Interactions of Surface Exopolysaccharides From Bifidobacterium and Lactobacillus Within the Intestinal Environment

Safety and Probiotics Evaluation of Bifidobacterial Genomes Isolated from Probiotic Products

Bifidobacterium is a common bacterium colonizing human intestines which is frequently used to produce probiotic-related products. Since the rapid development of probiotic products field over recent years, improving probiotic-related testing methods, as well as conducting systematic safety evaluations is urgently needed. Advances in sequencing technology enable clinicians to access the complete genome of bacteria more effectively via whole genome sequencing, thereby providing a solution for the safety evaluation of probiotics. In our current study, seven samples of the Bifidobacterium spp. were isolated from probiotic products, and genomic analysis were used to improve the identification of Bifidobacterium spp. at the species and subspecies levels. Notably, the obtained high-quality complete genomes were employed to predict the genetically encoded drug resistance and virulence attributes of seven Bifidobacterium strains, which further improve the evaluation of probiotics safety. Genes imparting beneficial functional properties, as well as those associated with colonization and survival within the gastrointestinal tract were presented in all strains. In addition, whole genome sequencing-based analysis combined with phylogenetic trees could help identify the subspecies and facilitate the analysis of the existing homology of samples and the previously reported differences between strains. Our study evaluated the accuracy of mainstream approaches in identifying the bacteria probiotic-related products, and uncovered the deceptive facts in bacteria labeling. Our findings could provide the experimental basis for subspecies level bacterial identification in probiotic-related industry, and to help establish a standard systematic safety evaluation method.

Dextran from human feces-derived Weissella cibaria facilitates intestinal mucosal barrier function by modulating gut bacteria and propionate levels

The disruption of the intestinal mucosal barrier is strongly associated with the onset of various diseases, including inflammatory bowel disease. Exopolysaccharides (EPS) support the functionality of the intestinal barrier. Weissella Cibaria (W. cibaria), belonging to the lactic acid bacteria, exhibits a significant capacity for EPS production. However, the specific mechanisms by which the EPS produced by W. cibaria confers intestinal barrier protection remain unexplored. Here, we characterized the polysaccharide, EPS-2, produced by W. cibaria isolated from the feces of healthy infants. EPS-2 was a novel dextran composed of α-(1 → 6) and α-(1 → 3,6) glycosidic linkages with a molecular weight of 845 kDa. EPS-2 alleviates intestinal mucosal barrier dysfunction in a mouse model of colitis, via a mechanism specifically reliant on the gut microbiota and their metabolic products, which is different from the well-known direct protective effects of other EPS on the intestinal barrier. EPS-2 reversed colitis-induced reductions in Muribaculaceae and propionate levels, thereby enhancing colonic goblet cell function and mucin content. Additionally, EPS-2 decreased the number of LPS-producing bacteria, such as Escherichia_Shigella. EPS-2 alleviated dextran sulfate sodium-induced intestinal inflammation and barrier damage. Therefore, EPS-2 shows promise as a postbiotic treatment for diseases associated with intestinal barrier dysfunction.

Effects of kefir fermented with or without 1% autolyzed yeast powder on dry matter intake, intestinal permeability, and rumen fermentation profile of Holstein calves

Co-fermenting kefir with Saccharomyces cerevisiae has been shown to enhance the exopolysaccharides (EPS) produced by lactic acid bacteria during fermentation, which may further promote intestinal development in the calf. Four different concentrations (0%, 0.25%, 0.5%, 1%) on a weight/weight basis (g/20 g kefir grain) of either dried, activated distiller's yeast or autolyzed yeast powder were evaluated for EPS optimization in kefir, and inclusion of 1% autolyzed yeast powder resulted in the greatest EPS yield. In a randomized, complete block design, 81 Holstein heifers were enrolled at 3 d of age, blocked by birth weight, and randomized within block to receive either 125 mL salable whole milk (CON), 125 mL of kefir (KEF), or 125 mL of kefir fermented with 1% autolyzed yeast powder (YAK) in milk replacer 1x/d until 28 d of age. Feed intake and health scores were recorded daily for each calf through 1-week postweaning (63 d of age). Growth measurements were recorded weekly until 9 wk. Indigestible markers D-mannitol and Cr-EDTA were administered at 15, 29, and 50 d to a subset of calves (n = 36) and recovered in plasma and serum to measure intestinal permeability. Rumen fluid was collected from calves (n = 35) via gastric tube at 63 ± 2 d to measure pH and VFA concentrations, as well as serum BHB at 14, 28, 42, 56, and 63 d. While health outcomes (diarrhea, respiratory illness, dehydration) were not affected by treatment, supplementation with YAK significantly improved starter DMI and BW in the preweaning period compared with CON and KEF, and postweaning DMI was significantly improved in both KEF and YAK compared with CON. Increased butyrate was observed in rumen fluid of calves fed YAK, though serum BHB was not affected. This work contributes to further understanding kefir as a promoter of gastrointestinal development in calves and the potential benefits of EPS in the developing ruminant.

Evaluating the Efficacy of Probiotics on Disease Progression, Quality of Life, and Nutritional Status Among Patients with Crohn's Disease: A Multicenter, Randomized, Single-Blinded Controlled Trial

BACKGROUND

There is growing interest in the role of gut microbiota in the pathophysiology of inflammatory bowel diseases (IBDs), including Crohn's disease (CD). Probiotics have been proposed as a potential adjunct therapy for these conditions by altering the intestinal environment, although studies on their effectiveness have yielded mixed results.

AIM

This study aims to evaluate the short-term (2 months) effects of a dietary supplement containing Lactobacilli, Bifidobacteria, and Lactococcus bacillus on disease progression, remission, quality of life, and nutritional intake in Lebanese patients with CD.

METHOD

A multicenter, randomized, single-blind controlled trial was conducted in 2 medical centers in Beirut from 1 April 2024 to 1 August 2024. Recruitment, prescreening, screening, enrollment, and protocol implementation were carried out at both centers. Data were collected from 21 patients with CD, who were randomly assigned to the control group (n = 10) and the intervention group (n = 11). At baseline and after two months, participants underwent clinical assessments, WHOQOL-BREF evaluation, and 24 h dietary recalls. Follow-up visits included surveys on disease progression, quality of life, adherence, and adverse events, along with repeat body composition and anthropometric measurements.

RESULTS

Probiotic supplementation over two months did not significantly alter symptoms, flares, or hospitalizations outcomes between the control and intervention groups. However, the intervention group experienced notable increases in body weight (p = 0.01), BMI (p = 0.01), body fat mass (p = 0.04), and arm muscle circumference (p = 0.01). Nutrient intake patterns differed, with the intervention group showing increased consumption of calcium, riboflavin, and folate compared to controls (p = 0.01, p = 0.04, p = 0.013, respectively). Probiotic supplementation led to significant within-group increases in dietary fiber (p = 0.01), total sugar (p = 0.02), and caffeine (p = 0.01) among the intervention participants. Adverse effects in the intervention group were mild, including nausea (18.2%) and abdominal discomfort (9.1%). QOL improved significantly in the intervention group, particularly in physical (p = 0.03), psychological (p = 0.04), and environmental domains (p = 0.003), while the control group exhibited improvements only in psychological health.

CONCLUSIONS

Overall, the findings suggest that probiotics can enhance body composition, nutrient intake, and certain aspects of QOL among CD patients, despite minimal impact on disease symptoms or dietary patterns.

Exopolysaccharides from Bifidobacterium longum subsp. infantis and Bifidobacterium adolescentis modulate Toll-like receptor signaling

BACKGROUND

Exopolysaccharides (EPS) from probiotic bacteria like bifidobacteria, have gained considerable attention for the beneficial effects they exert in the gastrointestinal environment. Here, we investigated whether EPS isolated from Bifidobacterium longum subsp. infantis and Bifidobacterium adolescentis can interact with Toll-like receptors (TLRs) in a structure-dependent way and subsequently we investigated whether they influence cytokine-production in dendritic cells (DCs).

RESULTS

EPS from both B. infantis and B. adolescentis were found to be structurally different and were able to inhibit signaling of TLR2 and TLR4 in an EPS-type dependent fashion. EPS from B. infantis was shown to have stronger inhibitory effects on TLR2/1, whereas EPS from B. adolescentis showed stronger effects for TLR2/6 and TLR4. Incubation of DCs with EPS alone had no effect, however stimulation of DCs with spend-medium of epithelial cells incubated with EPS reduced production of the cytokines MCP-1/CCL2 and TNFα.

CONCLUSION

Here we show that EPS from B. infantis and B. adolescentis have structure-dependent immunomodulatory effects, indicating that EPS might be important effector molecules responsible for the health benefits of bifidobacteria.

