@article{BrandstaetterRoesslerKleineidam2011, author = {Brandst{\"a}tter, Andreas and R{\"o}ssler, W. and Kleineidam, C. J.}, title = {Friends and foes from an ant brain's point of view - neuronal correlates of colony odors in a social insect}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69046}, year = {2011}, abstract = {Background: Successful cooperation depends on reliable identification of friends and foes. Social insects discriminate colony members (nestmates/friends) from foreign workers (non-nestmates/foes) by colony-specific, multi-component colony odors. Traditionally, complex processing in the brain has been regarded as crucial for colony recognition. Odor information is represented as spatial patterns of activity and processed in the primary olfactory neuropile, the antennal lobe (AL) of insects, which is analogous to the vertebrate olfactory bulb. Correlative evidence indicates that the spatial activity patterns reflect odor-quality, i.e., how an odor is perceived. For colony odors, alternatively, a sensory filter in the peripheral nervous system was suggested, causing specific anosmia to nestmate colony odors. Here, we investigate neuronal correlates of colony odors in the brain of a social insect to directly test whether they are anosmic to nestmate colony odors and whether spatial activity patterns in the AL can predict how odor qualities like ''friend'' and ''foe'' are attributed to colony odors. Methodology/Principal Findings: Using ant dummies that mimic natural conditions, we presented colony odors and investigated their neuronal representation in the ant Camponotus floridanus. Nestmate and non-nestmate colony odors elicited neuronal activity: In the periphery, we recorded sensory responses of olfactory receptor neurons (electroantennography), and in the brain, we measured colony odor specific spatial activity patterns in the AL (calcium imaging). Surprisingly, upon repeated stimulation with the same colony odor, spatial activity patterns were variable, and as variable as activity patterns elicited by different colony odors. Conclusions: Ants are not anosmic to nestmate colony odors. However, spatial activity patterns in the AL alone do not provide sufficient information for colony odor discrimination and this finding challenges the current notion of how odor quality is coded. Our result illustrates the enormous challenge for the nervous system to classify multi-component odors and indicates that other neuronal parameters, e.g., precise timing of neuronal activity, are likely necessary for attribution of odor quality to multi-component odors.}, subject = {Ameisen}, language = {en} } @phdthesis{Weiss2011, author = {Weiß, Sabine}, title = {Function of the Spir actin nucleators in intracellular vesicle transport processes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64589}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Spir proteins are the founding members of the novel class of WH2-actin nucleators. A C-terminal modified FYVE zinc finger motif is necessary to target Spir proteins towards intracellular membranes. The function and regulation of the Spir actin organizers at vesicular membranes is almost unknown. Live cell imaging analyses performed in this study show that Spir-2 is localized at tubular vesicles. Cytoplasmic Spir-2-associated vesicles branch and form protrusions, which can make contacts to the microtubule network, where the Spir-2 vesicles stretch and slide along the microtubule filaments. The analysis of living HeLa cells expressing eGFP-tagged Spir-2, Spir-2-ΔKIND and Spir-2-ΔKW (lacking the 4 WH2 domains and the KIND domain) showed Spir-2-associated tubular structures which differ in their length and motility. Throughout the course of that study it could be shown that the tail domain of the actin motor protein myosin Vb, as a force-generating molecule, is colocalizing and co-immunoprecipitating with Spir-2-ΔKW. By using the tail domain of myosin Vb as a dominant negative mutant for myosin Vb-dependent vesicle transport processes it could be shown that Spir-2-ΔKW/MyoVb-cc-tail- associated vesicles exhibit an increased elongation. Moreover, using the microtubule depolymerizing drug nocodazole it could be shown that the elongation and the motility of Spir-2-ΔKW-associated vesicles depends on an intact microtubule cytoskeleton. Motility and morphological dynamics of Spir-2-associated vesicles is therefore dependent on actin, actin motorproteins and microtubule filaments. These results propose a model in which myosin/F-actin forces mediate vesicle branching, allowing the vesicles to move to and in between the microtubule filaments and thereby providing a new degree of freedom in vesicular motility. To determine the exact subcellular localization of Spir-2, colocalization studies were performed. It could be shown that Spir-2 shows a partial colocalization to Rab11a-positive compartments. Furthermore, Spir-2 exhibits an almost identical localization to Arf1 and the Arf1 small G protein but not Rab11a could be immunoprecipitated with Spir-2-ΔKW. This suggests, that Arf1 recruits Spir-2 to Arf1/Rab11a-positive membranes. Another important function of the Spir-2 C-terminus is the membrane targeting by the FYVE domain. By performing a protein-lipid overlay assay, it has been shown that purified GST- and 6xHis-tagged Spir-2-ΔKW bind phosphatidic acid suggesting a mechanism in which Spir-2 is recruited to phosphatidic acid-enriched membranes. To further elucidate the mechanism in which Spir-2 membrane-targeting could be regulated, interaction studies of C-terminal parts of Spir-2 revealed that the Spir-2 proteins interact directly.