Description of Thermococcus kodakaraensis sp. nov., a well studied hyperthermophilic archaeon previously reported as Pyrococcus sp. KOD1
Haruyuki Atomi (1), Toshiaki Fukui (1), Tamotsu Kanai (1), Masaaki Morikawa (2) and Tadayuki Imanaka (1, 3)
1. Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan / 2. Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan / 3. Corresponding author ([email protected]) / Received December 12, 2003; accepted March 10, 2004; published online April 16, 2004
A hyperthermophilic archaeal strain, KOD1, isolated from a solfatara on Kodakara Island, Japan, has previously been reported as Pyrococcus sp. KOD1. However, a detailed phylogenetic tree, made possible by the recent accumulation of 16S rRNA sequences of various species in the order Thermococcales, indicated that strain KOD1 is a member of the genus Thermococcus. We performed DNA–DNA hybridization tests against species that displayed high similarity in terms of 16S ribosomal DNA sequences, including Thermococcus peptonophilus and Thermococcus stetteri. Hybridization results and differences in growth characteristics and substrate utilization differentiated strain KOD1 from T. peptonophilus and T. stetteri at the species level. Our results indicate that strain KOD1 represents a new species of Thermococcus, which we designate as Thermococcus kodakaraensis KOD1 sp. nov.
Keywords: Archaea, classification, hyperthermophile, taxonomy, Thermococcales.