优良动物源抗汞益生乳酸菌的筛选及其抗性基因的克隆

发布时间：2019-05-23 20:03

【摘要】：为了分离具有重金属汞抗性的优良益生乳酸菌,并挖掘细菌汞抗性的基因,应用于动物机体重金属中毒的解毒治疗,试验从健康狐狸和貉子粪便中筛选出耐酸、耐胰酶、耐胆汁、抗菌并具有较高汞抗性的乳酸菌,采用16S rRNA基因序列分析鉴定,并用PCR方法扩增mer A基因,从72株优良益生菌中逐级筛选出耐酸、耐胰酶、耐胆盐、抗菌性能好并能耐受500 mg/L HgCl_2的高浓度重金属汞的一株细菌,命名为CJT-KHg1,测定了其益生特性指标。结果表明:经过16S rRNA序列分析,该菌株为乳酸片球菌;该菌株的mer A基因序列与克雷伯氏菌、阴沟肠杆菌、希瓦氏菌mer A基因序列的同源性达到99%,证明为乳酸片球菌;从该菌株中克隆到的汞抗性基因为汞还原酶基因(Mercury reductase)。
[Abstract]:In order to isolate excellent probiotic lactic acid bacteria with mercury resistance of heavy metals and excavate genes resistant to mercury in bacteria, and to apply them to detoxification and treatment of heavy metal poisoning in animals, acid and pancreatic enzymes were screened out from the feces of healthy foxes and raccoon dogs. Lactic acid bacteria resistant to bile and bacteria with high mercury resistance were identified by 16s rRNA gene sequence analysis, and mer A gene was amplified by PCR. Acid resistance, pancreatic enzyme resistance and bile salt tolerance were screened out step by step from 72 strains of excellent probiotics. A strain of bacteria with good antibacterial performance and tolerance to 500 mg/L HgCl_2 of high concentration of heavy metal mercury was named CJT-KHg1, to determine its probiotics. The results showed that the strain was Lactococcus lactis after 16s rRNA sequence analysis, and the homology of mer A gene sequence with Klebsiella, Enterobacter cloacae and Shiva mer A gene sequence was 99%, which was proved to be Lactococcus lactococcus, and the homology of Lactic acid A gene sequence between the strain and Klebsiella, Enterobacter cloacae and Shiva was 99%. The mercury resistance gene cloned from the strain was due to the mercury reductase gene (Mercury reductase).
【作者单位】：东北农业大学动物医学学院;
【基金】：黑龙江省大学生创新创业训练计划项目(201510224031)
【分类号】：Q93

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