}, subject = {Aktin}, language = {en} } @phdthesis{Homola2011, author = {Homola, Gy{\"o}rgy {\´A}d{\´a}m}, title = {Functional and Microstructural MRI of the Human Brain Revealing a Cerebral Network Processing the Age of Faces}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-56740}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Although age is one of the most salient and fundamental aspects of human faces, its processing in the brain has not yet been studied by any neuroimaging experiment. Automatic assessment of temporal changes across faces is a prerequisite to identifying persons over their life-span, and age per se is of biological and social relevance. Using a combination of evocative face morphs controlled for global optical flow and functional magnetic resonance imaging (fMRI), we segregate two areas that process changes of facial age in both hemispheres. These areas extend beyond the previously established face-sensitive network and are centered on the posterior inferior temporal sulcus (pITS) and the posterior angular gyrus (pANG), an evolutionarily new formation of the human brain. Using probabilistic tractography and by calculating spatial cross-correlations as well as creating minimum intersection maps between activation and connectivity patterns we demonstrate a hitherto unrecognized link between structure and function in the human brain on the basis of cognitive age processing. According to our results, implicit age processing involves the inferior temporal sulci and is, at the same time, closely tied to quantity decoding by the presumed neural systems devoted to magnitudes in the human parietal lobes. The ventral portion of Wernicke's largely forgotten perpendicular association fasciculus is shown not only to interconnect these two areas but to relate to their activations, i.e. to transmit age-relevant information. In particular, post-hoc age-rating competence is shown to be associated with high response levels in the left angular gyrus. Cortical activation patterns related to changes of facial age differ from those previously elicited by other fixed as well as changeable face aspects such as gender (used for comparison), ethnicity and identity as well as eye gaze or facial expressions. We argue that this may be due to the fact that individual changes of facial age occur ontogenetically, unlike the instant changes of gaze direction or expressive content in faces that can be "mirrored" and require constant cognitive monitoring to follow. Discussing the ample evidence for distinct representations of quantitative age as opposed to categorical gender varied over continuous androgyny levels, we suggest that particular face-sensitive regions interact with additional object-unselective quantification modules to obtain individual estimates of facial age.}, subject = {Gesicht}, language = {en} } @article{SeherNickelMuelleretal.2011, author = {Seher, Axel and Nickel, Joachim and Mueller, Thomas D. and Kneitz, Susanne and Gebhardt, Susanne and Meyer ter Vehn, Tobias and Schlunck, Guenther and Sebald, Walter}, title = {Gene expression profiling of connective tissue growth factor (CTGF) stimulated primary human tenon fibroblasts reveals an inflammatory and wound healing response in vitro}, series = {Molecular Vision}, volume = {17}, journal = {Molecular Vision}, number = {08. Okt}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-140189}, pages = {53-62}, year = {2011}, abstract = {Purpose: The biologic relevance of human connective tissue growth factor (hCTGF) for primary human tenon fibroblasts (HTFs) was investigated by RNA expression profiling using affymetrix (TM) oligonucleotide array technology to identify genes that are regulated by hCTGF. Methods: Recombinant hCTGF was expressed in HEK293T cells and purified by affinity and gel chromatography. Specificity and biologic activity of hCTGF was confirmed by biosensor interaction analysis and proliferation assays. For RNA expression profiling HTFs were stimulated with hCTGF for 48h and analyzed using affymetrix (TM) oligonucleotide array technology. Results were validated by real time RT-PCR. Results: hCTGF induces various groups of genes responsible for a wound healing and inflammatory response in HTFs. A new subset of CTGF inducible inflammatory genes was discovered (e.g., chemokine [C-X-C motif] ligand 1 [CXCL1], chemokine [C-X-C motif] ligand 6 [CXCL6], interleukin 6 [IL6], and interleukin 8 [IL8]). We also identified genes that can transmit the known biologic functions initiated by CTGF such as proliferation and extracellular matrix remodelling. Of special interest is a group of genes, e.g., osteoglycin (OGN) and osteomodulin (OMD), which are known to play a key role in osteoblast biology. Conclusions: This study specifies the important role of hCTGF for primary tenon fibroblast function. The RNA expression profile yields new insights into the relevance of hCTGF in influencing biologic processes like wound healing, inflammation, proliferation, and extracellular matrix remodelling in vitro via transcriptional regulation of specific genes. The results suggest that CTGF potentially acts as a modulating factor in inflammatory and wound healing response in fibroblasts of the human eye.}, language = {en} } @article{KraeusslingWagnerSchartl2011, author = {Kraeussling, Michael and Wagner, Toni Ulrich and Schartl, Manfred}, title = {Highly Asynchronous and Asymmetric Cleavage Divisions Accompany Early Transcriptional Activity in Pre-Blastula Medaka Embryos}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68906}, year = {2011}, abstract = {In the initial phase of development of fish embryos, a prominent and critical event is the midblastula transition (MBT). Before MBT cell cycle is rapid, highly synchronous and zygotic gene transcription is turned off. Only during MBT the cell cycle desynchronizes and transcription is activated. Multiple mechanisms, primarily the nucleocytoplasmic ratio, are supposed to control MBT activation. Unexpectedly, we find in the small teleost fish medaka (Oryzias latipes) that at very early stages, well before midblastula, cell division becomes asynchronous and cell volumes diverge. Furthermore, zygotic transcription is extensively activated already after the 64-cell stage. Thus, at least in medaka, the transition from maternal to zygotic transcription is uncoupled from the midblastula stage and not solely controlled by the nucleocytoplasmic ratio.