【作者】 刘咪； 王银； 李光辉； 胡园园； 夏效东； 席美丽； 王新； 孟江洪； 杨保伟；

【Author】 Liu Mi;Wang Yin;Li Guanghui;Hu Yuanyuan;Xia Xiaodong;Xi Meili;Wang Xin;Meng Jianghong;Yang Baowei;College of Food Science and Engineering,Northwest A&F University;College of Food Engineering and Nutritional Science,Shaanxi Normal University;Joint Institute for Food Safety and Applied Nutrition,and Department of Nutrition and Food Science,University of Maryland,College Park;

【机构】 西北农林科技大学食品与科学学院； 陕西师范大学食品工程与营养科学学院； 美国马里兰大学食品科学系；

【摘要】 研究4株错配修复缺陷的野生型食源性沙门氏菌超级突变子中错配修复系统基因缺陷对其中20个功能基因突变与表达的影响,以及功能基因的变异对突变子突变频率和多重耐药性增加的作用。结果表明:4株超级突变子中,AcrB,TolC,MarR,ParC,MutS,MutL,MutT,UvrD,HilA和OmpF基因发生了氨基酸突变,其中AcrB和MutL中突变检出率最高。与标准沙门氏菌LT2相比,超级突变子中mutS,marR和parC的表达量增加,acrB和mutH的表达量降低,acrA,ompR和mutT的表达量没有显著差异,marA,gyrA和mutL也没有显示显著的过量表达。MMR系统中,MutS,MutL和UvrD的突变对AcrB,OmpF和HilA的突变影响显著,与MutS相比,MutI和UvrD的与相关基因突变的相关性更大。突变频率与MutS,MutL和UvrD的突变呈现负相关。MutS,MutL,MutT,UvrD,OmpF和AcrB基因突变显著影响着超级突变子的耐药能力,soxS,mutI和gyrA的表达也与超级突变子的耐药能力显著相关,而与mutS,mutI,ompF,ompR,acrE和marR无显著相关。MMR系统中,mutH的表达对基因的突变频率占主导地位,与mutS,mutL和uvrD相比,与突变频率呈正相关。更多还原

【Abstract】 Mutation and expression of 20 functional genes in four naturally occurring mismatch repair(MMR) system deficient foodborne Salmonella hypermutators were detected for the influence of MMR deficiency on gene mutation and expression,and their contribution to the increased mutation frequency and multi-drug resistance.Amino acid substitutions were detected in AcrB,TolC,MarR,ParC,MutS,MutL,MutT,UvrD,HilA and OmpF of four hypermuators,and mutations in AcrB and MutL were most frequently detected.Compared to those of Salmonella typhimurium LT2,among four hypermutators,expression levels of mutS,marR and parC increased while acrB and mutH decreased;no significant difference was detected among the expression level of acrA,ompR and mutT;marA,gyrA,and mutL did not show remarkable overexpression.Amino acid substitutions of MutS,MutL and UvrD in MMR system significantly influenced the mutations of AcrB,OmpF and HilA,and those mutations were more strongly related to the mutation of MutL and UvrD than that of MutS.Mutation frequency of the hypermutators was negatively correlated with amino acid substitution of MutS,MutL,and UvrD.Antimicrobial resistant capability of the hypermutators was significantly influenced by the mutations of MutS,MutL,MutT,UvrD,OmpF and AcrB,and significantly correlated with the expression of soxS,muth and gyrA,and was not so close to mutS,mutT,ompF,ompR,acrE and marR expression.Among genes in MMR system,expression of mutH played a dominant role to the mutation frequency and positively correlated with mutation frequency compared to that of mutS,muth,and uvrD.更多还原