乳杆菌喂食大鼠后目标菌克隆筛选与确认

Screening and confirming of target strains from the faeces of rats fed with lactobacilli strains feed to SD rat

目的确认乳杆菌能否顺利通过胃酸屏障并在肠道内定植为进一步研究乳杆菌对大鼠的生理代谢影响做基础,为乳杆菌菌株的应用提供有效依据。方法采用浓度梯度药物平板筛选利福平耐受菌株,用耐利福平(15 mg/L)乳杆菌菌株喂食SD雄性大鼠并采集其新鲜粪便,在耐药平板上筛选出能在大鼠结肠内定植良好的耐药菌株,并得到16S rDNA的鉴定结果,利用16S rDNA序列同源性分析对乳酸菌进行分类鉴定。结果粪便中检测出的乳杆菌耐药菌株经纯化鉴定后与所喂食的乳杆菌同源。结论实验所筛选出的耐利福平乳杆菌在大鼠结肠内成功定植。

Objective To confirm whether lactobacilli could overcome the gastric acid barrier and localize in the intestines of rats,so to provide basis for further studies on the effect of lactobacilli′s localization on rats′ physiological characteristics and for the application of the strains.Method Plates with grediant concentration of rifampicin were used to screen the resistant strains.Rifampicin-resistant lactobacilli（15 μg/mL） were fed to SD and then the fresh faeces of the SD male rats were collected.The strains which could localize in rats′ colons well were then genetically identified with 16S rDNA sequence analysis.Result After purification,the lactobacilli resistant strains detected from the male rats′ faeces were identified as homologous to the fed ones.Conclusion The lactobacillus strains screened in this study can localize stably in rat＇s colon.