乳酸菌BC299的鉴定及其对免疫抑制小鼠肠道菌群的影响

以传统发酵泡菜中分离得到的乳酸菌BC299为研究对象，通过形态观察、生理生化、16S rDNA基因序列分析等方法对其进行鉴定，研究其耐酸、耐胆盐、耐抗生素能力，并以环磷酰胺（CTX）诱导免疫抑制小鼠，研究菌株BC299对小鼠粪便中肠道细菌的多样性和相对丰度的影响。结果表明，菌株BC299被鉴定为植物乳杆菌（Lactobacillus plantarum），其对pH2.0和0.3%胆盐具有良好的耐受性；对常见抗生素敏感；能改善CTX诱导小鼠的小肠绒毛和组织形态的破坏，对免疫抑制小鼠的肠道菌群具有调节作用，能正向调节与免疫相关菌群的相对丰度，使小鼠肠道内毛螺菌科（Lachnospiraceae）和瘤胃球菌科（Ruminococcaceae）的相对丰度显著降低（P＜0.05），拟杆菌科（Bacteroidaceae）的相对丰度显著增加（P＜0.05）。

Identification of lactic acid bacterium BC299 and its effect on the intestinal flora of immunosuppressed mice

The lactic acid bacterium BC299 isolated from traditional fermented kimchi was identified by morphological observation, physiological and biochemical, 16S rDNA gene sequence analysis and other methods, and its acid tolerance, bile tolerance, and antibiotic tolerance were studied. Using cyclophosphamide (CTX)-induced immunosuppressive mice as the research objects, the effects of strain BC299 on the diversity and relative abundance of intestinal bacteria in mice feces were studied. The results showed that the strain BC299 was identified as Lactobacillus plantarum, which had good tolerance to pH 2.0 and bile salts 0.3%, the strain was sensitive to common antibiotics, and could improve the intestinal villi and tissue morphology of mice induced by CTX. The strain BC299 had regulatory effect on the intestinal flora of immunosuppressed mice, which could positively regulate the relative abundance of immune-related flora, which resulted in the relative abundance of Lachnospiraceae and Ruminococcaceae decreased significantly (P＜0.05), and that of Bacteroidaceae increased significantly (P＜0.05).