@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 Furthermore we provide unpublished data underscoring the requirement of posttranslational CaaX-box processing for proper protein localization at the nuclear envelope.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}
}
@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}
}
@article{HeindorffBaumann2014,
  author    = {Heindorff, Kristoffer and Baumann, Otto},
  title     = {Calcineurin is part of a negative feedback loop in the InsP(3)/Ca2+ signalling pathway in blowfly salivary glands},
  series = {Cell calcium},
  volume    = {56},
  journal   = {Cell calcium},
  number    = {3},
  publisher = {Churchill Livingstone},
  address   = {Edinburgh},
  issn      = {0143-4160},
  doi       = {10.1016/j.ceca.2014.07.009},
  pages     = {215 -- 224},
  year      = {2014},
  abstract  = {The ubiquitous InsP(3)/Ca2+ signalling pathway is modulated by diverse mechanisms, i.e. feedback of Ca2+ and interactions with other signalling pathways. In the salivary glands of the blowfly Calliphora vicina, the hormone serotonin (5-HT) causes a parallel rise in intracellular [Ca2+] and [cAMP] via two types of 5-HT receptors. We have shown recently that cAMP/protein kinase A (PKA) sensitizes InsP(3)-induced Ca2+ release. We have now identified the protein phosphatase that counteracts the effect of PKA on 5-HT-induced InsP(3)/Ca2+ signalling. We demonstrate that (1) tautomycin and okadaic acid, inhibitors of protein phosphatases PP1 and PP2A, have no effect on 5-HT-induced Ca2+ signals; (2) cyclosporin A and FK506, inhibitors of Ca2+/calmodulin-activated protein phosphatase calcineurin, cause an increase in the frequency of 5-HT-induced Ca2+ oscillations; (3) the sensitizing effect of cyclosporin A on 5-HT-induced Ca2+ responses does not involve Ca2+ entry into the cells; (4) cyclosporin A increases InsP(3)-dependent Ca2+ release; (5) inhibition of PKA abolishes the effect of cyclosporin A on the 5-HT-induced Ca2+ responses, indicating that PKA and calcineurin act antagonistically on the InsP(3)/Ca2+ signalling pathway. These findings suggest that calcineurin provides a negative feedback on InsP(3)/Ca2+ signalling in blowfly salivary glands, counteracting the effect of PKA and desensitizing the signalling cascade at higher 5-HT concentrations. (C) 2014 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{DamesZimmermannSchmidtetal.2006,
  author    = {Dames, Petra and Zimmermann, Bernhard and Schmidt, Ruth and Rein, Julia and Voss, Martin and Schewe, Bettina and Walz, Bernd and Baumann, Otto},
  title     = {cAMP regulates plasma membrane vacuolar-type H+-ATPase assembly and activity in blowfly salivary glands},
  issn      = {0027-8424},
  doi       = {10.1073/pnas.0600011103},
  year      = {2006},
  abstract  = {Reversible assembly of the V0V1 holoenzyme from V-0 and V-1 subcomplexes is a widely used mechanism for regulation of vacuolar-type H+-ATPases (V-ATPases) in animal cells. in the blowfly (Calliphora vicina) salivary gland, V- ATPase is located in the apical membrane of the secretory cells and energizes the secretion of a KCl-rich saliva in response to the hormone serotonin. We have examined whether the CAMP pathway, known to be activated by serotonin, controls V-ATPase assembly and activity. Fluorescence measurements of pH changes at the luminal surface of isolated glands demonstrate that CAMP, Sp-adenosine-3',5'-cyclic monophosphorothioate, or forskolin, similar to serotonin, cause V-ATPase-dependent luminal acidification. In addition, V-ATPase-dependent ATP hydrolysis increases upon treatment with these agents. Immunofluorescence microscopy and pelleting assays have demonstrated further that V, components become translocated from the cytoplasm to the apical membrane and V-ATPase holoenzymes are assembled at the apical membrane during conditions that increase intracellular cAMP. Because these actions occur without a change in cytosolic Ca2+, our findings suggest that the cAMP pathway mediates the reversible assembly and activation of V-ATPase molecules at the apical membrane upon hormonal stimulus},
