Study On The Mechanism Of Adhension And Immunologic Enhancement Of Probiotics

The Bifidobacteria adolescent and Lactobacillus acidophilus were tested in this experiment to study the mechanism of adhesion and immunologic enhancement. The aim of this study is to research on the adhesin of probiotics and the receptor of adhesin. The components with the function of immuno-boost were also studied.Bifidobacteria adolescent was treated by TritonX-100, Trypsin, DNase, RNase and Proteinase E to extract the Peptidoglycan(PG).Bifidobacterium and Lactobacillus are Gram positive bacterium. The cell wall of Gram positive bacterium are composed of Peptidoglycan, Polysaccharide and Surface-Layerprotein and they may play different roles during the adhension between Protiotics and the intestinal epithelia of host.This study concentrated on the functions of cell wall Peptidoglycan and Surface-Layerprotein" in adhesion. The Lactobacillus acidophilus was treated by Sod.Dodecyl Sulfate(SDS), TrichloroaceticAcid(TCA) and Trypsin with the same purpose. The 80g/L SDS and heated with boiling water bath for 10 minutes was the optimal process condition to collect PG.The protein content and amino acid composition of PG extracted were tested to ensure the protein in bacteria cell wall was eliminated.Several different measures were adopted to determine the function of metabolite and the surface components of bacteria tested and the adhesin receptor of intestinal epithelia in adhension.The adhesin of Bifidobacteria adolescent was confirmed to be a certain kind of protein produced and excreted to the media by bacteria, and the receptor on intestinal epithelia should be some kind of glycoprotein. While the adhesin of L. acidopholus is protein on the surface of bacteria cell wall and the receptor is protein.The adhension ability of heat-inactived probiotics was also tested. The result showed that the inactived B. adolescent still can adhere to the intestinal epithelia while L. acidophilus cann't. The result approved that the adhesin of them were different from each other.Mice were injected with bacteria suspension or PG and examed the influence on immunity. The Interleukin-6 level, Lysozyme level, numbers and phagocytic activity of Macrophage of mice injected with suspension or PG was improved significiently when compared with controls. The result showed that PG can boost the immunity of animals tested.