@article{NiewaldaVoellerEschbachetal.2011, author = {Niewalda, Thomas and V{\"o}ller, Thomas and Eschbach, Claire and Ehmer, Julia and Wen-Chuang, Chou and Timme, Marc and Fiala, Andr{\´e} and Gerber, Bertram}, title = {A Combined Perceptual, Physico-Chemical, and Imaging Approach to 'Odour-Distances' Suggests a Categorizing Function of the Drosophila Antennal Lobe}, series = {PLoS One}, volume = {6}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0024300}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133510}, pages = {e24300}, year = {2011}, abstract = {How do physico-chemical stimulus features, perception, and physiology relate? Given the multi-layered and parallel architecture of brains, the question specifically is where physiological activity patterns correspond to stimulus features and/or perception. Perceived distances between six odour pairs are defined behaviourally from four independent odour recognition tasks. We find that, in register with the physico-chemical distances of these odours, perceived distances for 3octanol and n-amylacetate are consistently smallest in all four tasks, while the other five odour pairs are about equally distinct. Optical imaging in the antennal lobe, using a calcium sensor transgenically expressed in only first-order sensory or only second-order olfactory projection neurons, reveals that 3-octanol and n-amylacetate are distinctly represented in sensory neurons, but appear merged in projection neurons. These results may suggest that within-antennal lobe processing funnels sensory signals into behaviourally meaningful categories, in register with the physico-chemical relatedness of the odours.}, language = {en} } @article{ElKeredySchleyerKoenigetal.2012, author = {El-Keredy, Amira and Schleyer, Michael and K{\"o}nig, Christian and Ekim, Aslihan and Gerber, Bertram}, title = {Behavioural Analyses of Quinine Processing in Choice, Feeding and Learning of Larval Drosophila}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0040525}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130811}, pages = {e40525}, year = {2012}, abstract = {Gustatory stimuli can support both immediate reflexive behaviour, such as choice and feeding, and can drive internal reinforcement in associative learning. For larval Drosophila, we here provide a first systematic behavioural analysis of these functions with respect to quinine as a study case of a substance which humans report as "tasting bitter". We describe the dose-effect functions for these different kinds of behaviour and find that a half-maximal effect of quinine to suppress feeding needs substantially higher quinine concentrations (2.0 mM) than is the case for internal reinforcement (0.6 mM). Interestingly, in previous studies (Niewalda et al. 2008, Schipanski et al 2008) we had found the reverse for sodium chloride and fructose/sucrose, such that dose-effect functions for those tastants were shifted towards lower concentrations for feeding as compared to reinforcement, arguing that the differences in dose-effect function between these behaviours do not reflect artefacts of the types of assay used. The current results regarding quinine thus provide a starting point to investigate how the gustatory system is organized on the cellular and/or molecular level to result in different behavioural tuning curves towards a bitter tastant.}, language = {en} } @article{RicoYepesRodriguezetal.2014, author = {Rico, Sergio and Yepes, Ana and Rodriguez, Hector and Santamaria, Jorge and Antoraz, Sergio and Krause, Eva M. and Diaz, Margarita and Santamaria, Ramon I.}, title = {Regulation of the AbrA1/A2 Two-Component System in Streptomyces coelicolor and the Potential of Its Deletion Strain as a Heterologous Host for Antibiotic Production}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {10}, issn = {1932-6203}, doi = {10.1371/journal.pone.0109844}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115151}, pages = {e109844}, year = {2014}, abstract = {The Two-Component System (TCS) AbrA1/A2 from Streptomyces coelicolor M145 is a negative regulator of antibiotic production and morphological differentiation. In this work we show that it is able to auto-regulate its expression, exerting a positive induction