冷冻胁迫对金黄色葡萄球菌亚致死及clfA,msrR毒力基因转录的影响  

Effect of Frozen Stress on Sublethal Rule and clf A and msr R Gene Transcriptions of Staphylococcus aureus

作　　者：索标[1,2,3] 居冉 王娜[1,2] 谢新华 潘治利[1] 范会平 艾志录[1,2,3] 

机构地区：[1]河南农业大学食品科学技术学院,郑州450002 [2]河南粮食作物协同创新中心,郑州450002 [3]速冻面米及调制食品河南省高校重点实验室培育基地,郑州450002

出　　处：《中国食品学报》2015年第11期154-159,共6页Journal of Chinese Institute Of Food Science and Technology

基　　金：国家自然科学基金项目(U1204331);"十二五"国家科技支撑计划项目(2012BAD37B07);河南省科技攻关重点项目(152102110055);郑州市重大科技专项(131PZDZX075)

摘　　要：通过测定-18℃冻藏条件下金黄色葡萄球菌亚致死及生理指标的变化规律，探究其冷冻亚致死及耐受机制。通过实时定量荧光PCR研究冷冻胁迫对亚致死金黄色葡萄球菌毒力基因dfA和船rR转录的影响。结果表明：-18℃下冷冻0—90d，金黄色葡萄球菌活性细胞数目减少，亚致死率上升，电导率、蛋白泄漏量、细胞破损率和总糖含量均升高。冷冻90—180d时，活细胞数目不再下降，电导率和蛋白泄漏量趋于平缓，总糖含量下降。实时定量荧光PCR结果显示亚致死金黄色葡萄球菌dfA，mrR基因转录表迭上调。本试验结果表明，在冷冻初期正常金黄色葡萄球菌因低温环境造成的细胞结构损伤而致死。90d后存活的亚致死细胞可抵御冷冻胁迫，维持细胞形态及代谢，然而仍具有感染致病能力和耐药性。With the purpose of investigating the sublethal injury and stress resistance mechanisms of Stahpylococcus aureus during frozen storage, we determined the change rules in sublethal injury and physiological indicators were determined in present study, as well as the transcriptional expressions of clf A and msr R virulence genes by real-time PCR assay. As shown in the results, under the initial 0-90 d of-18 ℃ frozen storage, the total viable cell number of S. aureus gradually reduced along with an increase in sublethal rate. Meanwhile, the electric conductivity, leakage of protein,total sugar content and cell lysis rate all showed increasing trends. However, during the further 90-180 d of frozen storage, the total viable and non-injured viable cell counts of S. aureus were not decreased anymore. The electric conductivity, protein leakage and total sugar content kept constant level from 90-180 d of frozen storage. Real-time PCR results showed that, there were a significant increases in clf A and msr R gene transcription upon 90 d of frozen. During early cold stress, there happened a structural damage in membrane of S. aureus that lead to cell death. Where as cells under sustained low temperature stress can still maintain membrane integrity, a certain degree of biological activity and pathogenicity as well.

关 键 词：金黄色葡萄球菌 冷冻胁迫 亚致死 毒力因子 

分 类 号：R446.5[医药卫生—诊断学]