Nitratiruptor tergarcus gen. nov., sp. nov. and Nitratifractor salsuginis gen. nov., sp. nov., nitrate-reducing chemolithoautotrophs of the ε-Proteobacteria isolated from a deep-sea hydrothermal system in the Mid-Okinawa Trough

• DOI: 10.1099/ijs.0.63480-0
• Publication Date: 2005-03-17T21:32:59Z
• Authors: Satoshi Nakagawa; Ken Takai; Fumio Inagaki; Koki Horikoshi; Yoshihiko Sako
• Keywords: DNA, Bacterial; 0301 basic medicine; 0303 health sciences; Hot Temperature; Nitrates; Molecular Sequence Data; Sequence Analysis, DNA; DNA, Ribosomal; 6. Clean water; Bacterial Typing Techniques; 03 medical and health sciences; Japan; Species Specificity; RNA, Ribosomal, 16S; Epsilonproteobacteria; Seawater; 14. Life underwater; Oxidation-Reduction; Phylogeny

Two novel denitrifying bacteria, designated strains MI55-1 T and E9I37-1 , were isolated from deep-sea hydrothermal vent chimney structures at the Iheya North field in Mid-Okinawa Trough, Japan. Both isolates strict chemolithoautotrophs growing by respiratory nitrate reduction with H 2 forming N as a metabolic product. Oxygen (at low concentrations) could serve an alternative electron acceptor for growth of isolates. Growth strain was observed temperatures between 40 57 °C (optimum, 55 °C; doubling time, h), pH values 5·4 6·9 6·4) presence 1·5 4·0 % (w/v) NaCl 2·5 %). 28 37 5·6 7·6 7·0) 3·5 3·0 The G+C contents genomic DNA 29·6 35·5 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that belonged to groups A F ε - Proteobacteria but they had distant phylogenetic relationships any species, within groups, validly published names (sequence similarities less than 91 On basis physiological molecular characteristics isolates, it is proposed should each be classified genus: Nitratiruptor tergarcus gen. nov., sp. (=JCM 12459 =DSM 16512 ) type strain, Nitratifractor salsuginis 12458 16511 strain.