  language  = {en}
}
@article{PitzenSanderBaumannetal.2021,
  author    = {Pitzen, Valentin and Sander, Sophia and Baumann, Otto and Gr{\"a}f, Ralph and Meyer, Irene},
  title     = {Cep192, a novel missing link between the centrosomal core and corona in Dictyostelium amoebae},
  series = {Cells : open access journal},
  volume    = {10},
  journal   = {Cells : open access journal},
  number    = {9},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4409},
  doi       = {10.3390/cells10092384},
  pages     = {19},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{HeindorffBlenauWalzetal.2012,
  author    = {Heindorff, Kristoffer and Blenau, Wolfgang and Walz, Bernd and Baumann, Otto},
  title     = {Characterization of a Ca2+/calmodulin-dependent AC1 adenylyl cyclase in a non-neuronal tissue, the blowfly salivary gland},
  series = {Cell calcium},
  volume    = {52},
  journal   = {Cell calcium},
  number    = {2},
  publisher = {Churchill Livingstone},
  address   = {Edinburgh},
  issn      = {0143-4160},
  doi       = {10.1016/j.ceca.2012.04.016},
  pages     = {103 -- 112},
  year      = {2012},
  abstract  = {Crosstalk between intracellular signalling pathways is a functionally important and widespread phenomenon in cell physiology across phyla. In the salivary gland of the blowfly, serotonin induces fluid secretion via parallel activation of both the InsP(3)/Ca2+ and the cAMP/PKA signalling pathways, which interact on multiple levels. We have determined the molecular identity of a link between both pathways that mediates a Ca2+-dependent rise of intracellular cAMP. Whereas hydrolysis of cAMP via phosphodiesterases is largely independent of Ca2+, cAMP synthesis by adenylyl cyclases (AC) is potentiated in a Ca2+/calmodulin (Ca2+/CaM)-dependent manner. The existence of a Ca2+/CaM-dependent AC is supported by physiological data and a molecular approach. We have cloned Cv rutabaga cDNA, encoding the first blowfly AC, and confirmed its expression in the salivary gland via reverse transcription followed by polymerase chain reaction. The putative gene product of Cv rutabaga is a Ca2+/CaM-dependent type I AC and shows highest homology to Rutabaga from Drosophila. Thus, a Ca2+/CaM-dependent AC serves as a link between the InsP(3)/Ca2+ and the cAMP/PKA signalling pathways in the salivary gland of the blowfly and might be important for the amplification and optimization of the secretory response.},
  language  = {en}
}
@article{BaumannArltRoemmlingetal.2000,
  author    = {Baumann, Otto and Arlt, Kathleen and R{\"o}mmling, Katja and Goller, Helmut and Walz, Bernd},
  title     = {Characterization of an extremely motile cellular network in the rotifer Asplanchna : Structure, kinetics and the cytoskeleton},
  year      = {2000},
  language  = {en}
}
@article{BaumannArltRoemmlingetal.2000,
  author    = {Baumann, Otto and Arlt, Kathleen and R{\"o}mmling, Katja and Goller, Helmut and Walz, Bernd},
  title     = {Characterization of an extremely motile cellular network in the rotifer Asplanchna spp. : structure, kinetics, and cytoskeleton},
  year      = {2000},
  language  = {en}
}
@article{KruegerBatsiosBaumannetal.2012,
  author    = {Kr{\"u}ger, Anne and Batsios, Petros and Baumann, Otto and Luckert, Eva and Schwarz, Heinz and Stick, Reimer and Meyer, Irene and Gr{\"a}f, Ralph},
  title     = {Characterization of NE81, the first lamin-like nucleoskeleton protein in a unicellular organism},
  series = {Molecular biology of the cell : the official publication of the American Society for Cell Biology},
  volume    = {23},
  journal   = {Molecular biology of the cell : the official publication of the American Society for Cell Biology},
  number    = {2},
  publisher = {American Society for Cell Biology},
  address   = {Bethesda},
  issn      = {1059-1524},
  doi       = {10.1091/mbc.E11-07-0595},
  pages     = {360 -- 370},
  year      = {2012},
