VAAM-Jahrestagung 2011 Karlsruhe, 3.–6. April 2011

MCPA in casts. The collective data indicate that Alphaproteobacteria aremajor MCPA degraders in soil and drilosphere.EMP070Microbial community adaptation and plasmid spreadingin near-natural remediation systems (CoTra) withBTEX-contaminated groundwaterT. Berthold* 1 , A. Chatzinotas 1 , I. Fetzer 1 , H. Harms 1 , B. Kiesel 1Department of Environmental Microbiology, Leipzig Helmholtz Center forEnvironmental Research (UFZ), Leipzig, GermanyAromatic contaminants like benzene, toluene, ethylbenzene and xylene(BTEX) are persistent under anoxic conditions. The transfer of contaminatedgroundwater from anaerobic into aerobic environments is thus a promisingstrategy to enhance bacterial degradation of such compounds. A pilot-scaleplant named Compartment Transfer (CoTra) with constructed wetlands(AP2, planted and unplanted) and aerobic trenches (AP5) was set up in 2007at a former refinery site near Leuna (Germany) to investigate efficient lowcostbioremediation strategies for BTEX contaminated groundwater. Thesystems were investigated after 1 and 3 years of operation, with the aim ofunderstanding (i) the changes of the catabolic gene pool within the microbialcommunities and (ii) the role of plasmids as carriers of genes involved inBTEX degradation.Significant changes in degradation but also in community compositiondetermined by T-RFLP analysis of 16S rRNA genes were found. Screeningof whole community DNA revealed that all sites were well equipped withupper and lower pathway genes for the degradation of aromatic compounds.However, degradation potential differed between the two time points, e.g.new degradation genes for dioxygenases (TODC1 & TODE) were foundafter 3 years while other genes became less abundant. Similar shifts wereobserved for the plasmid pool: initially plasmids carried BTEX-degradationgenes coding for subunits of the monooxygenases TBMD and TMOA and atoluene/biphenyl - dioxygenase (BEDe/BEDm). Later on these genes wereless abundant; instead a catechol-1,2-dioxygenase (C12O) gene could bedetected on plasmids. All sites (groundwater included) contained plasmidsof the IncP1 group, while the AP5 and the sediment community of theplanted AP2 were additionally equipped with IncP7-like plasmids.The results indicate that shifts within the microbial communities and/oruptake of catabolic genes resulted in an increased microbial ecosystemfunction. Plasmid mediated horizontal gene transfer may thus have played asignificant role in these events. We concluded that the microbialcommunities, whilst relying on plasmid-borne degradation genes in the earlyestablishment phase of the treatment sites, now have adapted to a pointwhere they no longer depend on degradation genes located on plasmids.EMP071Parasitic growth of Pseudomonas aeruginosa in coculturewith the chitinolytic bacterium AeromonashydrophilaN. Jagmann*, B. PhilippDepartment of Biologie, Group Microbial Ecology, University Konstanz,Konstanz, GermanyPolymer-degrading bacteria face exploitation by opportunistic bacteria thatgrow with the degradation products without investing energy into productionof extracellular hydrolytic enzymes. This scenario was investigated with aco-culture of the chitinolytic bacterium Aeromonas hydrophila strain AH-1N and Pseudomonas aeruginosa strain PAO1 as opportunist with chitin assole source of carbon, nitrogen, and energy.Co-cultures of both strains had a biphasic course. In the first phase, strainPAO1 grew along with strain AH-1N without affecting it. The second phasewas initiated by a rapid inactivation of and a massive acetate release bystrain AH-1N. Both processes coincided and were dependent on quorumsensing-regulated production of secondary metabolites by strain PAO1.Among these the redox-active phenazine compound pyocyanin caused therelease of acetate by strain AH-1N by blocking the citric acid cycle throughinhibition of aconitase. Thus, strain AH-1N was forced into an incompleteoxidation of chitin with acetate as end product, which supported substantialgrowth of strain PAO1 in the second phase of the co-culture [1].To identify the molecular mechanisms underlying this parasitic growthstrategy of strain PAO1 transposon mutagenesis was carried out, andmutants were screened for an altered phenotype in co-culture with strainAH-1N. From six mutants obtained three showed only slight growth and didnot inactivate strain AH-1N. These mutants had a defect in biosynthesis ofarginine, methionine, and histidine, respectively, indicating that prototrophyis important for growth of strain PAO1 in the co-culture. Three mutantsshowed strongly delayed inactivation of strain AH-1N and were altered inproduction of quorum sensing-regulated secondary metabolites. In onemutant the gene encoding Lon-protease was inactivated, and in two mutantsgenes with unknown functions were inactivated. We are currentlyinvestigating the function of these genes.