【作者】 索标； 居冉； 吕海鹏； 王娜； 艾志录；

【Author】 Suo Biao;Ju Ran;Lv Haipeng;Wang Na;Ai Zhilu;College of Food Science and Technology,Henan Agricultural University;Henan Key Laboratory Cultivation Base of Quick-Frozen Flour-Rice Food and Prepared Food,Henan Agricultural University;Henan Engineering Laboratory of Quick-Frozen Flour-Rice Food and Prepared Food,Henan Agricultural University;

【机构】 河南农业大学食品科学技术学院； 速冻面米及调制食品河南省高校重点实验室培育基地； 速冻面米及调制食品河南省工程实验室；

【摘要】 金黄色葡萄球菌在冷冻环境下可长期存活,目前对其存活的分子机制尚不了解。本研究测定了-18℃下冻藏150 d内的金黄色葡萄球菌细胞存活率、亚致死率及生理指标变化,并通过RNA-seq和Real time-PCR研究了正常细胞和亚致死细胞的全部转录本信息,以研究亚致死细胞在冷冻条件下存活的分子机制。研究结果显示,在-18℃冷冻条件下金黄色葡萄球菌能够以亚致死状态存活,亚致死细胞对NaCl胁迫耐受性降低,但较正常细胞的冷冻胁迫耐受性显著增强,可在冷冻环境中维持细胞完整和能量代谢,同时86.8%的基因可完成转录。这种高冷冻胁迫耐受性可能是通过一系列功能基因fdhD、glxK、ssaA、isaA、splA-C-E、cspLA、dnaX和一些非特异性蛋白因子的调节来实现的。此外,值得注意的是亚致死细胞在冷冻胁迫诱导下毒力因子msrR、clfA表达量升高,而耐药相关基因norB表达量降低,说明亚致死细胞在冷冻胁迫下未丧失感染致病性,而对特定药物的耐受性可能有所下降。更多还原

【Abstract】 Staphylococcus aureus(S.aureus) is capable of surviving for an extended time period in a freezing environment;however,its survival mechanism remains unclear.In order to study the molecular mechanism of sublethal cells under a freezing condition,we detected the survival rate,sublethal rate,and physiological indexes of S.aureus that was stored at-18 ℃ for 150 d as well as investigated the entire transcriptomic information of both the normal and sublethal cells using RNA-seq and real-time PCR.The results demonstrated that 5.aureus could survive in a sublethal state under the freezing condition of-18 ℃.The sublethal cells had a low tolerance for NaCl stress,but they were freezing-tolerant as compared to normal cells.Furthermore,the sublethal cells were capable of maintaining both cell integrity and energy metabolism in a freezing environment.Meanwhile,86.8%of genes could be transcribed.The freezing-tolerance may be obtained through the regulation of functional genes,such as fdhD,glxK,ssaA,isaA,splA-C-E,cspLA,and dnaX in addition to some non-specific protein factors.Furthermore,both msrR and clfA expression in the sublethal cells increased in response to freezing stress,whereas the resistance related gene,norB,was less expressed.This suggests that the sublethal cells do not lose infectious pathogenicity under freezing stress,but their resistance to certain drugs may be reduced.更多还原