Adhesion properties of Lactobacillus rhamnosus mucus-binding factor to mucin and extracellular matrix proteins.

We previously described potential probiotic Lactobacillus rhamnosus strains, isolated from fermented mare milk produced in Sumbawa Island, Indonesia, which showed high adhesion to porcine colonic mucin (PCM) and extracellular matrix (ECM) proteins. Recently, mucus-binding factor (MBF) was found in the GG strain of L. rhamnosus as a mucin-binding protein. In this study, we assessed the ability of recombinant MBF protein from the FSMM22 strain, one of the isolates of L. rhamnosus from fermented Sumbawa mare milk, to adhere to PCM and ECM proteins by overlay dot blot and Biacore assays. MBF bound to PCM, laminin, collagen IV, and fibronectin with submicromolar dissociation constants. Adhesion of the FSMM22 mbf mutant strain to PCM and ECM proteins was significantly less than that of the wild-type strain. Collectively, these results suggested that MBF contribute to L. rhamnosus host colonization via mucin and ECM protein binding.

Isolation of potential probiotic Lactobacillus rhamnosus strains from traditional fermented mare milk produced in Sumbawa Island of Indonesia.

To explore potential probiotics in the traditional foods of Indonesia, fermented mare milk produced in Sumbawa Island was investigated in this study. Gram stain, catalase activity, gas production, cell morphology, carbohydrate utilization pattern, and 16S rDNA sequencing were performed to identify isolated lactic acid bacteria. To assess their probiotic ability, tolerance of low pH, bile salts, artificial gastrointestinal fluids, and adhesion properties to extracellular matrices, were examined. In total 27 strains, 25 Lactobacillus rhamnosus and two Lactobacillus fermentum, were obtained. Among the isolated lactobacilli, three Lb. rhamnosus strains, FSMM15, FSMM22, and FSMM26, were selected as candidates for probiotics, using Lb. rhamnosus GG as index. In vitro binding assay of the three strains against several extracellular matrix proteins revealed that FSMM15 and FSMM26 gave greater binding ratios of mucin/bovine serum albumin (BSA) and significantly higher adhesive abilities to fibronectin than Lb. rhamnosus GG. FSMM22 showed significantly higher adhesion to laminin than Lb. rhamnosus GG.