@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} } @article{WeissSchultz2015, author = {Weiß, Clemens Leonard and Schultz, J{\"o}rg}, title = {Identification of divergent WH2 motifs by HMM-HMM alignments}, series = {BMC Research Notes}, volume = {8}, journal = {BMC Research Notes}, number = {18}, doi = {10.1186/s13104-015-0981-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126413}, year = {2015}, abstract = {Background The actin cytoskeleton is a hallmark of eukaryotic cells. Its regulation as well as its interaction with other proteins is carefully orchestrated by actin interaction domains. One of the key players is the WH2 motif, which enables binding to actin monomers and filaments and is involved in the regulation of actin nucleation. Contrasting conserved domains, the identification of this motif in protein sequences is challenging, as it is short and poorly conserved. Findings To identify divergent members, we combined Hidden-Markov-Model (HMM) to HMM alignments with orthology predictions. Thereby, we identified nearly 500 proteins containing so far not annotated WH2 motifs. This included shootin-1, an actin binding protein involved in neuron polarization. Among others, WH2 motifs of 'proximal to raf' (ptr)-orthologs, which are described in the literature, but not annotated in genome databases, were identified. Conclusion In summary, we increased the number of WH2 motif containing proteins substantially. This identification of candidate regions for actin interaction could steer their experimental characterization. Furthermore, the approach outlined here can easily be adapted to the identification of divergent members of further domain families.}, language = {en} } @article{WeisschuhMayerStrometal.2016, author = {Weisschuh, Nicole and Mayer, Anja K. and Strom, Tim M. and Kohl, Susanne and Gl{\"o}ckle, Nicola and Schubach, Max and Andreasson, Sten and Bernd, Antje and Birch, David G. and Hamel, Christian P. and Heckenlively, John R. and Jacobson, Samuel G. and Kamme, Christina and Kellner, Ulrich and Kunstmann, Erdmute and Maffei, Pietro and Reiff, Charlotte M. and Rohrschneider, Klaus and Rosenberg, Thomas and Rudolph, G{\"u}nther and V{\´a}mos, Rita and Vars{\´a}nyi, Bal{\´a}zs and Weleber, Richard G. and Wissinger, Bernd}, title = {Mutation Detection in Patients with Retinal Dystrophies Using Targeted Next Generation Sequencing}, series = {PLoS ONE}, volume = {11}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0145951}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167398}, pages = {e0145951}, year = {2016}, abstract = {Retinal dystrophies (RD) constitute a group of blinding diseases that are characterized by clinical variability and pronounced genetic heterogeneity. The different nonsyndromic and syndromic forms of RD can be attributed to mutations in more than 200 genes. Consequently, next generation sequencing (NGS) technologies are among the most promising approaches to identify mutations in RD. We screened a large cohort of patients comprising 89 independent cases and families with various subforms of RD applying different NGS platforms. While mutation screening in 50 cases was performed using a RD gene capture panel, 47 cases were analyzed using whole exome sequencing. One family was analyzed using whole genome sequencing. A detection rate of 61\% was achieved including mutations in 34 known and two novel RD genes. A total of 69 distinct mutations were identified, including 39 novel mutations. Notably, genetic findings in several families were not consistent with the initial clinical diagnosis. Clinical reassessment resulted in refinement of the clinical diagnosis in some of these families and confirmed the broad clinical spectrum associated with mutations in RD genes.}, language = {en} } @article{WeissSebaldSchwabetal.1973, author = {Weiss, H. and Sebald, Walter and Schwab, A. J. and Kleinow, W. and Lorenz, B.}, title = {Contribution of mitochondrial and cytoplasmic protein synthesis to the formation of cytochrome b and cytochrome aa\(_3\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62835}, year = {1973}, abstract = {A cytochrome b preparation from Neurospora crassa mitochondria is found to consist of three polypeptides (apparent molecular weight 10 000, 11 000 and 32 000), a cytochrome aa3 preparation of six to seven polypeptides (apparent molecular weight 8 000, 11 000, 13 000, 18 000, 28 000 and 36 000). Selective incorporation of radioactive amino acids by eilher mitochondrial protein synthesis when the cytoplasmic one is blocked or by the cytoplasmic protein synthesis, when the mitochondrial one is blocked, indicates that one cytochrome b polypeptide (mw 32 000) and one to three cytochrome aa3 polypeptides (mw 36 000, 28 000 and 18 000) are mitochondrial translation products, the other cytochrome b and cytochrome aa3 polypeptides cytoplasmic translation products. The delayed appearance of labeling in the cytochrome b and cytochrome aa3 polypeptides compared to the average cell protein after a pulse of <~H leueine revealed that these polypeptides are derived from separate pools of precursor polypeptides. The pool sizes range from 2 p. cent to 25 p. cent of the amount of the corresponding polypeptide present in the cytochromes. The 32 000 molecular weight polypeptide of cytochrome band at least the 18 000 molecular weight polypeptide of cytochrome aa\(_3\) are mitochondrial translation products as well in the fungus Neurospora crassa as in the insect Locusta migratoria. So, despite the fact that the size of mitochondrial DNA and mitochondrial ribosomes is reduced in insects, the products have maintained their characteristics.