Akkermansia muciniphila: new insights into resistance to gastrointestinal stress, adhesion, and protein interaction with human mucins through optimised in vitro trials and bioinformatics tools

According to the FAO/WHO guidelines, selection of probiotics requires the assessment of survival under gastrointestinal stress and adhesion to human epithelial cells. These attributes were evaluated on Akkermansia muciniphila ATCC BAA-835 simulating the gastrointestinal transit (GIT) immediately followed by adhesion to human intestinal cell lines (CaCo2, HT-29, and HT-29-MTX) as an alternative approach to in vitro methods performed with fresh cells in each trial. The survival rate after GIT, as determined by plate counts and fluorescent probes, was significantly higher for A. muciniphila (about 8 Log CFU/mL) than for the probiotic Lacticaseibacillus rhamnosus GG ATCC 53103 (about 3 Log CFU/mL). The use of Live/Dead assay highlighted that A. muciniphila forms cell aggregates in the gastric phase as protective mechanism, explaining its high viability in the intestine. The rate of adhesion to human cell lines was always lower for strains tested after simulated GIT than for strains that did not undergo simulated GIT. Akkermansia muciniphila exhibited significantly higher adhesion than Lbs. rhamnosus GG, particularly to the mucus-secreting HT-29-MTX cells across a range of concentrations (2-8 Log CFU/mL). Finally, the bioinformatic analysis of A. muciniphila proteome confirmed the Amuc_1434 as a potential factor in binding to the human MUC2 protein.

The anti-obesity effects of postbiotics: A systematic review of pre-clinical and clinical studies

BACKGROUND

The growing prevalence of obesity has become a major concern worldwide, therefore a great number of studies are conducted every day in the field of obesity. Since postbiotics are a newly introduced term, there is not much systematic evidence about their function and impact on obesity. We designed this study to systematically review the effect of different types of postbiotics on obesity.

METHODS

A systematic search was conducted using PubMed, SCOPUS, and Web of Science databases up to August 2023. Both human and animal interventional studies that investigated the effects of any type of postbiotic on obesity and obesity-related factors were eligible. Screening, data extraction, and quality assessment were conducted independently by two researchers. The quality of the studies was appraised using Cochrane and Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE's) risk of bias tool.

RESULTS

Of the 19373 retrieved studies, finally, 49 studies were included (9 human studies and 40 animal studies). Short-chain fatty acids and heat-killed (inactivated) bacteria were the most used postbiotics. In human clinical trials, inactivated Lactobacillus amylovorus (CP1563), Bifidobacterium animalis subsp. lactis (CECT 8145) and Pediococcus pentosaceus (LP28) were administered orally as postbiotics which improved body composition and anthropometric indices. Animal studies evaluated other types of postbiotics including muramyl dipeptide, cell-free extracts, urolithin A&B, extracellular Vesicles, exopolysaccharides, and surface Layer Proteins, supporting the anti-obesity effects of postbiotics.

CONCLUSION

Postbiotics seem to be a safe intervention and the results were in favor of a reduction in adipogenesis as well as an increase in energy expenditure. Further high-quality studies are required in this relatively new topic.

Comparison of the effects of three sourdough postbiotics on high-fat diet-induced intestinal damage

There is significant interest in using postbiotics as an intervention strategy to address obesity. This study assesses the efficacy of postbiotics derived from different sourdough strains (Lactiplantibacillus plantarum LP1, LP25, and Pediococcus pentosaceus PP18) in mitigating intestinal injury in zebrafish fed on a high-fat diet. We screened postbiotics for their anti-colon cancer cell effects and compared various preparation methods applied to live bacterial strains, including heat-killing at different temperatures, pH adjustments, and ultraviolet radiation exposure. Heat-killing at 120 °C proved to be the most effective preparation method. A marked variation in health effects was observed in the heat-killed microbial cells, as evidenced by their hydrophobicity and self-aggregation ability. A five-week high-fat dietary intervention study in zebrafish demonstrated that diets supplemented with 108 CFU g-1 K-LP25 significantly attenuated weight gain and body fat, along with reductions in FASN, Leptin, and SREBF1 mRNA expression. However, diets supplemented with 107 CFU g-1 K-PP18 only reduced Leptin and SREBF1 mRNA expression. K-PP18 was more effective at mitigating gut barrier damage, promoting colonic Occludin, ZO-1, and Claudin-1 levels. Additionally, K-LP25 supplementation markedly downregulated the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, reducing intestinal inflammation. Supplementation with K-LP1 and K-PP18 increased the abundance of Acinetobacter spp., whereas K-LP25 increased the abundance of Cetobacterium and Plesiomonas. Collectively, these findings suggest that inactivated strains confer protective effects against high-fat diet-induced intestinal damage in zebrafish, with variation observed across different species. Studying the effects of sourdough-derived postbiotics on gut health may open new avenues for dietary interventions to manage gut-related diseases.

Research progress on the regulatory mechanism of biofilm formation in probiotic lactic acid bacteria

Probiotic lactic acid bacteria (LAB) must undergo three key stages of testing, including food processing, storage, and gastrointestinal tract environment, their beneficial effects could exert. The biofilm formation of probiotic LAB is helpful for improving their stress resistances, survival rates, and colonization abilities under adverse environmental conditions, laying an important foundation for their probiotic effects. In this review, the formation process, the composition and function of basic components of probiotic LAB biofilm have been summarized. This review focuses on the regulatory mechanism of probiotic LAB biofilm formation. In addition, the characteristics and related mechanisms of probiotics in biofilm state have been analyzed to guide the application of probiotic LAB biofilms in the field of health and food. The biofilm formation of LAB is an extremely complex process involving multiple regulatory factors. Besides quorum sensing (QS), other regulatory factors are not yet fully understood. The probiotic LAB in biofilm state exhibit superior survival rate, adhesion performance, and immunomodulation ability, attribute to various metabolic processes, including stress response, exopolysaccharide (EPS) metabolism, amino acid and protein metabolisms, etc. The understanding about regulatory mechanism of biofilm formation of different probiotic species and strains will accelerate the development and application of probiotics products.

Rhizosphere bacterial exopolysaccharides: composition, biosynthesis, and their potential applications

Bacterial exopolysaccharides (EPS) are biopolymers of carbohydrates, often released from cells into the extracellular environment. Due to their distinctive physicochemical properties, biocompatibility, biodegradability, and non-toxicity, EPS finds applications in various industrial sectors. However, the need for alternative EPS has grown over the past few decades as lactic acid bacteria's (LAB) low-yield EPS is unable to meet the demand. In this case, rhizosphere bacteria with the diverse communities in soil leading to variations in composition and structure, are recognized as a potential source of EPS applicable in various industries. In addition, media components and cultivation conditions have an impact on EPS production, which ultimately affects the quantity, structure, and biological functions of the EPS. Therefore, scientists are currently working on manipulating bacterial EPS by developing cultures and applying abiotic and biotic stresses, so that better production of exopolysaccharides can be attained. This review highlights the composition, biosynthesis, and effects of environmental factors on EPS production along with the potential applications in different fields of industry. Ultimately, an overview of potential future paths and tactics for improving EPS implementation and commercialization is pointed out.

Roseburia intestinalis-derived extracellular vesicles ameliorate colitis by modulating intestinal barrier, microbiome, and inflammatory responses

Inflammatory bowel disease (IBD) is a chronic disorder characterized by recurrent gastrointestinal inflammation, lacking a precise aetiology and definitive cure. The gut microbiome is vital in preventing and treating IBD due to its various physiological functions. In the interplay between the gut microbiome and human health, extracellular vesicles secreted by gut bacteria (BEVs) are key mediators. Herein, we explore the role of Roseburia intestinalis (R)-derived EVs (R-EVs) as potent anti-inflammatory mediators in treating dextran sulfate sodium-induced colitis. R was selected as an optimal BEV producer for IBD treatment through ANCOM analysis. R-EVs with a 76 nm diameter were isolated from R using a tangential flow filtration system. Orally administered R-EVs effectively accumulated in inflamed colonic tissues and increased the abundance of Bifidobacterium on microbial changes, inhibiting colonic inflammation and prompting intestinal recovery. Due to the presence of Ile-Pro-Ile in the vesicular structure, R-EVs reduced the DPP4 activity in inflamed colonic tissue and increased the active GLP-1, thereby downregulating the NFκB and STAT3 via the PI3K pathway. Our results shed light on the impact of BEVs on intestinal recovery and gut microbiome alteration in treating IBD.

Assessment of Multifunctional Activity of a Postbiotic Preparation Derived from Lacticaseibacillus paracasei Postbiotic-P6

Postbiotics possess various functional activities, closely linked to their source bacterial strains and preparation methods. Therefore, the functional activities of postbiotics need to be evaluated through in vitro and in vivo methods. This study aims to prepare a postbiotic and explore its antihemolytic, anti-inflammatory, antioxidant, and antibacterial activities. Specifically, a postbiotic preparation named PostbioP-6 was prepared by intercepting 1-5 kDa of Lacticaseibacillus paracasei Postbiotic-P6 fermentation broth. The results demonstrate that PostbioP-6 exhibited notable biological activities across multiple assays. It showed significant antihemolytic activity, with a 4.9-48.1% inhibition rate at 10-50% concentrations. Anti-inflammatory effects were observed both in vitro, where 8-40% PostbioP-6 was comparable to 259.1-645.4 μg/mL diclofenac sodium, and in vivo, where 3.5 and 4.0 μL/mL PostbioP-6 significantly reduced neutrophil counts in inflamed zebrafish (p < 0.05). Antioxidant properties were evident through increased reducing power (OD700 increased from 0.279 to 2.322 at 1.25-12.5% concentrations), DPPH radical scavenging activity (38.9-92.4% scavenging rate at 2.5-50% concentrations), and hydroxyl radical scavenging activity (4.66-10.38% scavenging rate at 0.5-4% concentrations). Additionally, PostbioP-6 demonstrated antimicrobial activity against two Gram-positive bacteria, eight Gram-negative bacteria, and one fungus. Furthermore, PostbioP-6 significantly inhibited the increase in peroxide value and malondialdehyde content in cookies, highlighting its potential application in food preservation. In conclusion, we prepared a novel postbiotic, termed PostbioP-6, which proved to have prominent anti-hemolytic, anti-inflammatory, antioxidant, and broad-spectrum antimicrobial activities. The multifunctional properties of PostbioP-6 position it as a potentially effective functional food supplement or preservative. In the future, further research is necessary to elucidate the precise mechanisms of action, identify the active components, and validate its biological activities in animal models or clinical trials.