  abstract  = {Lamins build the nuclear lamina and are required for chromatin organization, gene expression, cell cycle progression, and mechanical stabilization. Despite these universal functions, lamins have so far been found only in metazoans. We have identified protein NE81 in Dictyostelium, which has properties that justify its denomination as a lamin-like protein in a lower eukaryote. This is based on its primary structure, subcellular localization, and regulation during mitosis, and its requirement of the C-terminal CaaX box as a posttranslational processing signal for proper localization. Our knockout and overexpression mutants revealed an important role for NE81 in nuclear integrity, chromatin organization, and mechanical stability of cells. All our results are in agreement with a role for NE81 in formation of a nuclear lamina. This function is corroborated by localization of Dictyostelium NE81 at the nuclear envelope in human cells. The discovery of a lamin-like protein in a unicellular organism is not only intriguing in light of evolution, it may also provide a simple experimental platform for studies of the molecular basis of laminopathies.},
  language  = {en}
}
@article{BlankenburgBalfanzHayashietal.2015,
  author    = {Blankenburg, Stefanie and Balfanz, Sabine and Hayashi, Y. and Shigenobu, S. and Miura, T. and Baumann, Otto and Baumann, Arnd and Blenau, Wolfgang},
  title     = {Cockroach GABA(B) receptor subtypes: Molecular characterization, pharmacological properties and tissue distribution},
  series = {Neuropharmacology},
  volume    = {88},
  journal   = {Neuropharmacology},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0028-3908},
  doi       = {10.1016/j.neuropharm.2014.08.022},
  pages     = {134 -- 144},
  year      = {2015},
  abstract  = {gamma-aminobutyric acid (GABA) is the predominant inhibitory neurotransmitter in the central nervous system (CNS). Its effects are mediated by either ionotropic GABA(A) receptors or metabotropic GABA(B) receptors. GABA(B) receptors regulate, via Gi/o, G-proteins, ion channels, and adenylyl cyclases. In humans, GABA(B) receptor subtypes are involved in the etiology of neurologic and psychiatric disorders. In arthropods, however, these members of the G-protein-coupled receptor family are only inadequately characterized. Interestingly, physiological data have revealed important functions of GABA(B) receptors in the American cockroach, Periplaneta americana. We have cloned cDNAs coding for putative GABA(B) receptor subtypes 1 and 2 of P. americana (PeaGB1 and PeaGB2). When both receptor proteins are co-expressed in mammalian cells, activation of the receptor heteromer with GABA leads to a dose-dependent decrease in cAMP production. The pharmacological profile differs from that of mammalian and Drosophila GABA(B) receptors. Western blot analyses with polyclonal antibodies have revealed the expression of PeaGB1 and PeaGB2 in the CNS of the American cockroach. In addition to the widespread distribution in the brain, PeaGB1 is expressed in salivary glands and male accessory glands. Notably, PeaGB1-like immunoreactivity has been detected in the GABAergic salivary neuron 2, suggesting that GABA(B) receptors act as autoreceptors in this neuron.},
  language  = {en}
}
@article{KuhnertBaumannMeyeretal.2012,
  author    = {Kuhnert, Oliver and Baumann, Otto and Meyer, Irene and Gr{\"a}f, Ralph},
  title     = {CP55, a novel key component of centrosomal organization in dictyostelium},
  series = {Cellular and molecular life sciences},
  volume    = {69},
  journal   = {Cellular and molecular life sciences},
  number    = {21},
  publisher = {Springer},
  address   = {Basel},
  issn      = {1420-682X},
  doi       = {10.1007/s00018-012-1040-3},
  pages     = {3651 -- 3664},
  year      = {2012},