}, subject = {Biochemie}, language = {en} } @article{WeissSebaldBuecher1971, author = {Weiss, H. and Sebald, Walter and B{\"u}cher, T.}, title = {Cycloheximide resistant incorporation of amino acids into a polypeptide of the cytochrome oxidase of Neurospora crassa}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62866}, year = {1971}, abstract = {Radioaetive leueine was ineorporated by N eurospora crassa mitoehondria in vivo in the presence of cyeloheximide. When the membrane protein of these mitochondria was ehromatographieally separated on oleyl polymethaerylie aeid resin, \& nurober of fraetions were obtained whieh differ with respeet to their eontents of radioaetivity and eytoehromes. The highest speeifie radioaetivity was found in the fraction eontaining eytoehrome aa3• This fraetion proved to be a pure and enzymatically aetive cytoehrome oxidase. Its ratio of absorbanee at 280 nm (ox)/ 443 nm (red.) was 2.1. By means of sodium dodeeylsulfate gel-electrophoresis, this enzymewas separated into five polypeptides with molecular weights of 30000, 20000, 13000, 10000, and 8000. Only the polypeptide with the molecular weight 20000 displayed a high specific radioaetivity.}, subject = {Biochemie}, language = {en} } @article{WeissSebald1978, author = {Weiss, H. and Sebald, Walter}, title = {Purification of cytochrome oxidase from Neurospora crassa and other sources}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82082}, year = {1978}, abstract = {A chromatographic procedure 1 is described by means of which cytochrome oxidase has been purified from a variety of organisms including the fungus N eurospora crassa,2,3 the unicellular alga Po/ytoma mirum, 4 the insect Locusta migratoria ,5 the frog Xenopus muel/eri,4 and the mammal Rattus norwegicus. 4 This procedure can be used to equal effect for large-scale preparations, starting from grams of mitochondrial protein, or for small-scale preparations starting from milligrams. The cytochrome oxidase preparations from the different organisms are enzymically active. They show similar subunit compositions.}, subject = {Biochemie}, language = {en} } @article{WeissSchlegelTerpitzetal.2020, author = {Weiss, Esther and Schlegel, Jan and Terpitz, Ulrich and Weber, Michael and Linde, J{\"o}rg and Schmitt, Anna-Lena and H{\"u}nniger, Kerstin and Marischen, Lothar and Gamon, Florian and Bauer, Joachim and L{\"o}ffler, Claudia and Kurzai, Oliver and Morton, Charles Oliver and Sauer, Markus and Einsele, Hermann and Loeffler, Juergen}, title = {Reconstituting NK Cells After Allogeneic Stem Cell Transplantation Show Impaired Response to the Fungal Pathogen Aspergillus fumigatus}, series = {Frontiers in Immunology}, volume = {11}, journal = {Frontiers in Immunology}, issn = {1664-3224}, doi = {10.3389/fimmu.2020.02117}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212581}, year = {2020}, abstract = {Delayed natural killer (NK) cell reconstitution after allogeneic stem cell transplantation (alloSCT) is associated with a higher risk of developing invasive aspergillosis. The interaction of NK cells with the human pathogen Aspergillus (A.) fumigatus is mediated by the fungal recognition receptor CD56, which is relocated to the fungal interface after contact. Blocking of CD56 signaling inhibits the fungal mediated chemokine secretion of MIP-1α, MIP-1β, and RANTES and reduces cell activation, indicating a functional role of CD56 in fungal recognition. We collected peripheral blood from recipients of an allograft at defined time points after alloSCT (day 60, 90, 120, 180). NK cells were isolated, directly challenged with live A. fumigatus germ tubes, and cell function was analyzed and compared to healthy age and gender-matched individuals. After alloSCT, NK cells displayed a higher percentage of CD56\(^{bright}\)CD16\(^{dim}\) cells throughout the time of blood collection. However, CD56 binding and relocalization to the fungal contact side were decreased. We were able to correlate this deficiency to the administration of corticosteroid therapy that further negatively influenced the secretion of MIP-1α, MIP-1β, and RANTES. As a consequence, the treatment of healthy NK cells ex vivo with corticosteroids abrogated chemokine secretion measured by multiplex immunoassay. Furthermore, we analyzed NK cells regarding their actin cytoskeleton by Structured Illumination Microscopy (SIM) and flow cytometry and demonstrate an actin dysfunction of NK cells shown by reduced F-actin content after fungal co-cultivation early after alloSCT. This dysfunction remains until 180 days post-alloSCT, concluding that further actin-dependent cellular processes may be negatively influenced after alloSCT. To investigate the molecular pathomechansism, we compared CD56 receptor mobility on the plasma membrane of healthy and alloSCT primary NK cells by single-molecule tracking. The results were very robust and reproducible between tested conditions which point to a different molecular mechanism and emphasize the importance of proper CD56 mobility.