鼠伤寒沙门菌rpoS基因缺失菌株的构建及RpoS因子在环境胁迫下的作用  

Construction of a Stationary-Phase Sigma Factor Gene(rpoS) Defective Mutant of Salmonella typhimurium and Function of RpoS Factor under Environmental Stress

作　　者：梁运改 桂萌[2] 王顺[2] 刘密 张清[1] 周康[1] LIANG Yungai;GUI Meng;WANG Shun;LIU Mi;ZHANG Qing;ZHOU Kang(College of Food Science, Sichuan Agricultural University, Ya’an 625014, China;Beijing Fisheries Research Institute, Beijing 100071, China)

机构地区：[1]四川农业大学食品学院,四川雅安625014 [2]北京市水产科学研究所,北京100071

出　　处：《食品科学》2018年第6期141-147,共7页Food Science

基　　金：教育部"春晖计划"项目(Z2016117)

摘　　要：鼠伤寒沙门菌在应对环境胁迫时,通过自身的调节机制适应环境,其中Rpo S因子在其中起着重要的作用。为研究Rpo S因子在环境胁迫下对鼠伤寒沙门菌的影响,本研究用Red同源重组技术构建鼠伤寒沙门菌Salmonella typhimurium 1344的rpo S缺失菌株SL1344/Drpo S,并在不同条件下比较亲本菌株SL1344和基因缺失菌株SL1344/Drpo S的生长情况,这些条件分别为:3.5%NaCl、42℃、pH 4.0。此外本实验还重点研究了沙门菌在不同盐质量分数中预处理不同时间后置于含3.5%NaCl的培养基中培养的生长情况,以说明rpo S对于沙门菌在逆境中适应性的影响。结果表明在3.5%NaCl条件下,二者生长均受到较大的抑制作用,且SL1344/Drpo S受到的抑制作用更大,SL1344的最大生长速率为SL1344/Drpo S的2.49倍;在42℃条件下,SL1344的最大生长速率仅为SL1344/Drpo S的1.33倍,而在pH 4.0条件下,SL1344的最大生长速率为SL1344/Drpo S的2.77倍;此外,二者在不同盐质量分数中处理不同时间后的生长情况也存在差异。rpo S基因缺失菌株SL1344/Drpo S的构建为进一步研究Rpo S因子在鼠伤寒沙门菌应对环境胁迫的作用机制,以及为预防和控制由沙门菌导致的食源性疾患提供了理论支持。Salmonella typhimurium adapts to environmental stresses through its own regulatory system,in which the stationary-phase sigma(RpoS)factor plays an important role.The objective of this study was to construct a rpoS-defective mutant strain(SL1344/DrpoS)of S.typhimurium SL1344using Red homologous recombination technique and to compare the growth of SL1344/DrpoS and SL1344under different stresses including3.5%NaCl,42℃,and pH4.0.Besides,this research also focused on the effect of pre-treatment of Salmonella with different concentrations of salt on its growth in a medium containing3.5%NaCl in order to demonstrate the effect of rpoS on the adaptability of S.typhimurium to the stressful environment.The results showed that the growth of both strains was inhibited by3.5%NaCl,and SL1344/DrpoS was more significantly inhibited.The maximum growth rate of SL1344was2.49times as higher as that of SL1344/DrpoS.Under the conditions of42℃and pH4.0,the maximum growth rate of SL1344was1.33and2.77times as higher as that of SL1344/DrpoS,respectively.There were differences in the growth of the two strains after stimulation by different salt concentrations for different times.The construction of SL1344/DrpoS can lay the foundation for further study on the role of RpoS of S.typhimurium in response to environmental stresses and for the prevention and treatment of salmonellosis.

关 键 词：鼠伤寒沙门菌 基因敲除 RPOS 渗透压 温度 pH值 

分 类 号：Q786[生物学—分子生物学]