of its own operon promoter, and that its activation is dependent on the presence of iron. The overexpression of the abrA2 response regulator (RR) gene in the mutant DabrA1/A2 results in a toxic phenotype. The reason is an excess of phosphorylated AbrA2, as shown by phosphoablative and phosphomimetic AbrA2 mutants. Therefore, non-cognate histidine kinases (HKs) or small phospho-donors may be responsible for AbrA2 phosphorylation in vivo. The results suggest that in the parent strain S. coelicolor M145 the correct amount of phosphorylated AbrA2 is adjusted through the phosphorylation-dephosphorylation activity rate of the HK AbrA1. Furthermore, the ABC transporter system, which is part of the four-gene operon comprising AbrA1/A2, is necessary to de-repress antibiotic production in the TCS null mutant. Finally, in order to test the possible biotechnological applications of the DabrA1/A2 strain, we demonstrate that the production of the antitumoral antibiotic oviedomycin is duplicated in this strain as compared with the production obtained in the wild type, showing that this strain is a good host for heterologous antibiotic production. Thus, this genetically modified strain could be interesting for the biotechnology industry.}, language = {en} } @article{VolceanovHerbstBiniosseketal.2014, author = {Volceanov, Larisa and Herbst, Katharina and Biniossek, Martin and Schilling, Oliver and Haller, Dirk and N{\"o}lke, Thilo and Subbarayal, Prema and Rudel, Thomas and Zieger, Barbara and H{\"a}cker, Georg}, title = {Septins Arrange F-Actin-Containing Fibers on the Chlamydia trachomatis Inclusion and Are Required for Normal Release of the Inclusion by Extrusion}, series = {MBIO}, volume = {5}, journal = {MBIO}, number = {5}, issn = {2150-7511}, doi = {10.1128/mBio.01802-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115421}, pages = {e01802-14}, year = {2014}, abstract = {Chlamydia trachomatis is an obligate intracellular human pathogen that grows inside a membranous, cytosolic vacuole termed an inclusion. Septins are a group of 13 GTP-binding proteins that assemble into oligomeric complexes and that can form higher-order filaments. We report here that the septins SEPT2, -9, -11, and probably -7 form fibrillar structures around the chlamydial inclusion. Colocalization studies suggest that these septins combine with F actin into fibers that encase the inclusion. Targeting the expression of individual septins by RNA interference (RNAi) prevented the formation of septin fibers as well as the recruitment of actin to the inclusion. At the end of the developmental cycle of C. trachomatis, newly formed, infectious elementary bodies are released, and this release occurs at least in part through the organized extrusion of intact inclusions. RNAi against SEPT9 or against the combination of SEPT2/7/9 substantially reduced the number of extrusions from a culture of infected HeLa cells. The data suggest that a higher-order structure of four septins is involved in the recruitment or stabilization of the actin coat around the chlamydial inclusion and that this actin recruitment by septins is instrumental for the coordinated egress of C. trachomatis from human cells. The organization of F actin around parasite-containing vacuoles may be a broader response mechanism of mammalian cells to the infection by intracellular, vacuole-dwelling pathogens. IMPORTANCE Chlamydia trachomatis is a frequent bacterial pathogen throughout the world, causing mostly eye and genital infections. C. trachomatis can develop only inside host cells; it multiplies inside a membranous vacuole in the cytosol, termed an inclusion. The inclusion is covered by cytoskeletal "coats" or "cages," whose organization and function are poorly understood. We here report that a relatively little-characterized group of proteins, septins, is required to organize actin fibers on the inclusion and probably through actin the release of the inclusion. Septins are a group of GTP-binding proteins that can organize into heteromeric complexes and then into large filaments. Septins have previously been found to be involved in the interaction of the cell with bacteria in the cytosol. Our observation that they also organize a reaction to bacteria living in vacuoles suggests that they have a function in the recognition of foreign compartments by a parasitized human cell.