Lactobacillus spp. belonging to the Casei group display a variety of adhesins.

BACKGROUND: n. Adhesion of bacteria from the genus Lactobacillus to the gastrointestinal epithelium is, to a considerable degree, dependent on the interactions between adhesins found on the surface of bacterial cells and elements found within the epithelium. A significant role in these interactions is played by bacterial pro teins exposed to the cell wall surface, which are capable of binding to molecules of substances comprising the extracellular matrix of the intestinal epithelium.

METHODS: In order to analyze the extracellular proteome of intestinal bacteria in terms of the presence of cell adhesion molecules, a total of twenty strains from the Lactobacillus spp. group Casei were tested. The analyses were conducted using SDS PAGE, 2-D electrophoresis, Western blot and mass spectrometry. An experiment was also conducted to assess the adhesion capacity of the tested strains to cervical epithelial cells (HeLa).

RESULTS: The tested strains varied in their adhesion efficiency to HeLa cells, ranging from 0.5% to 29%. Us- ing electrophoretic methods a total of 54 extracellular protein fractions were distinguished in these strains, additionally identifying potential adhesion molecules (e.g. a surface antigen of the NLP/P60 family and a small heat shock protein/chaperonin).

CONCLUSIONS: The identification of these proteins in the extracellular proteome of Latobacillus spp. isolates may suggest that they serve currently unknown functions on the cell surface, including those connected with the interactions between bacteria and the intestinal epithelium. Such analyses may provide insight into new factors promoting probiotic adhesion to various types of epithelial cells.