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

EMP025Fungi on Abies grandis woodM. Navarro Gonzalez, U. Kües*Division of Molecular Wood Biotechnology, Georg-August-University,Göttingen, GermanyAbies grandis (Grand Fir) is a neophyte in Germany. Little is known aboutfungi infesting its wood. In this study we isolated fungi from dead woodfrom forests for molecular identification. Most species were eitherascomycetes or related deuteromycetes but also a few basidiomycetes weredetected, some of which are brown rots. Most of the isolates could only beidentified to the genus level and some only to a family level, indicating alarge range of unknown fungi occuring on dead wood. Generally, for mosttree species dead wood has yet little been studied with molecular methods interms of fungal occupants. Conservative estimates predict that 1.5 milliondifferent fungi exist worldwide, most of which are still undiscovered. Thestudy showd that dead wood represents one of the biotops in which manymissing fungal species can be detected.EMP026The environmental fate of the NSAID fenoprofen -Microbial transformation processes in water sedimentsystemsM. Hoffmann* 1 , S.R. Kaschabek 1 , G. Schüürmann 2 , M. Schlömann 11 Group Environmental Microbiology, University of Mining and Technology,Freiberg, Germany2 Department of Ecological Chemistry, Helmholtz Center for EnvironmentalResearch (UFZ), Leipzig, GermanyDuring the last two decades the availability of highly sensitive MS-basedtechniques of organic trace analysis allowed the detection of cocktails ofpharmaceutical residues in large parts of the aquatic environment. As aconsequence considerable concern about the (eco)toxicological impact ofsuch compounds has arisen. Compared to the vast number of studies dealingwith the detection of drugs in the environment very little is known about themechanisms of microbial transformations representing an important sink formany of those compounds. Knowledge on metabolic pathways and oninvolved intermediates is of considerable interest in order to better assess the(eco)toxicological impact of pharmaceutical residues.The present work deals with investigations towards the microbialtransformation of the non-steroidal anti-inflammatory drug (NSAID)fenoprofen by fresh water and sediment of the creek Münzbach (Freiberg,Saxony, Germany). It was shown by RP-HPLC that spiked fenoprofen loadsbetween 160 μM up to 180 μM were eliminated within 10 to 20 days in thepresence of sediment and water. Comparison of removal rates of this drug inthe presence of water as well as by a water/sediment mixture pointed to alocalization of fenoprofen-transforming activity in the aqueous phase.In such incubations the (transient) occurrence of two different metabolitescould be detected. These compounds could be characterized by 1 H-NMR tobe 4′-hydroxyfenoprofen (3-(4-hydroxyphenoxy)-α-methylbenzeneaceticacid) and 3-hydroxyphenyl-α-methylacetic acid and a complete degradationby hydroxylation and ether cleavage is suggested.EMP027Detection of antibiotic resistances in surface water usingculture methods and PCRC. Stoll* 1 , V. Schuhmacher 2 , T. Binder 2 , S. Langer 1 , H.-P. Rohns 2 ,A. Tiehm 11 Department of Environmental Biotechnology, Water Technology CenterKarlsruhe, Karlsruhe, Germany2 Public Utility Company Düsseldorf, Qualitiy Control, Düsseldorf,GermanyAntibiotic resistances represent a serious problem in clinical therapy, andresistant bacteria have been detected frequently in hospitals. However, onlylimited data are available with respect to microbial antibiotic resistances inthe environment.In order to assess the occurrence and transport of antibiotic resistances in theaquatic environment, water samples were analyzed using culturing methodsas well as molecular biological techniques (polymerase chain reaction,PCR). 