Label-free quantitative proteomics reveals the antibacterial effects of benzyl isothiocyanate against Vibrio parahaemolyticus

Abstract

In this study, the antibacterial effects of benzyl isothiocyanate (BITC) against Vibrio parahaemolyticus (V. parahaemolyticus) were investigated at the protein level using label-free quantitative proteomic analysis. The results showed that 243 differentially expressed proteins were induced by BITC at 10 μmol/L in V. parahaemolyticus. In particular, outer membrane protein A (OmpA), outer membrane protein U (OmpU) and outer membrane protein W (OmpW) were significantly downregulated by 44.9%–66.3%. By combining scanning electron microscopy observations, and gene ontology enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and STRING analyses, the modes of BITC action against V. parahaemolyticus were speculated to be a reduction in biofilm production, loss of outer membrane integrity and inhibition of transmembrane transport, and inhibition of response to stimulus and metabolic pathways. Furthermore, molecular docking analysis was conducted to investigate the action sites of BITC with OmpA, OmpU and OmpW of V. parahaemolyticus. The results showed that the docking scores of BITC with OmpA, OmpU and OmpW were between −5.36 and −6.05 kcal/mol, confirming the stability of these complexes. Therefore, these results suggest that outer membrane proteins related to the reduction of biofilm production play an important role in the antibacterial activity of BITC against V. parahaemolyticus.