Characterization of the 16S ribosomal RNA genes and phylogenetic relationships of sulfur-dependent thermoacidophilic archaebacteria

NORIO KUROSAWA, KIYOTAKA OHKURA, TADAO HORIUCHI, YUKO H. ITOH
1995 Journal of General and Applied Microbiology  
A comparative sequence study of the 16S rRNAs showed that living organisms can be divided into the traditional eubacterial and eukarc yotic kingdoms and the newly recognized archaebacterial kingdom (28). Although archaebacteria exhibit a prokaryotic cell structure and organization, they show distinguishing and unifying features (1, 9, 12, 16, 18, 22). In sulfur-dependent thermophilic archaebacteria, the following five genera have been assigned to the order Sulfolobales: (i) the genus
more » ... he genus Sulfolobus, which is the type genus and includes the species S. acidocaldarius (3), S. solfataricus (31), S. shibatae (5) and S. metallicus (8); (ii) the genus Acidianus, which includes the species A. infernus (25) and A, brierleyi (2); (iii) the genus Metallosphaera, with one species, M. sedula (7); (iv) the genus Stygiolobus, with one species, S. azoricus (26); and (v) the genus Desulfurolobus, with one species, D. ambivalens (32). D. ambivalens has been suggested to belong to the genus Acidianus based on DNA-DNA hybridization experiments (26). Only in S. acidocaldarius and S. shibatae, have the complete nucleotide sequences of the 16S rRNA genes have been reported and were shown to have 90.8% homology (5,15). Except for their relationships, a phylogenetic analysis has never been done among the other species in the order Sulfolobales. Although the 16S rRNA sequence of S. solfataricus was reported by Olsen et al. (19), the strain used by Olsen was recognized as S. acidocaldarius (15, 30). We have determined the complete nucleotide sequences of the 16S rRNA genes as well as their flanking regions from the sulfur-dependent thermoacidophilic
doi:10.2323/jgam.41.75 fatcat:uwqvzclt3bai5iokgkinzravuq