枯草芽孢杆菌抗菌脂肽对嗜水气单胞菌抑菌效果

Study on the Anti-Aeromonas hydrophila Effect in vitro of Lipopeptide from Bacillus subtilis fmbJ

为了研究Bacillus subtilis fmbJ产生的抗菌脂肽对嗜水气单胞菌的抑菌效果,采用抑菌圈法测定抗菌脂肽对嗜水气单胞菌的最小抑菌质量浓度(MIC)和最小杀菌质量浓度(MBC),并从其对嗜水气单胞菌形态结构、膜通透性来探讨其抗菌作用。结果表明,嗜水气单胞菌对枯草芽孢杆菌抗菌脂肽具有较高的敏感性,最小抑菌质量浓度(MIC)为20μg/mL,最小杀菌质量浓度(MBC)为32μg/mL;该抗菌脂肽导致嗜水气单胞菌细胞膜通透性增加,使细胞内一些离子以及大分子的蛋白质和核酸泄漏到细胞外,从而引起细胞的死亡;显微结构影响的研究表明,该抗菌脂肽还可以造成嗜水气单胞菌细胞壁缺失、鞭毛散失、胞内物质模糊不清等现象,抑菌效果较明显,可用于嗜水气单胞菌感染引起的水生动物疾病预防和控制。

This paper describes the in vitro anti-Aeromonas hydrophila effect of the purified lipopeptide produced during the fermentation of Bacillus subtilis fmbJ.The inhibition zone method was adopted for the determination of minimal inhibitory concentration（MIC） and minimal bactericidal concentration（MBC）.The antibacterial activity of lipopeptide was also evaluated based on the influences on the morphosis and membrane permeability of Aeromonas hydrophila.The results showed that Aeromonas hydrophila was sensitive to the lipopeptide,with 20 μg/mL MIC and 32 μg/mL MBC.The lipopeptide induced the cell membrane permeabilty of Aeromonas hydrophila,which caused the death of cells for the leakage of intro-cellular ions,proteins and nucleic acids.Further observations under scanning electron microscope（SEM） and transmission electron microscope（TEM） indicated that the lipopeptide led to the lack of cell wall,flagella lost and unclear intra-cellar components in Aeromonas hydrophil.As a result of effective antibacterial activity,the tested lipopeptide could be applied in prevention and control of aquatic animal diseases caused by Aeromonas hydrophila infection.