}, language = {en} } @phdthesis{Weismann2002, author = {Weismann, Dirk Thorsten}, title = {Untersuchungen zum enzymatischen und immunchemischen Nachweis der Phytanoyl-CoA-Hydroxylase in CHO-Zellen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8064}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2002}, abstract = {In der vorliegenden Arbeit wurde nach Wegen gesucht, den Import peroxisomaler Matrixproteine, der {\"u}ber ein peroxisomales Targeting Signal Typ 2 gesteuert wird, zu messen. Es war vorgesehen, in erster Linie einen enzymchemischen Nachweis zu etablieren, da diese Methode den Vorteil einer Quantifizierbarkeit der Aktivit{\"a}t der gemessenen Enzyme bietet und somit R{\"u}ckschl{\"u}sse auf den Grad einer Beeintr{\"a}chtigung des Importes zulassen w{\"u}rden. Von dem Test wurde eine Sensitivit{\"a}t gefordert, die eine Messung auch in Homogenaten kultivierter Zellen, insbesondere von CHO-Zellen, erlaubt. Dieses war deswegen gefordert, weil der Test zur Charakterisierung induzierter CHO-Zell-Mutanten eingesetzt werden sollte, die die Merkmale eines PTS 2-Import-Defektes aufweisen. Dieser Nachweis sollte durch eine Messung der Phytanoyl-CoA-Hydroxylase erfolgen. Dieses Enzym ist eines von drei derzeit bekannten Proteinen, die eine PTS 2 besitzen und {\"u}ber diesen Weg importiert werden. Das Substrat f{\"u}r die Hydroxylase war als Phytans{\"a}ure mit einer 2,3-3H-Markierung in der Arbeitsgruppe vorr{\"a}tig und wurde f{\"u}r den Test zum CoA-Thioester chemisch umgesetzt. Nach erfolgter enzymatischer Umsetzung von Phytonoyl-CoA zu a-Hydroxyphytanoyl-CoA durch die Hydroxylase waren dann sowohl Edukt wie auch das Produkt durch eine radioaktive Markierung gekennzeichnet und konnten nach einer d{\"u}nnschicht-chromatographischen Trennung {\"u}ber Kieselgel durch einem Radiod{\"u}nnschichtscanner nachgewiesen werden. Zun{\"a}chst wurde mit Hilfe von Homogenaten aus Rattenlebergewebe ein bereits beschriebenes Verfahren zur Messung der Phytanoyl-CoA-Hydroxylase optimiert. Es stellte sich jedoch heraus, daß die Sensitivit{\"a}t dieses Testes nicht hoch genug ist, um die Hydroxylase-Aktivit{\"a}t in Homogenaten kultivierter CHO-Zellen zu messen. An dieser Stelle wurde die Etablierung eines immunchemischen Nachweises begonnen. Hierzu sollten Antik{\"o}rper gegen die Hydroxylase des chinesischen Zwerghamsters, des Ursprungsorganismus der CHO-Zellen, generiert werden. Eine Reinigung des Enzyms kam nicht in Betracht, weil die Hamster nicht im Labortierhandel erh{\"a}ltlich waren. Folglich musste die cDNA der Hydroxylase aus einer Hamster-cDNA-Bank kloniert werden, nachdem sie durch ihre bekannten Homologe aus Mensch und Maus identifizierbar war. In den verf{\"u}gbaren cDNA-Banken fand sich keine vollst{\"a}ndige Sequenz, so daß mit einer partiellen Sequenz ohne 5´-Ende weitergearbeitet werden musste. Es bot sich im Institut die M{\"o}glichkeit, aus dieser Sequenz Pepetide zu bestimmen, die mit hoher Wahrscheinlichkeit stark immunogen wirken. Solche Peptide wurden synthetisiert und nach Koppelung an Tr{\"a}gerproteine neuseel{\"a}ndischen weißen Kaninchen geimpft. Im Elisa wies das Antiserum zum Zeitpunkt seiner Gewinnung einen Titer von etwa 1:10000 auf, zeigte aber im Westernblot neben einer starken Detektion in Laufweite der Hydroxylase auch eine unspezifische Anf{\"a}rbung der Proben. In der nun durchgef{\"u}hrten Affinit{\"a}tsreinigung des Antiserums {\"u}ber einer mit den antigenen Peptiden beladenen S{\"a}ule tauchte das Problem auf, daß die Antik{\"o}rper so fest binden, daß sie von ihren Antigenen nicht mehr ohne dentaturierende Bedingungen zu l{\"o}sen waren. F{\"u}r die weitere Arbeit sollte sich nun eine affinit{\"a}tschromatographische Reinigung {\"u}ber Peptide, die den Antik{\"o}rper mit geringerer Avidit{\"a}t binden, anschließen, so daß nach Trennung der Immunkomplexe native Antik{\"o}rper isoliert werden k{\"o}nnten. Hierzu w{\"a}re ein Epitop-mapping w{\"u}nschenswert, damit auf dieser Grundlage Peptide mit den geforderten Eigenschaften synthetisiert werden k{\"o}nnen.