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

[2] Garcillan-Barcia, M. P. et al (2009): The diversity of conjugative relaxases and its application inplasmid classification. FEMS Microbiol Rev 33(3): 657-87.[3] Hamilton, H. L. et al (2005). Neisseria gonorrhoeae secretes chromosomal DNA via a novel typeIV secretion system. Mol Microbiol 55(6): 1704-21.[4] Salgado-Pabon, W. et al (2007): A novel relaxase homologue is involved in chromosomal DNAprocessing for type IV secretion in Neisseria gonorrhoeae. Mol Microbiol 66(4): 930-47.OTP014Interplay between zinc uptake and efflux systemsmediates zinc homeostasis in Cupriavidus metalliduransCH34M. Herzberg*, A. Kirsten, D.H. NiesMolecular Microbiology, Martin-Luther-University Halle-Wittenberg,Halle, GermanyCupriavidus metallidurans is adapted to high concentrations of transitionmetal cations. This bacterium harbors a variety of transition metal effluxsystems. Central to metal resistance is the CzcCBA transenvelope proteincomplex, which probably transports cations from the periplasm directly tothe outside. Overexpression of czcCBA led to zinc auxotrophy in mutantcells devoid of the zinc importer ZupT. Expression of zupT was studied byreporter gene fusions and compared to that of other secondary zinc uptakesystems. Production of ZupT and the other systems was regulated by zincavailability. Deletion of zupT but not of the other systems led to decreasedEDTA (ethylenediaminetetraacetate) resistance and decreased ability toacquire zinc in the presence of EDTA. Thus, prominent function of ZupT isto transport zinc from the periplasm to the cytoplasm under conditions oflow zinc availability, such as decreased periplasmic zinc concentrations dueto the action of the CzcCBA efflux complex. This provided another piece ofevidence in favor of outer membrane efflux (from the periplasm to theoutside) as main function of the CzcCBA complex.OTP015Assembling Next Generation reads and subsequentgenome analysis with BioNumericsL. Hauben* 1 , K. De Bruyne 1 , J. Dombrecht 1 , H. Pouseele 2 , L. Vauterin 11 Applied Maths nv, Sales & Support, Sint-Martens-Latem, Bosnia andHerzegovina2 Applied Maths nv, Development, Sint-Martens-Latem, BelgiumNext generation sequencing has considerably increased the data throughput.High performance bioinformatics systems are required to process the vastamounts of data generated.The computationally challenging problem of assembling up to millions ofreads is met by the Power Assembler, an assembly pipeline tool in theBioNumerics software, for managing high throughput sequence data. Thefeatures and possibilities of this tool will be illustrated using publiclyavailable sequence reads from bacterial genomes.A power assembly project is essentially a series of actions, which togetherconstitute a project pipeline. Besides a set of predefined actions for frequentmanipulations, there is also the possibility to construct user-defined actions.The project results can be overviewed in summarizing reports, andrepresented as sequence curves displaying e.g. coverage or sequence qualityinformation, summary graphs, or in an assembly view. There is aninformation flow path from the Power Assembler to the underlyingBioNumerics database, allowing further analyses of the resulting contigsequences.The Chromosome Comparison module allows full genome comparisons andclustering for evolutionary and population genetic studies to be calculated.Both DNA-based chromosome comparisons and CDS-based chromosomecomparisons can be performed. Moreover, the annotation of new genomes,mutation analysis and gene selection, and chromosome-wide comparisonscan be performed to study the organization and structure of genomes.OTP016Fecal indicators in particles of swimming poolsB. Hambsch* 1 , S. Stauder 21 Department of Microbiology, Water Technology Center (TZW), Karlsruhe,Germany2 Department of Technology, Water Technology Center (TZW), Karlsruhe,GermanyParticles in public swimming pools can contain pathogenic microorganisms.Therefore, a German standard for bathing water (DIN 19643) sets aminimum circulation volume to be treated by particle removal. Moreover, aminimum chlorine content of 0.3 mg/L in the pool water is fixed to avoidinfections by waterborne pathogens. For a revision of the standard DIN19643, it is planned to reduce the required minimum circulation volume by afactor of 2 in case that ultrafiltration is implemented for particle removal.To analyze, if particles in swimming pools are really hygienically relevant,the water from swimming pools was investigated in a worst case situation ona hot summer day by filtering volumes of 5L up to 150L for particles > 1μm. The water itself contained free chlorine in concentrations of more than0.5 mg/L. The particles were then analyzed for the presence of the indicatorbacteria E. coli and coliform bacteria. In 5 of 5 samples coliform bacteriawere detected, in 4 of 5 samples also E. coli could be detected. Thus, E. colicould survive in particles despite the presence of 0.5 mg/L free chlorine.Besides these fecal indicators also pathogenic microorganisms can bepresent in such particles. Therefore a reduction of the minimum flowthrough in the circulation has to be seen critically as it increases the turbidityand the concentration of particles in the pool water. As a result, also theconcentration of potentially pathogenic microorganisms will considerablyincrease.OTP017Tumor specific promoters of Salmonella enterica serovarTyphimuriumS. Leschner*Molecular Immunology, Helmholtz Center for Infection Research,Braunschweig, GermanyCancer is the second most frequent cause of death in the industrialized worldand still conventional therapies are often limited in effectiveness and exhibitstrong side effects. Therefore alternative therapeutic strategies aredemanded. The administration of tumor-colonizing bacteria that exertanti-cancer effects is a promising approach that is under increasinginvestigation since several years. Salmonella enterica serovar Typhimuriumis one such bacterium and has been used in many animal tumor models aswell as in first clinical studies already. It has an inherent tumoricidal effectthat should be improvable by using S. Typhimurium as a vector to delivertherapeutic agents. In this context, bacterial expression has to be restricted tothe tumor to prevent toxic substances to harm healthy tissue. Therefore, anS. Typhimurium promoter trap library has been screened in order to definepromoters that exclusively drive expression in the tumor tissue. 12 suchpromoters could be found that show reporter gene expression in tumor butnot in spleen and liver. In addition, a sequence motif has been identified thatappears to be necessary for the specificity of expression. Now, these tumorspecific promoters can be used to express therapeutic proteins intumor-colonizing S. Typhimurium.OTP018Structural insights into the activation mechanism ofbacterial di-heme cytochrome c peroxidasesJ. Seidel* 1 , A. Wuest 1 , M. Hoffmann 2 , O. Einsle 11 Institute for Biochemistry and Molecular Biology, Albert-Ludwigs-University, Freiburg, Germany2 University, Braunschweig, GermanyBacterial cytochrome c peroxidases (Ccps) are detoxifying enzymes thatprotect the cells from reactive oxygen species by reducing hydrogenperoxide to water. These proteins are located in the periplasm and show aconserved structure with two domains containing a high potential (HP)electron transfer heme group and one low potential (LP) catalytic hemegroup. The HP heme group is coordinated by a methionine and a histidineresidue whereas the LP heme group shows a bis-histidinyl coordination[1].With the exception of the constitutively active Nitrosomonas europaeaenzyme a reduction of the HP heme group is required for the activation [2].spektrum | Tagungsband 2011