}, subject = {Fische}, language = {en} } @phdthesis{Pahl2011, author = {Pahl, Mario}, title = {Honeybee Cognition: Aspects of Learning, Memory and Navigation in a Social Insect}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66165}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Honeybees (Apis mellifera) forage on a great variety of plant species, navigate over large distances to crucial resources, and return to communicate the locations of food sources and potential new nest sites to nest mates using a symbolic dance language. In order to achieve this, honeybees have evolved a rich repertoire of adaptive behaviours, some of which were earlier believed to be restricted to vertebrates. In this thesis, I explore the mechanisms involved in honeybee learning, memory, numerical competence and navigation. The findings acquired in this thesis show that honeybees are not the simple reflex automats they were once believed to be. The level of sophistication I found in the bees' memory, their learning ability, their time sense, their numerical competence and their navigational abilities are surprisingly similar to the results obtained in comparable experiments with vertebrates. Thus, we should reconsider the notion that a bigger brain automatically indicates higher intelligence.}, subject = {Biene}, language = {en} } @article{KronauerPetersSchoningetal.2011, author = {Kronauer, Daniel J. C. and Peters, Marcell K. and Schoning, Caspar and Boomsma, Jacobus J.}, title = {Hybridization in East African swarm-raiding army ants}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68798}, year = {2011}, abstract = {Background: Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites. Results: While the mitochondrial phylogeny had a strong geographic signal, different species were not recovered as monophyletic. At our main study site at Kakamega Forest, a mitochondrial haplotype was shared between a "Dorylus molestus-like" and a "Dorylus wilverthi-like" form. This pattern is best explained by introgression following hybridization between D. molestus and D. wilverthi. Microsatellite data from workers showed that the two morphological forms correspond to two distinct genetic clusters, with a significant proportion of individuals being classified as hybrids. Conclusions: We conclude that hybridization and gene-flow between the two army ant species D. molestus and D. wilverthi has occurred, and that mating between the two forms continues to regularly produce hybrid workers. Hybridization is particularly surprising in army ants because workers have control over which males are allowed to mate with a young virgin queen inside the colony.}, subject = {Zoologie}, language = {en} } @phdthesis{Halder2011, author = {Halder, Partho}, title = {Identification and characterization of synaptic proteins of Drosophila melanogaster using monoclonal antibodies of the Wuerzburg Hybridoma Library}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-67325}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {For a large fraction of the proteins expressed in the human brain only the primary structure is known from the genome project. Proteins conserved in evolution can be studied in genetic models such as Drosophila. In this doctoral thesis monoclonal antibodies (mAbs) from the Wuerzburg Hybridoma library are produced and characterized with the aim to identify the target antigen. The mAb ab52 was found to be an IgM which recognized a cytosolic protein of Mr ~110 kDa on Western blots. The antigen was resolved by two-dimensional gel electrophoresis (2DE) as a single distinct spot. Mass spectrometric analysis of this spot revealed EPS-15 (epidermal growth factor receptor pathway substrate clone 15) to be a strong candidate. Another mAb from the library, aa2, was already found to recognize EPS-15, and comparison of the signal of both mAbs on Western blots of 1D and 2D electrophoretic separations revealed similar patterns, hence indicating that both antigens could represent the same protein. Finally absence of the wild-type signal in homozygous Eps15 mutants in a Western blot with ab52 confirmed the ab52 antigen to be EPS-15. Thus both the mAbs aa2 and ab52 recognize the Drosophila homologue of EPS-15. The mAb aa2, being an IgG, is more suitable for applications like immunoprecipitation (IP). It has already been submitted to the Developmental Studies Hybridoma Bank (DSHB) to be easily available for the entire research community. The mAb na21 was also found to be an IgM. It recognizes a membrane associated antigen of Mr ~10 kDa on Western blots. Due to the membrane associated nature of the protein, it was not possible to resolve it by 2DE and due to the IgM nature of the mAb it was not possible to enrich the antigen by IP. Preliminary attempts to biochemically purify the endogenously expressed protein from the tissue, gave promising results but could not be completed due to lack of time. Thus biochemical purification of the protein seems possible in order to facilitate its identification by mass spectrometry. Several other mAbs were studied for their staining pattern on cryosections and whole mounts of Drosophila brains. However, many of these mAbs stained very few structures in the brain, which indicated that only a very limited amount of protein would be available as starting material. Because these antibodies did not produce signals on Western blots, which made it impossible to enrich the antigens by electrophoretic methods, we did not attempt their purification. However, the specific localization of these proteins makes them highly interesting and calls for their further characterization, as they may play a highly specialized role in the development and/or function of the neural circuits they are present in. The purification and identification of such low expression proteins would need novel methods of enrichment of the stained structures.}, subject = {Taufliege}, 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} } @phdthesis{Heisig2011, author = {Heisig, Julia}, title = {Identifizierung neuer Zielgene der Hey bHLH Transkriptionsfaktoren}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-65053}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Der Notch Signalweg spielt w{\"a}hrend der Embryonalentwicklung eine zentrale Rolle in der Spezifizierung des Zellschicksales, der Proliferation und der Kommunikation benachbarter Zellen. Die Hey bHLH Transkriptionsfaktoren sind Zielgene des Notch-Signalweges und besitzen wichtige Funktionen in der kardiovaskul{\"a}ren Entwicklung. Hey2 Knockout (KO) M{\"a}use und Hey1/HeyL Doppelknockout-M{\"a}use (DKO) sind gekennzeichnet durch eine fehlerhafte Ausbildung der Herzscheidewand und der Herzklappen und durch eine unzureichende Differenzierung w{\"a}hrend der Blutgef{\"a}ßentwicklung. Ziel dieser Arbeit war es, neue Zielgene der Hey Proteine zu finden, um ihre Funktion in der Organentwicklung und die Auspr{\"a}gung der Hey KO Maus-Ph{\"a}notypen besser