酸应激是导致益生菌制品活菌数目减少、菌体活性降低的重要因素之一。研究表明Ⅱ型毒素-抗毒素(TA)系统是一种特殊的压力反应元件，与细菌的压力反应调控过程密切相关。本课题组在获得长双歧杆菌JDM301全基因组数据的基础上，在其基因组中鉴定出功能Ⅱ型TA系统MazEFBif（MazEF：Ⅱ型TA系统中的一个家族），并发现MazEFBif参与菌株的酸应激反应，目前国际上尚未见相关报道。然而MazEFBif在JDM301酸应激调控网络中的作用、与其他应激蛋白的关系及相关分子机制尚不清楚。本项目拟在明确MazEFBif激活及作用机制基础上，结合蛋白质组学和细菌双杂交技术筛选JDM301酸应激过程中MazEFBif作用蛋白，并通过蛋白质-蛋白质、蛋白质-DNA相互作用分析技术鉴定上述相互作用关系。本项目的开展对挖掘双歧杆菌新的酸应激调控机制和解决目前双歧杆菌制剂过胃时存活率偏低的现象具有重要价值和意义。

Acid stress can result the reduction of the number and activity of probiotics. The type Ⅱtoxin-antitoxin (TA) systems are special stress element and they play important roles in the bacterial stress response. Based on the complete genomic sequences of Bifidobacterium longum JDM301, our group identified an functional type ⅡTA system-MazEFBif (MazEF: a family of type ⅡTA system ) and found that MazEFBif was involved in the stress response of JDM301 to acid stress. So far, there is no report about TA system in Bifidobacterium. However, the role of MazEFBif in the acid stress regulation of JDM301, the related molecular mechanism and the relationship between MazEFBif and the other stress proteins are still unclear. Our group will further reveal the mechanism of activation and function of MazEFBif and find the interaction proteins of MazEFBif in the acid stress response by proteomic approache and bacterial two-hybrid analysis. Furthermore, the relationship of MazEFBif and its interaction proteins and the related mechanisms will be explored by protein-protein interaction analysis and protein-DNA interaction analysis. The investigation of MazEFBif and its interaction proteins will bring us deeper insight into the mechanism regulating the acid stress response of Bifidobacteria and be helpful to improve the survival rate of Bifidobacterium-related products during the passage of stomach .