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

158compared to 20 ºC. An increase of the pH-value from 3.5 to 3.7 led tohigher formation of biogenic amines of at most 100%. In addition, thetested strains produced a maximum of 170 mg/l of the health-relevanttyramine, when amino acids including tyrosine were added.OTP093Impacts of climate-sensitive environmental factors on fecalbacterial loads in the river LahnI. Herrig*, S. Böer, W. ManzInstitute for Integrated Natural Sciences, Department of Biology, Koblenz,GermanyFecal pollution of rivers bears a public health risk and is diminishing thequality of ecological services provided by these important ecosystems [1].Therefore the aim of this study is the evaluation of potential impacts ofclimate change on the microbial water quality of rivers on an experimentalbasis.To get a deeper understanding of the hygienic state of a subset river andhow it is influenced by climatic relevant factors, a 12 months-monitoringis ongoing.During this monitoring, water samples are taken weekly at five differentsites of the river Lahn.Relative abundances of fecal indicator organisms comprising E. coli,somatic coliphages and intestinal Enterococci are determined. Presence ofenterohaemorrhagic E. coli (EHEC) is tracked by means of a commercialPCR assay. In addition, the amount of settleable particles and physicalchemicalparameters such as temperature and pH are measured.Main focus of the analysis is to investigate the influence of climatesensitive factors such as water temperature, rainfall and water discharge onthe relative abundance and spatial distribution of fecal indicator bacteria.To assess the public health risk and for the development of managingstrategies it is important to identify sources of fecal pollution as well.Microbial source tracking by means of qPCR will be performed on thebasis of signature sequences specific for Bacteroidetes in order to discovercontamination pathways.Preliminary data show that the amount of particles and the relativeabundance of indicator organisms increase with river discharge.Accordingly, highest rates could be observed after rainfall events. On theother hand, declining water temperatures also seem to have a positiveimpact on coliphages.Ongoing mesocosm experiments will aim at answering the questionwhether the high counts after rainfalls can be traced back only to the inputfrom external sources or if they are at least partly caused by resuspensionfrom the sediment.In general, numbers of E. coli were higher than those of coliphages andEnterococci. In particular cases they exceed the EU directive for bathingwaters.In addition, results obtained with a commercial PCR assay indicate thepresence of E. coli O104.[1] Gerbersdorf S. U., Hollert H., Brinkmann M., Wieprecht S., Schüttrumpf H., and Manz W.(2011). Anthropogenic pollutants affect ecosystem services of freshwater sediments: the need for a“triad plus x” approach. Journal Soils Sediments doi 10.1007/s11368-011-0373-0.OTP094Active groundwater bacterial communities in karstic aquifersin the Hainich (Thuringia, Germany)A. Rusznyak* 1 , I. Schulze 1 , D.M. Akob 1 , M. Gaspar 2 , F. Warnecke 2 ,M. Herrmann 1 , P. Geesink 3 , K.-U. Totsche 3 , K. Küsel 11 Friedrich Schiller University Jena, Institute of Ecology, Limnology/AquaticGeomicrobiology, Jena, Germany2 Friedrich Schiller University Jena, Institute of Microbiology, MicrobialEcology Group, Jena, Germany3 Friedrich Schiller University Jena, Institute of Earth Sciences, Chair ofHydrogeology, Jena, GermanyGroundwater ecosystems harbour a great proportion of the Earth`sprokaryotic biomass, however, knowledge about microbial diversity inpristine groundwater is scarce. In these ecosystems, characterized by loworganic carbon content, lithoautotrophy might represent an importantmicrobial metabolic strategy. This study aimed to investigate the diversityof active groundwater bacteria by targeting gene transcripts for 16S rRNAand RuBisCO II large-subunit (cbbM) responsible for CO 2-fixation in theCalvin Cycle. Groundwater was collected in November 2010 and April2011 from different wells along a land-use gradient, ranging from forest toagricultural fields, following groundwater flow at the northeastern slope ofthe Hainich region (Thuringia). The groundwater had a pH between 7.2and 7.4, contained low organic carbon, had 30% oxygen saturation, andcontained up to 30 mg/l dissolved CO 2. Analysis of the active communitymembers by pyrosequencing revealed great spatial variability in thediversity of active groundwater bacteria as well as differences between theautumn and spring samples. In contrast, the composition of bacterialcommunities expressing the RuBisCO II gene showed only little variationbetween sampling sites and time points. More than half of the 