Abstract:To evaluate the effects of surface proteins on the properties of Lactobacillus, different species containing slp gene were selected through sequence comparison. Subsequently, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to analyze some of them. The expression of slp gene in different Lactobacillus species was evaluated, and then the light absorbance, self-aggregation rate, biofilm formation rate, and co-aggregation rate with other pathogenic microorganisms associated with each of these species were assessed before and after the removal of surface proteins. The results revealed that 4 strains of L. acidophilus, 30 strains of L. crispatus, 3 strains of L. helveticus, and 30 strains of L. rhamnosus contain slp expressed surface proteins that were identified using SDS-PAGE. These surface proteins were found to be closely related to the properties of the strains. For example, the growth of L. helveticus before and after the removal of surface proteins was found to be significantly different. However, the light absorbance of the species of interest differed only slightly (within 0.2) after lithium chloride solution and proteinase K solution treatments. Meanwhile, for co-aggregation with other pathogenic microorganisms, most of the strains demonstrated no significant differences after different treatments. Interestingly, L. rhamnosus 3-1, which exhibits weak self-aggregation, exhibited strong co-aggregation with other pathogenic microorganisms, and therefore, the anti-caries potential of this strain is worth further exploration. This research would provide more information on the surface proteins of Lactobacillus species and lays a theoretical foundation for in-depth exploration of the functions and applications of surface proteins.