}, language = {de} } @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{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} } @phdthesis{Weisert2024, author = {Weisert, Nadine}, title = {Characterization of telomere-associated proteins in \(Trypanosoma\) \(brucei\)}, doi = {10.25972/OPUS-35273}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-352732}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2024}, abstract = {The unicellular pathogen Trypanosoma brucei is the causative agent of African trypanosomiasis, an endemic disease prevalent in sub-Saharan Africa. Trypanosoma brucei alternates between a mammalian host and the tsetse fly vector. The extracellular parasite survives in the mammalian bloodstream by periodically exchanging their ˈvariant surface glycoproteinˈ (VSG) coat to evade the host immune response. This antigenic variation is achieved through monoallelic expression of one VSG variant from subtelomeric ˈbloodstream form expression sitesˈ (BES) at a given timepoint. During the differentiation from the bloodstream form (BSF) to the procyclic form (PCF) in the tsetse fly midgut, the stage specific surface protein is transcriptionally silenced and replaced by procyclins. Due to their subtelomeric localization on the chromosomes, VSG transcription and silencing is partly regulated by homologues of the mammalian telomere complex such as TbTRF, TbTIF2 and TbRAP1 as well as by ˈtelomere-associated proteinsˈ (TelAPs) like TelAP1. To gain more insights into transcription regulation of VSG genes, the identification and characterization of other TelAPs is critical and has not yet been achieved. In a previous study, two biochemical approaches were used to identify other novel TelAPs. By using ˈco-immunoprecipitationˈ (co-IP) to enrich possible interaction partners of TbTRF and by affinity chromatography using telomeric repeat oligonucleotides, a listing of TelAP candidates has been conducted. With this approach TelAP1 was identified as a novel component of the telomere complex, involved in the kinetics of transcriptional BES silencing during BSF to PCF differentiation. To gain further insights into the telomere complex composition, other previously enriched proteins were characterized through a screening process using RNA interference to deplete potential candidates. VSG expression profile changes and overall proteomic changes after depletion were analyzed by mass spectrometry. With this method, one can gain insights into the functions of the proteins and their involvement in VSG expression site regulation. To validate the interaction of proteins enriched by co-IP with TbTRF and TelAP1 and to identify novel interaction proteins, I performed reciprocal affinity purifications of the four most promising candidates (TelAP2, TelAP3, PPL2 and PolIE) and additionally confirmed colocalization of two candidates with TbTRF via immunofluorescence (TelAP2, TelAP3). TelAP3 colocalizes with TbTRF and potentially interacts with TbTRF, TbTIF2, TelAP1 and TelAP2, as well as with two translesion polymerases PPL2 and PolIE in BSF. PPL2 and PolIE seem to be in close contact to each other at the telomeric ends and fulfill different roles as only PolIE is involved in VSG regulation while PPL2 is not. TelAP2 was previously characterized to be associated with telomeres by partially colocalizing with TbTRF and cells show a VSG derepression phenotype when the protein was depleted. Here I show that TelAP2 interacts with the telomere-binding proteins TbTRF and TbTIF2 as well as with the telomere-associated protein TelAP1 in BSF and that TelAP2 depletion results in a loss of TelAP1 colocalization with TbTRF in BSF. In conclusion, this study demonstrates that characterizing potential TelAPs is effective in gaining insights into the telomeric complex's composition and its role in VSG regulation in Trypanosoma brucei. Understanding these interactions could potentially lead to new therapeutic targets for combatting African trypanosomiasis.}, subject = {Telomer }, language = {en} } @article{WeisenbergerScheerBenavente1993, author = {Weisenberger, Dieter and Scheer, Ulrich and Benavente, Ricardo}, title = {The DNA topoisomerase I inhibitor camptothecin blocks postmitotic reformation of nucleoli in mammmalian cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41434}, year = {1993}, abstract = {No abstract available}, subject = {Cytologie}, language = {en} } @article{WeigelMeyerSebald1989, author = {Weigel, U. and Meyer, M. and Sebald, Walter}, title = {Mutant proteins of human interleukin 2. Renaturation yield, proliferative activity and receptor binding}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62543}, year = {1989}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @phdthesis{Weidenmueller2001, author = {Weidenm{\"u}ller, Anja}, title = {From individual behavior to collective structure}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-2448}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {The social organization of insect colonies has long fascinated naturalists. One of the main features of colony organization is division of labor, whereby each member of the colony specializes in a subset of all tasks required for successful group functioning. The most striking aspect of division of labor is its plasticity: workers switch between tasks in response to external challenges and internal perturbations. The mechanisms underlying flexible