Effect of quorum sensing and quorum sensing inhibitors on the expression of serine protease gene inHafnia alveiH4

摘要

Theserpgene codes for a protease that is considered to be an important factor associated with quorum sensing (QS)-based food spoilage caused by microorganisms. In this study, we evaluated the effect of temperature (4-37 degrees C) and QS inhibitors on the production ofN-acyl-L-homoserine lactones (AHLs) and relative expression of theluxR/I, as well asserpinHafnia alveiH4. Production of AHLs and expression ofluxR/Iwere found to reach maximum levels at 10 degrees C, suggesting that the QS system ofH. alveiH4 might have higher activity at low temperatures; similar result was also obtained forserpexpression. Mutants ofH. alveiH4 deficient in QS were used to identify the regulation of QS onserpexpression. Significant reduction (P < 0.05) inserpexpression was found in the mutants increment luxR, increment luxI, and increment luxR/I, with increment luxIand increment luxR/Ishowing greater reduction than increment luxR. Minimum inhibition concentrations (MIC) of Benzyl isothiocyanate and 3-Methylthiopropyl isothiocyanate forH. alveiH4 were determined to be 7.813 and 15.625 mM, respectively. Furthermore, the expression ofserp, as well as that ofluxRandluxI, was significantly repressed (P < 0.05) by the two QS inhibitors at 1/8 MIC and 1/16 MIC, indicating that these inhibitors might repressserpexpression through affectingluxRandluxIexpression inH. alveiH4. The findings of this study, therefore, suggested that food spoilage caused byH. alveicould be controlled through the application of QS inhibitors.