- Thermophilic bacteria -- Pacific Ocean,
- Water -- Microbiology,
- Thermophilic bacteria -- Phylogeny,
- Hydrothermal vent ecology -- Pacific Ocean
A novel moderately thermophilic, heterotrophic bacterium was isolated from a deep-sea hydrothermal vent deposit from the Mariner field along the Eastern Lau Spreading Center, Southwestern Pacific. Cells were short motile rods (about 0.4 μm-0.8 μm) that occurred singly or in pairs and were surrounded by a sheath-like membrane or ‘toga’. The cells grew between 45 and 65°C (optimum 57-60°C), pH 4.1-6.0 (optimum pH 5.5-5.7) and optimally at 3% (w/v) NaCl. The isolate grew on a range of carbon and proteinaceous substrates and reduced sulfur. The G + C content of the DNA was about 45 mol%. Phylogenetic analysis of the 16S rRNA gene placed the new isolate as a deeply diverging lineage within the Thermotogales. Based on the physiological, morphological and phylogenetic data, the isolate is a novel species of a new genus with the proposed name Mesoaciditoga lauensis gen. nov. sp. nov. The type strain is cd-1655RT (DSM 25116, OCM 1212).