Thermococcus onnurineus sp nov., a hyperthermophilic Archaeon isolated from a deep-sea hydrothermal vent area at the PACMANUS field

Abstract

A novel hyperthermophilic, anaerobic, heterotrophic archaeon, designated strain NA1(T), was isolated from a deep-sea hydrothermal vent area (depth, 1,650 m) within the Papua New Guinea-Australia-Canada-Manus (PACMANUS) field. Cells of this strain were motile by means of polar flagella, coccoid-shaped with a diameter of approximately 0.5-1.0 mu m, and occurred as single cells. Optimal temperature, pH, and NaCl concentration for growth were 80 degrees C, 8.5, and 3.5%, respectively. The new isolate was an obligate heterotroph that utilized yeast extract, beef extract, tryptone, peptone, casein, and starch as carbon and energy sources. Elemental sulfur was required for growth and was reduced to hydrogen sulfide. The G+C content of the genomic DNA was 52.0 mol%. Phylogenetic analysis of the 16S rRNA gene indicated that strain NA1(T) belongs to the genus Thermococcus, and the organism is most closely related to T. gorgonarius, T. peptonophilus, and T. celer; however, no significant homology was observed among species by DNA-DNA hybridization. Strain NA1(T) therefore represents a novel species for which the name Thermococcus onnurineus sp. nov. is proposed. The type strain is NA1(T) (=KCTC 10859, =JCM 13517).