南方医科大学学报

南方医科大学学报 ›› 2006, Vol. 26 ›› Issue (06): 839-842.

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乳链菌肽抗性基因的筛选、分离及鉴定

云雪霞； 胡静； 陈清；   

  1. 南方医科大学公共卫生与热带医学学院流行病教研室； 南方医科大学公共卫生与热带医学学院流行病教研室 广东广州510515； 广东广州510515；
  • 出版日期:2006-06-20 发布日期:2006-06-20

Screening, isolation and identification of nisin resistance determinant gene in strains of Lactococcus lactis

YUN Xue-xia, HU Jing, CHEN Qing Department of Epidemiology, Southern Medical University, Guangzhou 510515, China   

  1. 南方医科大学公共卫生与热带医学学院流行病教研室； 南方医科大学公共卫生与热带医学学院流行病教研室 广东广州510515； 广东广州510515；
  • Online:2006-06-20 Published:2006-06-20

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摘要： 目的筛选、分离、鉴定乳链菌肽抗性(NSR)基因。方法从20份经巴氏消毒的牛奶及未经任何处理的若干新鲜牛奶的混合样品中,在含有添加剂的选择性培养基上筛选含有NSR基因的乳酸乳球菌,用乳酸乳球菌特异性16SrRNA的PCR方法对菌株进行鉴定,进一步用一段保守序列进行NSR基因筛选,并扩增其全序列,分析其基因特征。结果两种牛奶样品中均可以分离到乳酸乳球菌,并在从新鲜牛奶中分离到的乳酸乳球菌中筛选出30株乳链菌肽抗性菌株,其中3株扩增出NSR基因,琼脂糖凝胶电泳确定其大小为1000bp左右,进一步酶切鉴定及测序确定其确为NSR基因,定位于质粒上。结论从来源于鲜牛奶的抗乳酸乳球菌菌株中扩增出完整NSR基因,定位于质粒上。 

Abstract: Objective To isolate and identify nisin resistance determinant (NSR) gene from Lactococcus lactis. Methods The Lactococcus lactis strains harboring NSR gene were isolated from different milk samples by selective culture supplemented with nisin and confirmed by PCR detection of 16S rRNA. Nisin resistance determinant gene was determined by PCR amplification, enzyme digestion and sequencing. Results Thirty nisin-resistant Lactococcus lactis strains from fresh milk samples were obtained. Three of these strains contained NSR gene of about 1000 bp as determined by agarose gel electrophoresis and further confirmed by enzyme digestion and sequence analysis. The NSR gene was located on the plasmid of Lactococcus lactis. Conclusion Complete NSR gene, located on the bacterial plasmid, has been successfully isolated from nisin-resistant Lactococcus lactis strains from fresh milk. 

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