EGCG抑制波罗的海希瓦氏菌生物被膜和腐败活性的研究

以海产品腐败菌波罗的海希瓦氏菌(Shewanella baltica)为对象,评价了儿茶素单体抑制生物被膜的效果,并分析效果最佳的单体对该菌生物被膜和腐败活性的影响。结果表明,5种儿茶素单体均能抑制S.baltica生物被膜形成,其中表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)抑制率最高,其最小抑菌质量浓度为40μg·m L-1,亚抑菌质量浓度10~30μg·m L-1的EGCG对细菌生长无显著影响。在30μg·m L-1 EGCG作用下,群体感应(Quorum sensing,QS)信号分子呋喃酮酰硼酸二酯(Autoinducer-2,AI-2)、二酮哌嗪类化合物(Diketopiperazine,DKPs)cyclo-(L-Pro-L-Leu)和cyclo-(L-Pro-L-Phe)活性显著下降(P0.05),其抑制率分别为63.95%、27.43%和21.94%。亚抑菌浓度EGCG能显著抑制S.baltica生物被膜形成、泳动能力和蛋白酶活性(P0.05),呈现浓度依赖性,在30μg·m L-1时抑制率分别为55.18%,66.71%和46.67%。因此,EGCG在亚抑菌浓度下能够干扰S.baltica的QS系统,有效抑制生物被膜形成,减弱致腐能力,研究为EGCG作为新型的QS抑制剂调控食品腐败菌奠定基础。

Inhibition of Biofilm Development and Spoilage Potential in Shewanella baltica by Epigallocatechin Gallate

The anti-biofilm activity of catechin monomers from tea polyphenols against S. baltica, as the specific spoilage organism in marine product, was investigated. Effects of catechin monomer with the highest inhibitory activity on biofilm formation and spoilage potential of S. baltica were further assessed. The results showed that all five monomer of catechins significantly repressed biofilm formation of S. baltica, in which epigallocatechin gallate (EGCG) exhibited the highest activity. The minimum inhibitory concentration (MIC) of EGCG against S. baltica was 40 μg·mL-1, and EGCG at the sub-inhibitory concentration of 10-30 μg·mL-1 had no effect on its growth. EGCG at 30 μg·mL-1 inhibited significantly the activity of quorum sensing (QS) autoinducers, AI-2, cyclo-(L-Pro-L-Leu) and cyclo-(L-Pro-L-Phe) (P<0.05), with reduction by 63.95%, 27.43% and 21.94% respectively. The biofilm development, swimming motility and protease activity also decreased considerably after incubation with sub-MIC of EGCG, and exhibited a dose dependent effect, which presented the reduction by 55.18%, 66.71% and 46.67% in the presence of 30 μg·mL-1 EGCG. Hence, our results indicated that the sub-MIC of EGCG could interfere with S. baltica QS system, and inhibit the biofilm formation and spoilage potential of S. baltica. The present study suggested the potential of EGCG as QS inhibitor in controlling food spoilage bacterial.