Folate production by bifidobacteria as a potential probiotic property

Exploring the interaction and impact of probiotic and commensal bacteria on vitamins, minerals and short chain fatty acids metabolism

There is increasing evidence that probiotic and commensal bacteria play a role in substrate metabolism, energy harvesting and intestinal homeostasis, and may exert immunomodulatory activities on human health. In addition, recent research suggests that these microorganisms interact with vitamins and minerals, promoting intestinal and metabolic well-being while producing vital microbial metabolites such as short-chain fatty acids (SCFAs). In this regard, there is a flourishing field exploring the intricate dynamics between vitamins, minerals, SCFAs, and commensal/probiotic interactions. In this review, we summarize some of the major hypotheses beyond the mechanisms by which commensals/probiotics impact gut health and their additional effects on the absorption and metabolism of vitamins, minerals, and SCFAs. Our analysis includes comprehensive review of existing evidence from preclinical and clinical studies, with particular focus on the potential interaction between commensals/probiotics and micronutrients. Finally, we highlight knowledge gaps and outline directions for future research in this evolving field.

Probiotics in the New Era of Human Milk Oligosaccharides (HMOs): HMO Utilization and Beneficial Effects of Bifidobacterium longum subsp. infantis M-63 on Infant Health

A healthy gut microbiome is crucial for the immune system and overall development of infants. Bifidobacterium has been known to be a predominant species in the infant gut; however, an emerging concern is the apparent loss of this genus, in particular, Bifidobacterium longum subsp. infantis (B. infantis) in the gut microbiome of infants in industrialized nations, underscoring the importance of restoring this beneficial bacterium. With the growing understanding of the gut microbiome, probiotics, especially infant-type human-residential bifidobacteria (HRB) strains like B. infantis, are gaining prominence for their unique ability to utilize HMOs and positively influence infant health. This article delves into the physiology of a probiotic strain, B. infantis M-63, its symbiotic relationship with HMOs, and its potential in improving gastrointestinal and allergic conditions in infants and children. Moreover, this article critically assesses the role of HMOs and the emerging trend of supplementing infant formulas with the prebiotic HMOs, which serve as fuel for beneficial gut bacteria, thereby emulating the protective effects of breastfeeding. The review highlights the potential of combining B. infantis M-63 with HMOs as a feasible strategy to improve health outcomes in infants and children, acknowledging the complexities and requirements for further research in this area.

Gut microbiota and their derivatives in the progression of colorectal cancer: Mechanisms of action, genome and epigenome contributions

Gut microbiota interacts with host epithelial cells and regulates many physiological functions such as genetics, epigenetics, metabolism of nutrients, and immune functions. Dietary factors may also be involved in the etiology of colorectal cancer (CRC), especially when an unhealthy diet is consumed with excess calorie intake and bad practices like smoking or consuming a great deal of alcohol. Bacteria including Fusobacterium nucleatum, Enterotoxigenic Bacteroides fragilis (ETBF), and Escherichia coli (E. coli) actively participate in the carcinogenesis of CRC. Gastrointestinal tract with chronic inflammation and immunocompromised patients are at high risk for CRC progression. Further, the gut microbiota is also involved in Geno-toxicity by producing toxins like colibactin and cytolethal distending toxin (CDT) which cause damage to double-stranded DNA. Specific microRNAs can act as either tumor suppressors or oncogenes depending on the cellular environment in which they are expressed. The current review mainly highlights the role of gut microbiota in CRC, the mechanisms of several factors in carcinogenesis, and the role of particular microbes in colorectal neoplasia.

Gut microbiota and acute kidney injury: immunological crosstalk link

The gut microbiota, often called the "forgotten organ," plays a crucial role in bidirectional communication with the host for optimal physiological function. This communication helps regulate the host's immunity and metabolism positively and negatively. Many factors influence microbiota homeostasis and subsequently lead to an immune system imbalance. The correlation between an unbalanced immune system and acute diseases such as acute kidney injury is not fully understood, and the role of gut microbiota in disease pathogenesis is still yet uncovered. This review summarizes our understanding of gut microbiota, focusing on the interactions between the host's immune system and the microbiome and their impact on acute kidney injury.

