A nonconserved carboxy-terminal segment of GroEL contributes to reaction temperature.

The role of the C-terminal segment of the GroEL equatorial domain was analyzed. To understand the molecular basis for the different active temperatures of GroEL from three bacteria, we constructed a series of chimeric GroELs combining the C-terminal segment of the equatorial domain from one species with the remainder of GroEL from another. In each case, the foreign C-terminal segment substantially altered the active temperature range of the chimera.

Oceanithermus desulfurans sp. nov., a novel thermophilic, sulfur-reducing bacterium isolated from a sulfide chimney in Suiyo Seamount.

A novel thermophilic, microaerophilic, sulfur-reducing bacterium designated strain St55BT was isolated from a sulfide chimney in the hydrothermal field of Suiyo Seamount (Izu-Bonin Arc, Western Pacific). Cells of the isolate were rod-shaped and tended to form a chain-link circular structure (a rotund body) at exponential phase under good growth conditions. The isolate was a chemoheterotroph requiring yeast extract for growth.

Microbial diversity in hydrothermal surface to subsurface environments of Suiyo Seamount, Izu-Bonin Arc, using a catheter-type in situ growth chamber.

After excavation using a portable submarine driller near deep-sea hydrothermal vents in the Suiyo Seamount, Izu-Bonin Arc, microbial diversity was examined in samples collected from inside the boreholes using an in situ growth chamber called a vent catheter. This instrument, which we devised for this study, consists of a heat-tolerant pipe tipped with a titanium mesh entrapment capsule that is packed with sterilized inorganic porous grains, which serve as an adhesion substrate. After this instrument was deployed inside each of the boreholes, as well as a natural vent, for 3-10 days in the vicinity of hot vent fluids (maxima: 156-305 degrees C), DNA was extracted from the adhesion grains, 16S rDNA was amplified, and randomly selected clones were sequenced.

Two bacteria phylotypes are predominant in the Suiyo seamount hydrothermal plume.

Microbial diversity and populations in a hydrothermal plume that was present inside the caldera of the Suiyo Seamount, a submarine volcano on the Izu-Bonin Arc, were investigated by performing a phylogenetic analysis of the 16S rRNA gene and by using fluorescence in situ hybridization (FISH). Corresponding to transmissivity, an indicator of turbidity, the vertical total cell count as determined by 4',6'-diamidino-2-phenylindole (DAPI) staining varied from 5.6 x 10(4) to 1.