新疆额尔齐斯河流域冷水鱼肠道耐低温乳酸菌的分离筛选及其遗传差异

Isolate and genetic heterogeneity of psychrotrophic lactic acid bacteria from the intestinal tract of cold-water fishes from the Eerqisi river，Xinjiang

摘要:

摘要:【目的】从新疆阿勒泰地区额尔齐斯河流域冷水鱼肠道中分离耐低温的乳酸菌，挖掘乳酸菌的物种和遗传多样性，为低温乳酸菌生物技术研发提供优良菌种。【方法】利用MRS、Elliker两种不同培养基从9种冷水鱼肠道中，分离筛选出耐低温菌，测定细菌最适生长温度并进行常规生理生化实验。根据16S rRNA基因序列初步确定耐低温菌的系统进化地位，并采用BOX、(GTG) 5、ERIC三种不同的引物进行rep-PCR，对16S rRNA 基因高度同源性的菌株进一步区分。【结果】分离得到78 株耐冷菌，最终确定有24株为耐低温乳酸菌，菌株的最适生长温度在15－24℃之间。系统发育分析结果表明:24 株耐低温乳酸菌隶属于6个属，其中肉杆菌属(Carnobacterium)3株，乳球菌属(Lactococcus)9株，肠球菌属(Enterococcus)7株，环丝菌属(Brochothrix)1株，魏斯氏菌属(Weissella)2株，链球菌属(Streptococcus)2株。指纹图谱聚类分析树状图显示乳球菌属(Lactococcus)和肠球菌属(Enterococcus)存在种及菌株水平上的遗传差异，前者包括4个种，后者2个种。【结论】新疆额尔齐斯河流域冷水鱼肠道中分离的耐低温乳酸菌以球菌为主，没分离到常见的乳杆菌，需进一步完善分离培养的方法，深入挖掘和研究其物种多样性和遗传多样性。

Abstract:

Abstract:［Objective］The purpose of this study was to select cold-adapted lactic acid bacteria (LAB) from the intestinal tract of cold-water fishes from the Eerqisi river Alatai． Xinjiang.［Methods］By using culture medium MRS and Elliker，isolation of lactic acid bacteria (LAB) from 9 intestinal canal of cold-water fishes was carried out. Taxonomic identity and genetic diversity of strains isolated were determined by partial 16S rRNA gene sequences and rep-PCR with three different kinds of primers named BOX，(GTG) 5，ERIC.［Results］A total of 78 ychrotrophic isolates were obtained．Among them，24 isolates had characteristics of LAB and showed the optimal growth temperature ranging from 15 to 24℃ ． The phylogenesis result showed that 24 strains belonged to 6 Genuses，Carnobacterium (3 strains)，Lactococcus (9 strains)，Enterococcus (7 strains)，Brochothrix (1 strain)，Weissella (2 strains)，Streptococcus (2 strains). rep-PCR clustering analysis showed that Lactococcus and Enterococcus strains were from different Species． Lactococcus were belonged to 4 species while Enterococcus assigned to 2 species． ［Conclusion］The phylogenetic diversity of cold-adapted LAB from the intestinal tract of cold-water fishes from the Eerqisi river in the Alatai Xinjiang was relatively abundant.