division of labor are far from being understood. In order to comprehend how the behavior of individuals gives rise to flexible collective behavior, several questions need to be addressed: We need to know how individuals acquire information about their colony's current demand situation; how they then adjust their behavior according; and which mechanisms integrate dozens or thousands of insect into a higher-order unit. With these questions in mind I have examined two examples of collective and flexible behavior in social bees. First, I addressed the question how a honey bee colony controls its pollen collection. Pollen foraging in honey bees is precisely organized and carefully regulated according to the colony's needs. How this is achieved is unclear. I investigated how foragers acquire information about their colony's pollen need and how they then adjust their behavior. A detailed documentation of pollen foragers in the hive under different pollen need conditions revealed that individual foragers modulate their in-hive working tempo according to the actual pollen need of the colony: Pollen foragers slowed down and stayed in the hive longer when pollen need was low and spent less time in the hive between foraging trips when pollen need of their colony was high. The number of cells inspected before foragers unloaded their pollen load did not change and thus presumably did not serve as cue to pollen need. In contrast, the trophallactic experience of pollen foragers changed with pollen need conditions: trophallactic contacts were shorter when pollen need was high and the number and probability of having short trophallactic contacts increased when pollen need increased. Thus, my results have provided support for the hypothesis that trophallactic experience is one of the various information pathways used by pollen foragers to assess their colony's pollen need. The second example of collective behavior I have examined in this thesis is the control of nest climate in bumble bee colonies, a system differing from pollen collection in honey bees in that information about task need (nest climate parameters) is directly available to all workers. I have shown that an increase in CO2 concentration and temperature level elicits a fanning response whereas an increase in relative humidity does not. The fanning response to temperature and CO2 was graded; the number of fanning bees increased with stimulus intensity. Thus, my study has evidenced flexible colony level control of temperature and CO2. Further, I have shown that the proportion of total work force a colony invests into nest ventilation does not change with colony size. However, the dynamic of the colony response changes: larger colonies show a faster response to perturbations of their colony environment than smaller colonies. Thus, my study has revealed a size-dependent change in the flexible colony behavior underlying homeostasis. I have shown that the colony response to perturbations in nest climate is constituted by workers who differ in responsiveness. Following a brief review of current ideas and models of self-organization and response thresholds in insect colonies, I have presented the first detailed investigation of interindividual variability in the responsiveness of all workers involved in a collective behavior. My study has revealed that bumble bee workers evidence consistent responses to certain stimulus levels and differ in their response thresholds. Some consistently respond to low stimulus intensities, others consistently respond to high stimulus intensities. Workers are stimulus specialists rather than task specialists. Further, I have demonstrated that workers of a colony differ in two other parameters of responsiveness: response probability and fanning activity. Response threshold, response probability and fanning activity are independent parameters of individual behavior. Besides demonstrating and quantifying interindividual variability, my study has provided empirical support for the idea of specialization through reinforcement. Response thresholds of fanning bees decreased over successive trials. I have discussed the importance of interindividual variability for specialization and the collective control of nest climate and present a general discussion of self-organization and selection. This study contributes to our understanding of individual behavior and collective structure in social insects. A fascinating picture of social organization is beginning to emerge. In place of centralized systems of communication and information transmission, insect societies frequently employ mechanisms based upon self-organization. Self-organization promises to be an important and unifying principle in physical, chemical and biological systems.}, subject = {Hummeln}, language = {en} } @article{WeichSebaldSchaireretal.1986, author = {Weich, H. A. and Sebald, Walter and Schairer, H. U. and Hoppe, J.