秦岭地区野生细鳞鲑肠道微生物多样性及产酶活性分析

为探究秦岭地区野生细鳞鲑(Brachymystax lenok)肠道细菌组成多样性,筛选出产胞外酶菌株,利用传统分离培养并分子鉴定的方法和基于16S r RNA基因克隆的现代分子生物技术相结合测定秦岭野生细鳞鲑肠道细菌菌群多样性并构建系统发育树,利用淀粉酶、蛋白酶、纤维素酶及脂肪酶4种胞外酶筛选培养基筛选出产上述酶的细菌。细菌传统分离培养并分子鉴定法从细鳞鲑肠道获得18个属的细菌类群,分别归属于变形菌门、拟杆菌门和厚壁菌门,其中,气单胞菌属(Aeromonas)为优势菌群。基于16S r RNA基因克隆的现代分子方法获得22个属的细菌类群,分别归属于变形菌门、拟杆菌门、厚壁菌门和放线菌门,其中,鞘氨醇杆菌属(Sphingomonas)为优势菌群。4种胞外酶筛选获得53株细菌产胞外酶,其中21株可在低温(10℃)环境下产胞外酶。结果表明,传统分离培养法与基于16S r RNA基因克隆的现代分子生物技术相结合能够更有效全面地分析细鳞鲑鱼肠道微生物的多样性,并且细鳞鲑肠道微生物具有一定的产酶活性。

Analysis of Microbial Diversity and Enzyme Activity in the Gut of Wild Brachymystax lenok from Qinling Mountains

This research aimed to understand the bacterial diversity in the gut of wild Brachymystax lenok and screen extracellular enzyme-producing strains. We analyzed the species diversity of bacteria based on 16S rRNA phylogenetic relationships and screened isolates that produced extracellular enzymes including amylase, protease, cellulase and lipase. A total of 18 bacterial genera isolated were respectively belonged to Proteobacteria, Bacteroidetes and Firmicutes. Aeromonas were the dominant groups. On the basis of culture-independent approach, a total of 22 bacterial genera were classified into Proteobacteria, Bacteroidetes and Firmicutes and Chlorophyta. Sphingomonas were the dominant genera (Table 1, Fig. 3, 4). Screening of enzyme activities showed that 53 strains produced different extracellular enzymatic activities and that 21 strains could produce extracellular enzymes in a low temperature (Table 2). This study revealed that combination of traditional separation culture and modern molecular biotechnology based on 16S rRNA gene cloning could be used to effectively analyze the bacterial diversity in the gut of wild B. lenok from Qinling mountainous regions and to obtain diverse enzyme-producing bacterial strains.