Bacteriostatic effects of benzyl isothiocyanate on Vibrio parahaemolyticus: Transcriptomic analysis and morphological verification

We investigated antibacterial activities of benzyl isothiocyanate (BITC) against V. parahaemolyticus by transcriptomic analysis and morphological verification. Treatment with 1/8MIC BITC resulted in 234 up-regulated genes and 273 down-regulated genes. In V. parahaemolyticus, we selected six genes that were significantly down-regulated from the transcriptome results and verified them using quantitative Real-time Polymerase Chain Reaction (qRT-PCR). The verification experiments indicated that the relative expressions of the six virulence genes VP0820, VP0548, VP2233, VPA2362, fliA and fliG were only 31.0%, 31.1%, 55.8%, 57.0%, 75.3%, and 79.9% of the control group, respectively. Among them, VP2233, fliA and fliG are related to flagella, and VP2362 can regulate a protein related to biofilm formation. From the morphological aspect, we verified that under the action of 1/8 MIC BITC, the swimming diffusion diameter of V. parahaemolyticus was significantly reduced by 14.9%, and biofilm formation was significantly inhibited. These results indicate that 1/8 MIC BITC can reduce the pathogenicity of V. parahaemolyticus by inhibiting virulence gene expression related to flagella and biofilm, which is helpful for further understanding of bacteriostatic mechanism of BITC on V. parahaemolyticus and other food-borne pathogens. Overall design: Analysis of genetic changes in Vibrio parahaemolyticus after BITC addition

本研究通过转录组学分析与形态学验证，探究了异硫氰酸苄酯（benzyl isothiocyanate, BITC）对副溶血性弧菌（Vibrio parahaemolyticus, V. parahaemolyticus）的抗菌活性。经1/8最低抑菌浓度（minimum inhibitory concentration, MIC）的BITC处理后，副溶血性弧菌中共出现234个上调基因与273个下调基因。本研究从转录组结果中筛选出6个显著下调的副溶血性弧菌基因，并通过实时荧光定量聚合酶链式反应（quantitative Real-time Polymerase Chain Reaction, qRT-PCR）对其进行验证。验证实验结果显示，VP0820、VP0548、VP2233、VPA2362、fliA及fliG这6个毒力基因的相对表达量仅分别为对照组的31.0%、31.1%、55.8%、57.0%、75.3%与79.9%。其中，VP2233、fliA与fliG与鞭毛结构相关，而VP2362可调控与生物被膜形成相关的蛋白。从形态学层面验证发现，经1/8 MIC BITC处理后，副溶血性弧菌的泳动扩散直径显著降低14.9%，生物被膜形成过程受到显著抑制。上述结果表明，1/8 MIC BITC可通过抑制与鞭毛及生物被膜相关的毒力基因表达，降低副溶血性弧菌的致病性，这有助于进一步阐明BITC对副溶血性弧菌及其他食源性致病菌的抑菌机制。整体实验设计：分析添加BITC后副溶血性弧菌的基因表达变化