtnisbildung stattfinden. In M{\"a}usen und Drosophila, die als Modellorganismen f{\"u}r CLS dienen, konnten auf makroskopischer Ebene keine Ver{\"a}nderungen in den Hirnstrukturen gefunden werden, dennoch wurden in verschiedenen Verhaltensstudien Defekte im Lernen und der Ged{\"a}chtnisbildung beobachtet. Die synaptische Plastizit{\"a}t und die einhergehenden Ver{\"a}nderungen in den Eigenschaften der Synapse sind fundamental f{\"u}r adaptives Verhalten. Zur Analyse der synaptischen Plastizit{\"a}t eignet sich das neuromuskul{\"a}re System von Drosophila als Modell wegen des stereotypen Innervierungsmusters und der Verwendung ionotroper Glutamatrezeptoren, deren Untereinheiten homolog sind zu den Untereinheiten der Glutamatrezeptoren des AMPA-Typs aus S{\"a}ugern, die wesentlich f{\"u}r die Bildung von LTP im Hippocampus sind. Zun{\"a}chst konnte gezeigt werden, dass RSK in den Motoneuronen von Drosophila an der pr{\"a}synaptischen Seite lokalisiert ist, wodurch RSK eine Synapsen-spezifische Funktion aus{\"u}ben k{\"o}nnte. Morphologische Untersuchungen der Struktur der neuromuskul{\"a}ren Synapsen konnten aufzeigen, dass durch den Verlust von RSK die Gr{\"o}ße der neuromuskul{\"a}ren Synapse, der Boutons sowie der Aktiven Zonen und Glutamatrezeptorfelder reduziert ist. Obwohl mehr Boutons gebildet werden, sind weniger Aktive Zonen und Glutamatrezeptorfelder in der neuromuskul{\"a}ren Synapse enthalten. RSK reguliert die synaptische Transmission, indem es die postsynaptische Sensitivit{\"a}t, nicht aber die Freisetzung der Neurotransmitter an der pr{\"a}synaptischen Seite beeinflusst, obwohl in immunhistochemischen Analysen eine postsynaptische Lokalisierung von RSK nicht nachgewiesen werden konnte. RSK ist demnach an der Regulation der synaptischen Plastizit{\"a}t glutamaterger Synapsen beteiligt. Durch immunhistochemische Untersuchungen konnte erstmals gezeigt werden, dass aktiviertes ERK an der pr{\"a}synaptischen Seite lokalisiert ist und diese synaptische Lokalisierung von RSK reguliert wird. Dar{\"u}ber hinaus konnte in dieser Arbeit nachgewiesen werden, dass durch den Verlust von RSK hyperaktiviertes ERK in den Zellk{\"o}rpern der Motoneurone vorliegt. RSK wird durch den ERK/MAPK-Signalweg aktiviert und {\"u}bernimmt eine Funktion sowohl als Effektorkinase als auch in der Negativregulation des Signalwegs. Demnach dient RSK in den Zellk{\"o}rpern der Motoneurone als Negativregulator des ERK/MAPK-Signalwegs. Dar{\"u}ber hinaus k{\"o}nnte RSK die Verteilung von aktivem ERK in den Subkompartimenten der Motoneurone regulieren. Da in vorangegangenen Studien gezeigt werden konnte, dass ERK an der Regulation der synaptischen Plastizit{\"a}t beteiligt ist, indem es die Insertion der AMPA-Rezeptoren zur Bildung der LTP reguliert, sollte in dieser Arbeit aufgekl{\"a}rt werden, ob der Einfluss von RSK auf die synaptische Plastizit{\"a}t durch seine Funktion als Negativregulator von ERK zustande kommt. Untersuchungen der genetischen Interaktion von rsk und rolled, dem Homolog von ERK in Drosophila, zeigten, dass die durch den Verlust von RSK beobachtete reduzierte Gesamtzahl der Aktiven Zonen und Glutamatrezeptorfelder der neuromuskul{\"a}ren Synapse auf die Funktion von RSK als Negativregulator von ERK zur{\"u}ckzuf{\"u}hren ist. Die Gr{\"o}ße der neuromuskul{\"a}ren Synapse sowie die Gr{\"o}ße der Aktiven Zonen und Glutamatrezeptorfelder beeinflusst RSK allerdings durch seine Funktion als Effektorkinase des ERK/MAPK-Signalwegs. Studien des axonalen Transports von Mitochondrien zeigten, dass dieser in vielen neuropathologischen Erkrankungen beeintr{\"a}chtigt ist. Die durchgef{\"u}hrten Untersuchungen des axonalen Transports in Motoneuronen konnten eine neue Funktion von RSK in der Regulation des axonalen Transports aufdecken. In den Axonen der Motoneurone von RSK-Nullmutanten wurden BRP- und CSP-Agglomerate nachgewiesen. RSK k{\"o}nnte an der Regulation des axonalen Transports von pr{\"a}synaptischem Material beteiligt sein. Durch den Verlust von RSK wurden weniger Mitochondrien in anterograder Richtung entlang dem Axon transportiert, daf{\"u}r verweilten mehr Mitochondrien in station{\"a}ren Phasen. Diese Ergebnisse zeigen, dass auch der anterograde Transport von Mitochondrien durch den Verlust von RSK beeintr{\"a}chtigt ist.