}, title = {The human osteosarcoma cell line U-2 OS expresses a 3.8 kilobase mRNA which codes for the sequence of the PDGF-B chain}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62588}, year = {1986}, abstract = {A cDNA clone of about 2500 basepairswas prepared from the human osteosarcoma cellline U-2 OS by hybridizing with a v-sis probe. Sequence analysis showed that this cDNA contains the coding region for the PDGF-B chain. Here we report that the mitogen secreted by these osteosarcoma cells contains the PDGF-B chain and is probably a homodimer of two B-chains.}, subject = {Biochemie}, language = {en} } @article{WegertVokuhZiegleretal.2017, author = {Wegert, Jenny and Vokuh, Christian and Ziegler, Barbara and Ernestus, Karen and Leuschner, Ivo and Furtw{\"a}ngler, Rhoikos and Graf, Norbert and Gessler, Manfred}, title = {TP53 alterations in Wilms tumour represent progression events with strong intratumour heterogeneity that are closely linked but not limited to anaplasia}, series = {The Journal of Pathology: Clinical Research}, volume = {3}, journal = {The Journal of Pathology: Clinical Research}, doi = {10.1002/cjp2.77}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158302}, pages = {234-248}, year = {2017}, abstract = {TP53 mutations have been associated with anaplasia in Wilms tumour, which conveys a high risk for relapse and fatal outcome. Nevertheless, TP53 alterations have been reported in no more than 60\% of anaplastic tumours, and recent data have suggested their presence in tumours that do not fulfil the criteria for anaplasia, questioning the clinical utility of TP53 analysis. Therefore, we characterized the TP53 status in 84 fatal cases of Wilms tumour, irrespective of histological subtype. We identified TP53 alterations in at least 90\% of fatal cases of anaplastic Wilms tumour, and even more when diffuse anaplasia was present, indicating a very strong if not absolute coupling between anaplasia and deregulation of p53 function. Unfortunately, TP53 mutations do not provide additional predictive value in anaplastic tumours since the same mutation rate was found in a cohort of non-fatal anaplastic tumours. When classified according to tumour stage, patients with stage I diffuse anaplastic tumours still had a high chance of survival (87\%), but this rate dropped to 26\% for stages II-IV. Thus, volume of anaplasia or possible spread may turn out to be critical parameters. Importantly, among non-anaplastic fatal tumours, 26\% had TP53 alterations, indicating that TP53 screening may identify additional cases at risk. Several of these non-anaplastic tumours fulfilled some criteria for anaplasia, for example nuclear unrest, suggesting that such partial phenotypes should be under special scrutiny to enhance detection of high-risk tumours via TP53 screening. A major drawback is that these alterations are secondary changes that occur only later in tumour development, leading to striking intratumour heterogeneity that requires multiple biopsies and analysis guided by histological criteria. In conclusion, we found a very close correlation between histological signs of anaplasia and TP53 alterations. The latter may precede development of anaplasia and thereby provide diagnostic value pointing towards aggressive disease.}, language = {en} } @article{WegertBausenweinKneitzetal.2011, author = {Wegert, Jenny and Bausenwein, Sabrina and Kneitz, Susanne and Roth, Sabine and Graf, Norbert and Geissinger, Eva and Gessler, Manfred}, title = {Retinoic acid pathway activity in Wilms tumors and characterization of biological responses in vitro}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-69137}, year = {2011}, abstract = {Background: Wilms tumor (WT) is one of the most common malignancies in childhood. With current therapy protocols up to 90\% of patients can be cured, but there is still a need to improve therapy for patients with aggressive WT and to reduce treatment intensity where possible. Prior data suggested a deregulation of the retinoic acid (RA) signaling pathway in high-risk WT, but its mode of action remained unclear. Results: The association of retinoid signaling and clinical parameters could be validated in a large independent tumor set, but its relevance in primary nephrectomy tumors from very young children may be different. Reduced RA pathway activity and MYCN overexpression were found in high risk tumors as opposed to tumors with low/ intermediate risk, suggesting a beneficial impact of RA especially on advanced WT. To search for possible modes of action of retinoids as novel therapeutic options, primary tumor cell cultures were treated in vitro with all-trans-RA (ATRA), 9cis-RA, fenretinide and combinations of retinoids and a histone deacetylase (HDAC) inhibitor. Genes deregulated in high risk tumors showed opposite changes upon treatment suggesting a positive effect of retinoids. 