面包乳杆菌ZHG2-1对荧光假单胞菌群体感应的淬灭作用OA北大核心CSCDCSTPCDEI

In this study,quorum-sensing quenching activity of Lactobacillus crustorum ZHG2-1 was verified with the Chromobacterium violaceum CV026 as a indicator strain.Based on the change of biofilm,phenotypes of spoilage factors and the expression levels of related genes,the quorum sensing quenching mechanism of Lb.crustorum ZHG2-1 on P.fluorescens was detected.The results showed that the degradation rate of cell-free supernatant from strain ZHG2-1 to P.fluorescens AHLs reached 100％.The sub-inhibitory concentration(1.0,2.0,3.0 mg/mL)of strain ZHG2-1 crude extract could inhibit and remove the biofilm of P.fluorescens,and the inhibition rate and clearance rate reached 9.66％-31.32％and 28.62％-62.82％,respectively.In addition,the inhibition rate of strain ZHG2-1 crude extract with sub-inhibitory concentration on P.fluorescens spoilage factors(exopolysaccharides,proteases,lipases,biogenic amines)reached 7.23％-100％.Meanwhile,the inhibition rate was mass concentration-dependent.Scanning electron microscope showed that the sub-inhibitory concentration of strain ZHG2-1 crude extract treatment significantly reduced the amount of biofilm and the bacterial colonies were in a dispersed state.The results of qRT-PCR showed that the crude extract of strain ZHG2-1 down-regulated the quorum-sensing genes rhlI and rhlR of P.fluorescens by 0.93 and 0.99,respectively,and the ex-pression levels of aprX,algA,orm,flgA,ldcA and other biofilm and spoilage genes was significantly inhibited.The re-sults indicated that Lb.crustorum interfered with the expression of quorum-sensing genes of P.fluorescens,thereby af-fecting the production of biofilm and spoilage factors.