}, language = {en} } @article{GoerlZhangStepanenkoetal.2015, author = {G{\"o}rl, Daniel and Zhang, Xin and Stepanenko, Vladimir and W{\"u}rthner, Frank}, title = {Supramolecular block copolymers by kinetically controlled co-self-assembly of planar and core-twisted perylene bisimides}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, number = {7009}, doi = {10.1038/ncomms8009}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148657}, year = {2015}, abstract = {New synthetic methodologies for the formation of block copolymers have revolutionized polymer science within the last two decades. However, the formation of supramolecular block copolymers composed of alternating sequences of larger block segments has not been realized yet. Here we show by transmission electron microscopy (TEM), 2D NMR and optical spectroscopy that two different perylene bisimide dyes bearing either a flat (A) or a twisted (B) core self-assemble in water into supramolecular block copolymers with an alternating sequence of (A\(_{m}\)BB)\(_{n}\). The highly defined ultralong nanowire structure of these supramolecular copolymers is entirely different from those formed upon self-assembly of the individual counterparts, that is, stiff nanorods (A) and irregular nanoworms (B), respectively. Our studies further reveal that the as-formed supramolecular block copolymer constitutes a kinetic self-assembly product that transforms into thermodynamically more stable self-sorted homopolymers upon heating.}, language = {en} } @phdthesis{Hillenbrand2019, author = {Hillenbrand, Timo}, title = {Das Spiel mit der Grenze - F{\"u}hrung im Spannungsfeld von Formalit{\"a}t und Informalit{\"a}t}, doi = {10.25972/OPUS-18929}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189290}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Seit ihrem Aufkommen besch{\"a}ftigt sich die Organisationsforschung mit dem Antagonismus von Organisation und Individuum, ohne jedoch immer eindeutig fassen zu k{\"o}nnen, worin genau der Unterschied zwischen beiden besteht. Wollte Taylor den „Horden-Menschen" noch durch wissenschaftliche Betriebsf{\"u}hrung domestizieren und in den Mechanismus der Organisation integrieren, erkannte Barnard bereits, dass nur ein gewisser Teil des Individu-ums in Organisationen kommunikativ erreichbar ist und ersann vor diesem Hintergrund eine F{\"u}hrungstheorie mit dem Ziel, den Bereich erwartbarer Aufgaben-Kommunikation auf ein Maximum auszudehnen und hierdurch die „zone of indifference" der Mitarbeiter so zu er-weitern, dass selbige m{\"o}glichst viele Aufgaben und Arbeiten als Teil ihrer Organisations-pers{\"o}nlichkeit internalisieren. Erst mit den Arbeiten Luhmanns in den 1960er Jahren war man jedoch in der Lage, Informa-lit{\"a}t - also auf personale Erwartungen abzielende Kommunikation - nicht mehr allein als St{\"o}rung oder Dysfunktionalit{\"a}t, sondern vielmehr als Folge des Umgangs mit der Formal-struktur des Organisationssystems zu beschreiben und die beiden Begriffe folglich in einen funktionalen Zusammenhang zu bringen. Innerhalb dieses theoriegeschichtlichen Rahmens geht unsere Untersuchung der Frage nach, in welcher Weise F{\"u}hrung im Kontext des Spannungsfeldes zwischen Formalit{\"a}t und Infor-malit{\"a}t operiert und welche Implikationen neuere Semantiken der Managementliteratur (z.B. „die authentische F{\"u}hrungskraft", „Vertrauen" oder „Menschsein"), die insbesondere auf eine Personalisierung des Mitarbeiters abzielen, dabei generieren. Hierdurch k{\"o}nnen wir zeigen, dass F{\"u}hrung mittels informaler Kommunikation, die wir als „Umweghandeln" be-zeichnen, ein Spiel mit der Grenze zwischen System und Umwelt - also Mitarbeiter - etab-liert, wodurch sie in der Lage ist, den Mitarbeiter als Beobachtung der Differenz zwischen System und Umwelt in das System wieder einzuf{\"u}hren und hierdurch informaler Kommuni-kation Anschlussf{\"a}higkeit zu verleihen. Letztlich wird f{\"u}r die Organisation so genau das kommunikativ anschlussf{\"a}hig, was formal eigentlich immer ausgeschlossen wurde - die Person des Mitarbeiters.}, subject = {F{\"u}hrung}, language = {de} }