Screening and selection of Bifidobacterium strains isolated from human feces capable of utilizing resistant starch

The mechanisms in the gut microbiota regulation and type 2 diabetes therapeutic activity of resistant starches

Resistant starch (RS) can potentially prevent type 2 diabetes through the modulation of intestinal microbiota and microbial metabolites. Currently, it has been wildly noted that altering the intestinal microbial composition and short-chain fatty acids levels can achieve therapeutic effects, although the specific mechanisms were rarely elucidated. This review systematically explores the structural characteristics of different RS, analyzes the cross-feeding mechanism utilized by intestinal microbiota, and outlines the pathways and targets of butyrate, a primary microbial metabolite, for treating diabetes. Different RS types may have a unique impact on microbiota composition and their cross-feeding, thus exploring regulatory mechanisms of RS on diabetes through intestinal flora interaction and their metabolites could pave the way for more effective treatment outcomes for host health. Furthermore, by understanding the mechanisms of strain-level cross-feeding and metabolites of RS, precise dietary supplementation methods targeted at intestinal composition and metabolites can be achieved to improve T2DM.

Effect of resistant starch types as a prebiotic

Since the role of intestinal microbiota in metabolism was understood, the importance of dietary components such as fibres and prebiotics, which affect the modulation of microbiota, has been increasing day by day. While all prebiotic components are considered dietary fibre, not every dietary fibre is considered a prebiotic. While fructooligosaccharides, galactooligosaccharides, inulin, and galactans are considered prebiotics, other fermentable carbohydrates are considered candidate prebiotic components based on in vitro and preclinical studies. Resistant starch, one of such carbohydrates, is considered a potential prebiotic component when it is made resistant to digestion naturally or chemically. In this review, both in vitro and in vivo studies in which the prebiotic capacity of type II, type III, and type IV resistant starch isolated from food and produced commercially was assessed were analyzed. According to the results of current studies, certain types of resistant starch are thought to have a high prebiotic capacity, and they may be candidate prebiotic components although positive results have not been achieved in all studies. KEY POINTS: • Resistant starch is undigested in the small intestine and is fermented in the large intestine. • Resistant starch fermentation positively affects the growth of Bifidobacterium and Lactobacillus. • Resistant starch can be considered a prebiotic ingredient.

Pea-Resistant Starch with Different Multi-scale Structural Features Attenuates the Obesity-Related Physiological Changes in High-Fat Diet Mice

The present study compared the modulatory effects of different resistant starches (RSs) isolated from native (NP-RS), acid-hydrolyzed (AHP-RS), and pullulanase debranched (PDP-RS) pea starches on the corresponding in vivo metabolic responses in high fat (HF)-diet-induced obese mice. The biochemical studies on serum lipid profile and antioxidant enzyme activities were supported by histological and gene expression analyses, which suggested a potential therapeutic role for RS in regulating obesity, possibly through the production of short-chain fatty acids and the proliferation of some beneficial colonic bacteria, including Allobaculum, Bifidobacterium, Odoribacter, Clostridium, and Prevotella. Particularly, a more pronounced effect of AHP-RS with a higher proportion of the crystalline region and a more ordered double-helical alignment on improving the hyperlipidemic symptoms in obese mice induced by a HF diet was observed. Our analysis revealed that the RS3 samples seemed to be more effective than RS2 in terms of attenuating obesity in mice that were fed a HF diet.

The potential role of Bifidobacterium spp. as a preventive and therapeutic agent in controlling inflammation via affecting inflammatory signalling pathways

Inflammatory bowel disease (IBD) is a chronic inflammatory disease with relapses and periods of remission. Forasmuch as, dysregulation of the immune system is one of the triggers of IBD, taking probiotics as one of the immunomodulators in the gut, could help to control inflammation and IBD via influencing signalling pathways. Here, we aimed to investigate the efficacy of five selected Bifidobacterium strains in modulating JAK/STAT and NF-kB inflammatory signalling pathways via using the in vitro assay. A quantitative real-time polymerase chain reaction assay was used to analyse the expression of JAK/STAT and inflammatory genes followed by potential probiotic treatments before, after and simultaneously with the inflammation induction (sonicated pathogen). The production of IL-6 and IL-1β after probiotic treatment was evaluated. Probiotic treatment resulted in the downregulation of TIRAP, IRAK4, NEMO and RIP genes in the NF-kB pathway, as well as JAK genes compared to sonicate-treated cells. The expression of STAT genes was different after our selected Bifidobacterium strains treatment. The production of IL-6 and IL-1β decreased after probiotic treatment. These strains of Bifidobacterium spp. showed anti-inflammatory effects on HT-29 cells via modulation of JAK/STAT and NF-kB signalling pathways. The use of Bifidobacterium spp. could be considered as a suitable preventive and complementary treatment for patients with inflammatory bowel disease.

Fermentation Profile and Probiotic-Related Characteristics of Bifidobacterium longum MC-42

This article presents new data on Bifidobacterium longum MC-42—a strain that has been actively used for the preparation of commercial dairy products in Russia for almost 40 years. It was demonstrated that this strain possesses high activities of β-galactosidase, α-glucosidase, and leucine arylaminidase; inhibits the growth of pathogens such as Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli; and can efficiently remove cholesterol from the cultural medium. The resistance of B. longum MC-42 determined for 15 commonly used antibiotics was in agreement with those previously reported for Bifidobacterium spp. The absence of frequently transmittable antibiotic resistance genes in the genome and the lack of undesirable activity of β-glucuronidase proved the safe use of B. longum МС-42 as a probiotic and starter culture. Additionally, the impact of two growth-promoting additives—yeast extract or milk protein hydrolysate containing supplementation—on the B. longum MC-42 fermentation profile was assessed. The introduction of these additives increases the maximum attainable viable cell count by orders of magnitude, significantly changed the profile of aminopeptidase activities in extracellular extracts, and influenced the antioxidant and antihypertensive properties of the obtained fermented products.

Updates on understanding of probiotic lactic acid bacteria responses to environmental stresses and highlights on proteomic analyses

Probiotics are defined as live microorganisms that improve the health of the host when administered in adequate quantities. Nonetheless, probiotics encounter extreme environmental conditions during food processing or along the gastrointestinal tract. This review discusses different environmental stresses that affect probiotics during food preparation, storage, and along the alimentary canal, including high temperature, low temperature, low and alkaline pH, oxidative stress, high hydrostatic pressure, osmotic pressure, and starvation. The understanding of how probiotics deal with environmental stress and thrive provides useful information to guide the selection of the strains with enhanced performance in specific situations, in food processing or during gastrointestinal transit. In most cases, multiple biological functions are affected upon exposure of the cell to environmental stress. Sensing of sublethal environmental stress can allow for adaptation processes to occur, which can include alterations in the expression of specific proteins.