verstehen zu k{\"o}nnen. Dazu wurde als Methode eine Kombination aus Microarray-Analyse und Chromatinimmunpr{\"a}zipitation (ChIP) gew{\"a}hlt, um gleichzeitig einen {\"U}berblick {\"u}ber die regulierten Zielgene und der direkt gebundenen Promotoren zu gewinnen. Als Zellkulturmodell wurden HEK293-Zellen genutzt, die doxyzyklin-induzierbar Flag-markiertes Hey1, bzw. Hey2 Protein {\"u}berexprimieren. Eine Microarray-Analyse nach {\"U}berexpression von Hey1, bzw. Hey2 ergab insgesamt ca. 100 bis zu 5-fach herunterregulierte Zielgene und nur f{\"u}r Hey2 15 Gene, die st{\"a}rker als 2-fach hochreguliert waren. Eine ChIP mit αFlag-Antik{\"o}rper zeigte eine direkte DNA-Bindung von Hey1, bzw. Hey2, im proximalen Promotorbereich von 4 herunterregulierten Zielgenen (HEY1, BMP2, KLF10 und FOXC1). Ist jedoch die DNA-bindende basische Dom{\"a}ne des Hey1-Proteins deletiert, bzw. durch Aminos{\"a}ureaustausche (3 Arginine zu 3 Lysine) vermutlich nicht mehr DNA-bindend, kann eine Herunterregulation der Zielgene nach {\"U}berexpression der Hey1-Mutanten nicht mehr festgestellt werden. Ebenso kann eine Bindung der Hey1-Mutanten an die ausgew{\"a}hlten Promotoren von HEY1, BMP2, KLF10 oder FOXC1 mit ChIP nicht mehr nachgewiesen werden. Dies deutet darauf hin, dass die basische Dom{\"a}ne essentiell f{\"u}r die DNA-Bindung und f{\"u}r die Funktion der Hey Proteine ist. Mit ChIP-PET und anschließender Hochdurchsatz-Sequenzierung wurde ein genomweiter Screen der Hey1- und der Hey2-Bindungsstellen in HEK293-Zellen durchgef{\"u}hrt. F{\"u}r Hey1 wurden 1453 Zielgene, f{\"u}r Hey2 4288 Zielgene bestimmt, wobei 1147 Gene gemeinsame Zielgene von Hey1 und Hey2 waren. Obwohl die Bindungsstellen in 5'- und 3'-Richtung von kodierenden Sequenzen und auch in Exons und Introns lokalisiert waren, waren 55 \%, bzw. 49 \% aller Bindungsstellen f{\"u}r Hey1, bzw. Hey2 im proximalen Promotorbereich von -0,5 kb und im ersten Exon lokalisiert. Eine in silico Analyse des Bindemotivs deutete auf eine repetitive GC-haltige Sequenz hin, die vermutlich in CpG Inseln lokalisiert ist. Diese Ergebnisse weisen auf eine direkte Regulation der Transkriptionsmaschinerie durch die Hey Proteine hin. Ein Vergleich der Zielgene aus den Microarray-Analysen mit den ChIP-PET Daten zeigte einen hohen Anteil an herunterregulierten Genen mit Bindestellen, die direkt von Hey gebunden waren. W{\"a}hrend 60 \% der herunterregulierten Hey2 Zielgene in der ChIP-PET Analyse eine direkte DNA-Bindung zeigen, weisen nur 20 \% der hochregulierten Gene Bindestellen f{\"u}r Hey2 auf. Dies spricht f{\"u}r eine {\"u}berwiegende Repressorfunktion der Hey Proteine. Um zu {\"u}berpr{\"u}fen, inwieweit die Hey Proteine zelltypspezifisch verschiedene Zielgene regulieren, wurden embryonale Stammzellen (ES-Zellen) generiert, die ebenfalls doxyzyklin-induzierbar Hey1, bzw. Hey2 {\"u}berexprimieren. Diese ES-Zellen konnten effektiv zu Kardiomyozyten differenziert werden, so dass auch in diesen Zellen eine Hey {\"U}berexpression induziert und somit eine Genexpressionsanalyse durchgef{\"u}hrt werden konnte. Microarray Analysen der ES-Zellen und Kardiomyozyten ergaben mehr hoch- als herunterregulierte Gene im Vergleich zu HEK293-Zellen. Die {\"U}berlappung an gemeinsam regulierten Zielgenen in HEK293, ES-Zellen und Kardiomyozyten war sehr gering. Nur zwei Hey2-Zielgene wurden gleichzeitig in HEK293 und ES-Zellen st{\"a}rker als 2-fach reguliert (Hes1, Zic2). Diese geringe {\"U}berlappung deutet auf ein enges zelltypspezifische Regulationspotential hin. Eine Genontologie-Analyse aller Zielgene zeigte Interaktionen der Hey Proteine mit verschiedenen Signalwegen (z.B. TGFβ-, Id- oder Wnt-Signalweg), die alle unersetzlich in fr{\"u}hen Entwicklungsprozessen sind. Diese Ergebnisse deuten darauf hin, dass die Hey Proteine zelltypspezifisch die Expression von Genen aus verschiedenen Signalwegen beeinflussen und modulieren k{\"o}nnen. Weiterhin er{\"o}ffnen diese Daten neue M{\"o}glichkeiten f{\"u}r zuk{\"u}nftige Forschung, um die Rolle der Hey Proteine in der fr{\"u}hen Organentwicklung genauer ergr{\"u}nden.}, subject = {Gen notch}, language = {de} } @article{UppaluriNaglerStellamannsetal.2011, author = {Uppaluri, Sravanti and Nagler, Jan and Stellamanns, Eric and Heddergott, Niko and Herminghaus, Stephan and Pfohl, Thomas and Engstler, Markus}, title = {Impact of Microscopic Motility on the Swimming Behavior of Parasites: Straighter Trypanosomes are More Directional}, series = {PLoS Computational Biology}, volume = {7}, journal = {PLoS Computational Biology}, number = {6}, doi = {10.1371/journal.pcbi.1002058}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-140814}, pages = {e1002058}, year = {2011}, abstract = {Microorganisms, particularly parasites, have developed sophisticated swimming mechanisms to cope with a varied range of environments. African Trypanosomes, causative agents of fatal illness in humans and animals, use an insect vector (the Tsetse fly) to infect mammals, involving many developmental changes in which cell motility is of prime importance. Our studies reveal that differences in cell body shape are correlated with a diverse range of cell behaviors contributing to the directional motion of the cell. Straighter cells swim more directionally while cells that exhibit little net displacement appear to be more bent. Initiation of cell division, beginning with the emergence of a second flagellum at the base, correlates to directional persistence. Cell trajectory and rapid body fluctuation correlation analysis uncovers two characteristic relaxation times: a short relaxation time due to strong body distortions in the range of 20 to 80 ms and a longer time associated with the persistence in average swimming direction in the order of 15 seconds. Different motility modes, possibly resulting from varying body stiffness, could be of consequence for host invasion during distinct infective stages.