6/7 primary cultures tested reduced proliferation, irrespective of prior RA signaling levels. The only variant culture was derived from mesoblastic nephroma, a distinct childhood kidney neoplasm. Retinoid/HDAC inhibitor combinations provided no synergistic effect. ATRA and 9cis-RA induced morphological changes suggestive of differentiation, while fenretinide induced apoptosis in several cultures tested. Microarray analysis of ATRA treated WT cells revealed differential expression of many genes involved in extracellular matrix formation and osteogenic, neuronal or muscle differentiation. The effects documented appear to be reversible upon drug withdrawal, however. Conclusions: Altered retinoic acid signaling has been validated especially in high risk Wilms tumors. In vitro testing of primary tumor cultures provided clear evidence of a potential utility of retinoids in Wilms tumor treatment based on the analysis of gene expression, proliferation, differentiation and apoptosis.}, subject = {Krebs}, language = {en} } @phdthesis{Wegert2010, author = {Wegert, Jenny}, title = {WTX-Mutationsscreen und funktionelle Analyse des Retins{\"a}ure-Signalwegs in Wilms Tumoren}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-52822}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Der Wilms Tumor (WT), auch Nephroblastom genannt, ist einer der h{\"a}ufigsten b{\"o}sartigen Tumoren im Kindesalter. Er entsteht aus embryonalem undifferenziertem Nierengewebe und tritt meist als unilateraler und sporadischer Tumor auf. In 10-15\% der Wilms Tumoren finden sich WT1- und/oder CTNNB1-Mutationen. W{\"a}hrend diese schon l{\"a}nger als genetische Ursachen des Nephroblastoms bekannt sind, wurde erst k{\"u}rzlich WTX als drittes Gen beschrieben, welches eine Rolle in der Tumorentstehung spielt. F{\"u}r einen Großteil der WT ist die genetische Ursache jedoch unklar. Da die bisher publizierten WTX-Mutationsraten auf Untersuchungen kleiner Gruppen basieren und sich stark unterscheiden, sollten in dieser Arbeit WTX-, CTNNB1- und WT1-Mutationen in einem großen WT-Set bestimmt werden. Verluste genetischen Materials in der WTX-Region traten in 17\% der F{\"a}lle auf und waren zwischen den Geschlechtern gleich verteilt. Die Sequenzierung von WT-Proben zeigte, dass nur 2\% von WTX-Punktmutationen betroffen sind. In weiteren 11,5\% der Proben konnte keine WTX-Expression nachgewiesen werden. Die WTX-Ver{\"a}nderungen traten z. T. gemeinsam mit WT1- und/oder CTNNB1-Mutationen auf. Die unvollst{\"a}ndige WTX-Deletion in einigen WT legte die Vermutung nahe, dass innerhalb eines Tumors eine Heterogenit{\"a}t in Bezug auf den WTX-Status m{\"o}glich ist. Dieser Verdacht konnte durch die detaillierte Untersuchung verschiedener Regionen solcher Tumoren erh{\"a}rtet werden: Hierzu wurden histologisch unterschiedliche Bereiche auf den Anteil einer WTX-Mutation bzw. eines WTX-LOH hin untersucht. Obwohl alle Regionen des jeweiligen Tumors einen kompletten LOH auf Chromosom 11 aufwiesen, waren die WTX-Ver{\"a}nderungen unterschiedlich stark ausgepr{\"a}gt. Diese Ergebnisse deuten darauf hin, dass WTX-Ver{\"a}nderungen keine notwendigen und fr{\"u}hen Ereignisse in der Tumorentstehung sind, sondern erst sp{\"a}ter auftreten und nur einen Teil der Tumorzellen betreffen k{\"o}nnen. Die Vermutung, dass WTX-Mutationen keinen direkten Einfluss auf die Tumorentwicklung und prognose haben, wird durch das Fehlen eines signifikanten Zusammenhangs zwischen WTX-Deletion bzw. WTX-Expression und den klinischen Eigenschaften der WT gest{\"u}tzt. Um die Rolle von Genen, die potentiell an der Entstehung und Entwicklung des Nephroblastoms beteiligt sind, zu untersuchen oder m{\"o}gliche neue Therapiestrategien zu {\"u}berpr{\"u}fen, sind in vitro-Modelle n{\"o}tig. Da ein solches f{\"u}r Wilms Tumoren nicht etabliert ist, wurden Prim{\"a}rkulturen aus verschiedenen WT-Proben angelegt. Kulturen aus Tumorgewebe von 12 Patienten mit unterschiedlichen genetischen Ver{\"a}nderungen konnten als echte Tumorzellen validiert werden. Zwei Zelltypen ließen sich morphologisch und immunhistochemisch unterscheiden: Zum einen runde, langsam wachsende Zellen mit Epithelcharakter und zum anderen fibroblasten{\"a}hnliche Zellen, welche weniger differenziert waren und h{\"a}ufig f{\"u}r viele Passagen kultiviert werden konnten. Somit wurde ein Set verschiedener WT-Prim{\"a}rkulturen etabliert, welches nun f{\"u}r in vitro-Experimente zur Untersuchung grundlegender Mechanismen der WT-Entstehung oder zum Test neuer Therapieans{\"a}tze eingesetzt werden kann. Fr{\"u}here Microarray-Analysen deuteten auf eine Deregulation des Retins{\"a}ure (RA)-Signalwegs in fortgeschrittenen Wilms Tumoren hin. Diese Ergebnisse sollten in einem großen unabh{\"a}ngigen Proben-Set mittels Realtime-RT-PCR validiert werden. Eine Deregulation des RA-Signalwegs und die {\"U}berexpression von NMYC wurden f{\"u}r Tumoren der Hochrisikogruppe im Vergleich zu Tumoren mit geringem/mittlerem Risiko nachgewiesen. So stellte sich die Frage, ob Patienten mit fortgeschrittenem WT von einem Retins{\"a}ure-Einsatz in der Therapie profitieren k{\"o}nnten. Um dies zu beantworten, wurde der Effekt von verschiedenen Retinoiden auf WT-Prim{\"a}rkulturen untersucht. Die WT-Zellen wurden mit all-trans RA (ATRA), 9cisRA, dem synthetischen Retinoid Fenretinid (4HPR) und