Effects of Sulforaphane, Grapefruit Seed Extracts, and Reuterin on Virulence Gene Expression Using hilA and invF Fusion Strains of Salmonella typhimurium
This study assessed the effects of the antimicrobial substances sulforaphane, grapefruit seed extracts (GSE), and reuterin on the expression of Salmonella HilA and InvF virulence gene using a LacZY assay (B-galactosidase assay) with hilA:lacZY and invF:lacZY fusion strains of Salmonella typhimurium SL1344. Salmonella was grown for 8 hr at 37℃ in the presence of diluted antimicrobial substances (2 ug/mL sulforaphane, $20{ug/mL$} GSE, and 0.26 mM reuterin) at concentrations that did not inhibit the cellular growth of Salmonella. Sulforaphane inhibited the expression of HilA and InvF by 50-90 and 20-80%, respectively. GSE also inhibited the expression of both genes, but to a lesser degree. Among the 3 antimicrobial substances, reuterin showed the least inhibition, which was abolished after 3-4 hr. None of the antimicrobial substances inhibited the B-galactosidase enzyme activity of S. typhimurium. The assay used in this study represents a very sensitive method for screening bioactive substances that inhibit the expression of virulence genes in Salmonella.
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Abstract Introduction Materials and Methods Results and Discussion Acknowledgments References