Characterisation of Indian gut microbiome for B-vitamin production and its comparison with Chinese cohort

The human gut microbiota can biosynthesize essential micronutrients such as B-vitamins and is also known for its metabolic cooperative behaviour. The present study characterises such B-vitamin biosynthesizers, their biosynthetic pathways, explores their prevalence and abundance, examines how lifestyle or diet affects them in multiple Indian cohorts and compares it with the Chinese cohort. To achieve this, publicly available faecal metagenome data of healthy individuals from multiple Indian (two urban and three tribal populations) and a Chinese cohort were analysed. The distribution of prevalence and abundance of B-vitamin biosynthesizers showed similar profiles to that of the entire gut community of the Indian cohort, and there were 28 B-vitamin biosynthesizers that had modest or higher prevalence and abundance. The omnivorous diet affected only the prevalence of a few B-vitamin biosynthesizers; however, lifestyle and/or location affected both prevalence and abundance. A comparison with the Chinese cohort showed that fourteen B-vitamin biosynthesizers were significantly more prevalent and abundant in Chinese as compared with Indian samples (False Discovery Rate (FDR) <= 0·05). The metabolic potential of the entire gut community for B-vitamin production showed that within India, the tribal cohort has a higher abundance of B-vitamin biosynthesis pathways as compared with two urban cohorts namely, Bhopal and Kasargod, and comparison with the Chinese cohort revealed a higher abundance in the latter group. Potential metabolic cooperative behaviour of the Indian gut microbiome for biosynthesis of the B-vitamins showed multiple pairs of species showed theoretical complementarity for complete biosynthetic pathways genes of thiamine, riboflavin, niacin and pantothenate.

Symbiotic Synergy from Sponges to Humans: Microflora-Host Harmony Is Crucial for Ensuring Survival and Shielding against Invading Pathogens

Gut microbiota plays several roles in the host organism's metabolism and physiology. This phenomenon holds across different species from different kingdoms and classes. Different species across various classes engage in continuous crosstalk via various mechanisms with their gut microbiota, ensuring homeostasis of the host. In this Review, the diversity of the microflora, the development of the microflora in the host, its regulations by the host, and its functional implications on the host, especially in the context of dysbiosis, are discussed across different organisms from sponges to humans. Overall, our review aims to address the indispensable nature of the microbiome in the host's survival, fitness, and protection against invading pathogens.

B-Group Vitamins as Potential Prebiotic Candidates: Their Effects on the Human Gut Microbiome

In recent years, thousands of studies have demonstrated the importance of the gut microbiome for human health and its relationship with certain diseases. The search for new gut microbiome modulators has thus become an objective to beneficially alter the gut microbiome composition and/or metabolic activity, which may modify intestinal physiology. Growing evidence has shown that B-group vitamins might be considered as potential candidates as gut microbiome modulators. However, the relationship between the B-group vitamins and the gut microbiome remains largely unexplored. Studies have suggested that non-absorbed B-group vitamins administered orally can reach the distal intestine or even the colon where these vitamins may have potential health benefits for the host. Clinical trials supporting this effect are still limited. In this review, we discuss evidence regarding the modulatory effects of B-group vitamins on the gut microbiome with a focus on their potential role as prebiotic candidates.

