@phdthesis{Wagh2005, author = {Wagh, Dhananjay Anil}, title = {"Bruchpilot" -molecular and functional characterization of a novel active zone protein at the Drosophila synapse}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14989}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {Chemical neurotransmission is a complex process of central importance for nervous system function. It is thought to be mediated by the orchestration of hundreds of proteins for its successful execution. Several synaptic proteins have been shown to be relevant for neurotransmission and many of them are highly conserved during evolution- suggesting a universal mechanism for neurotransmission. This process has checkpoints at various places like, neurotransmitter uptake into the vesicles, relocation of the vesicles to the vicinity of calcium channels in order to facilitate Ca2+ induced release thereby modulating the fusion probability, formation of a fusion pore to release the neurotransmitter and finally reuptake of the vesicles by endocytosis. Each of these checkpoints has now become a special area of study and maintains its own importance for the understanding of the overall process. Ca2+ induced release occurs at specialized membrane structures at the synapse known as the active zones. These are highly ordered electron dense grids and are composed of several proteins which assist the synaptic vesicles in relocating in the vicinity of Ca2+ channels thereby increasing their fusion probability and then bringing about the vesicular fusion itself. All the protein modules needed for these processes are thought to be held in tight arrays at the active zones, and the functions of a few have been characterized so far at the vertebrate active zones. Our group is primarily interested in characterizing the molecular architecture of the Drosophila synapse. Due to its powerful genetics and well-established behavioural assays Drosophila is an excellent system to investigate neuronal functioning. Monoclonal antibodies (MABs) from a hybridoma library against Drosophila brain are routinely used to detect novel proteins in the brain in a reverse genetic approach. Upon identification of the protein its encoding genetic locus is characterized and a detailed investigation of its function is initiated. This approach has been particularly useful to detect synaptic proteins, which may go undetected in a forward genetic approach due to lack of an observable phenotype. Proteins like CSP, Synapsin and Sap47 have been identified and characterized using this approach so far. MAB nc82 has been one of the shortlisted antibodies from the same library and is widely used as a general neuropil marker due to the relative transparency of immunohistochemical whole mount staining obtained with this antibody. A careful observation of double stainings at the larval neuromuscular junctions with MAB nc82 and other pre and post-synaptic markers strongly suggested an active zone localization of the nc82 antigen. Synaptic architecture is well characterized in Drosophila at the ultrastructural level. However, molecular details for many synaptic components and especially for the active zone are almost entirely unknown. A possible localization at the active zone for the nc82 antigen served as the motivation to initiate its biochemical characterization and the identification of the encoding gene. In the present thesis it is shown by 2-D gel analysis and mass spectrometry that the nc82 antigen is a novel active zone protein encoded by a complex genetic locus on chromosome 2R. By RT-PCR exons from three open reading frames previously annotated as separate genes are demonstrated to give rise to a transcript of at least 5.5 kb. Northern blots produce a prominent signal of 11 kb and a weak signal of 2 kb. The protein encoded by the 5.5 kb transcript is highly conserved amongst insects and has at its N-terminus significant homology to the previously described vertebrate active zone protein ELKS/ERC/CAST. Bioinformatic analysis predicts coiled-coil domains spread all over the sequence and strongly suggest a function involved in organizing or maintaining the structure of the active zone. The large C-terminal region is highly conserved amongst the insects but has no clear homologues in veretebrates. For a functional analysis of this protein transgenic flies expressing RNAi constructs under the control of the Gal4 regulated enhancer UAS were kindly provided by the collaborating group of S.Sigrist (G\&\#1616;ttingen). A strong pan-neuronal knockdown of the nc82 antigen by transgenic RNAi expression leads to embryonic lethality. A relatively weaker RNAi expression results in behavioural deficits in adult flies including unstable flight and impaired walking behavior. Due to this peculiar phenotype as observed in the first knockdown studies the gene was named "bruchpilot" (brp) encoding the protein "Bruchpilot (BRP)" (German for crash pilot). A pan-neuronal as well as retina specific downregulation of this protein results in loss of ON and OFF transients in ERG recordings indicating dysfunctional synapses. Retina specific downregulation also shows severely impaired optomotor behaviour. Finally, at an ultrastructural level BRP downregulation seems to impair the formation of the characteristic T-shaped synaptic ribbons at the active zones without significantly