DEINOCOCCUS-GEOTHERMALIS SP. NOV. AND DEINOCOCCUS-MURRAYI SP. NOV., 2EXTREMELY RADIATION-RESISTANT AND SLIGHTLY THERMOPHILIC SPECIES FROM HOT-SPRINGS

Strains of Deinococcus geothermalis sp. nov. were isolated from the ho t spring and runoff at Agnano, Naples, Italy, and from the hot spring at Sao Pedro do Sul in central Portugal, while strains of Deinococcus murrayi sp. nov. were isolated from the hot springs al Sao Pedro do Su l, Sao Gemil, and Alcafache in central Portugal. The strains of D. geo thermalis and D. murrayi produce orange-pigmented colonies and have an optimum growth temperature of about 45 to 50 degrees C. The type stra ins of the two new species are extremely gamma radiation resistant. Th e fatty acids of these new species are primarily branched-chain fatty acids. The two new species can be distinguished from each other by the lower pH range of D. geothermalis than of D. murrayi, by their fatty acid compositions, and by several biochemical parameters, including th e ability of D. geothermalis to grow in minimal medium without yeast e xtract. 16S rRNA gene sequencing also showed that the isolates constit ute two species and that these species are distinct from the other spe cies of the genus Deinococcus. The type strain of D. geothermalis is A G-3a (= DSM 11300), and the type strain of D. murrayi is ALT-1b (= DSM 11303).