VAAM-Jahrestagung 2012 18.–21. März in Tübingen

89HMP011Effects of antimicrobial peptides on methanogenic archaeaC. Bang* 1 , A. Schilhabel 1 , K. Weidenbach 1 , A. Kopp 2 , T. Goldmann 3 ,T. Gutsmann 2 , R. Schmitz-Streit 11 CAU Kiel, Institut für Allgemeine Mikrobiologie, Kiel, Germany2 Forschungszentrum Borstel, Division of Biophysics, Borstel, Germany3 Forschungszentrum Borstel, Division of Clinical and ExperimentalPathology, Borstel, GermanyMethanogenic archaea occur as members of the indigenous humanmicrobiota found on several mucosal tissues. Therefore they are exposedto antimicrobial peptides (AMPs) secreted by these epithelia. Although theantimicrobial and molecular effects of AMPs on bacteria are welldescribed, data for archaea are in general not available yet. As the archaealcell envelope differs profoundly in terms of chemical composition andstructure from that of bacteria it is not evident whether AMPs affect them.The effects of different natural and synthetic AMPs on the growth ofMethanobrevibacter smithii, Methanosphaera stadtmanae andMethanosarcina mazei strain Gö1 were tested with a microtiter plate assaythat had to be adapted to their anaerobic growth requirements and allowsmeasuring growth curves. Overall the tested methanogenic archaea werehighly sensitive against the used cathelicidins, lysins and one syntheticpeptide, however the sensitivities to the AMPs differed markedly amongthe different strains. Atomic force microscopy and transmission electronmicroscopy revealed that the structural integrity of the archaeal cells isdestroyed within 4 hours of incubation with AMPs. Using theLIVE/DEAD stain the disruption of the cell envelope of M. smithii, M.stadtmanae and M. mazei within a few minutes could be verified. Ourresults strongly suggest that the release of AMPs by eukaryotic cells is apotent defence mechanism not only against bacteria, but also againstmethanogenic archaea.HMP012Characterization of naturally occurring, industrial andmedical relevant biofilmsD. Langfeldt* 1 , N. Weiland 1 , N. Pinnow 1 , J. Eberhard 2 , R. Schmitz-Streit 11 CAU Kiel, Institut für Allgemeine Mikrobiologie, Kiel, Germany2 Medizinische Hochschule Hannover, Klinik für Zahnärztliche Prothetikund biomedizinische Werkstoffkunde, Hannover, GermanyBoth abiotic and biotic surfaces are subject to bacterial colonization andbiofilm formation. Biofilms formed on engineered surfaces or in medicalcontext can cause material degradation, fouling or infections. To provideinsights into various microbial biofilms, naturally occurring biofilms suchas microbial consortia on the widely distributed moon jellyfish Aureliaaurita, a glacial biofilm, industrial and medical relevant biofilms werecharacterized. Biofilm compositions were studied by 16S rDNAphylogenetic analysis revealing only a very limited number of bacterialspecies in case of the A. aurita consortia indicating specific interactions(attraction/defence) between the host and the microorganisms. The mainpart of the analyzed sequences from the glacial biofilm yielded homologiesto uncultured bacteria found in contaminated habitats that are potentiallyinvolved in bioremediation processes. Analysis of supragingival biofilmsfrom different persons showed in general high microbial diversity,however they differed in the frequency of paradontopathogenic bacteria.The frequencies of these pathogenic bacteria showed a strong correlationto the respective inflammatory reaction defined for the test persons. Theobtained results may allow understanding ecological systems, e.g. hostmicrobeinteractions, and provide insights into the prevention ofdetrimental biofilms in the medical sectors and industry.HMP013Impact of the intestinal microbiota on mucosal homeostasisI. Flade* 1 , K. Gronbach 1 , B. Stecher 2 , D. Huson 3 , H.-J. Ruscheweyh 3 ,I.B. Autenrieth 1 , J.-S. Frick 11 University of Tübingen, Med. Microbiology and Hygiene, Tübingen, Germany2 Max von Pettenkofer Institut, München, Germany3 University of Tübingen, Center for Bioinformatics, Tübingen, GermanyIn addition to genetic predisposition, environmental factors such ascommensal bacteria contribute to the development of inflammatory bowldisease (IBD).The gut of mammalians is colonised by a complex flora of microorganismscontaining 500-1000 different bacterial species. These bacterialpopulations contribute to the health of the host, among other things, bypromoting proper immune systeme development and limiting pathogencolonization. Bacteroides vulgatus mpk was shown to have the ability toprevent colitis, whereas E. coli mpk induces intestinal inflammation ininterleukin-2-deficient (IL-2 -/- ) mice. The mechanism however remainsunclear.In the current study we analyse the composition of the intestinalmicrobiota of T-cell transferred Rag1 -/- mice by 454-Seqeuncing of 16SrRNA encoding genes. With this method we want