核桃青皮中胡桃醌对大肠杆菌的抗菌作用及机制  

Antibacterial Effect and Mechanism of Juglone from Walnut Green Husk against Escherichia coli

作　　者：路振康 吴庆智[1] 张建[1] 毛晓英[1] LU Zhenkang;WU Qingzhi;ZHANG Jian;MAO Xiaoying(College of Food,Shihezi University,Shihezi 832000,China)

机构地区：[1]石河子大学食品学院,新疆石河子832000

出　　处：《食品科学》2023年第7期65-73,共9页Food Science

基　　金：兵团重点领域科技攻关计划项目(2018AB015)。

摘　　要：为研究胡桃醌对大肠杆菌的抗菌活性及其作用机理,用不同质量浓度胡桃醌处理大肠杆菌,分别对最小抑菌质量浓度(minimal inhibitory concentration,MIC)、生长曲线、细胞膜相对电导率、荧光发射光谱等进行测定,并进行生物膜形成和细胞活性分析、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulphate-polyacrylamide gel electrophoresis,SDS-PAGE)以及大肠杆菌基因组合成分析。结果表明,胡桃醌对大肠杆菌具有有效的抗菌活性,MIC为0.062 5 mg/mL。经不同质量浓度胡桃醌处理后大肠杆菌细胞膜相对电导率升高,表明胡桃醌破坏了大肠杆菌膜的完整性,增加了细胞膜的通透性。荧光发射光谱分析结果表明,胡桃醌能够与膜蛋白相互作用从而改变大肠杆菌细胞膜结构。结晶紫和刃天青染色实验结果表明胡桃醌能够通过抑制大肠杆菌生物膜的形成减弱大肠杆菌的呼吸作用,进而抑制其活性。SDS-PAGE和大肠杆菌基因组合成分析结果显示胡桃醌可抑制大肠杆菌中蛋白质、DNA和RNA的表达。通过分子对接实验可知,胡桃醌可以结合到基因组DNA的凹槽上,改变其二级结构和形态。综上,胡桃醌对大肠杆菌具有较好的抑制效果,可以作为一种天然抗菌剂用于食源性大肠杆菌的防控中。The antibacterial activity and mechanism of juglone from walnut green husk against Escherichia coli were studied.E.coli was treated with juglone from walnut green husk in different concentrations.The minimum inhibitory concentration(MIC) of juglone was determined,and its effect on the growth curve,cell membrane relative conductivity,fluorescence emission spectrum,biofilm formation,cell viability,protein formation and genomic DNA and RNA synthesis of E.coli were investigated.The results showed that juglone had effective antibacterial activity against E.coli with an MIC value of 0.062 5 mg/mL.The relative conductivity of E.coli cell membrane increased after treatment with different concentrations of juglone,indicating that juglone destroyed the integrity of the cell membrane and increased the permeability.The results of fluorescence emission spectroscopy showed that juglone was able to interact with membrane proteins to change the membrane structure of E.coli cells.The results of crystal violet and resazurin staining showed that juglone could weaken the respiration of E.coli by inhibiting the formation of E.coli biofilms,thereby inhibiting its viability.Sodium dodecyl sulphate-polyacrylamide gel electrophoresis(SDS-PAGE) and E.coli genome synthesis analysis showed that juglone inhibited the expression of protein,DNA and RNA in E.coli.Through molecular docking,it was found that juglone can bind to the grooves of genomic DNA,thereby changing its secondary structure and morphology.In summary,juglone has a good inhibitory effect on E.coli,and can therefore be used as a natural antibacterial agent in the prevention and control of foodborne E.coli.

关 键 词：胡桃醌 大肠杆菌 抗菌活性 膜蛋白 分子对接 

分 类 号：TS201.3[轻工技术与工程—食品科学]