Genome sequence of Kosmotoga olearia strain TBF 19.5.1, a thermophilic bacterium with a wide growth temperature range, isolated from the Troll B oil platform in the North Sea.

Kosmotoga olearia strain TBF 19.5.1 is a member of the Thermotogales that grows best at 65°C and very well even at 37°C. Information about this organism is important for understanding the evolution of mesophiles from thermophiles. Its genome sequence reveals extensive gene gains and a large content of mobile genetic elements. It also contains putative hydrogenase genes that have no homologs in the other member of the Thermotogales.

Genome sequence of Thermotoga sp. strain RQ2, a hyperthermophilic bacterium isolated from a geothermally heated region of the seafloor near Ribeira Quente, the Azores.

Thermotoga sp. strain RQ2 is probably a strain of Thermotoga maritima. Its complete genome sequence allows for an examination of the extent and consequences of gene flow within Thermotoga species and strains. Thermotoga sp. RQ2 differs from T. maritima in its genes involved in myo-inositol metabolism. Its genome also encodes an apparent fructose phosphotransferase system (PTS) sugar transporter. This operon is also found in Thermotoga naphthophila strain RKU-10 but no other Thermotogales. These are the first reported PTS transporters in the Thermotogales.

Kosmotoga olearia gen. nov., sp. nov., a thermophilic, anaerobic heterotroph isolated from an oil production fluid.

A novel thermophilic, heterotrophic bacterium, strain TBF 19.5.1(T), was isolated from oil production fluid at the Troll B oil platform in the North Sea. Cells of strain TBF 19.5.1(T) were non-motile rods with a sheath-like structure, or toga. The strain was Gram-negative and grew at 20-80 degrees C (optimum 65 degrees C), pH 5.5-8.0 (optimum pH 6.8) and NaCl concentrations of 10-60 g l(-1) (optimum 25-30 g l(-1)). For a member of the order Thermotogales, the novel isolate is capable of unprecedented growth at low temperatures, with an optimal doubling time of 175 min (specific growth rate 0.24 h(-1)) and a final optical density of >1.4 when grown on pyruvate at 37 degrees C. Various carbohydrates, proteinaceous compounds and pyruvate served as growth substrates. Thiosulfate, but not elemental sulfur, enhanced growth of the isolate. Sulfate also enhanced growth, but sulfide was not produced. The strain grew in the presence of up to approximately 15 % oxygen, but only if cysteine was included in the medium. Growth of the isolate was inhibited by acetate, lactate and propionate, while butanol and malate prevented growth. The major fermentation products formed on maltose were hydrogen, carbon dioxide and acetic acid, with traces of ethanol and propionic acid. The G+C content of the genomic DNA was 42.5 mol%. Phylogenetic analyses of the 16S and 23S rRNA gene sequences as well as 29 protein-coding ORFs placed the strain within the bacterial order Thermotogales. Based on the phylogenetic analyses and the possession of a variety of physiological characteristics not previously found in any species of this order, it is proposed that the strain represents a novel species of a new genus within the family Thermotogaceae, order Thermotogales. The name Kosmotoga olearia gen. nov., sp. nov. is proposed. The type strain of Kosmotoga olearia is TBF 19.5.1(T) (=DSM 21960(T) =ATCC BAA-1733(T)).