Cetia pacifica gen. nov., sp. nov., a chemolithoautotrophic, thermophilic, nitrate-ammonifying bacterium from a deep-sea hydrothermal vent.
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 H2 as the energy source, CO2 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 H2/CO2 (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)).
Grosche A
，Sekaran H
，Pérez-Rodríguez I
，Starovoytov V
，Vetriani C
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Anoxybacter fermentans gen. nov., sp. nov., a piezophilic, thermophilic, anaerobic, fermentative bacterium isolated from a deep-sea hydrothermal vent.
A novel piezophilic, thermophilic, anaerobic, fermentative bacterial strain, designated strain DY22613(T), was isolated from a deep-sea hydrothermal sulfide deposit at the East Pacific Rise (GPS position: 102.6° W 3.1° S). Cells of strain DY22613(T) were long, motile rods (10 to 20 µm in length and 0.5 µm in width) with peritrichous flagella and were Gram-stain-negative. Growth was recorded at 44-72 °C (optimum 60-62 °C) and at hydrostatic pressures of 0.1-55 MPa (optimum 20 MPa). The pH range for growth was from pH 5.0 to 9.0 with an optimum at pH 7.0. Growth was observed in the presence of 1 to 8 % (w/v) sea salts and 0.65 to 5.2 % (w/v) NaCl, with optimum salt concentrations at 3.5 % for sea salts and at 2.3 % for NaCl. Under optimal growth conditions, the shortest generation time observed was 27 min (60 °C, 20 MPa). Strain DY22613(T) was heterotrophic, able to utilize complex organic compounds, amino acids, sugars and organic acids including peptone, tryptone, beef extract, yeast extract, alanine, glutamine, methionine, phenylalanine, serine, threonine, fructose, fucose, galactose, gentiobiose, glucose, mannose, melibiose, palatinose, rhamnose, turanose, pyruvate, lactic acid, methyl ester, erythritol, galacturonic acid and glucosaminic acid. Strain DY22613(T) was able to reduce Fe(III) compounds, including Fe(III) oxyhydroxide (pH 7.0), amorphous iron(III) oxide (pH 9.0), goethite (α-FeOOH, pH 12.0), Fe(III) citrate and elementary sulfur. Products of fermentation were butyrate, acetate and hydrogen. Main cellular fatty acids were iso-C15 : 0, iso-C14 : 0 3-OH and C14 : 0. The genomic DNA G+C content of strain DY22613(T) was 36.7 mol%. Based on 16S rRNA gene sequence analysis, the strain forms a novel lineage within the class Clostridia and clusters with the order Haloanaerobiales (86.92 % 16S rRNA gene sequence similarity). The phylogenetic data suggest that the lineage represents at least a novel genus and species, for which the name Anoxybacter fermentans gen. nov., sp. nov. is proposed. The type strain is DY22613(T) ( = JCM 19466(T) = DSM 28033(T) = MCCC 1A06456(T)).
Zeng X
，Zhang Z
，Li X
，Zhang X
，Cao J
，Jebbar M
，Alain K
，Shao Z
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