Abstract
Three isolates of spherical thermoacidophilic archaebacteria (strains TA-1, TA-2 and N-8) were obtained from acidic hot springs at Hakone and Noboribetsu in Japan. We have studied the isolates using electron microscopy, Gram staining, sensitivity to lysozyme, growth conditions, lipid compositions, SDS-PAGE patterns of whole-cell proteins, DNA base composition and partial 16S rRNA sequences. These characteristics of the isolates were compared with those of the type strains, Sulfolobus acidocaldarius, Sulfolobus solfataricus, Acidianus brierleyi, Acidianus infernus, Metallosphaera sedula and Desulfurolobus ambivalens. Comparative studies indicated that the isolate TA-1 was novel species of either Sulfolobus or Acidianus, the isolate TA-2 belonged to the genus Metallosphaera, and the isolate N-8 belonged to the same species of S. acidocaldarius isolated from Yellowstone.
