研究评价了茶多酚对腐败希瓦氏菌(Shewanella putrefaciens)的抑菌和杀菌效果,并初步探讨了其抑菌机理。结果表明,茶多酚对腐败希瓦氏菌的最低抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为1 mg·mL^-1和16 mg·mL^-1,2 mg·mL^-1茶多酚处理能显著抑制细菌的生长曲线,在25℃和4℃作用96 h和192 h希瓦氏菌分别下降了105 CFU·mL^-1和106 CFU·mL^-1,杀菌作用表现时间依赖性。茶多酚单体的杀菌能力大小分别为EGCG〉ECG〉EGC〉EC。在茶多酚作用下,腐败希瓦氏菌胞外上清中 Na+/K+-ATP 酶和 AKP 酶活性显著上升,投射电镜(TEM)观察细菌出现了破损、变形等现象。可见,茶多酚能有效抑制腐败希瓦氏菌的生长,在低温长时间下仍表现出杀菌能力,其杀菌机制主要是引起细菌细胞壁和细胞外膜损伤,使胞内成分泄漏,导致细菌死亡。
Antimicrobial effect and mechanism of TP against Shewanella putrefaciens in vitro was investigated. The results showed that the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of TP against the S. putrefaciens were 1 mg·mL^-1 and 16 mg·mL^-1, respectively. Growth curves of S. putrefaciens were significantly inhibited in the addition of 2 mg·mL^-1 TP. The population of S. putrefaciens decreased about 105 CFU·mL^-1 and 106 CFU·mL^-1 with the 2 mg·mL^-1 TP addition after 96 h at 25℃ and 192 h at 4℃, respectively. The bactericidal activity of TP exhibited the time depending. Among the four monomer of TP, the order of bactericidal activity were EGCG〉ECG〉EGC〉EC. The enzyme activity of Na+/K+-ATP and AKP in the culture suspension of S. putrefaciens gradually increased with the time extension in the TP treated samples. TEM images revealed that treatment of TP might lead to damage and deformation of cell. Thus, TP exhibited the good antimicrobial and bactericidal activity against S. putrefaciens by disrupting cell walls and out membrane, which cause the permeability of intracellular components and the change of cell morphology.