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

235cell line-un-specific adherent and cell line-specific adherent. We definedVAGs (e.g.sfa/foc,malX) which presence was associated with higheradhesion to one specific cell line and thus host and/or tissue specificity.However, there were no differences in adhesion rates between pathogenicand commensal isolates.In conclusion, we show a broad variety of VAG and adhesion pattern inhuman and animal E. coli isolates. Adhesion is host- and cell type-specificenabling colonization of different microhabitats. There are confirmedadhesins but other hypothetical and yet unknown adhesins and their hostand tissue specificity have to be identified and characterized in futurestudies.SSP029A role for glutamine synthetase in regulation of prolinebiosynthesisS. Köcher, M. Thompson*, V. MüllerMolecular Microbiology & Bioenergetics, Institute for MolecularBiosciences, Goethe University, Frankfurt/Main, Germany, GermanyGlutamine and glutamate are the major compatible solutes in the moderatehalophile Halobacillus halophilus under moderate salinities and proline athigh salinities (1). One of the isogenes/-enzymes of glutamine synthetase(glnA2) was shown before to be the osmoregulated key player in salinitydependentglutamine and glutamate biosynthesis (2). Here, we havedeleted glnA2 from the chromosome of H. halophilus. Growth of themutant was not impaired, neither at low nor at high salt, and the mutant didnot have reduced levels of glutamine or glutamate, indicating a metabolicbypass for glutamine and gutamate production. Much to our surprise, themutant did no longer produce proline as compatible solute. The loss ofproline was compensated for by increased ectoine production. Consistentwith this is the observation that the transcript levels for ectA (and glnA1)were increased in the mutant.Our data demonstrate a regulatory role of glutamine synthetase 2 in prolinebiosynthesis. Possible regulatory scenarios are discussed.(1) Saum, S.H. & Müller, V., (2008) Regulation of osmoadaption in the moderate halophileHalobacillus halophilus: chloride, glutamate and switching osmolyte stategies. Saline Systems 4: 4(2) Saum, S.H., Sydow, S.F., Palm, P., Pfeiffer, F., Oesterhelt, D., and Müller, V., (2006)Biochemical and molecular characterization of the biosynthesis of glutamine and glutamate, twomajor compatible solutes in the moderately halophilic bacterium Halobacillus halophilus. J.Bacteriol. 188: 6808-6815SSP030The impact of a typical biofilm flora on the VBNC-state ofpathogens in drinking water biofilmsM. Kliefoth*, U. SzewzykTechnische Universität Berlin, FG Umweltmikrobiologie, Berlin, GermanyPathogens like Legionella pneumophilaand Pseudomonas aeruginosa areknown for their ability to persist in house installations and pose a risk ofinfections for humans. The standard approach for detection is still theheterotrophic plate count. But it is also common, that over 90 % of themicroorganisms in such oligothrophic environment are not growing onknown media.Only a few studies focus on the typical biofilm flora in drinking water,which is shown to be a mixture of mainly - , - and -subclasses ofProteobacteria. These bacteria can turn into a physiological state called“viable-but-not-culturable” (VBNC), in which no growth can be observedon plates. The bacteria show dwarfish cell forms and reduced metabolicactivity.In our investigations we study how these bacteria have an impact on theentrance or exit of P. aeruginosa in the VBNC-state. Therefore a biofilmreactor was developed to simulate a low nutrient environment and toinduce VBNC in P. aeruginosa as well as other selected bacteria, whichwere isolated in our group from native biofilms.Mono-species biofilms and multi-species biofilms with integratedpathogens are compared by using culture- (e.g. CFU) and cultureindependentmethods like Live/Dead staining, PAC (a direct- viable-countmethod), qPCR, FISH and CLSM. The aim of this project is to gaininsights in which manner P. aeruginosa can persist in drinking waterbiofilms and how native bacteria influences the resistance of P. aeruginosain water plumbing. Furthermore the reproducible induction of VBNC bylow nutrients (carbon, phosphate or trace elements) are being consideredand investigated.SSP031The CRISPR-Cas system of Haloferax volcaniiB. Stoll*, J. Brendel, A. MarchfelderUniversity of Ulm, Bio II, Ulm, GermanyThe recently discovered CRISPR-Cas system (CRISPR:clustered regularlyinterspaced short palindromic repeats, Cas: CRISPR-associated) is anadaptive and heritable resistance mechanism against foreign geneticelements. The CRISPR-Cas system consists of clusters of repetitivechromosomal DNA in which short palindromic DNA repeats are separatedby short spacers, the latter being sequences derived from the invader. Inaddition, a set of proteins, the Cas proteins, is involved. We areinvestigating the CRISPR-Cas system in the halophilic archaeon Haloferaxvolcanii. H. volcanii is an archaeal model organism which