@article{BatsiosPeterBaumannetal.2012, author = {Batsios, Petros and Peter, Tatjana and Baumann, Otto and Stick, Reimer and Meyer, Irene and Gr{\"a}f, Ralph}, title = {A lamin in lower eukaryotes?}, series = {Nucleus}, volume = {3}, journal = {Nucleus}, number = {3}, publisher = {Landes Bioscience}, address = {Austin}, issn = {1949-1034}, doi = {10.4161/nucl.20149}, pages = {237 -- 243}, year = {2012}, abstract = {Lamins are the major components of the nuclear lamina and serve not only as a mechanical support, but are also involved in chromatin organization, epigenetic regulation, transcription and mitotic events. Despite these universal tasks, lamins have so far been found only in metazoans. Yet, recently we have identified Dictyostelium NE81 as the first lamin-like protein in a lower eukaryote. Based on the current knowledge, we draw a model for nuclear envelope organization in Dictyostelium in this Extra View and we review the experimental data that justified this classification. Furthermore we provide unpublished data underscoring the requirement of posttranslational CaaX-box processing for proper protein localization at the nuclear envelope. Sequence comparison of NE81 sequences from four Dictyostelia with bona fide lamins illustrates the evolutional relationship between these proteins. Under certain conditions these usually unicellular social amoebae congregate to form a multicellular body. We propose that the evolution of the lamin-like NE81 went along with the invention of multicellularity.}, language = {en} } @article{StuermerBaumannWalz1995, author = {St{\"u}rmer, Karoline and Baumann, Otto and Walz, Bernd}, title = {Actin-dependent light-induced translocation of mitochondria and ER cisternae in the photoreceptor cells of the locust schistocerca gregaria}, year = {1995}, language = {en} } @article{FechnerBaumannWalz2013, author = {Fechner, Lennart and Baumann, Otto and Walz, Bernd}, title = {Activation of the cyclic AMP pathway promotes serotonin-induced Ca2+ oscillations in salivary glands of the blowfly Calliphora vicina}, series = {Cell calcium}, volume = {53}, journal = {Cell calcium}, number = {2}, publisher = {Churchill Livingstone}, address = {Edinburgh}, issn = {0143-4160}, doi = {10.1016/j.ceca.2012.10.004}, pages = {94 -- 101}, year = {2013}, abstract = {Ca2+ and cAMP signalling pathways interact in a complex manner at multiple sites. This crosstalk fine-tunes the spatiotemporal patterns of Ca2+ and cAMP signals. In salivary glands of the blowfly Calliphora vicina fluid secretion is stimulated by serotonin (5-hydroxytryptamine, 5-HT) via activation of two different 5-HT receptors coupled to the InsP(3)/Ca2+ (Cv5-HT2 alpha) or the cAMP pathway (Cv5-HT7), respectively. We have shown recently in permeabilized gland cells that cAMP sensitizes InsP(3)-induced Ca2+ release to InsP(3). Here we study the effects of the CAMP signalling pathway on 5-HT-induced oscillations in transepithelial potential (TEP) and in intracellular [Ca2+]. We show: (1) Blocking the activation of the cAMP pathway by cinanserin suppresses the generation of TEP and Ca2+ oscillations, (2) application of 8-CPT-cAMP in the presence of cinanserin restores 5-HT-induced TEP and Ca2+ oscillations, (3) 8-CPT-cAMP sensitizes the InsP(3)/Ca2+ signalling pathway to 5-HT and the Cv5-HT2 alpha, receptor agonist 5-MeOT, (4) 8-CPT-cAMP induces Ca2+ oscillations in cells loaded with subthreshold concentrations of InsP(3), (5) inhibition of protein kinase A by H-89 abolishes 5-HT-induced TEP and Ca2+ spiking and mimics the effect of cinanserin. These results suggest that activation of the cyclic AMP pathway promotes the generation of 5-HT-induced Ca2+ oscillations in blowfly salivary glands.}, language = {en} } @article{SamereierBaumannMeyeretal.2011, author = {Samereier, Matthias and Baumann, Otto and Meyer, Irene and Gr{\"a}f, Ralph}, title = {Analysis of dictyostelium TACC reveals differential interactions with CP224 and unusual dynamics of dictyostelium microtubules}, series = {Cellular and molecular life sciences}, volume = {68}, journal = {Cellular and molecular life sciences}, number = {2}, publisher = {Springer}, address = {Basel}, issn = {1420-682X}, doi = {10.1007/s00018-010-0453-0}, pages = {275 -- 287}, year = {2011}, abstract = {We have localized TACC to the microtubule-nucleating centrosomal corona and to microtubule plus ends. Using RNAi we proved that Dictyostelium TACC promotes microtubule growth during interphase and mitosis. For the first time we show in vivo that both TACC and XMAP215 family proteins can be differentially