Unveiling metabolic pathways of selected plant-derived glycans by Bifidobacterium pseudocatenulatum

Bifidobacteria are commonly encountered members of the human gut microbiota that possess the enzymatic machinery necessary for the metabolism of certain plant-derived, complex carbohydrates. In the current study we describe differential growth profiles elicited by a panel of 21 newly isolated Bifidobacterium pseudocatenulatum strains on various plant-derived glycans. Using a combination of gene-trait matching and comparative genome analysis, we identified two distinct xylanases responsible for the degradation of xylan. Furthermore, three distinct extracellular α-amylases were shown to be involved in starch degradation by certain strains of B. pseudocatenulatum. Biochemical characterization showed that all three α-amylases can cleave the related substrates amylose, amylopectin, maltodextrin, glycogen and starch. The genes encoding these enzymes are variably found in the species B. pseudocatenulatum, therefore constituting a strain-specific adaptation to the gut environment as these glycans constitute common plant-derived carbohydrates present in the human diet. Overall, our study provides insights into the metabolism of these common dietary carbohydrates by a human-derived bifidobacterial species.

Limosilactobacillus fermentum strains MC1 and D12: Functional properties and exopolysaccharides characterization

Lactic acid bacteria (LAB) produce a broad spectrum of exopolysaccharides (EPSs), commonly used as texturizers in food products. Due to their potential contribution to LAB probiotic properties, like adhesion to human epithelial cells and competitive exclusion of pathogens from human intestinal epithelial cells, this study was focussed on the structural and functional characterization of the EPSs produced by two Limosilactobacillus fermentum strains - MC1, originating from mother's milk, and D12, autochthonous from Croatian smoked fresh cheese. Whole-genome sequencing and functional annotation of both L. fermentum strains by RAST server revealed the genes involved in EPS production and transport, with some differences in functionally related genes. EPSs were extracted from the cell surface of both bacterial strains and purified by size-exclusion chromatography. Structural characterization of the EPSs, achieved by chemical analyses and 1D and 2D NMR spectroscopy, showed that both strains produce an identical mixture of three different EPSs containing galactofuranose and glucopyranose residues. However, a comparison of the functional properties showed that the MC1 strain adhered better to the Caco-2 cell line and exhibited stronger antimicrobial effect against Salmonella enterica serovar Typhimurium FP1 than the D12 strain, which may be attributed to the potential bacteriocin activity of the MC1 strain.

Both viable Bifidobacterium longum subsp. infantis B8762 and heat-killed cells alleviate the intestinal inflammation of DSS-induced IBD rats

In view of the safety concerns of probiotics, more and more attention is paid to the beneficial effects of dead probiotics cells. Herein, we investigated and compared the alleviation effects of viable Bifidobacterium longum subsp. infantis B8762 (B. infantis B8762) and its heat-killed cells on dextran sodium sulfate (DSS)-induced inflammatory bowel disease (IBD) rats. Four groups of rats (n = 12 per group) were included: normal control, DSS-induced colitis rats without bacterial administration (DSS), DSS-induced colitis rats with viable B. infantis B8762 administration (VB8762), and DSS-induced colitis rats with dead B. infantis B8762 administration (DB8762). Our results showed that both VB8762 and DB8762 administration exerted significant protective effects on DSS-induced IBD rats, as evidenced by a reduction in mortality, disease activity index score, body weight loss, as well as decreased histology score, which were companied by a significant decrease in serum pro-inflammatory factors compared with DSS group, and a stronger effect on modulating the fecal microbiota alpha-diversity and beta-diversity compared with DSS group. Additionally, the fecal metabolome results showed that both VB8762 and DB8762 interventions indeed altered the fecal metabolome profile and related metabolic pathways of DSS-induced IBD rats. Therefore, given the alleviation effects on colitis, the DB8762 can be confirmed to be a postbiotic. Overall, our findings suggested that VB8762 and DB8762 had similar ability to alleviate IBD although with some differences. Due to the minimal safety concern of postbiotics, we propose that the postbiotic DB8762 could be a promising alternative to probiotics to be applied in the prevention and treatment of IBDs.IMPORTANCEInflammatory bowel disease (IBD) has emerged as a global disease because of the worldwide spread of western diets and lifestyles during industrialization. Up to now, many probiotic strains are used as a modulator of gut microbiota or an enhancer of gut barrier to alleviate or cure IBD. However, there are still many issues of using probiotics, which were needed to be concerned about, for instance, safety issues in certain groups like neonates and vulnerable populations, and the functional differences between viable and dead microorganisms. Therefore, it is of interest to investigate the beneficial effects of dead probiotics cells. The present study proved that both viable Bifidobacterium longum subsp. infantis B8762 and heat-killed cells could alleviate dextran sodium sulfate-induced colitis in rats. The findings help to support that some heat-killed probiotics cells can also exert relevant biological functions and can be used as a postbiotic.

Effects of Probiotics on Gut Microbiota: An Overview

The role of probiotics in regulating intestinal flora to enhance host immunity has recently received widespread attention. Altering the human gut microbiota may increase the predisposition to several disease phenotypes such as gut inflammation and metabolic disorders. The intestinal microbiota converts dietary nutrients into metabolites that serve as biologically active molecules in modulating regulatory functions in the host. Probiotics, which are active microorganisms, play a versatile role in restoring the composition of the gut microbiota, helping to improve host immunity and prevent intestinal disease phenotypes. This comprehensive review provides firsthand information on the gut microbiota and their influence on human health, the dietary effects of diet on the gut microbiota, and how probiotics alter the composition and function of the human gut microbiota, along with their corresponding effects on host immunity in building a healthy intestine. We also discuss the implications of probiotics in some of the most important human diseases. In summary, probiotics play a significant role in regulating the gut microbiota, boosting overall immunity, increasing the abundance of beneficial bacteria, and helping ameliorate the symptoms of multiple diseases.

Bifidobacterium exopolysaccharides: new insights into engineering strategies, physicochemical functions, and immunomodulatory effects on host health

Bifidobacteria are a prominent type of bacteria that have garnered significant research attention for their exceptional probiotic properties and capacity to produce exopolysaccharides (EPSs). These compounds exhibit diverse physical, chemical, and biological characteristics, prompting numerous investigations into their potential applications. Researchers have noted their beneficial effects as immune modulators within the host's body across various industries. Extensive research has been conducted on the immunomodulatory effects of bifidobacteria-derived EPSs, with emerging engineering strategies aimed at enhancing their immune-modulating capabilities. Understanding the structure, physicochemical properties, and biological activities of these compounds is crucial for their effective utilization across different industries. Our review encompassed numerous studies exploring Bifidobacterium and its metabolites, including EPSs, across various sectors, drawing from diverse databases. The distinctive properties of EPSs have spurred investigations into their applications, revealing their potential to bolster the immune system, combat inflammation, and treat various ailments. Additionally, these compounds possess antioxidant and antimicrobial properties, making them suitable for incorporation into a range of products spanning food, health, and medicine.

Heat-Killed Enterococcus faecium KU22001 Having Effective Anti-Cancer Effects on HeLa Cell Lines at a Lower Temperature

The anti-cancer effects of heat-killed Enterococcus faecium KU22001 (KU22001), KU22002, and KU22005 isolated from human infant feces were investigated. The anti-proliferative activity of these strains against various cancer cell lines was evaluated using the MTT assay. To determine the production of exopolysaccharides (EPS) with potential anti-cancer effect, ethanol precipitation and phenol-sulfuric acid method was used with the cell free supernatant of strains grown at 25°C or 37°C. The EPS yield of E. faecium strains was higher at 25°C than at 37°C. Among these E. faecium strains, KU22001 grown at 25°C was associated with the highest bax/bcl-2 ratio, effective apoptosis rate, cell cycle arrest in the G0/G1 phase, and condensation of the nucleus in the cervical cancer HeLa cell line. In conclusion, these results suggest that KU22001 can be beneficial owing to the anti-cancer effects and production of functional materials, such as EPS.

Supplementation of Heat-Treated Lactiplantibacillus plantarum nF1 Changes the Production of Short-Chain Fatty Acids in Healthy Infants

Background

Imbalance of the gut microbiome and decrease in the number of short-chain fatty acid (SCFA)-producing bacteria often affect human health by altering intestinal and immune homeostasis. The use of probiotics has been shown to be an attractive method to modulate gut microbiota to prevent or treat intestinal dysbiosis. Likewise, this study aimed to determine whether the oral consumption of heat-treated Lactiplantibacillus plantarum nF1 (HLp-nF1) induces changes in the gut environment in healthy infants by measuring changes in fecal SCFAs.