[1] Jagmann et al (2010): Env Microbiol, 12:1787-802.EMP072Structure and function of the symbiosis partners of thelung lichen (Lobaria pulmonaria L. Hoffm.) analyzed bymetaproteomicsT. Schneider 1 , J. Cardinale 2 , M. Cardinale 3 , M. Kucklick* 4 , L. Eberl 1 ,M. Grube 5 , G. Berg 3 , K. Riedel 41 Institute of Plant Biology, University of Zurich, Zurich, Austria2 Helmholtz Center of Infection Research, Braunschweig, Germany3 Institute of Environmental Biotechnology, University of Technology, Graz,Austria4 Institute of Microbiology, University of Technology, Braunschweig,Germany5 Institute of Plant Sciences, Karl-Franzens-University, Graz, AustriaEnvironmental proteomics, also referred to as metaproteomics, is anemerging technology to study the structure and function of microbialcommunities. Here we applied semi-quantitative label-free proteomics usingone-dimensional gel electrophoresis combined with liquid chromatographycoupled to tandem mass spectrometry (LC-MS/MS) and normalized spectralcounting together with fluorescence in situ hybridization and confocal laserscanning microscopy (FISH-CLSM) to characterize the metaproteome of thelung lichen symbiosis Lobaria pulmonaria. In addition to the myco- andphotobiont, L. pulmonaria harbors proteins from a highly diverseprokaryotic community, which is dominated by Proteobacteria andincluding also Archaea. While fungal proteins are most dominant (75.4% ofall assigned spectra), about the same amount of spectra were assigned toprokaryotic proteins (10%) and to the green algal photobiont (9%). Whilethe latter proteins were found to be mainly associated with energy andcarbohydrate metabolism, a major proportion of fungal and bacterialproteins appeared to be involved in posttranslational modifications andprotein turnover and other diverse functions.EMP073Pyruvate uptake of the CO 2 -fixing, sulphide-oxidizingand nitrate-reducing „Sulfurimonas” sp. GD1S. Glaubitz* 1 , W.-R. Abraham 2 , G. Jost 1 , M. Labrenz 1 , K. Jürgens 11 Department ofBiological Oceanography, Leibniz Institute for Baltic SeaResearch, Rostock-Warnemünde, Germany2 Department of Chemical Microbiology, Helmholtz Center for InfectionResearch, Braunschweig, GermanyChemolithoautotrophy, mainly driven by Proteobacteria, plays a major rolein pelagic redoxclines of the central Baltic Sea. Interestingly, representativechemolithoautotrophic organisms are widely distributed over a relativelybroad depth interval where physico-chemical features change from oxic tosulfidic conditions. Because nitrate-reducing or aerobic respiratory processesas major energy source can be excluded in sulfidic depths, alternative carbonand energy pathways in the metabolism of chemolithoautotrophs have to betaken into consideration to explain high cell abundances in within theseareas.Our aim was to investigate a potential mixotrophic lifestyle of theepsilonproteobacterial strain GD1, which was isolated from a pelagicredoxcline of the central Baltic Sea, using pyruvate as a proxy for utilizationof organic substrates in vitro. Phylogenetically, GD1 is a member of thegenus Sulfurimonas and supposed to be a key player for autotrophicdenitrification in central Baltic Sea redoxclines. The experimental approachincluded radiocarbon measurements, mass spectrometric analyses ofbiomarkers and rRNA-based SIP analyses.In vitro, the uptake of radioactive pyruvate was present, with about 85% ofthe signal recovered in fractions usually containing lipids and proteins,whereas in nucleic-acid containing fractions the radioactivity could hardlybe detected. Mass spectrometric analyses of biomarkers of 13 C-labelled GD1cells revealed an absolute 13 C content of up to 30% in individual aminospektrum | Tagungsband 2011