Isolation and properties of barophilic and barotolerant bacteria from deep-sea mud samples

Abstract

Several barophilic and barotolerant bacteria were isolated from deep-sea mud samples of Suruga Bay (2485 m depth), the Ryukyu Trench (5110m depth), and the Japan Trench (land-side 6356 m, and sea-side 6269 m depth, respectively). The barophilic bacteria, strains DB5501, DB6101, DB6705 and DB6906, were able to grow better under high hydrostatic pressures than under atmospheric pressure (0.1 megapascals; MPa). The optimal growth pressures for the barophilic bacteria were approximately 50 MPa at 10°C. The barotolerant strains DSKl and DSS12 were determined to be psychrophilic, and had optimal growth temperatures of 10°C and 8°C respectively. The degree of barophily and barotolerance was shown to be very dependent on temperature. For example, at 4°C the barophilic strains were indistinguishable from barotolerant bacteria, whereas at 15°C the barotolerant strains behaved more like the barophilic strains. Based on sequence analysis of 16s ribosomal DNA, all of the strains included in this study belong to the gamma subgroup of the Proteobacteria. Phylogenetic relations between the isolated strains and the known gamma subgroup bacteria suggested that the isolated strains belong to a new sub-branch of this group.

Piezotolerance of the Respiratory Terminal Oxidase Activity of the PiezophilicShewanella violaceaDSS12 as Compared with Non-PiezophilicShewanellaSpecies

“…1A) contributed to the growth of DSS12, because it can grow at pressures between 0.1-70 MPa. 1) On the other hand, the temperature dependency of the activity was almost the same for all of the tested strains regardless of optimal growth temperatures and pressures (Fig. 1B).…”

“…This well-investigated bacterium displays optimal growth at a temperature of 8 C and a pressure of 30 MPa (growth from 0.1 MPa to 70 MPa). 1,2) It is known to alter in respiratory components according to the hydrostatic pressure of growth. 3) Under high pressure, 50 MPa, expression of cytochrome c 4 was repressed 4) and that of the d-type cytochrome was enhanced at the transcriptional level.…”

Shewanella gelidimarina sp. nov. and Shewanella frigidimarina sp. nov., Novel Antarctic Species with the Ability To Produce Eicosapentaenoic Acid (20:5 3) and Grow Anaerobically by Dissimilatory Fe(III) Reduction

“…16s rRNA-based phylogenetic analysis indicates that the psychrophilic, barophilic or barotolerant, deep-sea bacteria (6,7,16,17) are closely related to S. benthica or [K] marinus (Fig. 1).…”

“…Colwellia psychroerythrus, and an assortment of barophilic or barotolerant strains examined in other studies (6,16,17). S.…”

“…Sequences of the following organisms (with GenBank accession numbers in parentheses) were utilized in the phylogenetic analysis and were obtained directly from GenBank: Colwellia psy- (12), and barophilic or barotolerant strains DB6705 (D21222), DB6906 (D21223), DSKl (D21224), DSS12 (D21225), and DB5501 (D21229) (16). 16s rRNA sequences of the following strains were obtained in this study and were deposited in GenBank (accession numbers are given in parentheses): S. alga ACAM 541T (AF006669);…”