Project description:The synthetic microbial community used in this study was composed of the major functional guilds (cellulolytic fermenter, sulfate reducer, hydrogenotrophic methanogen and acetoclastic methanogen) that mediate the anaerobic conversion of cellulosic biomass to CH4 and CO2 in wetland soils. The choice of a facultative sulfate-reducing bacterium (Desulfovibrio vulgaris Hildenborough) introduced metabolic versatility and enabled investigations into the community response to sulfate intrusion. The growth status of these multi-species cultures was measured over a week by daily analysis of substrate consumption and product accumulation. The quad-cultures were analyzed with metaproteomics at the end of experiment to characterize the community structure and metabolic activities.
Project description:Analysis of microbial community composition in arctic tundra and boreal forest soils using serial analysis of ribosomal sequence tags (SARST). Keywords: other
Project description:Peatlands of the Lehstenbach catchment (Germany) house so far unidentified microorganisms with phylogenetically novel variants of the dissimilatory (bi)sulfite reductase genes dsrAB. These genes are characteristic for microorganisms that reduce sulfate, sulfite, or some organosulfonates for energy conservation, but can also be present in anaerobic syntrophs. However, nothing is currently known regarding the abundance, community dynamics, and biogeography of these dsrAB-carrying microorganisms in peatlands. To tackle these issues, soils from a Lehstenbach catchment site (Schlöppnerbrunnen II fen) from different depths were sampled at three time points over a six-year period to analyze the diversity and distribution of dsrAB-containing microorganisms by a newly developed functional gene microarray and quantitative PCR assays. Members of novel, uncultivated dsrAB lineages (approximately representing species-level groups) (i) dominated a temporally stable but spatially structured dsrAB community and (ii) represented ‘core’ members (up to 1-1.7% relative abundance) of the autochthonous microbial community in this fen. In addition, denaturing gradient gel electrophoresis (DGGE)- and clone library-based comparison of the dsrAB diversity in soils from a wet meadow, three bogs, and five fens of various geographic locations (distance ~1-400 km), identified one Syntrophobacter-related and nine novel dsrAB lineages to be widespread in low-sulfate peatlands. Signatures of biogeography in dsrB-DGGE data were not correlated with geographic distance but could largely be explained by soil pH and wetland type, implying that distribution of dsrAB-carrying microorganisms in wetlands on the scale of a few hundred kilometers is not limited by dispersal but determined by contemporary environmental conditions. 36 dsrAB clones for chip evaluation, 33 hybridizations of labeled dsrAB RNA from environmental peatsoil samples
Project description:Peatlands of the Lehstenbach catchment (Germany) house so far unidentified microorganisms with phylogenetically novel variants of the dissimilatory (bi)sulfite reductase genes dsrAB. These genes are characteristic for microorganisms that reduce sulfate, sulfite, or some organosulfonates for energy conservation, but can also be present in anaerobic syntrophs. However, nothing is currently known regarding the abundance, community dynamics, and biogeography of these dsrAB-carrying microorganisms in peatlands. To tackle these issues, soils from a Lehstenbach catchment site (Schlöppnerbrunnen II fen) from different depths were sampled at three time points over a six-year period to analyze the diversity and distribution of dsrAB-containing microorganisms by a newly developed functional gene microarray and quantitative PCR assays. Members of novel, uncultivated dsrAB lineages (approximately representing species-level groups) (i) dominated a temporally stable but spatially structured dsrAB community and (ii) represented ‘core’ members (up to 1-1.7% relative abundance) of the autochthonous microbial community in this fen. In addition, denaturing gradient gel electrophoresis (DGGE)- and clone library-based comparison of the dsrAB diversity in soils from a wet meadow, three bogs, and five fens of various geographic locations (distance ~1-400 km), identified one Syntrophobacter-related and nine novel dsrAB lineages to be widespread in low-sulfate peatlands. Signatures of biogeography in dsrB-DGGE data were not correlated with geographic distance but could largely be explained by soil pH and wetland type, implying that distribution of dsrAB-carrying microorganisms in wetlands on the scale of a few hundred kilometers is not limited by dispersal but determined by contemporary environmental conditions.