Methods

The study enrolled 43 infants aged under 2 months, with 30 infants in the HLp-nF1 group receiving HLp-nF1 orally (2.5 × 1010 cells/g/pack, daily dose of two packs) for 8 weeks. The fecal samples were collected and the questionnaires were administered at weeks 0 and 8.

Results

The concentrations of the total SCFAs, acetate, propionate, and butyrate significantly increased following HLp-nF1 supplementation (P < 0.0001, P < 0.0001, P < 0.0001, and P=0.028, respectively).

Conclusions

Supplementation of HLp-nF1 has a positive effect on SCFA production and could be a potentially useful and straightforward method to manipulate SCFA formation.

Immunomodulatory effect of probiotic exopolysaccharides in a porcine in vitro co-culture model mimicking the intestinal environment on ETEC infection

The aim of this study was to evaluate the immunomodulatory effect of EPS-L26 isolated from the probiotic strain Lactobacillus (Limosilactobacillus) reuteri L26 Biocenol™, in a model of infection with an enterotoxigenic E. coli (ETEC) by establishing monocultures consisting of the IPEC-J2 cell line or monocyte-derived dendritic cells (moDCs) and creating a 3D model of cell co-cultures established with IPEC-J2 cells and moDCs. The immunomodulatory and immunoprotective potential of used EPS-L26 was confirmed in monocultures in an experimental group of pretreated cells, where our study showed that pretreatment of cells with EPS-L26 and subsequent exposure to infection resulted in significantly down-regulated mRNA levels of genes encoding inflammatory cytokines compared to ETEC challenge in single cell cultures (in IPEC-J2, decreased mRNA levels for TNF-α, IL-6, IL-1β, IL-12p35; in moDCs, decreased mRNA levels for IL-1β). Similar to monocultures, we also demonstrated the immunostimulatory potential of the ETEC strain in the co-culture model on directly treated IPEC-J2 cells cultivated on insert chambers (apical compartment) and also on indirectly treated moDCs cultivated in the lower chamber (basolateral compartment), however in the co-culture model the expression of inflammatory cytokines was attenuated at the mRNA level compared to monocultures. Pretreatment of the cells on the insert chambers pointed to the immunoprotective properties of EPS-L26, manifested by decreased mRNA levels in both cell lines compared to ETEC challenge (in IPEC-J2 decreased mRNA levels for IL-12p35; in moDCs decreased mRNA levels for IL-1β, IL-6). Our results suggest intercellular communication via humoral signals derived from IPEC-J2 cells by influencing the gene expression of indirectly treated moDC cells located in the basolateral compartment.

Postbiotics Implication in the Microbiota-Host Intestinal Epithelial Cells Mutualism

To sustain host health and provide the microbial community with a nutrient-rich environment, the host and gut microbiota must interact with one another. These interactions between commensal bacterial and intestinal epithelial cells (IECs) serve as the first line of defense against gut microbiota in preserving intestinal homeostasis. In this microenvironment, the post-biotics and similar molecules such as p40 exert several beneficial effects through regulation of IECs. Importantly, post-biotics were discovered to be transactivators of the EGF receptor (EGFR) in IECs, inducing protective cellular responses and alleviating colitis. The transient exposure to post-biotics such as p40 during the neonatal period reprograms IECs by upregulation of a methyltransferase, Setd1β, leading to a sustained increase in TGF- β release for the expansion of regulatory T cells (Tregs) in the intestinal lamina propria and durable protection against colitis in adulthood. This crosstalk between the IECs and post-biotic secreted factors was not reviewed previously. Therefore, this review describes the role of probiotic-derived factors in the sustainability of intestinal health and improving gut homeostasis via certain signaling pathways. In the era of precision medicine and targeted therapies, more basic, preclinical, and clinical evidence is needed to clarify the efficacy of probiotics released as functional factors in maintaining intestinal health and preventing and treating disease.

Horizon scanning the application of probiotics for wildlife

The provision of probiotics benefits the health of a wide range of organisms, from humans to animals and plants. Probiotics can enhance stress resilience of endangered organisms, many of which are critically threatened by anthropogenic impacts. The use of so-called 'probiotics for wildlife' is a nascent application, and the field needs to reflect on standards for its development, testing, validation, risk assessment, and deployment. Here, we identify the main challenges of this emerging intervention and provide a roadmap to validate the effectiveness of wildlife probiotics. We cover the essential use of inert negative controls in trials and the investigation of the probiotic mechanisms of action. We also suggest alternative microbial therapies that could be tested in parallel with the probiotic application. Our recommendations align approaches used for humans, aquaculture, and plants to the emerging concept and use of probiotics for wildlife.

Bifidobacterial Genome Editing for Potential Probiotic Development

Genome editing is a promising tool in the era of modern biotechnology that can alter the DNA of many organisms. It is now extensively used in various industries to obtain the well-desired and enhanced characteristics to improve the yield and nutritional quality of products. The positive health attributes of Bifidobacteria, such as prevention of diarrhoea, reduction of ulcerative colitis, prevention of necrotizing enterocolitis, etc., have shown promising reports in many clinical trials. The potential use of Bifidobacteria as starter or adjunct cultures has become popular. Currently, Bifidobacterium bifidum, B. adolescentis, B. breve, B. infantis, B. longum, and B. lactis find a significant role in the development of probiotic fermented dairy products. However, Bifidobacteria, one of the first colonizers of the human GI tract and an indicator of the health status of an individual, has opened new avenues for research and, thereby, its application. Besides this, the GRAS/QPS (Generally Regarded as Safe/Qualified Presumption of Safety) status of Bifidobacteria makes it safe for use. They belong to the subgroup (which are the fermentative types that are primarily found in the natural cavities of humans and animals) of Actinomycetes. B. lactis has been used industrially in fermented foods, such as yogurt, cheese, beverages, sausages, infant formulas, and cereals. In the present book chapter, the authors tried to explore the origin, health attributes, and various genetic engineering tools for genome editing of Bifidobacteria for the development of starter culture for dairy and non-dairy industrial applications as well as probiotics.&nbsp;

Bacteroides thetaiotaomicron and its inactivated bacteria ameliorate colitis by inhibiting macrophage activation

BACKGROUND

Studies have demonstrated that Bacteroides thetaiotaomicron (BT) has protective effect against colon inflammation in murine models. Macrophages play an important role in gut immunity. However, the specific mechanisms of BT on macrophage are still unelucidated. Thus, our study investigates the anti-inflammatory effect of BT and its heat-treated inactivated bacteria on experimental colitis and macrophages.

METHODS

A dextran sulfate sodium (DSS)-induced acute colitis model with male C57BL/6 mice, BT (ATCC29148) strain, THP1 cell lines were used in this study. Live and heat-treated inactivated BT (IBT) solution (1 × 10^9cfu/ml) were intragastrically gavaged daily for 14 days. Colonic inflammation was determined by the disease activity index (DAI) score, colon length, histological score, and inflammatory factors. THP1 cells were induced towards M1, then treated with different concentrations of inactivated BT solution and p38 inhibitor. Western blotting, immunohistochemistry, immunofluorescence and qRT-PCR were performed to assess the levels of inflammatory cytokines and molecules of MAPK pathway including IL-6, TNF-α, IL-1β, IL-22, p38 and phosphor-p38 expressions. Moreover, 16S rRNA sequencing of colitis murine fecal samples was applied to investigate the influence of supplementation of BT to the gut microbiota homeostasis.

RESULTS

Both live and heat-treated inactivated BT decreased the DAI and histological scores as well as levels of inflammatory factors, particularly IL-6 while increasing IL-22 of DSS-induced colitis murine models. The cell experiments showed that inactivated BT downregulates IL-6 expression in THP1 via inhibiting p38 phosphorylation and affecting M1 polarization. Moreover, the 16S rRNA sequencing results showed that BT and IBT gavage could increase beta-diversity of gut flora in DSS-induced colitis mice. Furthermore, the significance test for differences between the groups showed that BT could increase Faecalebaculum, Lactobacillus and Bacteroides, while decreasing Akkermansia.

CONCLUSION

In summary, our findings imply that BT and its heat-treated inactivated bacteria exert a protective effect by suppressing macrophage-induced IL-6 through the inhibition of p38 MAPK pathway and ameliorating intestinal gut dysbiosis in experimental colitis.

Exopolysaccharide β-(2,6)-levan-type fructans have a molecular-weight-dependent modulatory effect on Toll-like receptor signalling

SCOPE

Fructans are a group of dietary fibers which are known to have many beneficial effects including immune-modulating effects. A family of fructans are β-(2,6)-linked levan-type fructans that are known to serve as exopolysaccharides in the cell wall of many species of bacteria including commensal bacteria and probiotics. It is still largely unknown whether and how they can serve as immunomodulating molecules.

RESULTS

Microbial β-(2,6)-fructans were found to induce TLR-dependent activation of THP-1 cells, in a dose-dependent fashion. Low molecular weight (Mw), medium Mw and high Mw β-(2,6)-fructans activated both TLR2 and 4 in a dose- and molecular weight-dependent fashion. In addition, it was found that β-(2,6)-fructans were able to inhibit signalling of various TLRs with the strongest effect on TLR5 and 8, which were inhibited by all the β-(2,6)-fructans in a dose- and molecular weight-dependent fashion. The final effect of this activation and inhibition of TLRs on cytokine responses in human dendritic cells (DCs) was minor which may be explained by the counter-activating effects of the different β-(2,6)-linked levan-type fructans on inhibition of TLR signalling in the DCs.

