摘要
以酸马奶酒中分离出的1株高产信号分子AI-2(Autoinducer-2)的屎肠球菌(Enterococcus faecium)8-3为研究对象,通过改变菌株生长环境(p H值、温度、渗透压、营养条件)探究对菌株Lux S/AI-2群体感应系统的影响。采用生物学方法和实时荧光定量聚合酶链式反应法检测信号分子AI-2产量及相关基因lux S和pfs表达量的变化。结果表明:轻度酸性胁迫会诱导E.faecium 8-3信号分子AI-2的产生,碱性条件下菌体生长旺盛,菌体密度主要介导信号分子AI-2产生;在渗透压和低温胁迫时,E.faecium 8-3菌体密度和信号分子AI-2的产生同时受到抑制,菌体密度调控信号分子AI-2的产生;低6-82营养胁迫可以诱导E.faecium 8-3产信号分子AI-2。不同环境胁迫下E.faecium8-3的lux S和pfs基因表达均有不同程度的变化,说明Lux S/AI-2群体感应系统参与菌株的抗逆过程。
Enterococcus faecium8-3,which was isolated from koumiss and screened for autoinducer-2(AI-2),was used to study the effects of growth conditions(pH value,temperature,osmotic pressure,and nutrient condition)on the LuxS/AI-2q uorum sensing system.The production of AI-2was detected by a biological method and the expression levels of luxS and pfs genes were detected by real-time quantitative PCR.The results showed that mild acid stress induced E.faecium8-3to produce the AI-2.Under alkaline conditions,the cell grew better,and the cell density mainly induced the production of AI-2.Under osmotic and low temperature stresses,the growth of E.faecium8-3and the production of AI-2were both inhibited.Cell density controlled AI-2production.Low nutrient stress could induce E.faecium8-3to produce AI-2.The expression of luxS and pfs genes in E.faecium8-3under different environmental stresses varied to different degrees,indicating that the LuxS/AI-2quorum sensing system mediates stress resistance in E.faecium8-3.
作者
顾悦
李博
吴荣
田建军
吴敬
贺银凤
GU Yue;LI Bo;WU Rong;TIAN Jianjun;WU Jing;HE Yinfeng(College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2018年第6期75-81,共7页
Food Science
基金
国家自然科学基金地区科学基金项目(31360396)