localized to microtubule plus ends during interphase and mitosis and that TACC is mainly required for recruitment of an XMAP215-family protein to interphase microtubule plus ends but not for recruitment to centrosomes and kinetochores. Moreover, we have now a marker to study dynamics and behavior of microtubule plus ends in living Dictyostelium cells. In a combination of live cell imaging of microtubule plus ends and fluorescence recovery after photobleaching (FRAP) experiments of GFP-alpha-tubulin cells we show that Dictyostelium microtubules are dynamic only in the cell periphery, while they remain stable at the centrosome, which also appears to harbor a dynamic pool of tubulin dimers.}, language = {en} } @article{Baumann1998, author = {Baumann, Otto}, title = {Association of spectrin with a subcompartment of the endoplasmic reticulum in honeybee photoreceptor cells.}, year = {1998}, language = {en} } @article{Baumann1997, author = {Baumann, Otto}, title = {Biogenesis of surface domains in fly photoreceptor cells: Fine-structural analysis of the plasma membrane and immunolocalization of Na+, K+-ATPase und alpha-spectrin during cell differentiation.}, year = {1997}, language = {en} } @article{KruegerSchwarzeBaumannetal.2018, author = {Kr{\"u}ger, Stefanie and Schwarze, Michael and Baumann, Otto and G{\"u}nter, Christina and Bruns, Michael and K{\"u}bel, Christian and Szabo, Dorothee Vinga and Meinusch, Rafael and Bermudez, Veronica de Zea and Taubert, Andreas}, title = {Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting}, series = {Beilstein journal of nanotechnology}, volume = {9}, journal = {Beilstein journal of nanotechnology}, publisher = {Beilstein-Institut zur F{\"o}rderung der Chemischen Wissenschaften}, address = {Frankfurt, Main}, issn = {2190-4286}, doi = {10.3762/bjnano.9.21}, pages = {187 -- 204}, year = {2018}, abstract = {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.}, language = {en} } @misc{KruegerSchwarzeBaumannetal.2018, author = {Kr{\"u}ger, Stefanie and Schwarze, Michael and Baumann, Otto and G{\"u}nter, Christina and Bruns, Michael and K{\"u}bel, Christian and Szab{\´o}, Doroth{\´e}e Vinga and Meinusch, Rafael and de Zea Bermudez, Ver{\´o}nica and Taubert, Andreas}, title = {Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {581}, issn = {1866-8372}, doi = {10.25932/publishup-42349}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-423499}, pages = {18}, year = {2018}, abstract = {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.}, language = {en} } @article{WalzBaumannZimmermannetal.1995, author = {Walz, Bernd and Baumann, Otto and Zimmermann, Bernhard and Ciriacy-Wantrup, E.v.}, title = {Caffeine- and ryanodine-sensitive Ca2+-induced Ca2+ release from the endo plasmatic reticulum in honeybee photoreceptors}, year = {1995}, language = {en} } @article{VossFechnerWalzetal.2010, author = {Voss, Martin and Fechner, Lennart and Walz, Bernd and Baumann, Otto}, title = {Calcineurin activity augments cAMP/PKA-dependent activation of V-ATPase in blowfly salivary glands}, issn = {0363-6143}, doi = {10.1152/ajpcell.00328.2009}, year = {2010}, abstract = {We have examined the role of the Ca2+-dependent protein phosphatase 2B (calcineurin) in the regulation of the vacuolar H+-ATPase (V-ATPase) in blowfly salivary glands. In response to the neurohormone serotonin [5-hydroxytryptamine (5-HT)] and under the mediation of the cAMP/PKA signaling pathway, the secretory cells assemble and activate V-ATPase molecules at the apical membrane. We demonstrate that the inhibition of calcineurin activity by cyclosporin A, by FK- 506, or by prevention of the elevation of Ca2+ diminishes the 5-HT-induced assembly and activation of V-ATPase. The effect of calcineurin on V-ATPase is mediated by the cAMP/PKA signaling pathway, with calcineurin acting upstream of PKA, because 1) cyclosporin A does not influence the 8-(4-chlorophenylthio) adenosine-3',5'-cyclic monophosphate (8-CPT-cAMP)-induced activation of V-ATPase, and 2) the 5-HT-induced rise in cAMP is highly reduced in the presence of cyclosporin A. Moreover, a Ca2+ rise evoked by the sarco(endo) plasmic reticulum Ca2+-ATPase (SERCA) inhibitor cyclopiazonic acid leads to an increase in intracellular cAMP concentration and a calcineurin-mediated PKA- dependent activation of V-ATPase. We propose that calcineurin activity mediates cross talk between the inositol 1,4,5- trisphosphate/Ca2+ and the cAMP/PKA signaling pathways, thereby augmenting the 5-HT-induced rise in cAMP and thus the cAMP/PKA-mediated activation of V-ATPase.}, language = {en} }