TY - JOUR A1 - Baumann, Otto T1 - Posterior midgut epithelial cells differ in their organization of the membrane skeleton from other Drosophila epithelia Y1 - 2001 ER - TY - JOUR A1 - Dubreuil, R. R. A1 - Grushko, T. A1 - Baumann, Otto T1 - Differential effects of a labial mutation on the development, structure, and function of stomach acid-secreting cells in Drosophila larvae and adults Y1 - 2001 ER - TY - JOUR A1 - Yasuhara, Jiro A1 - Baumann, Otto A1 - Takeyasu, Kunio T1 - Localization of Na/K-ATPase in developing and adult Drosophila melanogaster photoreceptors N2 - Drosophila melanogaster photoreceptors are highly polarized cells and their plasma membrane is organized into distinct domains. Zonula adherens junctions separate a smooth peripheral surface, the equivalent of the basolateral surface in other epithelial cells, from the central surface (cong apical surface). The latter consists of the microvillar rhabdomere and the juxtarhabdomeric domain, a nonmicrovillar area between the rhabdomere and the zonulae adherens. The distribution of Na/K-ATPase over these domains was examined by immunocytochemical, developmental, and genetic approaches. Immunofluorescence and immunogold labeling of adult compound eyes reveal that the distribution of Na/ K-ATPase is concentrated at the peripheral surface in the photoreceptors R1-R6, but extends over the juxtarhabdomeric domain to the rhabdomere in the photoreceptors R7/R8. Developmental analysis demonstrates further that Na/K-ATPase is localized over the entire plasma membrane in all photoreceptors in early pupal eyes. Redistribution of Na/K-ATPase in R1- R6 occurs at about 78% of pupal life, coinciding with the onset of Rh1-rhodopsin expression on the central surface of these cells. Despite the essential role of Rh1 in structural development and intracellular trafficking, Rh1 mutations do not affect the distribution of Na/K-ATPase. These results suggest that Na/K-ATPase and rhodopsin are involved in distinct intracellular localization mechanisms, which are maintained independent of each other. Y1 - 2000 UR - http://www.link.springer.de/link/service/journals/00441/bibs/030002/03000239.htm ER - TY - JOUR A1 - Baumann, Otto A1 - Arlt, Kathleen A1 - Römmling, Katja A1 - Goller, Helmut A1 - Walz, Bernd T1 - Characterization of an extremely motile cellular network in the rotifer Asplanchna spp. : structure, kinetics, and cytoskeleton Y1 - 2000 ER - TY - JOUR A1 - Baumann, Otto T1 - Distribution of ryanodine receptor Ca2+ channels in insect photoreceptor cells Y1 - 2000 ER - TY - JOUR A1 - Baumann, Otto A1 - Arlt, Kathleen A1 - Römmling, Katja A1 - Goller, Helmut A1 - Walz, Bernd T1 - Characterization of an extremely motile cellular network in the rotifer Asplanchna : Structure, kinetics and the cytoskeleton Y1 - 2000 ER - TY - JOUR A1 - Klose, Sascha Peter A1 - Rolke, Daniel A1 - Baumann, Otto T1 - Morphogenesis of honeybee hypopharyngeal gland during pupal development JF - Frontiers in zoology N2 - Background: The hypopharyngeal gland of worker bees contributes to the production of the royal jelly fed to queens and larvae. The gland consists of thousands of two-cell units that are composed of a secretory cell and a duct cell and that are arranged in sets of about 12 around a long collecting duct. Results: By fluorescent staining, we have examined the morphogenesis of the hypopharyngeal gland during pupal life, from a saccule lined by a pseudostratified epithelium to the elaborate organ of adult worker bees. The hypopharyngeal gland develops as follows. (1) Cell proliferation occurs during the first day of pupal life in the hypopharyngeal gland primordium. (2) Subsequently, the epithelium becomes organized into rosette-like units of three cells. Two of these will become the secretory cell and the duct cell of the adult secretory units; the third cell contributes only temporarily to the development of the secretory units and is eliminated by apoptosis in the second half of pupal life. (3) The three-cell units of flask-shaped cells undergo complex changes in cell morphology. Thus, by mid-pupal stage, the gland is structurally similar to the adult hypopharyngeal gland. (4) Concomitantly, the prospective secretory cell attains its characteristic subcellular organization by the invagination of a small patch of apical membrane domain, its extension to a tube of about 100 mu m in length (termed a canaliculus), and the expansion of the tube to a diameter of about 3 mu m. (6) Finally, the canaliculus-associated F-actin system becomes reorganized into rings of bundled actin filaments that are positioned at regular distances along the membrane tube. Conclusions: The morphogenesis of the secretory units in the hypopharyngeal gland of the worker bee seems to be based on a developmental program that is conserved, with slight modification, among insects for the production of dermal glands. Elaboration of the secretory cell as a unicellular seamless epithelial tube occurs by invagination of the apical membrane, its extension likely by targeted exocytosis and its expansion, and finally the reorganisation of the membrane-associated F-actin system. Our work is fundamental for future studies of environmental effects on hypopharyngeal gland morphology and development. KW - Exocrine gland KW - Insect KW - Epithelial tube KW - Organogenesis KW - Cell polarity KW - Actin cytoskeleton KW - Apoptosis KW - Invagination Y1 - 2017 U6 - https://doi.org/10.1186/s12983-017-0207-z SN - 1742-9994 VL - 14 SP - 2866 EP - 2875 PB - BioMed Central CY - London ER - TY - JOUR A1 - Krüger, Stefanie A1 - Schwarze, Michael A1 - Baumann, Otto A1 - Günter, Christina A1 - Bruns, Michael A1 - Kübel, Christian A1 - Szabo, Dorothee Vinga A1 - Meinusch, Rafael A1 - Bermudez, Veronica de Zea A1 - Taubert, Andreas T1 - Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting BT - combining renewable raw materials with clean fuels JF - Beilstein journal of nanotechnology N2 - The synthesis, structure, and photocatalytic water splitting performance of two new titania (TiO2)/gold(Au)/Bombyx mori silk hybrid materials are reported. All materials are monoliths with diameters of up to ca. 4.5 cm. The materials are macroscopically homogeneous and porous with surface areas between 170 and 210 m(2)/g. The diameter of the TiO2 nanoparticles (NPs) - mainly anatase with a minor fraction of brookite - and the Au NPs are on the order of 5 and 7-18 nm, respectively. Addition of poly(ethylene oxide) to the reaction mixture enables pore size tuning, thus providing access to different materials with different photocatalytic activities. Water splitting experiments using a sunlight simulator and a Xe lamp show that the new hybrid materials are effective water splitting catalysts and produce up to 30 mmol of hydrogen per 24 h. Overall the article demonstrates that the combination of a renewable and robust scaffold such as B. mori silk with a photoactive material provides a promising approach to new monolithic photocatalysts that can easily be recycled and show great potential for application in lightweight devices for green fuel production. KW - Bombyx mori silk KW - gold KW - photocatalytic water splitting KW - titania Y1 - 2018 U6 - https://doi.org/10.3762/bjnano.9.21 SN - 2190-4286 VL - 9 SP - 187 EP - 204 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, Main ER - TY - GEN A1 - Krüger, Stefanie A1 - Schwarze, Michael A1 - Baumann, Otto A1 - Günter, Christina A1 - Bruns, Michael A1 - Kübel, Christian A1 - Szabó, Dorothée Vinga A1 - Meinusch, Rafael A1 - de Zea Bermudez, Verónica A1 - Taubert, Andreas T1 - Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting BT - combining renewable raw materials with clean fuels T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - The synthesis, structure, and photocatalytic water splitting performance of two new titania (TiO 2 )/gold(Au)/Bombyx mori silk hybrid materials are reported. All materials are monoliths with diameters of up to ca. 4.5 cm. The materials are macroscopically homogeneous and porous with surface areas between 170 and 210 m 2/g. The diameter of the TiO 2 nanoparticles (NPs) – mainly anatase with a minor fraction of brookite – and the Au NPs are on the order of 5 and 7–18 nm, respectively. Addition of poly(ethylene oxide) to the reaction mixture enables pore size tuning, thus providing access to different materials with different photocatalytic activities. Water splitting experiments using a sunlight simulator and a Xe lamp show that the new hybrid materials are effective water splitting catalysts and produce up to 30 mmol of hydrogen per 24 h. Overall the article demonstrates that the combination of a renewable and robust scaffold such as B. mori silk with a photoactive material provides a promising approach to new monolithic photocatalysts that can easily be recycled and show great potential for application in lightweight devices for green fuel production. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 581 KW - Bombyx mori silk KW - gold KW - photocatalytic water splitting KW - titania Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-423499 SN - 1866-8372 IS - 581 ER - TY - JOUR A1 - Stuckas, Heiko A1 - Messerschmidt, Katrin A1 - Putzler, Sascha A1 - Baumann, Otto A1 - Schenk, Jörg A. A1 - Tiedemann, Ralph A1 - Micheel, Burkhard T1 - Detection and characterization of gamete-specific molecules in Mytilus edulis using selective antibody production N2 - The mussel Mytilus edulis can be used as model to study the molecular basis of reproductive isolation because this species maintains its species integrity, despite of hybridizing in zones of contact with the closely related species M. trossulus or M. galloprovincialis. This study uses selective antibody production by means of hybridoma technology to identify molecules which are involved in sperm function of M. edulis. Fragmented sperm were injected into mice and 25 hybridoma cell clones were established to obtain monoclonal antibodies (mAb). Five clones were identified producing mAb targeting molecules putatively involved in sperm function based on enzyme immunoassays, dot and Western blotting as well as immunostaining of tissue sections. Specific localization of these mAb targets on sperm and partly also in somatic tissue suggests that all five antibodies bind to different molecules. The targets of the mAb obtained from clone G26-AG8 were identified using mass spectrometry (nano-LC-ESI-MS/MS) as M6 and M7 lysin. These acrosomal proteins have egg vitelline lyses function and are highly similar (76%) which explains the cross reactivity of mAb G26- AG8. Furthermore, M7 lysin was recently shown to be under strong positive selection suggesting a role in interspecific reproductive isolation. This study shows that M6 and M7 lysin are not only found in the sperm acrosome but also in male somatic tissue of the mantle and the posterior adductor muscle, while being completely absent in females. The monoclonal antibody G26-AG8 described here will allow elucidating M7/M6 lysin function in somatic and gonad tissue of adult and developing animals. Y1 - 2009 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/37692 U6 - https://doi.org/10.1002/Mrd.20916 SN - 1040-452X ER - TY - JOUR A1 - Pitzen, Valentin A1 - Sander, Sophia A1 - Baumann, Otto A1 - Gräf, Ralph A1 - Meyer, Irene T1 - Cep192, a novel missing link between the centrosomal core and corona in Dictyostelium amoebae JF - Cells : open access journal N2 - The Dictyostelium centrosome is a nucleus-associated body with a diameter of approx. 500 nm. It contains no centrioles but consists of a cylindrical layered core structure surrounded by a microtubule-nucleating corona. At the onset of mitosis, the corona disassembles and the core structure duplicates through growth, splitting, and reorganization of the outer core layers. During the last decades our research group has characterized the majority of the 42 known centrosomal proteins. In this work we focus on the conserved, previously uncharacterized Cep192 protein. We use superresolution expansion microscopy (ExM) to show that Cep192 is a component of the outer core layers. Furthermore, ExM with centrosomal marker proteins nicely mirrored all ultrastructurally known centrosomal substructures. Furthermore, we improved the proximity-dependent biotin identification assay (BioID) by adapting the biotinylase BioID2 for expression in Dictyostelium and applying a knock-in strategy for the expression of BioID2-tagged centrosomal fusion proteins. Thus, we were able to identify various centrosomal Cep192 interaction partners, including CDK5RAP2, which was previously allocated to the inner corona structure, and several core components. Studies employing overexpression of GFP-Cep192 as well as depletion of endogenous Cep192 revealed that Cep192 is a key protein for the recruitment of corona components during centrosome biogenesis and is required to maintain a stable corona structure. KW - Cep192 KW - SPD-2 KW - centrosome KW - Dictyostelium KW - microtubule-organization KW - MTOC Y1 - 2021 U6 - https://doi.org/10.3390/cells10092384 SN - 2073-4409 VL - 10 IS - 9 PB - MDPI CY - Basel ER -