Molecular Mechanism Research Of Saliva Lactobacillus M3 Adhesion Protect Caco-2 Cells

Lactic acid bacteria are a kind of important probiotics,their use in livestock production can improve the health status of animals,reduce the use of antibiotics,and contribute to the healthy breeding of animal husbandry.Lactic acid bacteria can adhere in the gut of animals and form a barrier,in order to improve the disease resistance of animal body.In our previous studies,Lactobacillus salivarius M3 has been purified which has good antibacterial effect and adhesion efficiency.In this paper,we have done further research on M3 bacteriostasis,environmental tolerance,Caco-2 cell adhesive protection;illuminate the adhension of outer membrane proteins of strain M3,and provide theory basis for the compatetive adhension of strain M3.The main content includes the following:During study on the bacteriostatic action of M3,it showed that M3 had antibacterial activities to E.coli,Salmonella,Streptococcus,and Staphylococcus aureus.The strongest antibacterial effect was shown on E.coli,then followed by Streptococcus,Staphylococcus aureus,and Salmonella.During study on tolerance of M3 to acid,hydrogen peroxide and lysozyme,the results showed that M3 could survive in pH 1 HC1,30%Hydrogen peroxide and 3.5 mg/mL of Lysozyme,so M3 was proved to have a strong environmental tolerance.By comparing the extracting method of outer membrane proteins between Lysozyme method,PMSF method and Sarkosyl method,Lysozyme method with adding LiCl was proved to be the best one,as the protein concentration was significantly higher than PMSF and Sarkosyl methods(P<0.05).The outer membrane protein with the highest concentration was chosen to do spectrometry detection,and it was detected to be sGAPDH.E.coli was used to infect Caco-2 cells,and strain M3 was then added,the results showed that M3 could significantly adhere to Caco-2 cells compared to E.coli(P<0.05).The gene expression level of sGAPDH outer membrane protein of M3 was up-regulated highly significantly with E.coli inducing(P<0.01).M3 could promote the secretion of adhesion factors Plg and Mucin of Caco-2 cells,furtherly promote M3 adhesion to Caco-2 cells,and meanwhile prevent E.coli adhesion to Caco-2 cells,in order to achieve its bacteriostatic effect.The above results showed that M3 had good antibacterial effects and strong environmental tolerance.M3 could be up-regulated and controlled by its own sGAPDH protein expression to promote the secretion of adhesion factors of Caco-2 cells secrete,furtherly promote a lot of M3 adhesion to Caco-2 cells,in order to effectively protect Caco-2 cells from affection of pathogenic bacteria.