altering the overall synaptic architecture (in collaboration with E.Asan). Vertebrate active zone protein Bassoon is known to be involved in attaching the synaptic ribbons to the active zones as an adapter between active zone proteins RIBEYE and ERC/CAST. A mutation in Bassoon results in a floating synaptic ribbon phenotype. No protein homologous to Bassoon has been observed in Drosophila. BRP downregulation also results in absence of attached synaptic ribbons at the active zones. This invites the speculation of an adapter like function for BRP in Drosophila. However, while Bassoon mutant mice are viable, BRP deficit in addition to the structural phenotype also results in severe behavioural and physiological anomalies and even stronger downregulation causes embryonic lethality. This therefore suggests an additional and even more important role for BRP in development and normal functioning of synapses in Drosophila and also in other insects. However, how BRP regulates synaptic transmission and which other proteins are involved in this BRP dependant pathway remains to be investigated. Such studies certainly will attract prominent attention in the future.}, subject = {Taufliege}, language = {en} } @article{PliegerWolf2022, author = {Plieger, Tanja and Wolf, Matthias}, title = {18S and ITS2 rDNA sequence-structure phylogeny of Prototheca (Chlorophyta, Trebouxiophyceae)}, series = {Biologia}, volume = {77}, journal = {Biologia}, number = {2}, issn = {1336-9563}, doi = {10.1007/s11756-021-00971-y}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-269897}, pages = {569-582}, year = {2022}, abstract = {Protothecosis is an infectious disease caused by organisms currently classified within the green algal genus Prototheca. The disease can manifest as cutaneous lesions, olecranon bursitis or disseminated or systemic infections in both immunocompetent and immunosuppressed patients. Concerning diagnostics, taxonomic validity is important. Prototheca, closely related to the Chlorella species complex, is known to be polyphyletic, branching with Auxenochlorella and Helicosporidium. The phylogeny of Prototheca was discussed and revisited several times in the last decade; new species have been described. Phylogenetic analyses were performed using ribosomal DNA (rDNA) and partial mitochondrial cytochrome b (cytb) sequence data. In this work we use Internal Transcribed Spacer 2 (ITS2) as well as 18S rDNA data. However, for the first time, we reconstruct phylogenetic relationships of Prototheca using primary sequence and RNA secondary structure information simultaneously, a concept shown to increase robustness and accuracy of phylogenetic tree estimation. Using encoded sequence-structure data, Neighbor-Joining, Maximum-Parsimony and Maximum-Likelihood methods yielded well-supported trees in agreement with other trees calculated on rDNA; but differ in several aspects from trees using cytb as a phylogenetic marker. ITS2 secondary structures of Prototheca sequences are in agreement with the well-known common core structure of eukaryotes but show unusual differences in their helix lengths. An elongation of the fourth helix of some species seems to have occurred independently in the course of evolution.}, language = {en} } @article{RackeveiKarnkowskaWolf2023, author = {Rackevei, Antonia S. and Karnkowska, Anna and Wolf, Matthias}, title = {18S rDNA sequence-structure phylogeny of the Euglenophyceae (Euglenozoa, Euglenida)}, series = {Journal of Eukaryotic Microbiology}, volume = {70}, journal = {Journal of Eukaryotic Microbiology}, number = {2}, doi = {10.1111/jeu.12959}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311896}, year = {2023}, abstract = {The phylogeny of Euglenophyceae (Euglenozoa, Euglenida) has been discussed for decades with new genera being described in the last few years. In this study, we reconstruct a phylogeny using 18S rDNA sequence and structural data simultaneously. Using homology modeling, individual secondary structures were predicted. Sequence-structure data are encoded and automatically aligned. Here, we present a sequence-structure neighbor-joining tree of more than 300 taxa classified as Euglenophyceae. Profile neighbor-joining was used to resolve the basal branching pattern. Neighbor-joining, maximum parsimony, and maximum likelihood analyses were performed using sequence-structure information for manually chosen subsets. All analyses supported the monophyly of Eutreptiella, Discoplastis, Lepocinclis, Strombomonas, Cryptoglena, Monomorphina, Euglenaria, and Colacium. Well-supported topologies were generally consistent with previous studies using a combined dataset of genetic markers. Our study supports the simultaneous use of sequence and structural data to reconstruct more accurate and robust trees. The average bootstrap value is significantly higher than the average bootstrap value obtained from sequence-only analyses, which is promising for resolving relationships between more closely related taxa.