requires about2.1 M NaCl for optimal growth and raises the intracellular saltconcentration to similar values to cope with high salt concentration in themedium. The genome is sequenced and Haloferax is one of the fewarchaeal organisms where genetic systems are available.H. volcanii has three CRISPR loci, one located on the chromosome andtwo located on one of the chromosomal plasmids. Next to one of theCRISPR loci the Cas proteins are encoded in one long multicistronicoperon including genes for Cas1-8.We are analysing the expression and processing of the CRISPR RNA. Tothat end we generated a deletion strain for the cas6 gene and investigatedits effect on CRISPR RNA processing.SSP032Copper impacts the gold toxicity in Cupriavidus metalliduransN. Wiesemann* 1 , G. Hause 2 , J. Mohr 3 , F. Reith 4 , C. Große 1 , D.H. Nies 11 Martin-Luther-University, Moleculare Microbiology, Halle (Saale), Germany2 Biocenter of the Martin-Luther-University Halle-Wittenberg, Microscopy Unit,Halle (Saale), Germany3 Hannover Medical School, Hannover, Germany4 University of Adelaide, School of Earth and Environmental Sciences ,Adelaide, AustraliaCupriavidus metallidurans could be responsible for the formation ofbacteriogenic secondary gold nanoparticles 1,2 . We investigated if geneclusters that are up-regulated after treatment with gold complexes might beinvolved in this process. The megaplasmids of strain CH34, pMOL28 witha chromate and pMOL30 with an extensive copper resistance determinant,are not required for the formation of colloidal particles visible in TEM,which might be gold nanoparticles. A hypothesis that considered a goldtransformation process by the gig (gold induces genes) cluster productsreminiscent to mercury transformation by mer gene products could not beverified. Cells pre-incubated with non toxic concentrations of copperdisplayed increased copper resistance as expected, however, in some C.metallidurans strains, gold resistance decreased in parallel to increasingcopper resistance in the copper-treated cells. This demonstrated thathandling of gold ions by some - but not all - proteins involved in copperresistance led to enhanced toxicity of gold. Deletion of other genesinvolved in copper resistance led to a simultaneous decrease of copper andgold resistance but not in all strains. All these data demonstrated thatcopper resistance systems in C. metallidurans are involved intransformation of gold, however, not always to the advantage of the cells.The intriguing network of the copper and gold-handling factors in C.metallidurans is thus very complicated and needs a detailed in-depthanalysis.1 Reith, F., B. Etschmann, C. Grosse, H. Moors, M. A. Benotmane, P. Monsieurs, G. Grass, C. Doonan, S.Vogt, B. Lai, G. Martinez-Criado, G. N. George, D. H. Nies, M. Mergeay, A. Pring, G. Southam, and J.Brugger. 2009. Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans. ProcNatl Acad Sci U S A 106:17757-17762.2 Reith, F., S. L. Rogers, D. C. McPhail, and D. Webb. 2006. Biomineralization of gold: biofilms onbacterioform gold. Science 313:233-236.SSP033A combined transcriptomic and proteomic investigation into theosmoregulatory mechanisms of Halomonas elongata DSM 2581 TS. Faßbender 1 , B. Scheffer 2 , D. Oesterhelt 2 , F. Siedler 2 , H.J. Kunte* 11 Federal Institute for Materials Research and Testing (BAM), Materialsand Environment Division, Berlin, Germany2 Max Planck Institute of Biochemistry, Department of MembraneBiochemistry, Martinsried, GermanyThe halophilic -proteobacterium Halomonas elongata thrives at a widerange of salt concentrations by accumulating the compatible solute ectoine.Ectoine can be amassed in the cytoplasm either by synthesis or bytransport from the medium. To enable ectoine uptake, H. elongata isequipped with a specific transport system, named TeaABC. TeaABC is notonly required for the accumulation of ectoine, but also functions as asalvage system for ectoine leaking out of the cell. This observation led tothe hypothesis that TeaABC and potential efflux protein(s) might beinvolved in regulating the cytoplasmic ectoine concentration. In order toidentify membrane proteins involved in the efflux of compatible solutesand to gain more information about the changes in the protein compositionof halophiles in response to salt stress, we analyzed i) the transcriptomeand ii) the membrane-proteome of H. elongata. By applying a 15 N isotopemetabolic labeling strategy, a total of 135 membrane proteins wereidentified and quantified which are significantly up or down regulated inresponse to changes of the external salinity. In cells adapted to low saltmedium (100 mM NaCl) the level of 90 proteins has changed significantlycompared to cells adapted to the optimal salt concentration of 1 M NaCl.The content of only 45 proteins was changed when cells were adapted tohigh salt medium of 2 M NaCl compared to cells grown at 1 M NaCl. Themajority of the 135 regulated proteins are putative transport proteins. FourBIOspektrum | Tagungsband 2012