Strain-specific effects of Akkermansia muciniphila on the regulation of intestinal barrier

Akkermansia muciniphila, one of the most promising next-generation probiotics, was reported to exhibit beneficial modulatory effects on the gut barrier. However, the strain-specific and underlying regulatory mechanisms of this species on gut barrier function were not well studied. Therefore, this study evaluated the protective effect of A. muciniphila strains on the intestinal barrier and investigated the mode of action and material basis of this modulatory effect. We first confirmed the strain-specific effects of A. muciniphila on intestinal barrier regulation and found that this phenomenon may be explained by the different abilities of strains to affect tight junction protein expression in enterocytes. Comparative genomic analysis proved that the ability of A. muciniphila to regulate the intestinal barrier was exerted in part by the functional genes(such as COG0438, COG0463, and COG2244)related to the synthesis of cellular surface proteins. The role of these surface proteins in intestinal barrier regulation was further verified by strain-comparative experiments in animal and cell models and surface protein removal trials. This study confirmed the different effects of A. muciniphila strains on gut barrier modulation and provided molecular and genetic targets for the screening of A. muciniphila strains with superior protection against gut barrier dysfunction.

Probiotic yeasts: Anti-inflammatory potential of various non-pathogenic strains in experimental colitis in mice

AIM: To evaluate the in vitro immunomodulation capacity of various non-pathogenic yeast strains and to investigate the ability of some of these food grade yeasts to prevent experimental colitis in mice.METHODS: In vitro immunomodulation was assessed by measuring cytokines [interleukin (IL)-12p70,IL-10,tumor necrosis factor and interferon γ] released by human peripheral blood mononuclear cells after 24 h stimulation with 6 live yeast strains (Saccharomyces ssp.) and with bacterial reference strains.A murine model of acute 2-4-6-trinitrobenzene sulfonic acid (TNBS)-colitis was next used to evaluate the distinct prophylactic protective capacities of three yeast strains compared with the performance of prednisolone treatment.RESULTS: The six yeast strains all showed similar non-discriminating anti-inflammatory potential when tested on immunocompetent cells in vitro .However,although they exhibited similar colonization patterns in vivo ,some yeast strains showed significant anti-inflammatory activities in the TNBS-induced colitis model,whereas others had weaker or no preventive effect at all,as evidenced by colitis markers (body-weight loss,macroscopic and histological scores,myeloperoxidase activities and blood inflammatory markers).CONCLUSION: A careful selection of strains is required among the biodiversity of yeasts for specific clinical studies,including applications in inflammatory bowel disease and other therapeutic uses.

Review of copper and copper alloys as immune and antibacterial element

This review discussed the relationship among copper,human,and bacteria.Copper plays an important role in human immunity.Copper can boost human immune defense reactions at recommended intake level.The content mainly focused on copper antibacterial activity and copper antibacterial mechanisms.Conclusions stated that copper antibacterial activity is affected by copper homeostasis mechanisms in bacteria,adhesion,humidity,strain specificity,and manufacturing methods of antibacterial agents.For the preparation of particle antibacterial agents and surface antibacterial agents,this review discussed several manufacturing methods,such as sol−gel,cold spray,and biosynthesis belonging to chemical synthesis,physical synthesis,and biological synthesis,respectively.Sol−gel method contributes to the preparation of particle agents and surface agents.Cold spray technique is utilized in synthesis of surface copper agent.Biosynthesis is a novel technology which can be applied in nanoparticle agent preparation.