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The highly enriched deltaproteobacterial culture N47 anaerobically oxidizes the polycyelic aromatic hydrocarbons naphthalene and 2-methylnaphthalene, with sulfate as the electron acceptor. Combined genome sequencing and liquid chromatography-tandem mass spectrometry-based shotgun proteome analyses were performed to identify genes and proteins involved in anaerobic aromatic catabolism. Proteome analysis of 2-methylnaphthalene-grown N47 cells resulted in the identification of putative enzymes catalyzing the anaerobic conversion of 2-metbyluapbthalene to 2-naphthoyl eoenzyme A (2-naphthoyl-CoA), as well as the reductive ring cleavage of 2-naphthoyl-CoA, leading to the formation of acetyl-CoA and C[O.sub.2]. The glycyl radical-catalyzed fumarate addition to the methyl group of 2-methylnaphthalene is catalyzed by naphthyl-2-methyl-succinate synthase (Nms), composed of [alpha]-, [beta]-, and [gamma]-subunits that are encoded by the genes nmsABC. Located upstream of nmsABC is nmsD, encoding the Nms-activating enzyme, which harbors the characteristic [[Fe.sub.4][S.sub.4]] cluster sequence motifs of S-adenosylmethionine radical enzymes. The bns gene cluster, coding for enzymes involved in beta-oxidation reactions converting naphthyl-2-methyl-succinate to 2-naphthoyl-CoA, was found four intervening open reading frames further downstream. This cluster consists of eight genes (bnsABCDEFGH) corresponding to 8.1 kb, which are closely related to genes for enzymes involved in anaerobic toluene degradation within the denitrifiers 'Aromatoleum aromaticum' EbN1, Azoarcus sp. strain T, and Thauera aromatica. Another contiguous DNA sequence harbors the gene for 2-naphthoyl-CoA reductase (ncr) and 16 additional genes that were found to be expressed in 2-methylnaphthalene-grown cells. These genes code for enzymes that were supposed to catalyze the dearomatization and ring cleavage reactions converting 2-naphthoyl-CoA to acetylCoA and C[O.sub.2]. Comparative sequence analysis of the four encoding subunits (ncrABCD) showed the gene product to have the closest similarity to the Azoarcus type of benzoyl-CoA reductase. The present work provides the first insight into the genetic basis of anaerobic 2-methylnaphthalene metabolism and delivers implications for understanding contaminant degradation. doi: 10.1128/JB.00874-09

Research addresses potential bias in the polymerase chain reaction and their influence on terminal restriction fragment length polymorphism fingerprinting of methanogenic bacterial population structure in different habitats using small-subunit rRNA and the methyl-coenzyme M reductase genes as probes. Data reveal that small-subunit rRNA analysis is reproducible, whereas M reductase-based analysis is biased.

Different methanogenic bacteria are stimulated or inhibited when rice paddy soils are supplemented with ferrihydrite or gypsum. These electron acceptors are added to stimulate bacteria that would compete with methanogens. This is done to reduce methane emissions, which contribute to the greenhouse effect.

The first comprehensive analysis of the microbial community inside the gut of the termite Cubitermes orthognathus is described based on clonal analysis and terminal restriction fragment length polymorphism fingerprinting. This is also the first report of Crenarchaeota occurring in an arthropod intestinal tract.

Research has been conducted on the Archaea population dynamics after rice field soil flooding. The results of the molecular sequence retrieval and small-subunit rRNA gene fingerprinting are discussed.

The characterization of microbial community distribution across a high-resolution depth profile of a tar oil-impacted aquifer where benzene, toluene, ethylbenzene and xylene (BTEX) degradation has depended mainly on sulfate reduction is described. The results have shown that the distribution of specific aquifer microbiota and degradation processes in contaminated aquifers are tightly coupled, which are used for the assessment of natural attenuation based on intrinsic aquifer microbiota.

The first identification of active anaerobic microorganisms by stable-isotope probing (SIP), which are involved in the thermodyanimically unfavorable syntrophic oxidation of propionate under methanogenic conditions is presented. Three distinct lineages of syntrophic propionate oxidizers (Syntrophobacter, Smithella, and Pelotomaculum spp.) were identified to operate simultaneously in anoxic rice field soil slurries and their hydrogenotrophic and acetotrophic methanogenic partner organisms were also detected by assimilation of labeled intermediates.