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Study On Inhibition Of The Protein Produced By Lactobacillus Plantarum Y42 Aginst Biofilm Formation Of Listeria Monocytogenes

Posted on:2020-07-22Degree:MasterType:Thesis
Country:ChinaCandidate:J Q WangFull Text:PDF
GTID:2370330620970964Subject:Food engineering
Abstract/Summary:PDF Full Text Request
Listeria monocytogenes(LM)is a common foodborne pathogen,often in the form of biofilms in food and food processing equipment,which seriously endangers food safety and human health.Therefore,controlling the growth of L.monocytogenes and the formation of biofilms is an important issue in the food production process.In this paper,the inhibitory effect of crude protein in the culture supernatant of L.plantarum Y42 on the formation of L.monocytogenes biofilm was studied.Firstly,the culture supernatant of L.plantarum Y42 strain MRS was precipitated by using 20%,40%,50%,60%,70% and 80% ammonium sulfate,and 6 crude protein fractions were obtained by fractional precipitation,which were determined by crystal violet staining.The inhibitory effect of the six crude protein fractions on the formation of L.monocytogenes biofilm.It was concluded that 50%,60%,70% and 80% ammonium sulfate salting out to obtain 4 crude protein components can inhibit the formation of L.monocytogenes biofilm(p<0.05).Secondly,50%,60%,70% and 80% ammonium sulfate in the culture supernatant of L.plantaum Y42 was salted out to obtain 4 crude protein components,by reducing the motility of L.monocytogenes and extracellular proteins,exopolysaccharides and secretion of extracellular DNA interferes with the formation of L.monocytogenes biofilm.At the same time,50%,60%,70% and 80% ammonium sulfate salting out to obtain four crude protein components can inhibit the adhesion of L.monocytogenes on HT-29 cells,and reduce L.monocytogenes to stimulate HT-29 cells to produce the amount of expression of interleukin-8.Cyclohexoxacin and levofloxacin were used to determine the difference in antibiotic susceptibility between planktonic and biofilm L.monocytogenes.50%,60%,70% and 80% ammonium sulfate salting out to obtain 4 crude protein components can reduce cyclopropane The minimum biofilm eradicate concentration(MBEC)of the star and levofloxacin on the biofilm L.monocytogenes.In summary,the crude protein of L.plantaum Y42 culture supernatant can inhibit the formation of L.monocytogenes biofilm,and the sensitivity of the bacteria inside the membrane to antibiotics is enhanced by breaking the biofilm;by reducing the crawling of L.monocytogenes Exercise,reduce the secretion of extracellular DNA,extracellular and extracellular polysaccharides by L.monocytogenes,inhibit the adhesion of L.monocytogenes on HT-29 cells,and reduce the expression of interleukin-8 by L.monocytogenes to stimulate HT-29 cells to reduce the amount of L.monocytogenes that form biofilms.
Keywords/Search Tags:Lactobacillus, culture supernatant, crude protein, Listeria monocytogenes, biofilm
PDF Full Text Request
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