Abstract
Z Silva, C Horta, MS da Costa, AP Chung and FA Rainey
Centro de Neurociencias de Coimbra, Departamento de Zoologia, and Departamento de Bioquimica, Universidade de Coimbra, 3000 Coimbra, Portugal
DNA--DNA reassociation studies, 16S rRNA gene sequence comparisons and fatty acid analysis were used to reassess the taxonomic status of the type strain of Rhodothermus obamensis and several strains of the genus Rhodothermus isolated from widely distributed shallow marine hot springs. The results show that the type strain of R. obamensis, JCM 9785(T), has a DNA--DNA reassociation value of 78% with the type strain of R. marinus, DSM 4252(T). The other strains examined had DNA--DNA reassociation values that varied between about 68 and 94% with R. marinus. The 16S rRNA gene sequence was determined for the type strain of R. obamensis and found to share 99.5% similarity with the type strain of R. marinus. The fatty acid composition of R. obamensis was slightly different from that of the other strains examined, but indicated that this strain is very closely related to the other strains examined in this study. On the basis of DNA--DNA reassociation values, 16S rRNA gene sequence comparison and fatty acid profiles, it was concluded that R. obamensis and R. marinus represent the same species and that the name Rhodothermus obamensis should be regarded as a junior synonym of Rhodothermus marinus.