芳樟醇对莓实假单胞菌的抑菌活性及机制

Antibacterial Activity and Mechanism of Linalool Against Pseudomonas fragi

食品在生产、运输和贮藏过程中易受致病菌污染而引起食源性疾病。芳樟醇具有抗菌作用,但其作用机制尚不明确。研究芳樟醇对莓实假单胞菌的抑菌活性及作用机制,可为其作为天然食品防腐剂的开发提供理论依据。通过测定最小抑菌浓度、绘制细菌生长曲线评价芳樟醇的抑菌活性;通过扫描电子显微镜观察、结晶紫染色实验、二乙酸荧光素染色实验以及测定电导率、核酸泄漏、呼吸代谢活力和呼吸链脱氢酶活性的变化探究芳樟醇的抑菌机制。结果表明:芳樟醇对莓实假单胞菌具有较强的抑制作用,最小抑菌浓度为1.5 mL/L;芳樟醇能破坏莓实假单胞菌细胞的结构形态和细胞膜的完整性,增加细胞膜的通透性,导致胞内物质泄漏、膜外电导率升高;能抑制呼吸代谢活力和呼吸链脱氢酶活性,破坏呼吸链,导致胞内代谢紊乱。研究认为,芳樟醇可通过破坏莓实假单胞菌的细胞结构和抑制其呼吸代谢而发挥抑菌作用,有望作为天然防腐剂应用于食品的防腐保鲜。

Foods are vulnerable to contamination by pathogenic bacteria during production,transportation and storage,and this can cause foodborne illness.Linalool has antibacterial effects,but the mechanism of action remains unclear.In order to provide a theoretical basis for the development of linalool as a natural food preservative,the antibacterial activity and mechanism of linalool against Pseudomonas fragi were studied.The antibacterial activity of linalool was evaluated by measuring the minimum inhibitory concentration and plotting the bacterial growth curve.The antibacterial mechanism was investigated by scanning electron microscope observation,crystalline violet staining experiments,fluorescein diacetate staining experiments,and measuring the changes in electrical conductivity,nucleic acid leakage,respiratory metabolic activity and respiratory chain dehydrogenase activity.The results showed that linalool had a strong inhibitory effect against Pseudomonas fragi,and the minimum inhibitory concentration was 1.5 mL/L.Linalool could damage the structure morphology and cell membrane of Pseudomonas fragi,and improve the permeability of the cell membrane,thus leading to the leakage of intracellular materials and the increase of electrical conductivity outside the cell membrane.It could inhibit the activity of respiratory metabolic and respiratory chain dehydrogenase,and damage the respiratory chain,thus leading to the disorder of intracellular metabolism.The research confirmed that linalool exerted a antibacterial effect by damaging the cell structure of Pseudomonas fragi and inhibiting its respiratory metabolism,and linalool could be studied and developed as a natural preservative.