A denitrifying bacterium from the deep sea at 11 000-m depth

Abstract

The denitrifying bacterium strain MT-1 was isolated from the mud of the Mariana Trench. The optimal temperature and pressure for growth of this bacterium were found to be 30 degrees C and 0.1 MPa, respectively. However, it showed greater tolerance to low temperature (4 degrees C) and high hydrostatic pressure (50 MPa) as compared with denitrifiers obtained from land. From the results, it can be said that this organism is adapted to the environment of the deep sea. Strain MT-1 was shown to belong to the genus Pseudomonas by analysis of its 16S rDNA. The cytochrome contents of the bacterium were similar to those of Ps. stutzeri in spectrophotometric studies.

Biology of Pseudomonas stutzeri

“…On 28 February 1996, a sediment sample was obtained from the Mariana Trench by the unmanned submersible Kaiko. It seems likely that this was the first time sediment samples were collected from the world's deepest point without any microbiological contamination from other depths (351). The analysis of amplified 16S rRNA sequences from DNA directly extracted from these sediment samples demonstrated the presence of bacteria belonging to the P. aeruginosa branch (Mariana bacteria no.…”

The Respiratory System of the PiezophilePhotobacterium profundumSS9 Grown under Various Pressures

“…Spectral analysis of the fractions for cytochrome contents was performed basically as described previously. 13,26) Reduced forms were prepared by adding a small amount of Na 2 S 2 O 4 , and oxidized forms were prepared by adding a small amount of (NH 4 ) 2 S 2 O 8 . Measurements were carried out with a Shimadzu UV-1800 spectrophotometer (Shimadzu, Kyoto, Japan).…”

Purification, Characterization, and Overexpression of Psychrophilic and Thermolabile Malate Dehydrogenase of a Novel Antarctic Psychrotolerant,Flavobacterium frigidimarisKUC-1

“…[2][3][4][5][6] Most of Earth's environment is cold, since about three-quarters of its surface is covered by deep oceans, high mountains, and the Arctic and Antarctica, where the temperatures are permanently below 4 C. Various psychrophilic microorganisms that have adapted not only to cold environments but also to other extreme environments, such as high osmotic pressure and high ion-strength environments, have been found in soils and waters. [7][8][9] These microorganisms generally produce various psychrophilic and thermolabile enzymes in order to grow effectively under cold conditions. [10][11][12][13][14][15] These psychrophilic enzymes have effective threedimensional structures, show high catalytic activity under a cold environment, and usually lose their activities completely even at about 30 C. 16) Psychrophilic enzymes show a character opposite to the thermostable enzymes, and much attention has been paid to their molecular structure, function, and detailed properties.…”