M. Ohno et al., Symbiobacterium thermophilum gen. nov., sp nov., a symbiotic thermophile that depends on co-culture with a Bacillus strain for growth, INT J SY EV, 50, 2000, pp. 1829-1832
Citations number
12
Categorie Soggetti
Microbiology
Journal title
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY
A Gram-negative and tryptophanase-positive thermophile, whose growth is dep
endent on co-culture with an associating Bacillus strain, had been reported
and tentatively named Symbiobacterium thermophilum strain T-T. Axenic cult
ure of strain T-T was recently established by dialysing cultures with the s
upporting bacterial strains or adding their culture broth. Phylogenetic ana
lysis of strain T-T, based on the 16S rDNA sequence, was conducted for the
validation of S. thermophilum, the sequence of strain T-T was located at th
e outermost position in the high-G+C Gram-positive group distinctly isolate
d from any other branches hitherto known. Ten sequences identical to that o
f strain T-T, and one sequence closely related to it, were identified for t
he first time from soil and compost samples. The outer membrane of strain T
-T had a three-layered structure, outside the cytoplasmic membrane, which i
s similar to the S-layer in the cells of members of the Bacillaceae. Chemic
al analysis of the cells revealed that menaquinone-6 is a major component o
f the quinone system. According to these results, along with several previo
us observations (i.e. a G+C DNA content of 65 mol% and the identification o
f iso-C-15:0 and iso-C-17:0 acids as major cellular fatty acids), the new t
axon Symbiobacterium thermophilum gen, nov., sp. nov. is proposed. The type
strain is S. thermophilum strain T-T (= IAM 14863(T)).