}, subject = {Taufliege}, language = {de} } @article{KarlDandekar2013, author = {Karl, Stefan and Dandekar, Thomas}, title = {Jimena: Efficient computing and system state identification for genetic regulatory networks}, series = {BMC Bioinformatics}, volume = {14}, journal = {BMC Bioinformatics}, doi = {10.1186/1471-2105-14-306}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128671}, year = {2013}, abstract = {Background: Boolean networks capture switching behavior of many naturally occurring regulatory networks. For semi-quantitative modeling, interpolation between ON and OFF states is necessary. The high degree polynomial interpolation of Boolean genetic regulatory networks (GRNs) in cellular processes such as apoptosis or proliferation allows for the modeling of a wider range of node interactions than continuous activator-inhibitor models, but suffers from scaling problems for networks which contain nodes with more than ~10 inputs. Many GRNs from literature or new gene expression experiments exceed those limitations and a new approach was developed. Results: (i) As a part of our new GRN simulation framework Jimena we introduce and setup Boolean-tree-based data structures; (ii) corresponding algorithms greatly expedite the calculation of the polynomial interpolation in almost all cases, thereby expanding the range of networks which can be simulated by this model in reasonable time. (iii) Stable states for discrete models are efficiently counted and identified using binary decision diagrams. As application example, we show how system states can now be sampled efficiently in small up to large scale hormone disease networks (Arabidopsis thaliana development and immunity, pathogen Pseudomonas syringae and modulation by cytokinins and plant hormones). Conclusions: Jimena simulates currently available GRNs about 10-100 times faster than the previous implementation of the polynomial interpolation model and even greater gains are achieved for large scale-free networks. This speed-up also facilitates a much more thorough sampling of continuous state spaces which may lead to the identification of new stable states. Mutants of large networks can be constructed and analyzed very quickly enabling new insights into network robustness and behavior.}, language = {en} } @article{HuserRohwedderApostolopoulouetal.2012, author = {Huser, Annina and Rohwedder, Astrid and Apostolopoulou, Anthi A. and Widmann, Annekathrin and Pfitzenmaier, Johanna E. and Maiolo, Elena M. and Selcho, Mareike and Pauls, Dennis and von Essen, Alina and Gupta, Tript and Sprecher, Simon G. and Birman, Serge and Riemensperger, Thomas and Stocker, Reinhard F. and Thum, Andreas S.}, title = {The Serotonergic Central Nervous System of the Drosophila Larva: Anatomy and Behavioral Function}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {10}, doi = {10.1371/journal.pone.0047518}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130437}, pages = {e47518}, year = {2012}, abstract = {The Drosophila larva has turned into a particularly simple model system for studying the neuronal basis of innate behaviors and higher brain functions. Neuronal networks involved in olfaction, gustation, vision and learning and memory have been described during the last decade, often up to the single-cell level. Thus, most of these sensory networks are substantially defined, from the sensory level up to third-order neurons. This is especially true for the olfactory system of the larva. Given the wealth of genetic tools in Drosophila it is now possible to address the question how modulatory systems interfere with sensory systems and affect learning and memory. Here we focus on the serotonergic system that was shown to be involved in mammalian and insect sensory perception as well as learning and memory. Larval studies suggested that the serotonergic system is involved in the modulation of olfaction, feeding, vision and heart rate regulation. In a dual anatomical and behavioral approach we describe the basic anatomy of the larval serotonergic system, down to the single-cell level. In parallel, by expressing apoptosis-inducing genes during embryonic and larval development, we ablate most of the serotonergic neurons within the larval central nervous system. When testing these animals for naive odor, sugar, salt and light perception, no profound phenotype was detectable; even appetitive and aversive learning was normal. Our results provide the first comprehensive description of the neuronal network of the larval serotonergic system. Moreover, they suggest that serotonin per se is not necessary for any of the behaviors tested. However, our data do not exclude that this system may modulate or fine-tune a wide set of behaviors, similar to its reported function in other insect species or in mammals. Based on our observations and the availability of a wide variety of genetic tools, this issue can now be addressed.