李斯特菌对IIa类细菌素诱导性抵抗的产生和机制研究

项目名称： 李斯特菌对IIa类细菌素诱导性抵抗的产生和机制研究

项目编号： No.31501583

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 农业科学

项目作者： 刘珊娜

作者单位： 天津农学院

项目金额： 20万元

中文摘要： 单增李斯特菌是重要的食源性致病菌，可通过污染的食品进入人体，引发食品安全事件。为了降低李斯特菌感染的风险，必须采取高效可行的方法进行防治。乳酸菌产生的IIa类细菌素对食源性单增李斯特菌具有明显的抑制作用，有望作为生物防腐剂应用于食品工业。本项目以野生型单增李斯特菌为研究对象，通过在实验室条件下诱导获得IIa类细菌素抗性菌，探讨细菌素抗性的产生原因和特点。首先，将筛选获得的细菌素抗性突变菌株的抗性强度水平、频率、稳定性进行研究，分析环境因素对突变菌株抗性特点的影响作用。继而着重从基因表达和调控水平对比野生型菌株和抗性菌株之间的生长代谢差异。对甘露糖磷酸转移酶系统及可能存在的其他细菌素抗性产生机制进行分析，加深对IIa类细菌素作用方式的认识。为IIa类细菌素在食源性致病菌生物防腐领域的应用提供理论依据。

中文关键词： 李斯特菌；细菌素；抗性；食品污染；分子机制

英文摘要： Listeria monocytogenes is an important genus of food-borne pathogens which can transmit into human body through food contamination and cause food safety issue. It is necessary to adopt efficient and feasible control to decrease the risk of Listeria infection. Class IIa bacteriocins produced by lactic acid bacteria show strong inhibition activities against food-borne L. monocytogenes, which have prospect of application in food industry as biopreservatives. This project aims at the wild type L. monocytogenes strains, which are planned to obtain induced resistance to class IIa bacteriocin under laboratory conditions, for exploring the reasons and characteristics of developing bacteriocin resistance. Firstly, the resistant level, frequency, and stability are studied. The influence of environmental factors on the resistant characteristics of mutant strains are analysed. Then the different patterns of growth and metabolism between wild type and resistant strains are evaluated at the levels of gene expression and regulation, targeting to the crucial genes and related metabolism regulation routes. The mannose phosphotransferase system and other possible bacteriocin-resistant mechanisms are evaluated for better understanding the mode of action of class IIa bacteriocins. The results may provide theoretical reference for application of class IIa bacteriocins in biopreservation of food-borne pathogens.

英文关键词： Listeria;Bacteriocin;Resistance;Food contamination;Molecular mechanism