}, language = {en} } @phdthesis{Kapustjansky2011, author = {Kapustjansky, Alexander}, title = {In vivo imaging and optogenetic approach to study the formation of olfactory memory and locomotor behaviour in Drosophila melanogaster}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69535}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Understanding of complex interactions and events in a nervous system, leading from the molecular level up to certain behavioural patterns calls for interdisciplinary interactions of various research areas. The goal of the presented work is to achieve such an interdisciplinary approach to study and manipulate animal behaviour and its underlying mechanisms. Optical in vivo imaging is a new constantly evolving method, allowing one to study not only the local but also wide reaching activity in the nervous system. Due to ease of its genetic accessibility Drosophila melanogaster represents an extraordinary experimental organism to utilize not only imaging but also various optogenetic techniques to study the neuronal underpinnings of behaviour. In this study four genetically encoded sensors were used to investigate the temporal dynamics of cAMP concentration changes in the horizontal lobes of the mushroom body, a brain area important for learning and memory, in response to various physiological and pharmacological stimuli. Several transgenic lines with various genomic insertion sites for the sensor constructs Epac1, Epac2, Epac2K390E and HCN2 were screened for the best signal quality, one line was selected for further experiments. The in vivo functionality of the sensor was assessed via pharmacological application of 8-bromo-cAMP as well as Forskolin, a substance stimulating cAMP producing adenylyl cyclases. This was followed by recording of the cAMP dynamics in response to the application of dopamine and octopamine, as well as to the presentation of electric shock, odorants or a simulated olfactory signal, induced by acetylcholine application to the observed brain area. In addition the interaction between the shock and the simulated olfactory signal by simultaneous presentation of both stimuli was studied. Preliminary results are supporting a coincidence detection mechanism at the level of the adenylyl cyclase as postulated by the present model for classical olfactory conditioning. In a second series of experiments an effort was made to selecticvely activate a subset of neurons via the optogenetic tool Channelrhodopsin (ChR2). This was achieved by recording the behaviour of the fly in a walking ball paradigm. A new method was developed to analyse the walking behaviour of the animal whose brain was made optically accessible via a dissection technique, as used for imaging, thus allowing one to target selected brain areas. Using the Gal4-UAS system the protocerebral bridge, a substructure of the central complex, was highlighted by expressing the ChR2 tagged by fluorescent protein EYFP. First behavioural recordings of such specially prepared animals were made. Lastly a new experimental paradigm for single animal conditioning was developed (Shock Box). Its design is based on the established Heat Box paradigm, however in addition to spatial and operant conditioning available in the Heat Box, the design of the new paradigm allows one to set up experiments to study classical and semioperant olfactory conditioning, as well as semioperant place learning and operant no idleness experiments. First experiments involving place learning were successfully performed in the new apparatus.}, subject = {Taufliege}, language = {en} } @article{BollazziRoces2011, author = {Bollazzi, Martin and Roces, Flavio}, title = {Information Needs at the Beginning of Foraging: Grass-Cutting Ants Trade Off Load Size for a Faster Return to the Nest}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68940}, year = {2011}, abstract = {Background: Acquisition of information about food sources is essential for animals that forage collectively like social insects. Foragers deliver two commodities to the nest, food and information, and they may favor the delivery of one at the expenses of the other. We predict that information needs should be particularly high at the beginning of foraging: the decision to return faster to the nest will motivate a grass-cutting ant worker to reduce its loading time, and so to leave the source with a partial load. Principal Findings: Field results showed that at the initial foraging phase, most grass-cutting ant foragers (Acromyrmex heyeri) returned unladen to the nest, and experienced head-on encounters with outgoing workers. Ant encounters were not simply collisions in a probabilistic sense: outgoing workers contacted in average 70\% of the returning foragers at the initial foraging phase, and only 20\% at the established phase. At the initial foraging phase, workers cut fragments that were shorter, narrower, lighter and tenderer than those harvested at the established one. Foragers walked at the initial phase significantly faster than expected for the observed temperatures, yet not at the established phase. Moreover, when controlling for differences in the fragment-size carried, workers still walked faster at the initial phase. Despite the higher speed, their individual transport rate of vegetable tissue was lower than that of similarly-sized workers foraging later at the same patch. Conclusions/Significance: At the initial foraging phase, workers compromised their individual transport rates of material in order to return faster to the colony. We suggest that the observed flexible cutting rules and the selection of partial loads at the beginning of foraging are driven by the need of information transfer, crucial for the establishment and maintenance of a foraging process to monopolize a discovered resource.}, subject = {Blattschneiderameisen}, language = {en} } @phdthesis{Beisser2011, author = {Beisser, Daniela}, title = {Integrated functional analysis of biological networks}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70150}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {In recent years high-throughput experiments provided a vast amount of data from all areas of molecular biology, including genomics, transcriptomics, proteomics and metabolomics. Its analysis using bioinformatics methods has developed accordingly, towards a systematic approach to understand how genes and their resulting proteins give rise to biological form and function. They interact with each other and with other molecules in highly complex structures, which are explored in network biology. The in-depth knowledge of genes and proteins obtained from high-throughput experiments can be complemented by the architecture of molecular networks to gain a deeper understanding of biological processes. This