16S rRNAsequences (51.4%) were affiliated with Proteobacteria (dominated by the- and -subgroups) and unclassified Bacteria were also detected in highnumbers (23.6%). RuBisCO II sequences were related to thegeneraThiobacillus andSulfuricella and tocbbM sequences of unculturedbacteria originating from hypersaline water and tar oil-contaminatedaquifers. We are currently working with multivariate statistics to correlatemicrobial observations with long-term physiochemical data sets to revealthe possible impact of land use on the groundwater bacterial communities.OTP095Will not be presented!OTP096Efficient marker recycling using the optimized FLP/FRTrecombination system in filamentous fungiK. Kopke* 1 , B. Hoff 2 , U. Kück 11 Ruhr-Universitaet Bochum, Christian Doppler Laboratory for “FungalBiotechnology”, Lehrstuhl fuer Allgemeine & Molekulare Botanik, Bochum,Germany2 BASF SE, Ludwigshafen, GermanyThe genetic manipulation of many filamentous fungi is limited by thenumber of functional resistance marker. For this reason we have developeda marker recycling for the penicillin producer Penicillium chrysogenumbased on the FLP/FRT recombination system from the yeastSaccharomyces cerevisiae. In a first approach the functionality of thesystem was tested. Therefore a nourseothricin resistance cassette flankedby FRT sequences in direct repeat orientation (FRTnat1 cassette) wasectopically integrated into a P. chrysogenum recipient strain. Thecorresponding transformants were used to complete the system bytransforming a codon-optimized Pcflp recombinase gene. Our analysis ofseveral transformants showed that successful recombination events wereachievable with the codon-optimized recombinase. To further extend theapplication of the FLP/FRT recombination system, we generated a markerfreePcku70FRT2 strain which enables the production of multipledeletion strains by highly efficient homologous recombination. Moreoverwe have established a one-step marker recycling. For this purpose theFLP/FRT system and the nat1 marker gene were combined in a so-callednat1-Flipper cassette. To regulate the recombinase gene expression theinducible xyl promoter was used. In future we intend to use differentFlipper cassettes together with the Pcku70FRT2 strain to constructmarker-free double and triple mutants.Furthermore the applicability of the developed marker recycling systemwas demonstrated in the ascomycetes Sordaria macrospora andAcremonium chrysogenum indicating, that the optimized FLP/FRTrecombination system will be suitable to fungi unrelated to the speciesinvestigated in this study.OTP097Methanogenic archaea from Siberian permafrost: unveilingbiosignatures using Raman spectroscopyP. Serrano* 1 , U. Boettger 2 , J.P. de Vera 2 , D. Wagner 11 Alfred Wegener Institute for Polar Research, Geomicrobiology ofPermafrost Regions, Potsdam, Germany2 Deutsches Zentrum für Luft- und Raumfahrt e.V., Institut fürPlanetenforschung, Berlin, GermanyThe Mars Express and Phoenix Missions have reported the presence ofpermafrost sediments as well as high levels of methane in certain areas ofthe northern hemisphere of the Red Planet. The fact that methane breaksup with UV-light and has a chemical lifetime of about 300 to 600 years inthe Martian atmosphere is of great interest because of its potentialbiological origin (although geochemical explanations may also be possiblebut have not been confirmed yet).Methanogenic archaea from Siberian permafrost have been recentlyisolated at the Alfred Wegener Institute (AWI) in Germany. They present achemolithotrophic, anaerobic methabolism and are methane producers. Inaddition, they have proven to be remarkably resistant against desiccation,osmotic stress, extremely low temperatures and starvation. Preliminarystudies show that these archaea are able to survive simulated thermophysicalMartian conditions as well as the presence of UV-C and ionizingradiation. These features support that the methanogenic archea fromSiberian permafrost are strong candidates for potential present/past life inthe Martian subsurface.The ExoMars Missions planned for 2016 and 2018 will include a Ramanspectroscope among the analytical instruments. Therefore, it is veryrelevant to get a deeper insight in the Raman signatures of the terrestrialmethanogenic archaea to better interpret the future data from Mars. As partof the “Biology and Mars Experiment” (BIOMEX) project, biosignaturesof methanogenic archaea from Siberian permafrost are being studied usinga novel approach of Raman spectroscopy, never used before to describebiosignatures. Using a Raman source of 533nm, interesting spectra wasobtained for different species of methanogenic archaea, showing commonpeaks to all the studied species (around 2900nm) and other peaks of moreBIOspektrum | Tagungsband 2012