内陆土壤冷适应细菌的筛选分类与细胞膜脂肪酸的适冷机制

Isolation and Classification of Cold-adapted Microorganisms and Pattern of Membrane Fatty Acids in Cold-adaptation

摘要:

嗜冷菌及耐冷菌是冷适应酶及生物活性物质的重要资源。本研究从内陆土壤筛得33株冷适应细菌, 包括6株革兰氏阳性菌与27株革兰氏阴性菌。通过细胞膜脂肪酸分析表明, 革兰氏阳性菌的膜脂肪酸主要为分支脂肪酸, 推测分支结构是阳性菌膜脂的主要适冷机制。革兰氏阴性菌呈现了不饱和、分支、短链等多样的膜脂适冷调节方式。根据脂肪酸组分的多样性, 选择并鉴定了17株嗜冷及耐冷菌分布在11个属中, 细胞膜脂肪酸组成的变化规律与细菌16S rRNA的进化分布高度一致。研究还表明同为不饱和脂肪酸为主的革兰氏阴性菌呈现了不同的适冷机理。相关研究不仅阐述了冷适应细菌的细胞膜脂肪酸的适应机制, 而且为相关适冷酶源的开发利用提供了宝贵的资源。

Abstract:

Psychrophiles and Psychrotolerants are important resources of biologically active substances and cold-adapted enzymes. A total of 33 cold-adapted strains, including 6 Gram-positive strains and 27 Gram-negative strains, were isolated from soil samples. The analysis of these membrane fatty acids showed that the branched chain fatty acids were the major lipid pattern in Gram-positive bacteria, which may indicates their main cold adapted mechanism. However, the membrane fatty acids of Gram-negative bacteria were various, including unsaturated, branched and short-chain fatty acid. Species identifications were committed for 17 strains with typical fatty acid compositions. They were distributed in 11 genus. Variation of cell membrane lipid composition was consistent with the result of 16S rRNA. In addition, the Gram-negative bacteria exhibited the different strategies on cold adaptation, even that these strains mainly contained the unsaturated fatty acid. Related researches would not only represent cold adapted mechanism of cold-adapted microorganisms, but also provide the precious resources for the utilization of cold-adapted enzymes.