南极海冰耐盐细菌NJ82的分子鉴定及其耐盐性初步研究

Molecular Identification of a Halotolerant Bacterium NJ82 from Antarctic Sea Ice and Preliminary Study on Its Salt Tolerance

从129株南极海冰细菌筛选到1株耐盐细菌NJ82，该菌最适生长盐度是12％，能够耐受最高盐度为18％。对该菌株进行16S rRNA基因序列的同源性和系统发育分析，结果表明：菌株NJ82属于Pseudoalteromonas属。从总蛋白质、脯氨酸、丙二醛（MDA）含量及膜透性变化等方面对高盐的适应性进行初步探讨。结果表明，当盐度介于3．3％～12．0％时，随着盐度升高，菌株的蛋白质和脯氨酸含量呈快速增加趋势，而MDA含量和膜透性变化幅度不大；随着盐度进一步升高，蛋白质含量呈下降趋势，脯氨酸变化幅度不大；而MDA含量升高和膜透性变化都达到极显著水平（P〈0．01）。这些重要生理参数的变化将有助于了解海冰细菌在高盐环境下的适应机制。

Halotolerant bacterium NJ82 was screened from 129 strains of Antarctic sea ice bacteria. Optimum salinity for the growth of this strain was 12% （W/V）, and the highest salinity tolerance was 18% （W/V）. The 16S rRNA gene sequences homology and phylogenetic analysis showed that strain NJ82 belonged to the genus Pseudoalteromonas. The contents of protein, proline, Malondialdehyde（MDA）and cell membrane permeability growing at different salinity were analyzed. When salinity was in the range of 3.3%-12.0% （W/V）, the protein and praline content both greatly rose with the increase of salinity, but the MDA content and cell membrane permeability varied little. When the salinity was above 12.0 % （W/V）, protein content decreased, while MDA contents and cell membrane permeability significantly increased with the increase of salinity. These changes of important physiological parameters would offer significant information to understand the adaptation mechanism of sea ice bacterium to high salinity conditions.