CONCLUSION

A mechanism by which exopolysaccharide levan β-(2,6)-fructans can be immune-modulating is by impacting TLR signalling. This knowledge could lead to food in which exopolysaccharide levan β-(2,6)-fructans are added for preventing disorders where TLR-signalling is modulated.

Physicochemical Characterization and Immunomodulatory Activity of Polyelectrolyte Multilayer Coatings Incorporating an Exopolysaccharide from Bifidobacterium longum

Immunoregulatory polysaccharides from probiotic bacteria have potential in biomedical engineering. Here, a negatively charged exopolysaccharide from Bifidobacterium longum with confirmed immunoregulatory activity (EPS624) was applied in multilayered polyelectrolyte coatings with positively charged chitosan. EPS624 and coatings (1, 5, and 10 layers and alginate-substituted) were characterized by the zeta potential, dynamic light scattering, size exclusion chromatography, scanning electron microscopy, and atomic force microscopy. Peripheral blood mononuclear cells (hPBMCs) and fibroblasts were exposed for 1, 3, 7, and 10 days with cytokine secretion, viability, and morphology as observations. The coatings showed an increased rugosity and exponential growth mode with an increasing number of layers. A dose/layer-dependent IL-10 response was observed in hPBMCs, which was greater than EPS624 in solution and was stable over 7 days. Fibroblast culture revealed no toxicity or metabolic change after exposure to EPS624. The EPS624 polyelectrolyte coatings are cytocompatible, have immunoregulatory properties, and may be suitable for applications in biomedical engineering.

The mobilome of Lactobacillus crispatus M247 includes two novel genetic elements: Tn7088 coding for a putative bacteriocin and the siphovirus prophage ΦM247

Lactobacillus crispatus is a member of the vaginal and gastrointestinal human microbiota. Here we determined the complete genome sequence of the probiotic strain M247 combining Nanopore and Illumina technologies. The M247 genome is organized in one circular chromosome of 2 336 109 bp, with a GC content of 37.04 % and 2303 ORFs, of which 1962 could be annotated. Analysis of the M247 mobilome, which accounts for 14 % of the whole genome, revealed the presence of: (i) Tn7088, a novel 14 105 bp long integrative and mobilizable element (IME) containing 16 ORFs; (ii) ΦM247, a novel 42 510 bp long siphovirus prophage containing 52 ORFs; (iii) three clustered regularly interspaced short palindromic repeats (CRISPRs); and (iv) 226 insertion sequences (ISs) belonging to 14 different families. Tn7088 has a modular organization including a mobilization module encoding FtsK homologous proteins and a relaxase, an integration/excision module coding for an integrase and an excisionase, and an adaptation module coding for a class I bacteriocin and homologous to the listeriolysin S (lls) locus of Listeria monocytogenes. Genome-wide homology search analysis showed the presence of Tn7088-like elements in 12 out of 23 L. crispatus complete public genomes. Mobilization and integration/excision modules are essentially conserved, while the adaptation module is variable since it is the target site for the integration of different ISs. Prophage ΦM247 contains genes for phage structural proteins, DNA replication and packaging, lysogenic and lytic cycles. ΦM247-like prophages are present in seven L. crispatus complete genomes, with sequence variability mainly due to the integration of ISs. PCR and sequencing showed that the Tn7088 IME excises from the M247 chromosome producing a circular form at a concentration of 4.32×10-5 copies per chromosome, and reconstitution of the Tn7088 chromosomal target site occurred at 6.65×10-4 copies per chromosome. The ΦM247 prophage produces an excised form and a reconstituted target site at a level of 3.90×10-5 and 2.48×10-5 copies per chromosome, respectively. This study identified two novel genetic elements in L. crispatus. Tn7088 represents the first example of an IME carrying a biosynthetic gene cluster for a class I bacteriocin in L. crispatus.

Bifidobacterium mechanisms of immune modulation and tolerance

Bifidobacterium is a widely distributed commensal bacterial genus that displays beneficial pro-homeostatic and anti-inflammatory immunomodulatory properties. Depletion or absence of Bifidobacterium in humans and model organisms is associated with autoimmune responses and impaired immune homeostasis. At the cellular level, Bifidobacterium upregulates suppressive regulatory T cells, maintains intestinal barrier function, modulates dendritic cell and macrophage activity, and dampens intestinal Th2 and Th17 programs. While there has been a large volume of literature characterizing the probiotic properties of various Bifidobacterial species, the likely multifactorial mechanisms underlying these effects remain elusive, in particular, its immune tolerogenic effect. However, recent work has shed light on Bifidobacterium surface structural polysaccharide and protein elements, as well as its metabolic products, as commensal mediators of immune homeostasis. This review aims to discuss several mechanisms Bifidobacterium utilizes for immune modulation as well as their indirect impact on the regulation of gut microbiome structure and function, from structural molecules to produced metabolites. These mechanisms are pertinent to an increasingly networked understanding of immune tolerance and homeostasis in health and disease.

Microbial isolation and characterization from two flex lines from the urine processor assembly onboard the international space station

Urine, humidity condensate, and other sources of non-potable water are processed onboard the International Space Station (ISS) by the Water Recovery System (WRS) yielding potable water. While some means of microbial control are in place, including a phosphoric acid/hexavalent chromium urine pretreatment solution, many areas within the WRS are not available for routine microbial monitoring. Due to refurbishment needs, two flex lines from the Urine Processor Assembly (UPA) within the WRS were removed and returned to Earth. The water from within these lines, as well as flush water, was microbially evaluated. Culture and culture-independent analysis revealed the presence of Burkholderia, Paraburkholderia, and Leifsonia. Fungal culture also identified Fusarium and Lecythophora. Hybrid de novo genome analysis of the five distinct Burkholderia isolates identified them as B. contaminans, while the two Paraburkholderia isolates were identified as P. fungorum. Chromate-resistance gene clusters were identified through pangenomic analysis that differentiated these genomes from previously studied isolates recovered from the point-of-use potable water dispenser and/or current NCBI references, indicating that unique populations exist within distinct niches in the WRS. Beyond genomic analysis, fixed samples directly from the lines were imaged by environmental scanning electron microscopy, which detailed networks of fungal-bacterial biofilms. This is the first evidence of biofilm formation within flex lines from the UPA onboard the ISS. For all bacteria isolated, biofilm potential was further characterized, with the B. contaminans isolates demonstrating the most considerable biofilm formation. Moreover, the genomes of the B. contaminans revealed secondary metabolite gene clusters associated with quorum sensing, biofilm formation, antifungal compounds, and hemolysins. The potential production of these gene cluster metabolites was phenotypically evaluated through biofilm, bacterial-fungal interaction, and hemolytic assays. Collectively, these data identify the UPA flex lines as a unique ecological niche and novel area of biofilm growth within the WRS. Further investigation of these organisms and their resistance profiles will enable engineering controls directed toward biofilm prevention in future space station water systems.

Milk phospholipids protect Bifidobacterium longum subsp. infantis during in vitro digestion and enhance polysaccharide production

Bifidobacterium longum subsp. infantis is associated with the gut microbiota of breast-fed infants. Bifidobacterium infantis promotes intestinal barrier and immune function through several proposed mechanisms, including interactions between their surface polysaccharides, the host, and other gut microorganisms. Dairy foods and ingredients are some of the most conspicuous food-based niches for this species and may provide benefits for their delivery and efficacy in the gut. Milk phospholipid (MPL)-rich ingredients have been increasingly recognized for their versatile benefits to health, including interactions with the gut microbiota and intestinal cells. Therefore, our objective was to investigate the capacity for MPL to promote survival of B. infantis during simulated digestion and to modulate bacterial polysaccharide production. To achieve these aims, B. infantis was incubated with or without 0.5% MPL in de Man, Rogosa, and Sharpe (MRS) media at 37°C under anaerobiosis. Survival across the oral, gastric, and intestinal phases using in vitro digestion was measured using plate count, along with adhesion to goblet-like intestinal cells. MPL increased B. infantis survival at the end of the intestinal phase by at least 7% and decreased adhesion to intestinal cells. The bacterial surface characteristics, which may contribute to these effects, were assessed by ζ-potential, changes in surface proteins using comparative proteomics, and production of bound polysaccharides. MPL decreased the surface charge of the bifidobacteria from -17 to -24 mV and increased a 50 kDa protein (3-fold) that appears to be involved in protection from stress. The production of bound polysaccharides was measured using FTIR, HPLC, and TEM imaging. These techniques all suggest an increase in bound polysaccharide production at least 1.7-fold in the presence of MPL. Our results show that MPL treatment increases B. infantis survival during simulated digestion, induces a stress resistance surface protein, and yields greater bound polysaccharide production, suggesting its use as a functional ingredient to enhance probiotic and postbiotic effects.

Antioxidant effect of lactic acid bacteria in human bronchial epithelial cells exposed to cigarette smoke

AIMS

Chronic lung diseases are a major and increasing global health problem, commonly caused by cigarette smoke. We aimed to explore the antioxidant effects of lactic acid bacteria (LAB) against cigarette smoke in bronchial epithelial cells.