100 coliform bacteria from River Rhine water were isolated andscreened for antibiotic resistance by determining the minimum inhibitionconcentration (MIC) of trimethoprim/sulfamethoxazol, tetracycline,amoxicillin, gentamicin, meropenem, cefotaxime, ciprofloxacin andchloramphenicol in agar diffusion assays. For the coliform bacteria,resistances against amoxicillin, trimethoprim / sulfamethoxazol andtetracycline were observed. Some bacteria were multiresistant against two,three or four of the tested antibiotics (4%, 5%, and 1%). Using PCRanalysis, most of the observed resistances could be attributed to specificresistance genes.PCR also was applied to analyze resistance genes in water samples withoutpre-cultivation. The bacteria were concentrated via filtration and total DNAwas extracted. The DNA was analyzed for 24 resistance genes according toeight antimicrobial groups. In conclusion, genes encoding for resistanceagainst sulfonamides, trimethoprim, tetracycline, and erythromycin weredetected frequently in surface water samples. In particular the resistancegenes sul1, sul2, dfrA1, tet(C) and erm(B) proved to be important.The authors gratefully acknowledge financial support by the GermanWaterworks Association (DVGW, project no. W1/01/05).EMP028Investigation of the Microbial Gut Flora in VietnameseStick Insect Medauroidea extradentataM. Freiherr von Neubeck*, A. Hiergeist, E. Stupperich*Department of Microbiology and Biotechnology, University of Ulm, Ulm,GermanyInsects contribute positively to the earth´s ecosystem, but less is knownabout their microbial gut population. This also applies to our experimentalorganism Medauroidea extradentata, which eats only leafs and lives underwet tropical conditions. Thus, we focused onto its bacterial gut flora inrespect to microbial diversity. The blackberry leafs are highly populatedwith different bacteria and fungi. However, the gut is scarcely populated asshown by raster - and transmissions electron microscopy as well asmicrobiological methods. We isolated a facultative anaerobic, Gramnegativeenterobacterial species from the gut of the stick insect. Thisbacterium is classified into the genus Kluyvera spp. basicly due to severalbiochemical reactions and to sequence analysis. Therefore we comparedcharacteristics of our isolate with those of Kluyvera cryocrescens type strain(DSM 4588). The biochemical reactions of our isolate within api®20 E andID 32 E support the affiliation to Kluyvera spp. and the 16S rRNAsequences of both Kluyvera strains shared 99% identities. In contrast,antibiograms (Mastring M-14) of both strains revealed surprising results.Our isolate showed resistance to eight different antibiotics whereas the typestrain was resistant to only three. The multidrug resistance probablyaccounts for an integron I system, because a PCR amplification of thecorresponding integrase gene was positive, when primers detecting thehighly conserved enterobacterial integrase genes were used. We furtherinvestigated the genoms of both Kluyvera strains for vitamin B 12transporters. A putative BtuB, the B 12 uptake protein associated with theouter membrane of Gram-negative bacteria was present in bothenterobacterial strains. Their genes were sequenced, cloned into (plasmids)and expressed in E. coli.EMP029Structure and mechanism of the diiron benzoyl coenzymeA epoxidase BoxBT. Weinert* 1 , L.J. Rather 2 , E. Bill 3 , G. Fuchs 2 , U. Ermler 11 Department of Molecular Membrane Biology, Max Planck Institute ofBiophysics Frankfurt, Germany2 Institute for Biology II, Albert-Ludwigs-University, Freiburg im Breisgau,Germany3 Department of Bioinorganic Chemistry, Max Planck Institute forBioinorganic Chemistry, Mühlheim an der Ruhr, GermanyA recently elucidated coenzyme A (CoA) dependent aerobic benzoatemetabolic pathway [1] uses an unprecedented chemical strategy to cope withthe high resonance energy of aromates by forming the non-aromatic 2,3-epoxybenzoyl-CoA [2]. The crucial dearomatizing and epoxidizing reactionis carried out by BoxB and the two required electrons are delivered byBoxA, a NADPH dependent reductase. We determined the X-ray structureof the key enzyme BoxB from Azoarcus evansii including the diiron centerwithout and with bound benzoyl-CoA in the diferric and semi-reducedstates, respectively [3]. Complementary Mössbauer and EPR spectroscopicstudies revealed the later as well as the diferrous state [3]. These studiesshowed that the semi-reduced state with bound benzoyl-CoA is aprerequisite for O 2 activation. The crystal structures reveal redox dependentspektrum | Tagungsband 2011