CHARACTERIZATION OF BAROPHILIC DEEP-SEA MICROORGANISMS

为了确定深海常压微生物的特征，从两种方式进行了研究，一种是在东京大学海洋研究所的Hakuho-Maru或Tansei-Maru科考船上巡航期间进行的，另一种是在实验室中进行的来自深海的分离菌株的研究。在白尾丸的巡航过程中，在压力下从日本海沟分离出了几株耐压深海细菌。用高压温度梯度仪(PTG仪)研究了这些菌株的生长特性。从4000m中分离到一株弧菌JT403，其最适生长压力为0.047 h~(-1)，最适温度为5.1℃；另一株专性耐压菌JT 761的最适生长时间为0.054h~(-1)，最适生长压力为600 MPa，最适生长温度为1.8℃。聚类群依赖于分离菌株的n生态位，来自日本深海和沿海的菌株在基因组成上存在显著差异。一个较大的系统发育系是嗜冷或嗜冷的深海弧菌，与海洋弧菌非常接近。另一条线是分布于日本沿海的类华丽弧菌群。

To characterize barophilic deep-sea microorganisms, studies were conducted from two ways, namely, one during a cruise on board the research vessel, Hakuho-maru or Tansei-maru, Ocean Research Institute, University of Tokyo, and another one in the laboratory with isolated strains of bacteria from deep-sea. During the cruise by Hakuho-maru, several strains of barophilic deep-sea bacteria were isolated from the Japan Trench under pressure. The growth characteristics of these strains were investigated using High-Pressure-Temperature-Gradient Instrument (PTG apparatus). One strain JT403, isolated from 4000m, showed optimum growth, 0.047 h^<-1>, at 20MPa and 5.1C.Another obligate barophilic bacterial strain JT 761, showed optimum growth, 0.054h-1, at 600MPa and 1.8 C.Grouping of 60 marine Vibrio strains isolated from surface water to deep-sea in the Pacific Ocean using PCR/RFLP analysis of 16S rRNA genes were conducted. The clusters were depended on the isolated n niche of the strains and showed significant differences in the genotype composition between the strains from the deep-sea and the coastal area of Japan. One large phylogenetic line was psychrophilic or psychrotrophic deep-sea vibrios very close to Vibrio marinus. Another line was V.splendidus-like group distributed in the coastal area of Japan.