Kombinationen von ATRA bzw. 4HPR und einem HDAC-Inhibitor (SAHA) behandelt. Gene, welche in Hochrisiko-WT differenziell reguliert waren, wurden untersucht und zeigten nach RA-Behandlung eine entgegengesetzte Expression. In sechs der sieben verwendeten Prim{\"a}rkulturen wurde eine RA-vermittelte Proliferationsreduktion nachgewiesen. F{\"u}r die Kombinationen von Retinoiden mit SAHA wurden keine synergistischen Effekte beobachtet. W{\"a}hrend Fenretinid in den meisten Kulturen Apoptose induzierte, verursachten ATRA und 9cisRA morphologische Ver{\"a}nderungen, welche auf Differenzierungsvorg{\"a}nge hindeuteten. Eine Microarray-Analyse ATRA-behandelter WT-Zellen zeigte die differenzielle Regulation vieler Gene, welche eine Rolle in der Bildung der extrazellul{\"a}ren Matrix oder bei Differenzierungsvorg{\"a}ngen von Knochen-, Knorpel-, Nerven- oder Muskelgewebe spielen. Diese Befunde bieten einen weiteren Hinweis darauf, dass Retinoide f{\"u}r den Einsatz in der Therapie des Nephroblastoms geeignet sein k{\"o}nnten.}, subject = {Nephroblastom}, language = {de} } @article{WegenerKarsaiPollaketal.2013, author = {Wegener, Christian and Karsai, Gergely and Poll{\´a}k, Edit and Wacker, Matthias and V{\"o}mel, Matthias and Selcho, Mareike and Berta, Gergely and Nachman, Ronald J. and Isaac, R. Elwyn and Moln{\´a}r, L{\´a}szl{\´o}}, title = {Diverse in- and output polarities and high complexity of local synaptic and non-synaptic signaling within a chemically defined class of peptidergic Drosophila neurons}, series = {Frontiers in Neural Circuits}, journal = {Frontiers in Neural Circuits}, doi = {10.3389/fncir.2013.00127}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-96914}, year = {2013}, abstract = {Peptidergic neurons are not easily integrated into current connectomics concepts, since their peptide messages can be distributed via non-synaptic paracrine signaling or volume transmission. Moreover, the polarity of peptidergic interneurons in terms of in- and out-put sites can be hard to predict and is very little explored. We describe in detail the morphology and the subcellular distribution of fluorescent vesicle/dendrite markers in CCAP neurons (NCCAP), a well defined set of peptidergic neurons in the Drosophila larva. NCCAP can be divided into five morphologically distinct subsets. In contrast to other subsets, serial homologous interneurons in the ventral ganglion show a mixed localization of in- and output markers along ventral neurites that defy a classification as dendritic or axonal compartments. Ultrastructurally, these neurites contain both pre- and postsynaptic sites preferably at varicosities. A significant portion of the synaptic events are due to reciprocal synapses. Peptides are mostly non-synaptically or parasynaptically released, and dense-core vesicles and synaptic vesicle pools are typically well separated. The responsiveness of the NCCAP to ecdysis-triggering hormone may be at least partly dependent on a tonic synaptic inhibition, and is independent of ecdysteroids. Our results reveal a remarkable variety and complexity of local synaptic circuitry within a chemically defined set of peptidergic neurons. Synaptic transmitter signaling as well as peptidergic paracrine signaling and volume transmission from varicosities can be main signaling modes of peptidergic interneurons depending on the subcellular region. The possibility of region-specific variable signaling modes should be taken into account in connectomic studies that aim to dissect the circuitry underlying insect behavior and physiology, in which peptidergic neurons act as important regulators.}, language = {en} } @article{WegenerChen2022, author = {Wegener, Christian and Chen, Jiangtian}, title = {Allatostatin A signalling: progress and new challenges from a paradigmatic pleiotropic invertebrate neuropeptide family}, series = {Frontiers in Physiology}, volume = {13}, journal = {Frontiers in Physiology}, issn = {1664-042X}, doi = {10.3389/fphys.2022.920529}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-278749}, year = {2022}, abstract = {Neuropeptides have gained broad attraction in insect neuroscience and physiology, as new genetic tools are increasingly uncovering their wide-ranging pleiotropic functions with high cellular resolution. Allatostatin A (AstA) peptides constitute one of the best studied insect neuropeptide families. In insects and other panarthropods, AstA peptides qualify as brain-gut peptides and have regained attention with the discovery of their role in regulating feeding, growth, activity/sleep and learning. AstA receptor homologs are found throughout the protostomia and group with vertebrate somatostatin/galanin/kisspeptin receptors. In this review, we summarise the current knowledge on the evolution and the pleiotropic and cell-specific non-allatostatic functions of AstA. We speculate about the core functions of AstA signalling, and derive open questions and challengesfor future research on AstA and invertebrate neuropeptides in general.}, language = {en} }