}, language = {en} } @article{HendriksmaKuetingHaerteletal.2013, author = {Hendriksma, Harmen P. and K{\"u}ting, Meike and H{\"a}rtel, Stephan and N{\"a}ther, Astrid and Dohrmann, Anja B. and Steffan-Dewenter, Ingolf and Tebbe, Christoph C.}, title = {Effect of Stacked Insecticidal Cry Proteins from Maize Pollen on Nurse Bees (Apis mellifera carnica) and Their Gut Bacteria}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0059589}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131025}, pages = {e59589}, year = {2013}, abstract = {Honey bee pollination is a key ecosystem service to nature and agriculture. However, biosafety research on genetically modified crops rarely considers effects on nurse bees from intact colonies, even though they receive and primarily process the largest amount of pollen. The objective of this study was to analyze the response of nurse bees and their gut bacteria to pollen from Bt maize expressing three different insecticidal Cry proteins (Cry1A.105, Cry2Ab2, and Cry3Bb1). Naturally Cry proteins are produced by bacteria (Bacillus thuringiensis). Colonies of Apis mellifera carnica were kept during anthesis in flight cages on field plots with the Bt maize, two different conventionally bred maize varieties, and without cages, 1-km outside of the experimental maize field to allow ad libitum foraging to mixed pollen sources. During their 10-days life span, the consumption of Bt maize pollen had no effect on their survival rate, body weight and rates of pollen digestion compared to the conventional maize varieties. As indicated by ELISA-quantification of Cry1A.105 and Cry3Bb1, more than 98\% of the recombinant proteins were degraded. Bacterial population sizes in the gut were not affected by the genetic modification. Bt-maize, conventional varieties and mixed pollen sources selected for significantly different bacterial communities which were, however, composed of the same dominant members, including Proteobacteria in the midgut and Lactobacillus sp. and Bifidobacterium sp. in the hindgut. Surprisingly, Cry proteins from natural sources, most likely B. thuringiensis, were detected in bees with no exposure to Bt maize. The natural occurrence of Cry proteins and the lack of detectable effects on nurse bees and their gut bacteria give no indication for harmful effects of this Bt maize on nurse honey bees.}, language = {en} } @article{KatoLuRapaportetal.2013, author = {Kato, Hiroki and Lu, Qiping and Rapaport, Doron and Kozjak-Pavlovic, Vera}, title = {Tom70 Is Essential for PINK1 Import into Mitochondria}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0058435}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131061}, pages = {e58435}, year = {2013}, abstract = {PTEN induced kinase 1 (PINK1) is a serine/threonine kinase in the outer membrane of mitochondria (OMM), and known as a responsible gene of Parkinson's disease (PD). The precursor of PINK1 is synthesized in the cytosol and then imported into the mitochondria via the translocase of the OMM (TOM) complex. However, a large part of PINK1 import mechanism remains unclear. In this study, we examined using cell-free system the mechanism by which PINK1 is targeted to and assembled into mitochondria. Surprisingly, the main component of the import channel, Tom40 was not necessary for PINK1 import. Furthermore, we revealed that the import receptor Tom70 is essential for PINK1 import. In addition, we observed that although PINK1 has predicted mitochondrial targeting signal, it was not processed by the mitochondrial processing peptidase. Thus, our results suggest that PINK1 is imported into mitochondria by a unique pathway that is independent of the TOM core complex but crucially depends on the import receptor Tom70.}, language = {en} }