A Fluorescence Labeling Method for the Study on Mechanism of Adhesion of Lactobacillus plantarum ST-Ⅲ on Caco-2 Cells

Abstract:

To study the mechanism of adhesion of Lactobacillus plantarum ST-Ⅲ on Caco-2 cells, the adhesive ability of the bacterial cell to the mammal cells was investigated by fluorescence labeling with CFDA-SE and the components on the cell surface involved in the adhesion were extracted. After treatments by chemicals and enzymes, it was shown that pepsin, trypsin, LiCl, phenol, guanidine hydrochloride and heat treatment could signigfantly decrease the adhesive ability of ST-Ⅲ, indicating that the S-layer protein or lipoteichoic acid may be related to the adhesion of ST-Ⅲ to Caco-2 cells. The suppressive test and reversible binding test confirmed that the S-layer protein mediated the adhesion process, whereas the lipoteichoic acid on the bacterial cell surface did not participated in the adhesion. The results showed that the crude surface protein extracts of ST-Ⅲ might contain S-layer protein which participated in the adhesion. The SDS-PAGE assay showed that the crude extracts was composed of three proteins with molecular weight of 72.7 kD, 34.1 kD and 24.3 kD respectively.

Key words:Lactobacillus plantarum, Adhesion, Fluorescence labeling, S-layer protein