}, language = {en} } @article{BreyerGruenerKleinetal.2024, author = {Breyer, Maximilian and Gr{\"u}ner, Julia and Klein, Alexandra and Finke, Laura and Klug, Katharina and Sauer, Markus and {\"U}{\c{c}}eyler, Nurcan}, title = {\(In\) \(vitro\) characterization of cells derived from a patient with the GLA variant c.376A>G (p.S126G) highlights a non-pathogenic role in Fabry disease}, series = {Molecular Genetics and Metabolism Reports}, volume = {38}, journal = {Molecular Genetics and Metabolism Reports}, issn = {22144269}, doi = {10.1016/j.ymgmr.2023.101029}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350295}, year = {2024}, abstract = {Highlights • The GLA variant S126G is not associated with Fabry symptoms in the presented case • S126G has no effect on α-GAL A activity or Gb3 levels in this patient • S126G sensory neurons show no electrophysiological abnormalities Abstract Fabry disease (FD) is a life-limiting disorder characterized by intracellular globotriaosylceramide (Gb3) accumulations. The underlying α-galactosidase A (α-GAL A) deficiency is caused by variants in the gene GLA. Variants of unknown significance (VUS) are frequently found in GLA and challenge clinical management. Here, we investigated a 49-year old man with cryptogenic lacunar cerebral stroke and the chance finding of the VUS S126G, who was sent to our center for diagnosis and initiation of a costly and life-long FD-specific treatment. We combined clinical examination with in vitro investigations of dermal fibroblasts (HDF), induced pluripotent stem cells (iPSC), and iPSC-derived sensory neurons. We analyzed α-GAL A activity in iPSC, Gb3 accumulation in all three cell types, and action potential firing in sensory neurons. Neurological examination and small nerve fiber assessment was normal except for reduced distal skin innervation. S126G iPSC showed normal α-GAL A activity compared to controls and no Gb3 deposits were found in all three cell types. Baseline electrophysiological characteristics of S126G neurons showed no difference compared to healthy controls as investigated by patch-clamp recordings. We pioneer multi-level cellular characterization of the VUS S126G using three cell types derived from a patient and provide further evidence for the benign nature of S126G in GLA, which is of great importance in the management of such cases in clinical practice.}, language = {en} } @article{GilmoreCruzRodzLeimeisterWaechteretal.1989, author = {Gilmore, Michael S. and Cruz-Rodz, Armando L. and Leimeister-W{\"a}chter, Michaela and Kreft, J{\"u}rgen and Goebel, Werner}, title = {A Bacillus cereus cytolytic determinant, cereolysin AB, which comprises the phospholipase C and sphingomyelinase genes: nucleotide sequence and genetic linkage}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60588}, year = {1989}, abstract = {A cloned cytolytic determinant from the genome of Bacillus cereus GP-4 has been characterized at the molecular Ievel. Nucleotide sequence determination revealed the presence of two open reading frames. 8oth open reading frames were found by deletion and complementation analysis to be necessary for expression of the hemolytic phenotype by Bacillus subtilis and Escherichia coli hosts. The 5' open reading frame was found to be nearly identical to a recently reported phospholipase C gene derived from a mutant B. cereus strain which overexpresses the respective protein, and it conferred a lecithinase-positive phenotype to the B. subtilis host. The 3' open reading frame encoded a sphingomyelinase. The two tandemly encoded activities, phospholipase C and sphingomyelinase, constitute a biologically functional cytolytic determinant of B. cereus termed cereolysin AB.}, subject = {Biologie}, language = {en} } @article{DuettingGaitsIacovoniStegneretal.2017, author = {D{\"u}tting, Sebastian and Gaits-Iacovoni, Frederique and Stegner, David and Popp, Michael and Antkowiak, Adrien and van Eeuwijk, Judith M.M. and Nurden, Paquita and Stritt, Simon and Heib, Tobias and Aurbach, Katja and Angay, Oguzhan and Cherpokova, Deya and Heinz, Niels and Baig, Ayesha A. and Gorelashvili, Maximilian G. and Gerner, Frank and Heinze, Katrin G. and Ware, Jerry and Krohne, Georg and Ruggeri, Zaverio M. and Nurden, Alan T. and Schulze, Harald and Modlich, Ute and Pleines, Irina and Brakebusch, Cord and Nieswandt, Bernhard}, title = {A Cdc42/RhoA regulatory circuit downstream of glycoprotein Ib guides transendothelial platelet biogenesis}, series = {Nature Communications}, volume = {8}, journal = {Nature Communications}, number = {15838}, doi = {10.1038/ncomms15838}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170797}, year = {2017}, abstract = {Blood platelets are produced by large bone marrow (BM) precursor cells, megakaryocytes (MKs), which extend cytoplasmic protrusions (proplatelets) into BM sinusoids. The molecular cues that control MK polarization towards sinusoids and limit transendothelial crossing to proplatelets remain unknown. Here, we show that the small GTPases Cdc42 and RhoA act as a regulatory circuit downstream of the MK-specific mechanoreceptor GPIb to coordinate polarized transendothelial platelet biogenesis. Functional deficiency of either GPIb or Cdc42 impairs transendothelial proplatelet formation. In the absence of RhoA, increased Cdc42 activity and MK hyperpolarization triggers GPIb-dependent transmigration of entire MKs into BM sinusoids. These findings position Cdc42 (go-signal) and RhoA (stop-signal) at the centre of a molecular checkpoint downstream of GPIb that controls transendothelial platelet biogenesis. Our results may open new avenues for the treatment of platelet production disorders and help to explain the thrombocytopenia in patients with Bernard-Soulier syndrome, a bleeding disorder caused by defects in GPIb-IX-V.