METHODS AND RESULTS

The antioxidant effects of 21 heat-killed (HK) LAB strains were tested in cigarette smoke-stimulated BEAS-2B cells and 3-D bronchospheres organoids. We showed that HK Lactiplantibacillus plantarum BGPKM22 possesses antioxidant activity against cigarette smoke, resistance to hydrogen peroxide, and free radical neutralizing activity. We demonstrated that HK BGPKM22 inhibited cigarette smoke-induced expression of the Aryl hydrocarbon receptor (AhR) and Nuclear factor erythroid 2 related factor 2 (Nrf2) genes. The cell-free supernatant (SN) of BGPKM22 fully confirmed the effects of HK BGPKM22.

CONCLUSIONS

For the first time, we revealed that HK and SN of Lactip. plantarum BGPKM22 possess antioxidant activity and modulate AhR and Nrf2 gene expression in bronchial epithelial cells exposed to cigarette smoke.

Dietary ethylenediamine dihydroiodide improves intestinal health in Cherry Valley ducks

This study investigated the effect of ethylenediamine dihydroiodide (EDDI) on the growth performance, thyroid function, immune function, intestinal development, intestinal permeability, intestinal barrier functions and microbial characteristics of Cherry Valley ducks. The results showed that the addition of EDDI significantly increased body weight, average daily gain, serum level of lymphocytes, basophils, triiodothyronine, thyroxine and thyrotropin, villus height, and villus height-to-crypt depth ratio, and significantly decreased crypt depth, diamine oxidase, serum D-Lactic acid of ducks (P < 0.05). EDDI also significantly up-regulated the mRNA expression of zonula occludens-1, zonula occludens-2, zonula occludens-3, mucin 2, secretory immunoglobulin A, interleukin-10 and avian β-defensin 2 in the jejunum and ileum (P < 0.05), and down-regulated the mRNA expression of occludin and interleukin-6 in the jejunum and ileum. Additionally, the addition of EDDI significantly increased cecal level of acetic acid, propionic acid, butyric acid (P < 0.05). Cecal microbiome analysis indicated that the addition of EDDI significantly increased the relative abundance of these microorganisms that can produce short-chain fatty acids, mainly including Actinobacteria, Verrucomicrobia, Clostridiales and Lactobacillales, and decreased the relative abundance of pathogenic bacteria Deferribactere. Interestingly, triiodothyronine and thyroxine levels were highly positively correlated with the relative abundance of Actinobacteria. These results revealed that the addition of EDDI could promote the growth and development of meat ducks by improving their thyroid function, immune function, intestinal development and intestinal barrier functions of ducks.

Limosilactobacillus vaginalis Exerts Bifidogenic Effects: A Novel Postbiotic Strategy for Infant Prebiotic Supplementation

Infant microbiota shaping strictly influences newborns' well-being and long-term health, and babies born by cesarean-section and formula-fed generally show low microbial gut diversity and are more prone to develop various disorders. The supplementation with beneficial microbes of vaginal origin or derivatives (postbiotics, including heat-inactivated cells) represents a valid strategy to drive the correct gut microbiota shaping. Here, we explored for the first time the bifidogenic activity of a heat-killed vaginal strain (Limosilactobacillus vaginalis BC17), in addition to the assessment of its safety. L. vaginalis BC17 whole genome was sequenced by Nanopore technology and highlighted the absence of antibiotic resistance genes and virulence factors, indicating the strain safety profile for human health. MIC values confirmed that L. vaginalis BC17 is susceptible to widely employed antibiotics. Heat-killed BC17 cells significantly enhanced the planktonic growth of Bifidobacterium spp. For the first time, stimulating effects were observed also toward biofilm formation of bifidobacteria and their pre-formed biofilms. Conversely, heat-killed BC17 cells exerted antibacterial and anti-biofilms activities against Gram-positive and Gram-negative pathogens. Lyophilized heat-killed BC17 cells were formulated in a sunflower oil suspension (1010 heat-killed cell/g) intended for infant oral intake. This possessed optimal technological (i.e., re-dispersibility and stability) and functional properties (i.e., bifidogenic activity) that were maintained even after pre-digestion in acidic conditions.

Effect of coadministration of Lactiplantibacillus fabifermentans and linear/branched fructans mixtures on the intestinal health of Wistar rats

A completely randomized experimental design was conducted to evaluate the effect of the coadministration of Lactiplantibacillus fabifermentans (Lpb. fabifermentans) and inulin/agave fructans mixtures on gut microbiota of healthy Wistar rats. Inulin, Agave salmiana fructans or fructan mixtures (1:1) at 12.5 % w/w, and Lpb. fabifermentans at 109 CFU/mL/day were used in the rats' diet for 35 days. Biochemical parameters, short-chain fatty acids (SCFA), structural changes and the bacterial abundance in rats' cecum were evaluated. A significant decrease (p < 0.05) in glucose, cholesterol and triglycerides levels with fructan mixtures combined with Lpb. Fabifermentans was observed. The weight of the small and large intestines, and cecum was higher than the control; no changes were observed in the heart, liver, spleen and kidneys. SCFA concentration mainly, propionate and butyrate was improved (p < 0.05) throughout the gastrointestinal tract in all treatments. Finally, the administration of Lpb. fabifermentans alone or combined with the fructan mixtures promoted an increase in the abundance of cecum intestinal microbiota: Lactobacillus, Bifidobacterium, Prevotella, Blautia, Faecalibacterium, Butyricimonas, Coprococcus, Akkermansia, Methanobrevibacter, Adlercreutzia, Collinsella, Odoribacter, and Roseburia. The inclusion of fructan mixtures in combination with Lpb. fabifermentans could be a good alternative for the development of functional foods that enhance consumer health.

Probiotic Fermented Goat's and Sheep's Milk: Effect of Type and Dose of Collagen on Survival of Four Strains of Probiotic Bacteria during Simulated In Vitro Digestion Conditions

Microbial tolerance of digestive stresses depends not only on the bacterial strain but also on the structure and physicochemical properties of the supply chain and the foods that contain it. In the present study, we aimed to evaluate the effects of the type of milk (ovine, caprine) and the type and dose of collagen on the viability of four probiotic strains, Lacticaseibacillus paracasei L-26, Lacticaseibacillus casei 431, Lactobacillus acidophilus LA-5, and Lacticaseibacillus rhamnosus Lr-32, during in vitro gastrointestinal digestion. The highest survival rate under simulated in vitro digestion conditions compared to the number of cells before digestion was found in two strains, L. casei and L. paracasei, where survival rates were greater than 50% in each batch. The survival rate of the L. rhamnosus strain ranged from 41.05% to 64.23%. In caprine milk fermented by L. acidophilus, a higher survival rate was found in milk with 1.5% hydrolysate than the control, by about 6%. Survival of the L. rhamnosus strain was favorably affected by the 3% addition of bovine collagen in caprine milk, which increased survival by about 14% compared to the control sample. Adding 3% of hydrolysate to sheep's and goat's milk enhanced the survival of the L. rhamnosus strain by 3% and 19%, respectively. This study reports that fermented caprine and ovine milk may be suitable matrices for the probiotic supply of commercial dairy starter cultures and promote gut homeostasis.

Exploring probiotic effector molecules and their mode of action in gut-immune interactions

Probiotics, live microorganisms that confer health benefits when consumed in adequate amounts, have gained significant attention for their potential therapeutic applications. The beneficial effects of probiotics are believed to stem from their ability to enhance intestinal barrier function, inhibit pathogens, increase beneficial gut microbes, and modulate immune responses. However, clinical studies investigating the effectiveness of probiotics have yielded conflicting results, potentially due to the wide variety of probiotic species and strains used, the challenges in controlling the desired number of live microorganisms, and the complex interactions between bioactive substances within probiotics. Bacterial cell wall components, known as effector molecules, play a crucial role in mediating the interaction between probiotics and host receptors, leading to the activation of signaling pathways that contribute to the health-promoting effects. Previous reviews have extensively covered different probiotic effector molecules, highlighting their impact on immune homeostasis. Understanding how each probiotic component modulates immune activity at the molecular level may enable the prediction of immunological outcomes in future clinical studies. In this review, we present a comprehensive overview of the structural and immunological features of probiotic effector molecules, focusing primarily on Lactobacillus and Bifidobacterium. We also discuss current gaps and limitations in the field and propose directions for future research to enhance our understanding of probiotic-mediated immunomodulation.

Postbiotics as potential new therapeutic agents for sepsis

Sepsis is the main cause of death in critically ill patients and gut microbiota dysbiosis plays a crucial role in sepsis. On the one hand, sepsis leads to the destruction of gut microbiota and induces and aggravates terminal organ dysfunction. On the other hand, the activation of pathogenic gut flora and the reduction in beneficial microbial products increase the susceptibility of the host to sepsis. Although probiotics or fecal microbiota transplantation preserve gut barrier function on multiple levels, their efficacy in sepsis with intestinal microbiota disruptions remains uncertain. Postbiotics consist of inactivated microbial cells or cell components. They possess antimicrobial, immunomodulatory, antioxidant and antiproliferative activities. Microbiota-targeted therapy strategies, such as postbiotics, may reduce the incidence of sepsis and improve the prognosis of patients with sepsis by regulating gut microbial metabolites, improving intestinal barrier integrity and changing the composition of the gut microbiota. They offer a variety of mechanisms and might even be superior to more conventional 'biotics' such as probiotics and prebiotics. In this review, we present an overview of the concept of postbiotics and summarize what is currently known about postbiotics and their prospective utility in sepsis therapy. Overall, postbiotics show promise as a viable adjunctive therapy option for sepsis.

