基于群体感应通路解析保加利亚乳杆菌自溶的分子机制

项目名称： 基于群体感应通路解析保加利亚乳杆菌自溶的分子机制

项目编号： No.31471603

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 农业科学

项目作者： 逄晓阳

作者单位： 中国农业科学院原子能利用研究所

项目金额： 80万元

中文摘要： 乳酸菌自溶会导致乳酸菌的死亡和胞内酶的释放，对发酵乳制品的风味形成、品质特性及生产周期等具有重要影响。阐明乳酸菌自溶的机理，为实现今后定向筛选和构建不同自溶度的乳品工业用菌株具有重要意义。本课题组在前期的研究过程中发现乳酸菌发生自溶的程度与发酵液中菌体密度呈正相关，并以此为切入点从保加利亚乳杆菌Ljj-6基因组中克隆出了群体感应（quorum-sensing）相关的双组分信号转导系统（TCS）和QS信号分子基因全序列，通过菌体培养液中添加人工合成信号分子实验，证实了周围培养液中信号分子浓度的累积是导致保加利亚乳杆菌菌体发生自溶的重要因素。但是菌体感知环境密度信号后，通过哪条通路触发了菌体的自溶过程是下一步需要解决的关键问题。本研究以上述实验为基础，采用转录组测序分析手段对QS信号分子传导通路的相关基因进行研究，筛选出乳酸菌自溶过程中的起主导作用的关键调控基因，为阐释乳酸菌自溶机理奠定基础。

中文关键词： 保加利亚乳杆菌；自溶；群体感应；信号分子

英文摘要： Autolysis of Lactic acid bacteria (LAB) plays a vital role in the process of flavour during cheese ripening while restricts the proliferation of cell in yogurt fermentation and probiotics production.Therefore,It is necessary to clarify the mechanism of autolysis for the different requirement of various products.Because the bacteria autolysis is often accompanied by cell lysis, the previous research on cell autolysis mostly around the autolytic enzyme. But so far, mechanism of lactic acid bacteria autolysis is still no clear. With bacterial quorum-sensing phenomenon was found, revealing the bacterial flora has social attribute, the researchers found that many physiological activities including biofilm formation, antibiotic synthesis, competent cell formation had intimate relationships with the quorum sensing system. But for the autolysis of lactic acid bacteria and quorum-sensing signal molecules secreted whether there is a correlation, no related research in this area by now. Therefore, this study focuses on the research of lactic acid bacteria quorum-sensing system, degeneracy primers will be designed by using biological information, using the degeneracy primers, gene sequences of the lactic acid bacteria QS signal molecules will be cloned. Analysis of related genes of QS signal transduction pathway will be studied by using transcriptome sequencing method. Objective is to find the key regulatory gene of lactic acid bacteria autolysis, and will lay the theoretical foundation for directional control and selection of different autolytic lactic acid bacterias.

英文关键词： lactobacillus bulgaricus;autolysis;quorum-sensing;signal molecule