摘要
以食源性致病菌大肠杆菌为指示菌,研究抗菌肽brevilaterin与柠檬酸的协同抑菌效应和机理,为抗菌肽和柠檬酸应用于大肠杆菌的控制提供理论依据。利用DiSC_3(5)荧光探针考察brevilaterin与柠檬酸对大肠杆菌细胞膜电势的影响,结果表明两者单独使用均能消散大肠杆菌的跨膜电势,两者联用呈现协同消散效果;通过碘化丙啶/SYTO 9探针标记结合流式细胞术考察brevilaterin与柠檬酸对细胞膜完整性的影响,结果表明brevilaterin与柠檬酸均会破坏细胞膜完整性;利用透射电子显微镜观察大肠杆菌超微结构的变化,结果发现brevilaterin和柠檬酸联用组对菌体超微结构呈现协同破坏作用,即细胞产生变形、发生质壁分离与内容物泄漏等;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示brevilaterin、柠檬酸对大肠杆菌的蛋白质合成没有明显影响;琼脂糖凝胶电泳表明brevilaterin与柠檬酸可以降解大肠杆菌菌体DNA,两者联用呈现协同降解作用。综上,brevilaterin与柠檬酸可通过破环细胞膜的完整性与降解菌体DNA以发挥协同抑制大肠杆菌的作用。
The synergistic antibacterial effect and underlying mechanism of the antibacterial peptide brevilaterin combined with citric acid were studied against the food-borne pathogen Escherichia coli,with the aim to provide a theoretical basis for the application of this antibacterial peptide and citric acid in the control of E.coli.The effects of brevilaterin and citric acid on the membrane potential of E.coli were investigated by using DiSC3(5)fluorescence probe.The results showed that brevilaterin and citric acid could separately and synergistically dissipate the transmembrane potential of E.coli.Both of them could destroy membrane integrity as determined by propidium iodide/SYTO 9 probe marking combined with flow cytometry.Transmission electron microscopy(TEM)demonstrated that combination of brevilaterin with citric acid synergistically destroyed the ultrastructure of E.coli cells,specifically leading to cell deformation,plasmolysis and the leakage of cell contents.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)showed that brevilaterin and citric acid had no significant effect on protein synthesis in E.coli.Agarose gel electrophoresis showed that brevilaterin and citric acid could separately and synergistically degrade the DNA of E.coli.Therefore,brevilaterin and citric acid can synergistically inhibit the growth of E.coli by disrupting the integrity of cell membrane and degrading bacterial DNA.
作者
宁亚维
苏丹
付浴男
刘杨柳
王志新
贾英民
NING Yawei;SU Dan;FU Yunan;LIU Yangliu;WANG Zhixin;JIA Yingmin(College of Bioscience and Bioengineering,Hebei University of Science and Technology,Shijiazhuang 050018,China;School of Food and Health,Beijing Technology and Business University,Beijing 100048,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2020年第19期31-37,共7页
Food Science
基金
“十三五”国家重点研发计划重点专项(2016YFD0400805)
国家自然科学基金面上项目(31771951)。
