北极耐冷假交替单胞菌的培养温度对其胞外蛋白酶合成的影响

Effect of cultivation temperature on extracellular proteases production of psychrotolerant Pseudoalteromonas strains isolated from the Chukchi Sea, Arctic

从北极楚科奇海水中分离筛选到2株产蛋白酶耐冷细菌BSw20308及BSw20353,经分子鉴定为假交替单胞菌属。这2株菌虽存在较近亲缘关系,16SrDNA序列相似性为98%,但属于不同种,表型方面也存在差异。酶谱分析显示,此2株菌的胞外产物中存在至少3种蛋白水解活性组分。培养温度的变化对这2株菌胞外蛋白水解活性组分的生成具有不同的影响效果,表明极地海洋细菌可能在酶学水平上通过酶的种类与活力的调整和采取不同的策略来适应环境温度的变化。

Two psychrotolerant bacterial strains, BSw20308 and BSw20353, were isolated from the Chuckchi Sea in the Arctic, and they were classified phylogenetically in the genus Pseudoalteromonas based on 16S rRNA gene analysis. Differences in phenotype were found between the two strains, though close relationships existed between them with 16S rDNA sequence similarity of 98 %. The use of zymogram gels revealed the presence of three or more proteolytic bands in culture extract from both strains. These bands may represent individual isozymes, different pmteases, or active subunits of a larger pmteolytic complex. Different effect of the change of cultivation temperature on extracellular pmtease＇ production was found between the two bacterial strains, indicating that different strategies at the enzyme level can be adopted by polar marine bacterium via change of enzyme type as well as enzymatic activity to acclimatize to the change of environmental temperature.