摘要
为了解单核细胞性李斯特菌(Listeria monocytogenes,Lm)污染食品基质后毒力因子表达的变化,本研究以Lm标准株ATCC 19115为研究对象,将其接种于三文鱼基质及胰酪胨大豆酵母浸膏琼脂(tryptic soy agar-yeast extract,TSA-YE)(对照组)上,于0、4、7℃贮藏条件下分别培养24 h和48 h后,收集菌体提取总RNA,采用反转录实时定量聚合酶链式反应(reverse transcript-quantitative polymerase chain reaction,RT-qPCR)对其4个毒力因子hlyA、inlB、prfA、sigB的表达进行分析。结果表明,在0、4℃和7℃分别培养24 h和48 h后,4个主要毒力因子在三文鱼基质上的表达量均高于平板对照,其中hlyA在贮藏4℃的三文鱼基质上表达上调的最为显著。此外,prfA和sigB在4℃贮藏条件下,表达量极显著高于7℃和0℃(P<0.01);在不同的温度贮藏24 h,inlB和hlyA的表达量均表现为7℃>4℃>0℃(P<0.01);且4个主要毒力因子在三文鱼基质上的相对表达量均表现为48 h>24 h(P<0.01)。综上所述,本研究为该菌在食品基质上的风险评估和有效防控提供一定的理论依据。
The aim of the present study was to assess the influence of storage temperature on virulence gene expression of Listeria monocytogenes（Lm） grown in a food matrix.Lm ATCC 19115 was grown in a salmon matrix or tryptone soya agar containing 0.6% yeast extract（TSA-YE）（control） at different temperatures（0,4 and 7 ℃） for 24 and 48 h,respectively.Then,the bacterial cells were collected by centrifugation for RNA extraction using a commercial kit（Tian Gen,Dalian）,and the expression levels of hlyA,inlB,prfA and sig B were assessed by RT-qPCR.The RT-qPCR data showed that the expression of all four major virulence genes was up-regulated when the strain was grown in a salmon matrix compared to TSA-YE at each temperature.In addition,hlyA possessed the highest expression level among these four genes.The expression levels of prfA and sigB in Lm from salmon stored at 4 ℃ were significantly higher than those at 0 and 7 ℃（P 0.01）.The expression levels of inlB and hlyA in salmon stored for 24 h at different temperatures were in the descending order of 7 ℃ 4 ℃ 0 ℃（P 0.01）.In the salmon matrix,the expression levels of all four major virulence genes at 48 h were significantly higher than those at 24 h（P 0.01）.The results of this study can provide basic information for risk assessment and control of Lm in food matrices.
作者
朱雅慧
朱洪日
王佳莹
张公亮
郝洪顺
侯红漫
ZHU Yahui;ZHU Hongri;WANG Jiaying;ZHANG Gongliang;HAO Hongshun;HOU Hongman(Liaoning Key Lab for Aquatic Processing Quality and Safety, Dalian Polytechnic University, Dalian 116034, China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2018年第2期138-143,共6页
Food Science
基金
辽宁省自然科学基金项目(201602049)
"十二五"国家科技支撑计划项目(2015BAD17B00)
