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Cetia pacifica gen. nov., sp. nov., a chemolithoautotrophic, thermophilic, nitrate-ammonifying bacterium from a deep-sea hydrothermal vent

Grosche, Ashley, Sekaran, Hema, Pérez-Rodríguez, Ileana, Starovoytov, Valentin, Vetriani, Costantino
International journal of systematic and evolutionary microbiology 2015 v.65 no.Pt 4 pp. 1144-1150
DNA, acetates, bacteria, carbon, carbon dioxide, casamino acids, energy, fatty acids, flagellum, gases, genes, growth retardation, hydrogen sulfide, nitrates, oxygen, pH, phylogeny, ribosomal RNA, sodium chloride, sucrose, sulfur, tryptones, yeast extract
A thermophilic, anaerobic, chemolithoautotrophic bacterium, strain TB-6 ᵀ, was isolated from a deep-sea hydrothermal vent located on the East Pacific Rise at 9° N. The cells were Gram-staining-negative and rod-shaped with one or more polar flagella. Cell size was approximately 1–1.5 µm in length and 0.5 µm in width. Strain TB-6 ᵀ grew between 45 and 70 °C (optimum 55–60 °C), 0 and 35 g NaCl l ⁻¹ (optimum 20–30 g l ⁻¹) and pH 4.5 and 7.5 (optimum pH 5.5–6.0). Generation time under optimal conditions was 2 h. Growth of strain TB-6 ᵀ occurred with H ₂ as the energy source, CO ₂ as the carbon source and nitrate or sulfur as electron acceptors, with formation of ammonium or hydrogen sulfide, respectively. Acetate, (+)- d -glucose, Casamino acids, sucrose and yeast extract were not used as carbon and energy sources. Inhibition of growth occurred in the presence of lactate, peptone and tryptone under a H ₂/CO ₂ (80 : 20; 200 kPa) gas phase. Thiosulfate, sulfite, arsenate, selenate and oxygen were not used as electron acceptors. The G+C content of the genomic DNA was 36.8 mol%. Phylogenetic analysis of the 16S rRNA gene of strain TB-6 ᵀ showed that this organism branched separately from the three most closely related genera, Caminibacter , Nautilia and Lebetimonas , within the family Nautiliaceae . Strain TB-6 ᵀ contained several unique fatty acids in comparison with other members of the family Nautiliaceae . Based on experimental evidence, it is proposed that the organism represents a novel species and genus within the family Nautiliaceae , Cetia pacifica, gen. nov., sp. nov. The type strain is TB-6 ᵀ (= DSM 27783 ᵀ = JCM 19563 ᵀ).