  abstract  = {Dictyostelium centrosomes consist of a layered core structure surrounded by a microtubule-nucleating corona. At the G2/M transition, the corona dissociates and the core structure duplicates, yielding two spindle pole bodies. Finally, in telophase, the spindle poles mature into two new, complete centrosomes. CP55 was identified in a centrosomal proteome analysis. It is a component of the centrosomal core structure, and persists at the centrosome throughout the entire cell cycle. FRAP experiments revealed that during interphase the majority of centrosomal GFP-CP55 is immobile, which indicates a structural task of CP55 at the centrosome. The CP55null mutant is characterized by increased ploidy, a less structured, slightly enlarged corona, and by supernumerary, cytosolic MTOCs, containing only corona proteins and lacking a core structure. Live cell imaging showed that supernumerary MTOCs arise in telophase. Lack of CP55 also caused premature recruitment of the corona organizer CP148 to mitotic spindle poles, already in metaphase instead of telophase. Forces transmitted through astral microtubules may expel prematurely acquired or loosely attached corona fragments into the cytosol, where they act as independent MTOCs. CP55null cells were also impaired in growth, most probably due to difficulties in centrosome splitting during prophase. Furthermore, although they were still capable of phagocytosis, they appeared unable to utilize phagocytosed nutrients. This inability may be attributed to their partially disorganized Golgi apparatus.},
  language  = {en}
}
@article{StuckasMesserschmidtPutzleretal.2009,
  author    = {Stuckas, Heiko and Messerschmidt, Katrin and Putzler, Sascha and Baumann, Otto and Schenk, J{\"o}rg A. and Tiedemann, Ralph and Micheel, Burkhard},
  title     = {Detection and characterization of gamete-specific molecules in Mytilus edulis using selective antibody production},
  issn      = {1040-452X},
  doi       = {10.1002/Mrd.20916},
  year      = {2009},
  abstract  = {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.},
  language  = {en}
}
@article{BaumannBauer2013,
  author    = {Baumann, Otto and Bauer, Alexandra},
  title     = {Development of apical membrane organization and V-ATPase regulation in blowfly salivary glands},
  series = {The journal of experimental biology},
  volume    = {216},
  journal   = {The journal of experimental biology},
  number    = {7},
  publisher = {Company of Biologists Limited},
  address   = {Cambridge},
  issn      = {0022-0949},
  doi       = {10.1242/jeb.077420},
  pages     = {1225 -- 1234},
  year      = {2013},
  abstract  = {Secretory cells in blowfly salivary gland are specialized via morphological and physiological attributes in order to serve their main function, i.e. the transport of solutes at a high rate in response to a hormonal stimulus, namely serotonin (5-HT). This study examines the way that 5-HT-insensitive precursor cells differentiate into morphologically complex 5-HT-responsive secretory cells. By means of immunofluorescence microscopy, immunoblotting and measurements of the transepithelial potential changes, we show the following. (1) The apical membrane of the secretory cells becomes organized into an elaborate system of canaliculi and is folded into pleats during the last pupal day and the first day of adulthood. (2) The structural reorganization of the apical membrane is accompanied by an enrichment of actin filaments and phosphorylated ERM protein (phospho-moesin) at this membrane domain and by the deployment of the membrane-integral part of vacuolar-type H+-ATPase (V-ATPase). These findings suggest a role for phospho-moesin, a linker between actin filaments and membrane components, in apical membrane morphogenesis. (3) The assembly and activation of V-ATPase can be induced immediately after eclosion by way of 8-CPT-cAMP, a membrane-permeant cAMP analogue. (4) 5-HT, however, produces the assembly and activation of V-ATPase only in flies aged for at least 2 h after eclosion, indicating that, at eclosion, the 5-HT receptor/adenylyl cyclase/cAMP signalling pathway is inoperative upstream of cAMP. (5) 5-HT activates both the Ca2+ signalling pathway and the cAMP signalling cascade in fully differentiated secretory cells. However, the functionality of these signalling cascades does not seem to be established in a tightly coordinated manner during cell differentation.},
  language  = {en}
}