to reveal differencesbetween the gut microbiota of mice that develop colitis compared to micethat stay healthy and the composition of the intestinal microbiota beforeand during development of colitis.MEV001Mass spectrometric analysis of antibiotics from bacteriaM. Kai* 1 , O. Genilloud 2 , S. Singh 3 , A. Svatoš 11 Max-Planck Institute for Chemical Ecology, Mass Spectrometry, Jena,Germany2 Fundación Medina Centro de Excelencia en Investigación de MedicamentosInnovadores en Andalucía, Armilla/Granada, Spain3 Merck Research Laboratories, Rahway, United StatesThiazolyl peptids are naturally occurring antibiotics produced by severalactinobacteria. The sulfur-containing, highly modified, macrocyclicpeptides are some of the most potent in vitro growth inhibitors of Grampositivebacteria by inhibition of protein synthesis. Because ofcontinuously developing antibiotic-resistance of many bacteria there is stilla medical need to find new antibiotics. The natural function of antibioticsis still not sufficiently clarified, but antagonistic features are assumedwhich occur due to interaction with other organisms. The previousantibiotic screenings were often performed under laboratory conditionsand did not simulate environmental circumstances for antibioticproduction, e.g. co-cultivation with other species. A reinvestigation withthese modified conditions consumes time and money. To allow a fast,sensitive, and cost-effective screening of cultivable bacteria we arecurrently establishing a high throughput infusion mass spectrometrymethod in which liquid extraction surface analysis using TriversaNanomate technology is combined with the high mass accuracy andresolution available on LTQ-OrbitrapXL tandem mass spectrometer. Thescreening method was evaluated using different thiazolyl peptideproducing Streptomyces strains. The obtained data indicate that in additionto antibiotic discovery this technique can be a powerful tool for manyother microbiological approaches, e.g. surface studies of signal moleculesdirectly between different bacterial species or other microorganisms.MEV002Mining for new lantibiotic producer in microbial genomesequencesJ. Dischinger* 1 , M. Josten1 , A.-M. Herzner 1 , A. Yakéléba 1 ,M. Oedenkoven 1 , H.-G. Sahl 1 , J. Piel 2 , G. Bierbaum 11 University Bonn, Institute of Medical Microbiology, Bonn, Germany2 Universität Bonn, Kekulé-Institut für Organische Chemie und Biochemie,Bonn, GermanyThe discovery of antibiotics was one of the most important milestones inmedicine and in the fight against infectious disease. Today, more than 80%of anti-infective drugs are natural or semi-synthetic compounds. Rapidlydeveloping superbugs, i.e. pathogens that are resistant to almost allcommonly used antibiotics, have become an enormous problem. Thisnecessitates a further search for new antibiotic substances and sources. Tothis end, bacteria and their huge potential to produce antimicrobialsrepresent an inexhaustible resource.Lantibiotics (lanthionine containing antibiotics) are ribosomally producedbacterial peptide antibiotics that show interesting activities even in thenanomolar range against (multiresistant) human pathogens. Thecharacteristic thioether aa (methyl-)lanthionine is introduced by extensiveenzyme-mediated posttranslational modifications. These rare aa formintramolecular rings that are essential for the three-dimensional structureof lantibiotics, their enhanced stability against proteases and oxidation, aswell as antimicrobial activity. These features make lantibiotics interestingcandidates or lead structures for novel antimicrobial applications inmedical and food industry.Blast searches employing characteristic lantibiotic biosynthesis enzymes(LanM,B,C) in the NCBI database showed that ORFs coding for proteinsinvolved in lantibiotic production are widespread in bacteria of differentphyla. Based on these genomic data, we identified putative lantibiotic geneclusters in bacterial strains, for some of which production of lantibioticshad never been described before. The focus of our project is thehomologous and/or heterologous expression of those, so faruncharacterized, lantibiotics. In this context, we were able to identify andcharacterize the novel two-peptide lantibiotic lichenicidin that is producedby Bacillus licheniformis DSM 13. Additionally, a partial lantibiotic genecluster coding for proteins involved in producer self-protection against thewell-known lantibiotic mersacidin is present in Bacillus amyloliquefaciensFZB42. Transfer of the biosynthetic part of the mersacidin gene cluster toB. amyloliquefaciens FZB42 resulted in successful expression of fullymodified and active mersacidin in this strain. Other putative lantibioticproducers, including a Caldicellulosiruptor bescii strain, were identifiedand are still in the focus of the ongoing work in this project.BIOspektrum | Tagungsband 2012