Lactic acid bacteria-derived exopolysaccharide: Formation, immunomodulatory ability, health effects, and structure-function relationship

Exopolysaccharides (EPSs) synthesized by lactic acid bacteria (LAB) have implications for host health and act as food ingredients. Due to the variability of LAB-EPS (lactic acid bacteria-derived exopolysaccharide) gene clusters, especially the glycosyltransferase genes that determine monosaccharide composition, the structure of EPS is very rich. EPSs are synthesized by LAB through the extracellular synthesis pathway and the Wzx/Wzy-dependent pathway. LAB-EPS has a strong immunomodulatory ability. The EPSs produced by different genera of LAB, especially Lactobacillus, Leuconostoc, and Streptococcus, have different immunomodulatory abilities because of their specific structures. LAB-EPS possesses other health effects, including antitumor, antioxidant, intestinal barrier repair, antimicrobial, antiviral, and cholesterol-lowering activities. The bioactivities of LAB-EPS are tightly related to their structures such us monosaccharide composition, glycosidic bonds, and molecular weight (MW). For the excellent physicochemical property, LAB-EPS acts as product improvers in dairy, bakery food, and meat in terms of stability, emulsification, thickening, and gelling. We systematically summarize the detailed process of EPS from synthesis to application, with emphasis on physiological mechanisms of EPS, and specific structure-function relationship, which provides theoretical support for the potential commercial value in the pharmaceutical, chemical, food, and cosmetic industries.

Crypt-like patterned electrospun nanofibrous membrane and probiotics promote intestinal epithelium models close to tissues

In vitro intestinal epithelium models have drawn great attention to investigating intestinal biology in recent years. However, the difficulty to maintain the normal physiological status of primary intestinal epithelium in vitro limits the applications. Here, we designed patterned electrospun polylactic acid (PLA) nanofibrous membranes with crypt-like topography and mimic ECM fibrous network to support crypt culture and construct in vitro intestinal epithelium models. The patterned electrospun PLA nanofibrous membranes modified with Matrigels at 0 °C showed high biocompatibility and promoted cell growth and proliferation. The constructed duodenum epithelium models and colon epithelium models on the patterned electrospun PLA nanofibrous membranes expressed the typical differentiation markers of intestinal epithelia and the gene expression levels were close to the original tissues, especially with the help of probiotics. The constructed intestinal epithelium models could be used to assess probiotic adhesion and colonization, which were verified to show significant differences with the Caco-2 cell models due to the different cell types. These findings provide new insights and a better understanding of the roles of biophysical, biochemical, and biological signals in the construction of in vitro intestinal epithelium models as well as the potential applications of these models in the study of host-gut microbes interactions. KEY POINTS: • Patterned electrospun scaffold has crypt-like topography and ECM nanofibrous network. • Matrigels at 0°C modify scaffolds more effectively than at 37°C. • Synergy of biomimic scaffold and probiotics makes in vitro model close to tissue.

Probiotics and novel probiotic delivery systems

Necrotizing enterocolitis (NEC) is an infectious and inflammatory intestinal disease that is the most common surgical emergency in the premature patient population. Although the etiology of the disease is multifactorial, intestinal dysbiosis is a hallmark of this disease. Based on this, probiotics may play a therapeutic role in NEC by introducing beneficial bacteria with immunomodulating, antimicrobial, and anti-inflammatory functions into the gastrointestinal tract. Currently, there is no Food and Drug Administration (FDA)-approved probiotic for the prevention and treatment of NEC. All probiotic clinical studies to date have administered the bacteria in their planktonic (free-living) state. This review will discuss established probiotic delivery systems including planktonic probiotics, prebiotics, and synbiotics, as well as novel probiotic delivery systems such as biofilm-based and designer probiotics. We will also shed light on whether or not probiotic efficacy is influenced by administration with breast milk. Finally, we will consider the challenges associated with developing an FDA-approved probiotic for NEC.

Deciphering the effect of maternal postpartum antibiotic prophylaxis on the infant gut microbiome: a whole metagenomic analysis

Aim: To analyze the impact of postpartum antibiotic (Ab) prophylaxis on the infant gut microbiome. Materials & methods: Whole metagenomic analysis was performed on breast milk and infant fecal samples collected from mother-infant pairs who belonged to two groups: an Ab group comprising mothers who had received a single course of Abs in the immediate postpartum period and a non-Ab group comprising mothers who had not received Abs. Results: The characteristic presence of Citrobacter werkmanii, an emerging multidrug-resistant uropathogen, and a higher relative abundance of genes encoding resistance to specific Abs were noted in samples from the Ab group compared with those from the non-Ab group. Conclusion: Policies regarding prophylactic Ab prescription across government and private health sectors in the postpartum period need to be strengthened.

Bacterial exopolysaccharides as emerging bioactive macromolecules: from fundamentals to applications

Microbial exopolysaccharides (EPS) are extracellular carbohydrate polymers forming capsules or slimy coating around the cells. EPS can be secreted by various bacterial genera that can help bacterial cells in attachment, environmental adaptation, stress tolerance and are an integral part of microbial biofilms. Several gut commensals (e.g., Lactobacillus, Bifidobacterium) produce EPS that possess diverse bioactivities. Bacterial EPS also has extensive commercial applications in the pharmaceutical and food industries. Owing to the structural and functional diversity, genetic and metabolic engineering strategies are currently employed to increase EPS production. Therefore, the current review provides a comprehensive overview of the fundamentals of bacterial exopolysaccharides, including their classification, source, biosynthetic pathways, and functions in the microbial community. The review also provides an overview of the diverse bioactivities of microbial EPS, including immunomodulatory, anti-diabetic, anti-obesity, and anti-cancer properties. Since several gut microbes are EPS producers and gut microbiota helps maintain a functional gut barrier, emphasis has been given to the intestinal-level bioactivities of the gut microbial EPS. Collectively, the review provides a comprehensive overview of microbial bioactive exopolysaccharides.

Advances in Research on the Relationship between Vaginal Microbiota and Adverse Pregnancy Outcomes and Gynecological Diseases

The human microbiota inhabiting different parts of the body has been shown to have a significant impact on human health, with the gut microbiota being the most extensively studied in relation to disease. However, the vaginal microbiota is also an essential commensal microbiota in the female body that plays a crucial role in female health. Despite receiving less attention than gut microbiota, its importance in regulating reproductive immunity and its complex dynamic properties have been increasingly recognized in recent years. Advances in research on the relationship between vaginal microbiota and pregnancy outcomes & gynecological diseases in women have shed light on the importance of maintaining a healthy vaginal microbiota. In this review, we aim to compile recent developments in the study of the vaginal microbial ecosystem and its role in female health and reproductive outcomes. We provide a comprehensive account of the normal vaginal microbiota, the association between the vaginal microbiota and pregnancy outcomes, and the impact of the vaginal microbiota on gynecological diseases in women. By reviewing recent research, we hope to contribute to the advancement of academic medicine's understanding of the vaginal microbiota's importance in female health. We also aim to raise awareness among healthcare professionals and the general public of the significance of maintaining a healthy vaginal microbiota for better reproductive health and the prevention of gynecological diseases.

Modulating the Microbiome for Crohn's Disease Treatment

The central role of the gut microbiota in the regulation of health and disease has been convincingly demonstrated. Polymicrobial interkingdom interactions between bacterial (the bacteriome) and fungal (the mycobiome) communities of the gut have become a prominent focus for development of potential therapeutic approaches. In addition to polymicrobial interactions, the complex gut ecosystem also mediates interactions between the host and the microbiota. These interactions are complex and bidirectional; microbiota composition can be influenced by host immune response, disease-specific therapeutics, antimicrobial drugs, and overall ecosystems. However, the gut microbiota also influences host immune response to a drug or therapy by potentially transforming the drug's structure and altering bioavailability, activity, or toxicity. This is especially true in cases where the gut microbiota has produced a biofilm. The negative ramifications of biofilm formation include alteration of gut permeability, enhanced antimicrobial resistance, and alteration of host immune response effectiveness. Natural modulation of the gut microbiota, using probiotic and prebiotic approaches, may also be used to affect the host microbiome, a type of "natural" modulation of the host microbiota composition. In this review, we discuss potential bidirectional interactions between microbes and host, and we describe the changes in gut microbiota induced by probiotic and prebiotic approaches as well as their potential clinical consequences, including biofilm formation. We outline a systematic approach to designing probiotics capable of altering the host microbiota in disease states, using Crohn's disease as a model chronic disease. Understanding how the effective changes in the microbiome may enhance treatment efficacy may unlock the possibility of modulating the gut microbiome to improve treatment using a natural approach.