Hypothetical Regulation of Folate Biosynthesis and Strategies for Folate Overproduction in Lactic Acid Bacteria

Folate (vitamin B9) is an essential nutrient for cell metabolism, especially in pregnant women; however, folate deficiency is a major global health issue. To address this issue, folate-rich fermented foods have been used as alternative sources of natural folate. Lactic acid bacteria (LAB), which are commonly involved in food fermentation, can synthesize and excrete folate into the medium, thereby increasing folate levels. However, screening for folate-producing LAB strains is necessary because this ability is highly dependent on the bacterial strain. Some strains of LAB consume folate, and their presence in a fermentation mix can lower the folate levels of the final product. Since microorganisms efficiently regulate folate biosynthesis to meet their growth needs, some strains of folate-producing LAB can deplete folate levels if folate is available in the media. Such folate-efficient producers possess a feedback inhibition mechanism that downregulates folate biosynthesis. Therefore, the application of folate-overproducing strains may be a key strategy for increasing folate levels in media with or without available folate. Many studies have been conducted to screen folate-producing bacteria, but very few have focused on the identification of overproducers. This is probably because of the limited understanding of the regulation of folate biosynthesis in LAB. In this review, we discuss the roles of folate-biosynthetic genes and their contributions to the ability of LAB to synthesize and regulate folate. In addition, we present various hypotheses regarding the regulation of the feedback inhibition mechanism of folate-biosynthetic enzymes and discuss strategies for obtaining folate-overproducing LAB strains.

Folate-producing bifidobacteria: metabolism, genetics, and relevance

Folate (the general term for all bioactive forms of vitamin B9) plays a crucial role in the evolutionary highly conserved one-carbon (1C) metabolism, a network including central reactions such as DNA and protein synthesis and methylation of macromolecules. Folate delivers 1C units, such as methyl and formyl, between reactants. Plants, algae, fungi, and many bacteria can naturally produce folate, whereas animals, including humans, must obtain folate from external sources. For humans, folate deficiency is, however, a widespread problem. Bifidobacteria constitute an important component of human and many animal microbiomes, providing various health advantages to the host, such as producing folate. This review focuses on bifidobacteria and folate metabolism and the current knowledge of the distribution of genes needed for complete folate biosynthesis across different bifidobacterial species. Biotechnologies based on folate-trophic probiotics aim to create fermented products enriched with folate or design probiotic supplements that can synthesize folate in the colon, improving overall health. Therefore, bifidobacteria (alone or in association with other microorganisms) may, in the future, contribute to reducing widespread folate deficiencies prevalent among vulnerable human population groups, such as older people, women at child-birth age, and people in low-income countries.

Molecular Mechanism Biomarkers Predict Diagnosis in Schizophrenia and Schizoaffective Psychosis, with Implications for Treatment

Diagnostic uncertainty and relapse rates in schizophrenia and schizoaffective disorder are relatively high, indicating the potential involvement of other pathological mechanisms that could serve as diagnostic indicators to be targeted for adjunctive treatment. This study aimed to seek objective evidence of methylenetetrahydrofolate reductase MTHFR C677T genotype-related bio markers in blood and urine. Vitamin and mineral cofactors related to methylation and indolamine-catecholamine metabolism were investigated. Biomarker status for 67 symptomatically well-defined cases and 67 asymptomatic control participants was determined using receiver operating characteristics, Spearman's correlation, and logistic regression. The 5.2%-prevalent MTHFR 677 TT genotype demonstrated a 100% sensitive and specific case-predictive biomarkers of increased riboflavin (vitamin B2) excretion. This was accompanied by low plasma zinc and indicators of a shift from low methylation to high methylation state. The 48.5% prevalent MTHFR 677 CC genotype model demonstrated a low-methylation phenotype with 93% sensitivity and 92% specificity and a negative predictive value of 100%. This model related to lower vitamin cofactors, high histamine, and HPLC urine indicators of lower vitamin B2 and restricted indole-catecholamine metabolism. The 46.3%-prevalent CT genotype achieved high predictive strength for a mixed methylation phenotype. Determination of MTHFR C677T genotype dependent functional biomarker phenotypes can advance diagnostic certainty and inform therapeutic intervention.

