绿色魏斯氏菌对单增李斯特菌毒力特性的影响

[目的]本文旨在研究绿色魏斯氏菌与单增李斯特菌共存对单增李斯特菌的生长能力、毒力基因表达及细胞黏附能力的影响，揭示乳酸菌与单增李斯特菌之间的交互作用机制。[方法]采用膜隔离装置，取4℃贮藏条件下放置0、12、24、48和96 h的菌悬液分别测定单增李斯特菌和绿色魏斯氏菌的数量，同时提取单增李斯特菌的RNA进行反转录和荧光定量PCR，分析单增李斯特菌6种主要毒力基因（hlyA、prfA、bsh、actA、sigB和inlA）的表达情况。利用Caco-2细胞进行绿色魏斯氏菌与单增李斯特菌的竞争、排斥和置换试验，观察单增李斯特菌对Caco-2细胞的黏附效果。[结果]产细菌素绿色魏斯氏菌C1可降低单增李斯特菌的数量，而不产细菌素绿色魏斯氏菌C2对单增李斯特菌的生长影响不大。C1和C2的代谢产物使单增李斯特菌6种毒力基因表达量下调，且C1导致的下调趋势比C2大。C1主要通过置换和竞争作用来抑制单增李斯特菌对Caco-2细胞的黏附，而C2的作用较弱。[结论]产细菌素绿色魏斯氏菌C1比不产细菌素绿色魏斯氏菌C2能够更好地控制单增李斯特菌的生长，抑制相关毒力基因的表达，并主要通过置换和竞争作用来抑制单增李斯特菌对Caco-2细胞的黏附。产细菌素绿色魏斯氏菌C1可作为单增李斯特菌的防控菌株。
[Objectives]Under coexistence conditions,the effects of Weissella viridescens on the virulence property,virulence gene expression and cell adhesion ability of Listeria monocytogenes were studied,aiming to provide a theoretical basis for further supplementation mechanism between lactic acid bacteria and L. monocytogenes.[Methods]The number of colonies of L. monocytogenes and W. viridescens was determined by using membrane isolator at 4℃,in 0,12,24,48 and 96 h. At the same time,the RNA of L. monocytogenes was extracted and subjected to reverse transcription and quantitative real-time PCR. Six virulence genes including hlyA,prfA,bsh,actA,sigB in L. monocytogenes were studied. The effect of L. monocytogenes on Caco-2 cells was studied by competition,exclusion and displacement.[Results]The results showed that the bacteriocinogenic W. viridescens C1 was able to inhibit L. monocytogenes at the initial concentration while the non-bacteriocinogenic W. viridescens C2 had little effect. The metabolition of C1 and C2 could decline virulence gene of L. monocytogenes,and W. viridescens C1,compared with W. viridescens C2,had larger downward trend. W. viridescens C1 inhibited the adherence of L. monocytogenes to Caco-2 cells mainly through replacement and competition,while C2 had a weaker effect.[Conclusions]Bacterial toxin of W. viridescens C1 had a better control than non-bacterial toxin of W. viridescens C2 on the growth ability,virulence gene expression and adhesion to Caco-2 cells which was mainly realized through the replacement and compition effect. Bacteriocinogenic W. viridescens C1 can be used as bio-protective culture for L. monocytogenes