}, language = {en} } @article{DrescherKleinSchmittetal.2019, author = {Drescher, Nora and Klein, Alexandra-Maria and Schmitt, Thomas and Leonhardt, Sara Diana}, title = {A clue on bee glue: New insight into the sources and factors driving resin intake in honeybees (Apis mellifera)}, series = {PLoS ONE}, volume = {14}, journal = {PLoS ONE}, number = {2}, doi = {10.1371/journal.pone.0210594}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200935}, pages = {e0210594}, year = {2019}, abstract = {Honeybees (Apis mellifera) are threatened by numerous pathogens and parasites. To prevent infections they apply cooperative behavioral defenses, such as allo-grooming and hygiene, or they use antimicrobial plant resin. Resin is a chemically complex and highly variable mixture of many bioactive compounds. Bees collect the sticky material from different plant species and use it for nest construction and protection. Despite its importance for colony health, comparatively little is known about the precise origins and variability in resin spectra collected by honeybees. To identify the botanical resin sources of A. mellifera in Western Europe we chemically compared resin loads of individual foragers and tree resins. We further examined the resin intake of 25 colonies from five different apiaries to assess the effect of location on variation in the spectra of collected resin. Across all colonies and apiaries, seven distinct resin types were categorized according to their color and chemical composition. Matches between bee-collected resin and tree resin indicated that bees used poplar (Populus balsamifera, P. x canadensis), birch (Betula alba), horse chestnut (Aesculus hippocastanum) and coniferous trees (either Picea abies or Pinus sylvestris) as resin sources. Our data reveal that honeybees collect a comparatively broad and variable spectrum of resin sources, thus assuring protection against a variety of antagonists sensitive to different resins and/or compounds. We further unravel distinct preferences for specific resins and resin chemotypes, indicating that honeybees selectively search for bioactive resin compounds.}, language = {en} } @article{SchuhmannScheiner2023, author = {Schuhmann, Antonia and Scheiner, Ricarda}, title = {A combination of the frequent fungicides boscalid and dimoxystrobin with the neonicotinoid acetamiprid in field-realistic concentrations does not affect sucrose responsiveness and learning behavior of honeybees}, series = {Ecotoxicology and Environmental Safety}, volume = {256}, journal = {Ecotoxicology and Environmental Safety}, doi = {10.1016/j.ecoenv.2023.114850}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350047}, year = {2023}, abstract = {The increasing loss of pollinators over the last decades has become more and more evident. Intensive use of plant protection products is one key factor contributing to this decline. Especially the mixture of different plant protection products can pose an increased risk for pollinators as synergistic effects may occur. In this study we investigated the effect of the fungicide Cantus® Gold (boscalid/dimoxystrobin), the neonicotinoid insecticide Mospilan® (acetamiprid) and their mixture on honeybees. Since both plant protection products are frequently applied sequentially to the same plants (e.g. oilseed rape), their combination is a realistic scenario for honeybees. We investigated the mortality, the sucrose responsiveness and the differential olfactory learning performance of honeybees under controlled conditions in the laboratory to reduce environmental noise. Intact sucrose responsiveness and learning performance are of pivotal importance for the survival of individual honeybees as well as for the functioning of the entire colony. Treatment with two sublethal and field relevant concentrations of each plant protection product did not lead to any significant effects on these behaviors but affected the mortality rate. However, our study cannot exclude possible negative sublethal effects of these substances in higher concentrations. In addition, the honeybee seems to be quite robust when it comes to effects of plant protection products, while wild bees might be more sensitive. Highlights • Mix of SBI fungicides and neonicotinoids can lead to synergistic effects for bees. • Combination of non-SBI fungicide and neonicotinoid in field-realistic doses tested. • Synergistic effect on mortality of honeybees. • No effects on sucrose responsiveness and learning performance of honeybees. • Synergistic effects by other pesticide mixtures or on wild bees cannot be excluded.}, language = {en} } @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{NiewaldaVoellerEschbachetal.2011, author = {Niewalda, Thomas and V{\"o}ller, Thomas and Eschbach, Claire and Ehmer, Julia and Chou, Wen-Chuang and Timme, Marc and Fiala, Andr{\´e} and Gerber, Bertram}, title = {A Combined Perceptual, Physico-Chemical, and ImagingApproach to 'Odour-Distances' Suggests a CategorizingFunction of the Drosophila Antennal Lobe}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-74769}, 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 3-octanol 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.}, subject = {Drosophila Antennal Lobe}, language = {en} }