Metagenomic Insights into the Microbiome and Resistance Genes of Traditional Fermented Foods in Arabia

This study uncovered microbial communities and evaluated the microbiological safety of traditional fermented foods consumed in the Arab region. Samples of dairy and non-dairy fermented foods-mish, jibneh, zabadi, and pickles-were collected from local markets in Saudi Arabia. Using the MiSeq system, samples were sequenced using 16S amplicons and shotgun metagenomics. Alpha and beta diversity indicated inter- and intra-variation in the studied fermented foods' bacterial communities. In the case of mish, the replicates were clustered. Twenty-one genera were found to be significantly different (FDR < 0.05) in abundance in pairwise comparison of fermented foods. Five high-quality, metagenome-assembled genomes (MAGs) of Lactococcus lactis, Lactobacillus helveticus, Pseudoalteromonas nigrifaciens, Streptococcus thermophiles, and Lactobacillus acetotolerans were retrieved from the shotgun sequencing representing the dominant taxa in the studied fermented foods. Additionally, 33 genes that cause antimicrobial resistance (ARGs) against ten different antibiotic classes were detected. Metabolic pathways were abundant in the studied metagenomes, such as amino acid metabolism, carbohydrate metabolism, cofactors, and vitamin biosynthesis. Metagenomic evaluation of Arabian fermented foods, including the identification of probiotics, pathogenic bacteria, and ARGs, illustrates the importance of microbiological analysis in evaluating their health effects.

The role of the gut microbiome and microbial metabolism in mediating opioid-induced changes in the epigenome

The current opioid pandemic is a major public health crisis in the United States, affecting millions of people and imposing significant health and socioeconomic burdens. Preclinical and clinical research over the past few decades has delineated certain molecular mechanisms and identified various genetic, epigenetic, and environmental factors responsible for the pathophysiology and comorbidities associated with opioid use. Opioid use-induced epigenetic modifications have been identified as one of the important factors that mediate genetic changes in brain regions that control reward and drug-seeking behavior and are also implicated in the development of tolerance. Recently, it has been shown that opioid use results in microbial dysbiosis, leading to gut barrier disruption, which drives systemic inflammation, impacting the perception of pain, the development of analgesic tolerance, and behavioral outcomes. In this review, we highlight the potential role of microbiota and microbial metabolites in mediating the epigenetic modifications induced by opioid use.

Dietary pattern in autism increases the need for probiotic supplementation: A comprehensive narrative and systematic review on oxidative stress hypothesis

Autism spectrum disorders (ASDs) are associated with specific dietary habits, including limited food selection and gastrointestinal problems, resulting in an altered gut microbiota. Autistic patients have an elevated abundance of certain gut bacteria associated with increased oxidative stress in the gastrointestinal tract. Probiotic supplementation has been shown to decrease oxidative stress in a simulated gut model, but the antioxidant effects of probiotics on the oxidative stress of the gut in autistic patients have not been directly studied. However, it is speculated that probiotic supplementation may help decrease oxidative stress in the gastrointestinal tract of autistic patients due to their specific dietary habits altering the microbiota. PubMed, Scopus and Web of Science databases and Google Scholar were searched up to May 2023. This systematic-narrative review aims to present the latest evidence regarding the changes in eating habits of autistic children which may further increase the gut microbiota induced oxidative stress. Additionally, this review will assess the available literature on the effects of probiotic supplementation on oxidative stress parameters.

Results and lessons learned from the sbv IMPROVER metagenomics diagnostics for inflammatory bowel disease challenge

A growing body of evidence links gut microbiota changes with inflammatory bowel disease (IBD), raising the potential benefit of exploiting metagenomics data for non-invasive IBD diagnostics. The sbv IMPROVER metagenomics diagnosis for inflammatory bowel disease challenge investigated computational metagenomics methods for discriminating IBD and nonIBD subjects. Participants in this challenge were given independent training and test metagenomics data from IBD and nonIBD subjects, which could be wither either raw read data (sub-challenge 1, SC1) or processed Taxonomy- and Function-based profiles (sub-challenge 2, SC2). A total of 81 anonymized submissions were received between September 2019 and March 2020. Most participants' predictions performed better than random predictions in classifying IBD versus nonIBD, Ulcerative Colitis (UC) versus nonIBD, and Crohn's Disease (CD) versus nonIBD. However, discrimination between UC and CD remains challenging, with the classification quality similar to the set of random predictions. We analyzed the class prediction accuracy, the metagenomics features by the teams, and computational methods used. These results will be openly shared with the scientific community to help advance IBD research and illustrate the application of a range of computational methodologies for effective metagenomic classification.

