PHENOTYPIC CHARACTERIZATION, DNA SIMILARITIES, AND PROTEIN PROFILES OF 20 SULFUR-METABOLIZING HYPERTHERMOPHILIC ANAEROBIC ARCHAEA ISOLATED FROM HYDROTHERMAL VENTS IN THE SOUTHWESTERN PACIFIC-OCEAN
Vt. Marteinsson et al., PHENOTYPIC CHARACTERIZATION, DNA SIMILARITIES, AND PROTEIN PROFILES OF 20 SULFUR-METABOLIZING HYPERTHERMOPHILIC ANAEROBIC ARCHAEA ISOLATED FROM HYDROTHERMAL VENTS IN THE SOUTHWESTERN PACIFIC-OCEAN, International journal of systematic bacteriology, 45(4), 1995, pp. 623-632
We performed phenotypic and physiological studies with 20 hyperthermop
hilic microorganisms isolated from hydrothermal vents located in the N
orth Fiji Basin (southwestern Pacific Ocean) at a depth of 2,000 m. Th
ese isolates were strict anaerobes that were regular to irregular cocc
oids and used elemental sulfur in their metabolism. Growth was observe
d at temperatures ranging from 50 to 101 degrees C. The DNA base compo
sitions varied from 43 to 60 mol%. All of these organisms were heterot
rophs and fermented peptides to acetate, isovalerate, isobutyrate, and
propionate, They contained both diether and tetraether lipids in thei
r membranes, which indicates that they belong to the domain Archaea. D
NA-DNA hybridization experiments revealed that there were two distinct
homology groups, which correlated well with results obtained from sod
ium dodecyl sulfate-polyacrylamide gel electrophoresis of soluble whol
e-cell proteins, and these groups corresponded to the genera Pyrococcu
s and Thermococcus. Five isolates exhibited levels of DNA-DNA relatedn
ess with Pyrococcus abyssi ranging from 71 to 100% and produced almost
identical protein patterns. The remaining isolates formed a weakly ho
mogeneous group based on DNA-DNA similarity data and protein patterns;
the results of unweighted pair group duster analyses suggested that t
hese isolates were members of five new species of the genus Thermococc
us.