Strain-Specific Features of Extracellular Polysaccharides and Their Impact on Lactobacillus plantarum-Host Interactions

Abstract

Lactobacilli are found in diverse environments and are widely applied as probiotic, health-promoting food supplements. Polysaccharides are ubiquitously present on the cell surface of lactobacilli and are considered to contribute to the species-and strainspecific probiotic effects that are typically observed. Two Lactobacillus plantarum strains, SF2A35B and Lp90, have an obvious ropy phenotype, implying high extracellular polysaccharide (EPS) production levels. In this work, we set out to identify the genes involved in EPS production in these L. plantarum strains and to demonstrate their role in EPS production by gene deletion analysis. A model L. plantarum strain, WCFS1, and its previously constructed derivative that produced reduced levels of EPS were included as reference strains. The constructed EPS-reduced derivatives were analyzed for the abundance and sugar compositions of their EPS, revealing cps2-like gene clusters in SF2A35B and Lp90 responsible for major EPS production. Moreover, these mutant strains were tested for phenotypic characteristics that are of relevance for their capacity to interact with the host epithelium in the intestinal tract, including bacterial surface properties as well as survival under the stress conditions encountered in the gastrointestinal tract (acid and bile stress). In addition, the Toll-like receptor 2 (TLR2) signaling and immunomodulatory capacities of the EPS-negative derivatives and their respective wild-type strains were compared, revealing strain-specific impacts of EPS on the immunomodulatory properties. Taken together, these experiments illustrate the importance of EPS in L. plantarum strains as a strain-specific determinant in host interaction. IMPORTANCEThis study evaluates the role of extracellular polysaccharides that are produced by different strains of Lactobacillus plantarum in the determination of the cell surface properties of these bacteria and their capacity to interact with their environment, including their signaling to human host cells. The results clearly show that the consequences of removal of these polysaccharides are very strain specific, illustrating the diverse and unpredictable roles of these polysaccharides in the environmental interactions of these bacterial strains. In the context of the use of lactobacilli as health-promoting probiotic organisms, this study exemplifies the importance of strain specificity.

Functional Determinants of Extracellular Polymeric Substances in Membrane Biofouling: Experimental Evidence from Pure-Cultured Sludge Bacteria

“…Differences in the quantities and compositions of EPS among the strains are likely attributed to differing metabolic activities (43) or varied DNA compositions. For example, significant differences in EPS between parent and mutant strains have been reported in numerous studies (42,44,45) and support our conclusion of the strain-specific IR features of EPS. Moreover, glucose-yeast extract medium and the steady-growth stage of bacteria (48 h) were used for EPS formation and extraction in this work.…”

Putative Adhesion Factors in Vaginal Lactobacillus gasseri DSM 14869: Functional Characterization

“…Impact of EPSs on adhesion of L. gasseri DSM 14869 to different epithelial cells. Previous studies have shown that EPSs from intestinal lactobacilli are involved in adhesion to intestinal epithelial cells (16,18,19). In this study, we investigated the role of EPSs in the adhesive capacity of the vaginal strain L. gasseri DSM 14869.…”

“…Bacterial polysaccharides vary in sugar composition, position of branches, and modifications, contributing to the wide diversity of surface structures (15). EPSs have been reported to be involved in aggregation, biofilm formation, adhesive properties, and immunomodulation by probiotic strains (16)(17)(18)(19).…”

Beneficial microbiomes: Biodiversity and potential biotechnological applications for sustainable agriculture and human health

“…The procedures of microorganisms by which they act as probiotics or do their effects are not properly known, but the many studies revealed that they may be involved in modifying the pH value, may neutralize the pathogens through production of compounds that exerts property of antimicrobial, and may occupy the receptor sites of the pathogens as well as chase them for available nutrient [123]. The role of functional food which includes the probiotics microorganisms in human health is well known.…”