An Overview of the Public Health Challenges in Diagnosing and Controlling Human Foodborne Pathogens

Pathogens found in food are believed to be the leading cause of foodborne illnesses; and they are considered a serious problem with global ramifications. During the last few decades, a lot of attention has been paid to determining the microorganisms that cause foodborne illnesses and developing new methods to identify them. Foodborne pathogen identification technologies have evolved rapidly over the last few decades, with the newer technologies focusing on immunoassays, genome-wide approaches, biosensors, and mass spectrometry as the primary methods of identification. Bacteriophages (phages), probiotics and prebiotics were known to have the ability to combat bacterial diseases since the turn of the 20th century. A primary focus of phage use was the development of medical therapies; however, its use quickly expanded to other applications in biotechnology and industry. A similar argument can be made with regards to the food safety industry, as diseases directly endanger the health of customers. Recently, a lot of attention has been paid to bacteriophages, probiotics and prebiotics most likely due to the exhaustion of traditional antibiotics. Reviewing a variety of current quick identification techniques is the purpose of this study. Using these techniques, we are able to quickly identify foodborne pathogenic bacteria, which forms the basis for future research advances. A review of recent studies on the use of phages, probiotics and prebiotics as a means of combating significant foodborne diseases is also presented. Furthermore, we discussed the advantages of using phages as well as the challenges they face, especially given their prevalent application in food safety.

Folate intake and risk of colorectal cancer: a systematic review and up-to-date meta-analysis of prospective studies

PURPOSE

Colorectal cancer is one of the most commonly diagnosed and deadly cancers worldwide. Epidemiological studies on the relationship between folate intake and the risk of colorectal cancer have reported inconsistent findings since folate fortification in the USA. For this situation, we conducted a large number of data analyses to study the relationship between folate intake and colorectal cancer risk.

METHODS

PubMed and EMBASE databases were used to search the literature systematically. Eligible studies were reviewed and meta-analyzed to assess the relationship.

RESULTS

A total of 24 cohort studies involving 37 280 patients and 6 165 894 individuals were included. The results showed that high folate intake was associated with a reduced risk of colorectal cancer. The combined relative risk (RR) for the highest intake compared with the lowest was 0.88 [95% confidence interval (CI), 0.83-0.92, P  = 10 -4 ). Further studies indicated that the increase of folate intake may decrease the risk of colorectal cancer in people with medium or high alcohol consumption (RR = 0.97, 95% CI: 0.96-0.99, P  = 0.008; RR = 0.95, 95% CI: 0.92-0.98, P   =  0.003), but not in non-drinkers (RR = 1.00, 95% CI: 0.98-1.02, P  = 0.827). Next, high folate intake may decrease the risk of colon cancer (RR = 0.86, 95% CI: 0.81-0.92, P  = 10 -4 ) but not rectal cancer (RR = 0.92, 95% CI: 0.84-1.02, P  = 0.112). Additionally, the result that high folate intake may decrease the risk of colorectal cancer was observed in the USA and Europe but not in other regions.

CONCLUSION

High folate intake may be protective against colon cancer, particularly in people with middle or high alcohol consumption, but it still needs to be further confirmed.

