李妍萍,孙恒,杨林狄,王浩宇,黄洁,黄郁葱

• 1:广东海洋大学水产学院/广东省水产动物病害防控与健康养殖重点实验室/水产经济动物病害控制广东省普通高等学校重点实验室

摘要(Abstract)：

【目的】研究月桂酸单甘油酯（Glycerol monolaurate, GML）对海豚链球菌（Streptococcus iniae）的体外抑菌效果及其作用机制，为鱼类养殖中防控海豚链球菌感染提供新的依据。【方法】以珍珠龙胆石斑鱼（♀Epinephelus fuscoguttatus×♂Epinephelus lanceolatus）源海豚链球菌为研究对象，运用微量二倍稀释法测定GML对海豚链球菌的最小抑菌浓度（MIC）和最小杀菌浓度（MBC），并通过生长曲线、电导率、菌体形态变化、菌体蛋白表达、生物被膜形成和毒力相关基因转录的测定评估GML对海豚链球菌的潜在作用机制。【结果】GML对海豚链球菌的最小抑菌浓度和最小杀菌浓度别为16 mg/L和32 mg/L；抑制作用呈现浓度依赖性，浓度越高抑制效果越强，且在MIC浓度作用下对菌体生长及生物被膜形成抑制作用最强；不同浓度GML作用后的菌体均能观察到细胞排列松散、大小不均一、胞间间距增大，并出现显著凹陷、皱褶等不同程度的损伤。此外，在1/2 MIC与MIC浓度GML处理后，菌悬液电导率明显上升，表明在此浓度下药物导致菌体出现一定损伤；1/4 MIC浓度促进蛋白条带增多，而MIC浓度则呈现出抑制效应引起蛋白条带变淡甚至消失。【结论】月桂酸单甘油酯对珍珠龙胆石斑鱼源海豚链球菌具有良好的体外抑菌活性。其主要作用途径是通过破坏细胞结构完整性，导致内容物流失，抑制细菌的生长及生物被膜形成，影响细菌毒力基因及蛋白表达等方面发挥抗菌作用。

关键词(KeyWords)： 海豚链球菌;月桂酸单甘油酯;抗菌机制;绿色养殖;抗生素

Abstract:

Keywords:

基金项目(Foundation): 国家重点研发计划（2022YFD2401204）;; 广东省驻镇帮镇扶村农村科技特派员项目;; 广东海洋大学科研启动经费资助项目

作者(Author): 李妍萍,孙恒,杨林狄,王浩宇,黄洁,黄郁葱

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