Evaluation of adhesion properties of lactobacilli probiotic candidates

Advancements in fluorescent labeling in assessing the probiotic adhesion capacity - A review

Adhesion capacity of probiotics is closely related to their intestinal-protective effects. The conventional techniques used to evaluate probiotic adhesion capacity have limitations in terms of imaging resolution and quantitative analysis. Fluorescent labelling technology has shown immense potential in recent years owing to its high specificity and sensitivity for resolving probiotic adhesion mechanisms. Although there are still problems with the fluorescence signal intensity and hysteresis effect, this technology has significantly advanced the accurate detection and evaluation of probiotic adhesion capacity. This review examines the critical role of probiotic adhesion and its detection methods, with a special focus on the application of fluorescent-labeling technology. Our objective was to identify more accurate and efficient approaches for evaluating the adhesion capacity of probiotic bacteria while promoting in-depth research into the underlying mechanisms that govern probiotic adhesion.

The Characterization of Lactic Acid Bacteria Strains as Components of a Biopreparation for Chickens for Slaughter

Since 2022, the European Union has banned the use of antibiotics in animal production. We conducted studies to characterize Lactiplantibacillus plantarum (47, AN8, and OK-B) and Ligilactobacillus salivarius (AN9) and evaluate their potential to create a biopreparation based on fermented whey for chickens. The following methods were used: lactic acid bacteria (LAB) culture and storage, crystal violet staining, Koch's plate method, Caco-2 cell culture, hydrophobicity test, and spectrophotometric measurements. All bacteria showed weak adhesion to polystyrene and collagen, and the L. plantarum species demonstrated weak adhesion to mucus. All bacteria showed strong adhesion to the intestinal epithelial cell line Caco-2. LAB showed strong autoaggregation and coaggregation with E. coli ATCC10536. The highest affinity for xylene was exhibited by L. salivarius AN9 (above 30%) while, for chloroform, the highest affinity was exhibited by L. plantarum OK-B (approx. 95%); the affinity for n-hexadecane for all strains was below 20%. The highest survival in the presence of bile salts (0.3%) was demonstrated by L. plantarum 47 (above 54%). The effect of low pH resulted in decreased viability for all strains. Significant differences were demonstrated in the concentration of lactic acid between MRS and whey medium after culturing LAB. These results will aid in qualifying these strains for further research to create a functional feed for chickens.

Adhesion and Anti-Adhesion Abilities of Potentially Probiotic Lactic Acid Bacteria and Biofilm Eradication of Honeybee (Apis mellifera L.) Pathogens

Lactic acid bacteria (LAB) naturally inhabits the organisms of honeybees and can exhibit adhesive properties that protect these insects against various pathogenic microorganisms. Thus, cell surface (auto-aggregation, co-aggregation, hydrophobicity) and adhesive properties of LAB to two abiotic (polystyrene and glass) and four biotic (collagen, gelatin, mucus, and intestinal Caco-2 cells) surfaces were investigated. Additionally, anti-adhesion activity and the eradication of honeybee pathogen biofilms by LAB metabolites (culture supernatants) were determined. The highest hydrophobicity was demonstrated by Pediococcus pentosaceus 19/1 (63.16%) and auto-aggregation by Lactiplantibacillus plantarum 18/1 (71.91%). All LAB showed a broad spectrum of adhesion to the tested surfaces. The strongest adhesion was noted for glass. The ability to co-aggregate with pathogens was tested for the three most potently adherent LAB strains. All showed various levels of co-aggregation depending on the pathogen. The eradication of mature pathogen biofilms by LAB metabolites appeared to be weaker than their anti-adhesive properties against pathogens. The most potent anti-adhesion activity was observed for L. plantarum 18/1 (98.80%) against Paenibacillus apiarius DSM 5582, while the strongest biofilm eradication was demonstrated by the same LAB strain against Melissococcus plutonius DSM 29964 (19.87%). The adhesive and anti-adhesive activity demonstrated by LAB can contribute to increasing the viability of honeybee colonies and improving the conditions in apiaries.

Adhesion to pharyngeal epithelium and modulation of immune response: Lactobacillus salivarius AR809, a potential probiotic strain isolated from the human oral cavity

Microbiome modulators such as probiotics are known to modulate oral diseases. Very few probiotics are commercially available for use in the oral cavity. In this context, we selected human-origin Lactobacillus salivarius AR809 as a promising oropharyngeal probiotic and characterized its functional and immunomodulatory properties. Results demonstrated that AR809 could efficiently adhere to pharyngeal epithelial FaDu cells, antagonize Staphylococcus aureus, adapt to the oral environment, and modulate host innate immunity by inducing potentially protective effects. Particularly, AR809 diminished proinflammatory activity by enhancing the production of IL10 and inhibiting the expression of tumor necrosis factor-α, IL1B, inducible nitric oxide synthase, and RELA. Finally, we observed that AR809 grew efficiently when cultured in milk, suggesting that the preparation of a fermented milk product containing AR809 could be a practical way to administer this probiotic to humans. In conclusion, AR809 has high potential to adhere to the pharyngeal mucosa and could be applied in novel milk-based probiotic fermented food products.

Structure and immunomodulatory activity of a recombinant mucus-binding protein of Lactobacillus acidophilus

AIM

The role of mucus-binding protein (MUB) on the adhesion activity and immunomodulatory effect of Lactobacillus acidophilus.

MATERIALS & METHODS

The current research mainly focuses on the adhesion and immune function of MUB from L. acidophilus. The structural characteristics and adhesion properties of MUB were analyzed in the intestinal cell models.

RESULTS

MUB can promote the aggregation and formation of a membrane-like morphology in L. acidophilus, which could increase the survival rate of L. acidophilus in gastrointestinal tract (GIT). Furthermore, MUB could trigger immune regulation and intestinal protection through the Toll-like receptor 4 (TLR4) signaling pathway and inhibit the activation of mitogen-activated protein kinase (MAPK) signaling pathway.

CONCLUSION

MUB of L. acidophilus is an important component involved in bacterial-mucus interactions and immunomodulatory effect in gastrointestinal tract.