Screening, isolation and biotechnological potentials of foodborne Lactobacillus fermentum strains MT903311 and MT903312

Vitamins are an essential food source with excellent roles in the cellular metabolism and other essential nutrients required in food intake but cannot be synthesized by humans. There have been reports of some lactic acid bacteria (LAB) abilities with probiotic activities to produce food-grade vitamins. Our study aimed to investigate lactic acid bacteria (LAB) possessing antimicrobial activities and extracellular production of folate from different Nigerian fermented foods. LAB was assayed for their antimicrobial activities against clinical isolates of Escherichia coli and Salmonella typhimurium and their extracellular production of essential vitamins. Among the 43 isolates of LAB, two strains of Lactobacillus fermentum showed the highest inhibitions against the test bacteria and demonstrated the highest concentrations of extracellular vitamins production. The range of vitamins produced at 24 h was between 12.23 and 801.79 μg/ml, while the highest vitamin production of 801.79 and 310.55 μg/ml was observed for folate and vitamin B12 respectively, the lowest production was for B1+B2. Consistent vitamin production was typical with only L. fermentum MT903311 and L. fermentum MT903312, so were their antimicrobial activities. The L. fermentum strains isolated in this study could be exploited and applied in food products to substitute synthetic vitamin enrichment and fortification.

Infant Fecal Fermentations with Galacto-Oligosaccharides and 2′-Fucosyllactose Show Differential Bifidobacterium longum Stimulation at Subspecies Level

The objective of the current study was to evaluate the potential of 2′-FL and GOS, individually and combined, in beneficially modulating the microbial composition of infant and toddler (12–18 months) feces using the micro-Matrix bioreactor. In addition, the impacts of GOS and 2′-FL, individually and combined, on the outgrowth of fecal bifidobacteria at (sub)species level was investigated using the baby M-SHIME® model. For young toddlers, significant increases in the genera Bifidobacterium, Veillonella, and Streptococcus, and decreases in Enterobacteriaceae, Clostridium XIVa, and Roseburia were observed in all supplemented fermentations. In addition, GOS, and combinations of GOS and 2′-FL, increased Collinsella and decreased Salmonella, whereas 2′-FL, and combined GOS and 2′-FL, decreased Dorea. Alpha diversity increased significantly in infants with GOS and/or 2′-FL, as well as the relative abundances of the genera Veillonella and Akkermansia with 2′-FL, and Lactobacillus with GOS. Combinations of GOS and 2′-FL significantly stimulated Veillonella, Lactobacillus, Bifidobacterium, and Streptococcus. In all supplemented fermentations, Proteobacteria decreased, with the most profound decreases accomplished by the combination of GOS and 2′-FL. When zooming in on the different (sub)species of Bifidobacterium, GOS and 2’-FL were shown to be complementary in stimulating breast-fed infant-associated subspecies of Bifidobacterium longum in a dose-dependent manner: GOS stimulated Bifidobacterium longum subsp. longum, whereas 2′-FL supported outgrowth of Bifidobacterium longum subsp. infantis.

Perspective: microbial interventions in the urinary tract

Despite multiple advances in medicine, the management of urinary tract infections (UTIs) in women has remained stalled for decades. To prevent the development of symptomatic recurrences, low-dose antibiotics are the mainstay, while alternative approaches have been attempted with limited success. The use of probiotics was first considered forty years ago, and while some promising studies have been published, additional evidence in larger patient groups is needed to recommend specific strains as a primary preventive regimen. Overall, the role of beneficial microbes in reducing the risk of UTI and other urological diseases, such as urolithiasis, remains a target for researchers. The aim of this perspective is to offer a viewpoint on the status of this approach and recommendations for how to develop novel probiotic therapies.