thesis provides methods and statistical analyses for the integration of molecular data into biological networks and the identification of functional modules, as well as its application to distinct biological data. The integrated network approach is implemented as a software package, termed BioNet, for the statistical language R. The package includes the statistics for the integration of transcriptomic and functional data with biological networks, the scoring of nodes and edges of these networks as well as methods for subnetwork search and visualisation. The exact algorithm is extensively tested in a simulation study and outperforms existing heuristic methods for the calculation of this NP-hard problem in accuracy and robustness. The variability of the resulting solutions is assessed on perturbed data, mimicking random or biased factors that obscure the biological signal, generated for the integrated data and the network. An optimal, robust module can be calculated using a consensus approach, based on a resampling method. It summarizes optimally an ensemble of solutions in a robust consensus module with the estimated variability indicated by confidence values for the nodes and edges. The approach is subsequently applied to two gene expression data sets. The first application analyses gene expression data for acute lymphoblastic leukaemia (ALL) and differences between the subgroups with and without an oncogenic BCR/ABL gene fusion. In a second application gene expression and survival data from diffuse large B-cell lymphomas are examined. The identified modules include and extend already existing gene lists and signatures by further significant genes and their interactions. The most important novelty is that these genes are determined and visualised in the context of their interactions as a functional module and not as a list of independent and unrelated transcripts. In a third application the integrative network approach is used to trace changes in tardigrade metabolism to identify pathways responsible for their extreme resistance to environmental changes and endurance in an inactive tun state. For the first time a metabolic network approach is proposed to detect shifts in metabolic pathways, integrating transcriptome and metabolite data. Concluding, the presented integrated network approach is an adequate technique to unite high-throughput experimental data for single molecules and their intermolecular dependencies. It is flexible to apply on diverse data, ranging from gene expression changes over metabolite abundances to protein modifications in a combination with a suitable molecular network. The exact algorithm is accurate and robust in comparison to heuristic approaches and delivers an optimal, robust solution in form of a consensus module with confidence values. By the integration of diverse sources of information and a simultaneous inspection of a molecular event from different points of view, new and exhaustive insights into biological processes can be acquired.}, subject = {Bioinformatik}, language = {en} } @article{BuchheimKellerKoetschanetal.2011, author = {Buchheim, Mark A. and Keller, Alexander and Koetschan, Christian and F{\"o}rster, Frank and Merget, Benjamin and Wolf, Matthias}, title = {Internal Transcribed Spacer 2 (nu ITS2 rRNA) Sequence-Structure Phylogenetics: Towards an Automated Reconstruction of the Green Algal Tree of Life}, series = {PLoS ONE}, volume = {6}, journal = {PLoS ONE}, number = {2}, doi = {10.1371/journal.pone.0016931}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-140866}, pages = {e16931}, year = {2011}, abstract = {Background: Chloroplast-encoded genes (matK and rbcL) have been formally proposed for use in DNA barcoding efforts targeting embryophytes. Extending such a protocol to chlorophytan green algae, though, is fraught with problems including non homology (matK) and heterogeneity that prevents the creation of a universal PCR toolkit (rbcL). Some have advocated the use of the nuclear-encoded, internal transcribed spacer two (ITS2) as an alternative to the traditional chloroplast markers. However, the ITS2 is broadly perceived to be insufficiently conserved or to be confounded by introgression or biparental inheritance patterns, precluding its broad use in phylogenetic reconstruction or as a DNA barcode. A growing body of evidence has shown that simultaneous analysis of nucleotide data with secondary structure information can overcome at least some of the limitations of ITS2. The goal of this investigation was to assess the feasibility of an automated, sequence-structure approach for analysis of IT2 data from a large sampling of phylum Chlorophyta. Methodology/Principal Findings: Sequences and secondary structures from 591 chlorophycean, 741 trebouxiophycean and 938 ulvophycean algae, all obtained from the ITS2 Database, were aligned using a sequence structure-specific scoring matrix. Phylogenetic relationships were reconstructed by Profile Neighbor-Joining coupled with a sequence structure-specific, general time reversible substitution model. Results from analyses of the ITS2 data were robust at multiple nodes and showed considerable congruence with results from published phylogenetic analyses. Conclusions/Significance: Our observations on the power of automated, sequence-structure analyses of ITS2 to reconstruct phylum-level phylogenies of the green algae validate this approach to assessing diversity for large sets of chlorophytan taxa. Moreover, our results indicate that objections to the use of ITS2 for DNA barcoding should be weighed against the utility of an automated, data analysis approach with demonstrated power to reconstruct evolutionary patterns for highly divergent lineages.}, language = {en} } @article{LamatschTrifonovSchoriesetal.2011, author = {Lamatsch, D. K. and Trifonov, V. and Schories, S. and Epplen, J. T. and Schmid, M. and Schartl, M.