Biopolymers Produced by Lactic Acid Bacteria: Characterization and Food Application

Plants, animals, bacteria, and food waste are subjects of intensive research, as they are biological sources for the production of biopolymers. The topic links to global challenges related to the extended life cycle of products, and circular economy objectives. A severe and well-known threat to the environment, the non-biodegradability of plastics obliges different stakeholders to find legislative and technical solutions for producing valuable polymers which are biodegradable and also exhibit better characteristics for packaging products. Microorganisms are recognized nowadays as exciting sources for the production of biopolymers with applications in the food industry, package production, and several other fields. Ubiquitous organisms, lactic acid bacteria (LAB) are well studied for the production of exopolysaccharides (EPS), but much less as producers of polylactic acid (PLA) and polyhydroxyalkanoates (PHAs). Based on their good biodegradability feature, as well as the possibility to be obtained from cheap biomass, PLA and PHAs polymers currently receive increased attention from both research and industry. The present review aims to provide an overview of LAB strains' characteristics that render them candidates for the biosynthesis of EPS, PLA, and PHAs, respectively. Further, the biopolymers' features are described in correlation with their application in different food industry fields and for food packaging. Having in view that the production costs of the polymers constitute their major drawback, alternative solutions of biosynthesis in economic terms are discussed.

Exopolysaccharides from vaginal lactobacilli modulate microbial biofilms

BACKGROUND

Exopolysaccharides (EPS) secreted by beneficial lactobacilli exert a plethora of positive activities, but little is known about their effects on biofilms of opportunistic vaginal pathogens and especially on biofilms of lactobacilli themselves. Here, the EPS produced by six vaginal lactobacilli, belonging to Lactobacillus crispatus (BC1, BC4, BC5) and Lactobacillus gasseri (BC9, BC12, BC14) species were isolated from cultural supernatants and lyophilized.

RESULTS

Lactobacillus EPS were chemically characterized in terms of monosaccharide composition by liquid chromatography (LC) analysis coupled to UV and mass spectrometry (MS) detection. Moreover, the ability of EPS (0.1, 0.5, 1 mg/mL) to stimulate the biofilm formation of lactobacilli and to inhibit the formation of pathogens' biofilms was evaluated by crystal violet (CV) staining and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Isolated EPS (yields 133-426 mg/L) were heteropolysaccharides mainly composed of D-mannose (40-52%) and D-glucose (11-30%). For the first time we demonstrated that Lactobacillus EPS were able to stimulate in a dose-dependent manner (p < 0.05) the formation of biofilms of ten strains belonging to L. crispatus, L. gasseri and Limosilactobacillus vaginalis species, in terms of cell viability (84-282% increase at 1 mg/mL) and especially biofilm biomass (40-195% increase at 1 mg/mL), quantified with MTT assay and CV staining, respectively. EPS released from L. crispatus and L. gasseri were found to better stimulate the biofilms of the same producer species rather than that of other species, including producing strains themselves and other strains. Conversely, the biofilm formation of bacterial (Escherichia coli, Staphylococcus spp., Enterococcus spp. and Streptococcus agalactiae) and fungal (Candida spp.) pathogens was inhibited. The anti-biofilm activity was dose-dependent and was more marked for L. gasseri-derived EPS (inhibition up to 86%, 70%, and 58% at 1 mg/mL, 0.5 mg/mL, and 0.1 mg/mL, respectively), whilst L. crispatus-derived EPS resulted overall less efficient (inhibition up to 58% at 1 mg/mL and 40% at 0.5 mg/mL) (p < 0.05).

CONCLUSIONS

Lactobacilli-derived EPS favour the biofilm formation of lactobacilli preventing, at the same time, that of opportunistic pathogens. These results support the possible employment of EPS as postbiotics in medicine as a therapeutic/preventive strategy to counteract vaginal infections.

In vitro evaluation of probiotic properties of Lactobacillus acidophilus AD125 and antagonism against Escherichia coli O157:H7 adhesion to Caco-2 cell

This study investigated the in vitro antibacterial activity of Lactobacillus acidophilus AD125 against Escherichia coli (E. coli) O157:H7 and its probiotic properties: gastrointestinal tolerance, surface hydrophobicity, autoaggregation, coaggregation, and adhesion to Caco-2 cells. In addition, the action mode of the strain's antagonism against adhesion of E. coli O157:H7 to Caco-2 cells was analyzed, and related substances were also determined. Results showed that L. acidophilus AD125 had stronger antibacterial activity (inhibition zone of 20.47 ± 0.43 for AD125 culture solution and 14.55 ± 1.12 for cell-free supernatant) against E. coli O157:H7 than other Lactobacillus spp. Also, this strain had higher gastrointestinal tolerance, autoaggregation percentage (26.51 ± 0.71%), and coaggregation percentage (23.97 ± 0.44%) with E. coli O157:H7. High surface hydrophobicity of toluene and xylene (83.59 ± 2.54% and 93.45 ± 1.24%) was also observed. Bacterial adhesion counts were 1176.54 100 per cells, indicating good adhesion to Caco-2 cells. Furthermore, the exclusion, competition, and antibacterial effect of AD125 may have driven its antagonism against E. coli O157:H7 adhesion. Finally, surface-layer proteins, extracellular polysaccharides, and thermosensitive substances all participated in the antagonism against E. coli O157:H7, with surface-layer proteins the main related substances. These results show that Lactobacillus acidophilus AD125 is promising for inhibiting E. coli O157:H7 and preventing and treating intestinal diseases induced by E. coli O157:H7.

Structural analysis and prebiotic activity of exopolysaccharide produced by probiotic strain Bifidobacterium bifidum EPS DA-LAIM

Exopolysaccharide (EPS)-producing Bifidobacterium bifidum EPS DA-LAIM was isolated from healthy human feces, the structure of purified EPS from the strain was analyzed, and its prebiotic activity was evaluated. The EPS from B. bifidum EPS DA-LAIM is a glucomannan-type heteropolysaccharide with a molecular weight of 407-1007 kDa, and its structure comprises 2-mannosyl, 6-mannosyl, and 2,6-mannosyl residues. The purified EPS promoted the growth of representative lactic acid bacteria and bifidobacterial strains. Bifidobacterium bifidum EPS DA-LAIM increased nitric oxide production in RAW 264.7 macrophage cells, indicating its immunostimulatory activity. Bifidobacterium bifidum EPS DA-LAIM also exhibited high gastrointestinal tract tolerance, gut adhesion ability, and antioxidant activity. These results suggest that EPS from B. bifidum EPS DA-LAIM is a potentially useful prebiotic material, and B. bifidum EPS DA-LAIM could be applied as a probiotic candidate.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01213-w.

Recent advances in understanding of multifaceted changes in the vaginal microenvironment: implications in vaginal health and therapeutics

The vagina endures multifaceted changes from neonatal to menopausal phases due to hormonal flux, metabolite deposition, and microbial colonization. These features have important implications in women's health. Several pre-factors show dynamic characteristics according to the phases that shift the vaginal microbiota from anaerobes to aerobes which is a hallmark of healthy vaginal environment. These factors include oestrogen levels, glycogen deposition, and vaginal microstructure. In the adult phase, Lactobacillus is highly dominant and regulates pH, adherence, aggregation, immune modulation, synthesis of bacteriocins, and biosurfactants (BSs) which are antagonistic to pathogens. Maternal factors are protective by favouring the colonization of lactobacilli in the vagina in the neonatal phase, which diminishes with age. The dominance of lactobacilli and dysbiosis in the adult phase depends on intrinsic and extrinsic factors in women, which vary between ethnicities. Recent developments in probiotics used against vaginal microbiome dysbiosis have shown great promise in restoring the normal microbiota including preventing the loss of beneficial bacteria. However, further in-depth studies are warranted to ensure long-term protection by probiotics. This review highlights various aspects of the vaginal microenvironment in different phases of growth and diverse ethnicities. Furthermore, it discusses future trends for formulating more effective population-specific probiotics and implications of paraprobiotics and postbiotics as effective therapeutics.

κ-Selenocarrageenan Oligosaccharides Prepared by Deep-Sea Enzyme Alleviate Inflammatory Responses and Modulate Gut Microbiota in Ulcerative Colitis Mice

κ-Selenocarrageenan (KSC) is an organic selenium (Se) polysaccharide. There has been no report of an enzyme that can degrade κ-selenocarrageenan to κ-selenocarrageenan oligosaccharides (KSCOs). This study explored an enzyme, κ-selenocarrageenase (SeCar), from deep-sea bacteria and produced heterologously in Escherichia coli, which degraded KSC to KSCOs. Chemical and spectroscopic analyses demonstrated that purified KSCOs in hydrolysates were composed mainly of selenium-galactobiose. Organic selenium foods through dietary supplementation could help regulate inflammatory bowel diseases (IBD). This study discussed the effects of KSCOs on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in C57BL/6 mice. The results showed that KSCOs alleviated the symptoms of UC and suppressed colonic inflammation by reducing the activity of myeloperoxidase (MPO) and regulating the unbalanced secretion of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10). Furthermore, KSCOs treatment regulated the composition of gut microbiota, enriched the genera Bifidobacterium, Lachnospiraceae_NK4A136_group and Ruminococcus and inhibited Dubosiella, Turicibacter and Romboutsia. These findings proved that KSCOs obtained by enzymatic degradation could be utilized to prevent or treat UC.