S-layer Protein Of Lactobacillus Amylovorus Affected Of TGEV Infecting On ST Cells

Piglet viral diarrhea is a kind of serious harm infectious diseases. Enteritis or septicemia is mainly Symptom. Piglet viral diarrhea caused of death in newborn piglets, brought huge economic losses to the pig industry. There is no effective prevention commercialization of drugs.As we all known, probiotic inhibited a variety of bacterial diarrhea. Some probiotics have antiviral activity. Probiotics is safety and reliability. Study on the nature of antiviral mechanisms is also important.Diarrhea caused by virus common with TGEV, PEDV and RV. TGEV and PEDV belong to coronavirus I. Studies have shown that S-layer protein may be combined with viral receptor protein.In this way S-layer protein hindered viral infecting cells. This study was designed to screen out probiotic strains,which can inhibit TGEV and PEDV. This work also study the relationship between S-layer protein and virus receptor.In order to explore the antiviral mechanism of S-layer protein.This study selected probiotic strains with anti-TGEV and anti-PEDV characteristics from the laboratory screened probiotic strains, and choosed one with S-layer protein as an experimental strains.Taking identified viral receptors TGEV as studying virus and the ST cells which surface containing procine aminopeptidase as a platform to isolate the S-layer proteins and metabolites from the experimental strains.S-layer protein, bovine serum albumin, metabolites and Bestatin were divided into two groups according to different concentrations and different adding ways to study the mechanism of S-layer inhibited TGEV proliferation on ST cell.Using the Reed-Muench measured the TCID50of the TGEV which treated by the metabolites or the S-layer protein.The experiments studied the four components influence on the TGEV adsorping and invading ST cells.Added S-layer proteins, bovine serum albumin and metabolites after the cells pretreated with Bestatin to study inhibition of Bestatin with various combinations of ingredients on TGEV.This study selected9probiotic strains with anti-TGEV and anti-PEDV characteristics from the laboratory screened probiotic strains.Lactobacillus amylovorus had S-layer gene and protein as an experimental strains. In the maximum non-toxic dose concentrations S-layer protein, metabolites, Bestatin inhibition rate of TGEV above80%,but bovine serum albumin inhibited rate of TGEV below60%was significantly lower than the others. Bovine serum albumin, metabolites, Bestatin inhibition rates of TGEV and its concentration were dose-effect relationship.The inhibition rate between the S-layer protein to its concentration no dose-depend relationship. S-layer protein at the maximum non-toxic dose with1:2dilution showed strongest inhibition rate of TGEV. Study added four component in four ways. When four components and TGEV treated ST cells at the same time, inhibition rate of the TGEV were low. S-layer proteins and Bestatin cell treated cells before TGEV infection,the inhibition rate of TGEV was higher than they were treated TGEV first. Metabolites treaed TGEV first had higher inhibition rate of TGEV than first contact with the cells.Bovine serum albumin with four added order showed inhibition rate less than50%. TGEV were treaed by metabolites and S-layer protein.S-layer had litter change TCID50of TGEV. TCID50of TGEV significantly reduced after metabolites treated.S-layer proteins and Bestatin significantly reduced TGEV the adsorption rate on ST cells.The metabolite significantly reduced the invasion rate of TGEV on ST. Bestatin in combination with S-layer protein significantly inhibited the proliferation of the TGEV on ST cells.The inhibition rate was90.52%. And Bestatin with bovine serum albumin, metabolite did not enhance the effect of inhibition.In summary, S-layer protein with anti-TGEV ability was confirmed-Pretreated S-layer protein on the ST cells before infected with TGEV,the inhibititon rate was higher than TGEV and S-layer proteins co-involved in the cell. S-layer protein and Bestatin had similar inhibition strength, suggesting a similar mechanism. Bestatin pretreatment cells together with S-layer protein had synergistic enhaced inhibition rate of TGEV.