}, title = {Isolation of a Cancer-Associated Microchromosome in the Sperm-Dependent Parthenogen Poecilia formosa}, series = {Cytogenetic and Genome Research}, volume = {135}, journal = {Cytogenetic and Genome Research}, number = {2}, issn = {1424-8581}, doi = {10.1159/000331271}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196785}, pages = {135-142}, year = {2011}, abstract = {In the asexual all-female fish species Poecilia formosa, the Amazon molly, supernumerary chromosomes have frequently been found in both laboratory-reared and wild-caught individuals. While wild-caught individuals with B chromosomes are phenotypically indifferent from conspecifics, individuals carrying B chromosomes from recent introgression events in the laboratory show phenotypic changes. Former analyses showed that the expression of a pigment cell locus is associated with the presence of these B chromosomes. In addition, they contain a so far unidentified locus that confers a higher susceptibility to tumor formation in the presence of pigmentation pattern. Isolation by microdissection and hybridization to metaphase chromosomes revealed that they contain one or several sequences with similarity to a highly repetitive pericentromeric and subtelomeric sequence in A chromosomes. Isolation of one particular sequence by AFLP showed that the B chromosomes contain at least 1 copy of an A-chromosomal region which is highly conserved in the whole genus Poecilia, i.e. more than 5 million years old. We propose it to be a single copy sequence.}, language = {en} } @article{PahlZhuTautzetal.2011, author = {Pahl, Mario and Zhu, Hong and Tautz, J{\"u}rgen and Zhang, Shaowu}, title = {Large Scale Homing in Honeybees}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68985}, year = {2011}, abstract = {Honeybee foragers frequently fly several kilometres to and from vital resources, and communicate those locations to their nest mates by a symbolic dance language. Research has shown that they achieve this feat by memorizing landmarks and the skyline panorama, using the sun and polarized skylight as compasses and by integrating their outbound flight paths. In order to investigate the capacity of the honeybees' homing abilities, we artificially displaced foragers to novel release spots at various distances up to 13 km in the four cardinal directions. Returning bees were individually registered by a radio frequency identification (RFID) system at the hive entrance. We found that homing rate, homing speed and the maximum homing distance depend on the release direction. Bees released in the east were more likely to find their way back home, and returned faster than bees released in any other direction, due to the familiarity of global landmarks seen from the hive. Our findings suggest that such large scale homing is facilitated by global landmarks acting as beacons, and possibly the entire skyline panorama.}, subject = {Biene}, language = {en} } @phdthesis{Zirkel2011, author = {Zirkel, Janina}, title = {Malaria in Burkina Faso - Chancen f{\"u}r eine neue Strategie mit Hilfe von Methylenblau}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-72583}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Trotz betr{\"a}chtlicher Anstrengung Malaria zu kontrollieren bzw. zu eradizieren, stellt die Krankheit weiterhin eines der gravierendsten Gesundheitsprobleme unseres Jahrtausends dar. Malaria fordert j{\"a}hrlich zwischen 0,7 und 2,7 Millionen Menschenleben, beeintr{\"a}chtigt schulische und soziale Entwicklung und hemmt erheblich das Wirtschaftswachstum der betroffenen L{\"a}nder. In Burkina Faso, einem der {\"a}rmsten L{\"a}nder der Welt, ist Malaria eines der gr{\"o}ßten Gesundheitsprobleme und ca. ein Drittel aller Todesf{\"a}lle werden hier Malaria angelastet. Die sich weiter ausbreiteten Resistenzen gegen die g{\"a}ngigen Malariamedikamente machen die Bek{\"a}mpfung der Malaria zunehmend schwierig. Artemisinin basierende Kombinationstherapien sind aktuell, trotz relativ hoher Therapiekosten und erster Resistenzen, die Erstlinien Behandlung. Effektive und billige neue Kombinationstherapien werden dringend ben{\"o}tigt. In dieser Doktorarbeit wurde das Resistenzpotential von Artemisinin modelliert. Die Homologiemodellierungen unterst{\"u}tzen die These von Krishna und Kollegen von SERCA als einzige Zielstruktur von Artemisinin. Des Weiteren wurde Methylenblau als neues altes Malariamittel evaluiert. Methylenblau ist das erste gegen Malaria eingesetzte Medikament, agiert als ein prooxidatives Agens und inhibiert selektiv und nicht-kompetitiv die P. falciparum Glutathion Reduktase. Die additiven und multiplen Zielprotein Effekte von Methylenblau wurden experimentell untersucht und hier in einem bioinformatischem Modell getestet. Unter dem Einfluss von Methylenblau werden einige Schl{\"u}sselenzyme des Redoxstoffwechsels in ihrer Aktivit{\"a}t beeintr{\"a}chtigt und der Parasit wird verst{\"a}rkt oxidativem Stress ausgesetzt. Des Weiteren konnte in dieser Dr. Arbeit eine starke Kooperationsbereitschaft der urbanen und l{\"a}ndlichen Bev{\"o}lkerung an zuk{\"u}nftigen Malaria Projekten gezeigt werden.}, subject = {Methylenblau}, language = {de} } @phdthesis{Saumweber2011, author = {Saumweber, Timo}, title = {Mechanism of Learning and Plasticity in Larval Drosophila}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66354}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {According to a changing environment it is crucial for animals to make experience and learn about it. Sensing, integrating and learning to associate different kinds of modalities enables animals to expect future events and to adjust behavior in the way, expected as the most profitable. Complex processes as memory formation and storage make it necessary to investigate learning and memory on different levels. In this context Drosophila melanogaster represents a powerful model organism. As the adult brain of the fly is still quite complex, I chose the third instar larva as model - the more simple the system, the easier to isolate single, fundamental principles of learning. In this thesis I addressed several kinds of questions on different mechanism of olfactory associative and synaptic plasiticity in Drosophila larvae. I focused on short-term memory throughout my thesis. First, investigating larval learning on behavioral level, I developed a one-odor paradigm for olfactory associative conditioning. This enables to estimate the learnability of single odors, reduces the complexity of the task and simplify analyses of "learning mutants". It further allows to balance learnability of odors for generalization-type experiments to describe the olfactory "coding space". Furthermore I could show that innate attractiveness and learnability can be dissociated and found finally that paired presentation