Project description:Experimentally mapped transcriptome structure of Methanococcus maripaludis S2 by hybridizing total RNA (including RNA species <200 nt) to genome-wide high-density tiling arrays (60 mer probes tiled every 14 nt). Methanococcus maripaludis MM901, a wild type Methanococcus maripaludis S2 with an in frame deletion of the uracil phosphoribosyltransferase gene (Proc. Natl. Acad. Sci. U S A 107: 11050-11055) growth curve experiments were conducted in batch culture. Reference samples were cultured at mid-log phase (OD660 = 0.804). Eight samples were collected that spanned the key phases of the growth curve. Total RNA from samples of growth curve and reference were directly labeled with Cy3 or Cy5, and were hybridized to the tiling array. Dye-flip experiments were done for each sample. Log ratios were calculated for each probe (growth curve sample/reference). Transcriptome browser is available at http://baliga.systemsbiology.net/enigma/.
Project description:Experimentally mapped transcriptome structure of Methanococcus maripaludis S2 by hybridizing total RNA (including RNA species <200 nt) to genome-wide high-density tiling arrays (60 mer probes tiled every 14 nt).
Project description:Hydrogenotrophic methanogenic Archaea are defined by a H2 requirement for growth. Despite this requirement, many hydrogenotrophs are also capable of growth with formate as an electron donor for methanogenesis. Hydrogenotrophs respond to H2 starvation both phenotypically and at the level of gene expression; however, the responses during growth on formate have not been characterized. Here we report that during continuous culture of Methanococcus maripaludis under defined nutrient conditions, growth yields relative to methane production decreased markedly with either H2 excess or formate excess, suggesting that energy spilling occurs. Using microarray analysis, we show that the expression of genes encoding F420-dependent steps of methanogenesis, including one of two formate dehydrogenases, increased with H2 starvation, but with formate occurred at high levels regardless of limitation or excess. One gene, encoding H2-dependent methylene-tetrahydromethanopterin dehydrogenase, decreased in expression with either H2 limitation or formate limitation. Expression of genes for the second formate dehydrogenase, molybdenum-dependent formylmethanofuran dehydrogenase, and molybdenum transport increased specifically with formate limitation. Of the two formate dehydrogenases, only the first could support growth on formate in batch culture where formate was in excess.