of a given odor with reward increase performance, whereas unpaired presentations of these two stimuli decrease performance, indicating that larva are able to learn about the presence as well as about the absence of a reward. Second, on behavioral level, together with Thomas Niewalda and colleagues we focussed on salt processing in the context of choice, feeding and learning. Salt is required in several physiological processes, but can neither be synthesized nor stored. Various salt concentrations shift the valence from attraction to repulsion in reflexive behaviour. Interestingly, the reinforcing effect of salt in learning is shifted by more than one order of magnitude toward higher concentrations. Thus, the input pathways for gustatory behavior appear to be more sensitive than the ones supporting gustatory reinforcement, which is may be due to the dissociation of the reflexive and the reinforcing signalling pathways of salt. Third, in cooperation with Michael Schleyer we performed a series of behavioral gustatory, olfactory preference tests and larval learning experiments. Based on the available neuroanatomical and behavioral data we propose a model regarding chemosensory processing, odor-tastant memory trace formation and the 'decision' like process. It incorporates putative sites of interaction between olfactory and gustatory pathways during the establishment as well as behavioral expression of odor-tastant memory. We claim that innate olfactory behavior is responsive in nature and suggest that associative conditioned behavior is not a simple substitution like process, but driven more likely by the expectation of its outcome. Fourth, together with Birgit Michels and colleagues we investigated the cellular site and molecular mode of Synapsin, an evolutionarily conserved, presynaptic vesicular phosphoprotein and its action in larval learning. We confirmed a previously described learning impairment upon loss of Synapsin. We localized this Synapsin dependent memory trace in the mushroom bodies, a third-order "cortical" brain region, and could further show on molecular level, that Synapsin is as a downstream element of the AC-cAMP-PKA signalling cascade. This study provides a comprehensive chain of explanation from the molecular level to an associative behavioral change. Fifth, in the main part of my thesis I focused on molecular level on another synaptic protein, the Synapse associated protein of 47kDa (Sap47) and its role in larval behavior. As a member of a phylogenetically conserved gene family of hitherto unknown function. It is localized throughout the whole neuropil of larval brains and associated with presynaptic vesicles. Upon loss of Sap47 larvae exhibit normal sensory detection of the to-be-associated stimuli as well as normal motor performance and basic synaptic transmission. Interestingly, short-term plasticity is distorted and odorant-tastant associative learning ability is reduced. This defect in associative function could be rescued by restoring Sap47 expression. Therefore, this report is the first to suggest a function for Sap47 and specifically argues that Sap47 is required for synaptic as well as for behavioral plasticity in Drosophila larva. This prompts the question whether its homologs are required for synaptic and behavioral plasticity also in other species. Further in the last part of my thesis I contributed to the study of Ayse Yarali. Her central topic was the role of the White protein in punishment and relief learning in adult flies. Whereas stimuli that precede shock during training are subsequently avoided as predictors for punishment, stimuli that follow shock during training are later on approached, as they predict relief. Concerning the loss of White we report that pain-relief learning as well as punishment learning is changed. My contribution was a comparison between wild type and the white1118 mutant larvae in odor-reward learning. It turned out that a loss of White has no effect on larval odorant-tastant learning. This study, regarding painrelief learning provides the very first hints concerning the genetic determinants of this form of learning.}, subject = {Taufliege}, language = {en} } @phdthesis{Philippi2011, author = {Philippi, Nicole}, title = {Modellierung von Signalwegen in verschiedenen biologischen Systemen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57690}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Die Apoptose der Leberzellen ist abh{\"a}ngig von externen Signalen wie beispielsweise Komponenten der Extrazellul{\"a}ren Matrix sowie anderen Zell-Zell-Kontakten, welche von einer Vielfalt und Vielzahl an Knoten verarbeitet werden. Einige von ihnen wurden im Rahmen dieser Arbeit auf ihre Systemeffekte hin unter- sucht. Trotz verschiedener {\"a}ußerer Einfl{\"u}sse und nat{\"u}rlicher Selektion ist das System daraufhin optimiert, eine kleine Anzahl verschiedener und klar voneinander unterscheidbarer Systemzust{\"a}nde anzunehmen. Die verschiedenartigen Einfl{\"u}sse und Crosstalk-Mechanismen dienen der Optimierung der vorhandenen Systemzust{\"a}nde. Das in dieser Arbeit vorgestellte Modell zeigt zwei apoptotische sowie zwei nicht-apoptotische stabile Systemzust{\"a}nde, wobei der Grad der Aktivierung eines Knotens bis zu dem Moment stark variieren kann, in welchem der absolute Systemzustand selbst ver{\"a}ndert wird (Philippi et al., BMC Systems Biology,2009) [1]. Dieses Modell stellt zwar eine Vereinfachung des gesamten zellul{\"a}ren Netzwerkes und seiner verschiedenen Zust{\"a}nde dar, ist aber trotz allem in der Lage, unabh{\"a}ngig von detaillierten kinetischen Daten und Parametern der einzelnen Knoten zu agieren. Gleichwohl erlaubt das Modell mit guter qualitativer {\"U}bereinstimmung die Apoptose als Folge einer Stimulation mit FasL zu modellieren. Weiterhin umfasst das Modell sowohl Crosstalk-M{\"o}glichkeiten des Collagen-Integrin-Signalwegs, ebenso ber{\"u}cksichtigt es die Auswirkungen der genetischen Deletion von Bid sowie die Konsequenzen einer viralen Infektion. In einem zweiten Teil werden andere Anwendungsm{\"o}glichkeiten dargestellt. Hormonale Signale in Pflanzen, Virusinfektionen und intrazellul{\"a}re Kommunikation werden semi-quantitativ modelliert. Auch hier zeigte sich eine gute Ubereinstimmung der Modelle mit den experimentellen Daten.}, subject = {Systembiologie}, language = {de} }