Probiotic characterization and comparison of broiler-derived lactobacillus strains based on technique for order preference by similarity to ideal solution analysis

A total of 10 lactobacillus strains were isolated from broiler chickens and their probiotic properties including tolerance to gastrointestinal fluids and heat treatment, antimicrobial activity, adhesion capacity to intestinal cells, surface hydrophobicity, autoaggregation, antioxidative activity, and immunomodulatory effects on chicken macrophages were evaluated. The Limosilactobacillus reuteri (LR) was the most frequently isolated species, followed by Lactobacillus johnsonii (LJ) and Ligilactobacillus salivarius (LS). All isolates showed good resistance to simulated gastrointestinal conditions and antimicrobial activity against 4 indicator strains including Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, and Proteus mirabilis LR 21 exhibited excellent performances on autoaggregation, hydrophobicity and adhesion capacity to Caco-2 intestinal cells. In the meantime, this strain also possessed considerable tolerance to heat treatment, which indicated great potential to be used in the feed industry. However, LJ 20 strain had the highest free radical scavenging activity compared with the other strains. Furthermore, qRT-PCR results revealed that all isolated strains significantly increased the transcriptional levels of proinflammatory genes and tended to induce the M1-type polarization on HD11 macrophages. Particularly, the technique for order preference by similarity to ideal solution (TOPSIS) was adopted in our study to compare and select the most promising probiotic candidate based on in vitro evaluation tests.

Galactooligosaccharide (GOS) Reduces Branched Short-Chain Fatty Acids, Ammonium, and pH in a Short-Term Colonic Fermentation Model

Prebiotics beneficially affect the gut microbiome. Bimuno®, a prebiotic supplement containing galactooligosaccharides (GOS), has multiple demonstrated prebiotic effects. Using short-term colonic incubations, the influence of GOS on the colonic microbiota of three healthy human adults was evaluated. Colonic reactors inoculated with fecal samples were untreated (blank) or supplemented with GOS. pH, gas pressure, short-chain fatty acids (SCFAs), lactic acid, branched SCFAs, ammonium, and microbial community composition were evaluated at 0 h, 6 h, 24 h, and 48 h. pH decreased and gas pressure increased (+29.01 kPa) with GOS treatment versus blank. Total SCFA (+22.4 mM), acetate (+14.1 mM), propionate (+5.5 mM), and butyrate (+5.8 mM) were higher for GOS than blank. Acetate and propionate production were highest earlier in the experiment, while butyrate production was highest between 24 h and 48 h. With GOS, lactic acid production increased between 0 h and 6 h (+14.4 mM) followed by apparent consumption. Levels of branched SCFAs and ammonium were low with GOS and reduced versus blank (respectively, −2.1 mM and −256.0 mg/L). GOS significantly increased the relative abundance of Bifidobacterium longum (LDA = 4; p = 0.006), and significantly increased the absolute abundance of Bifidobacteriaceae (p < 0.001), Lactobacillaceae (p < 0.05), Bifidobacterium adolescentis (LDA = 4.5; p < 0.001), and Bifidobacterium ruminantium (LDA= 3.2; p = 0.01). This in vitro model demonstrated the prebiotic potential of GOS as supplementation resulted in increased beneficial bacteria, SCFA, and lactic acid and decreased branched SCFA, pH, and ammonium.

The Effect of the Gut Microbiota on Transplanted Kidney Function

The intestinal microflora is extremely important, not only in the processes of absorption, digestion and biosynthesis of vitamins, but also in shaping the immune and cognitive functions of the human body. Several studies demonstrate a correlation between microbiota composition and such events as graft rejection, kidney interstitial fibrosis, urinary tract infections, and diarrhoea or graft tolerance. Some of those changes might be directly linked with pathologies such as colonization with pathogenic bacterial strains. Gut microbiota composition also plays an important role in metabolic complications and viral infections after transplantation. From the other side, gut microbiota might induce graft tolerance by promotion of T and B regulatory cells. Graft tolerance induction is still an extremely important issue regarding transplantology and might allow the reduction or even avoidance of immunosuppressive treatment. Although there is a rising evidence of the pivotal role of gut microbiota in aspects of kidney transplantation there is still a lack of knowledge on the direct mechanisms of microbiota action. Furthermore, some of those negative effects could be reversed by probiotics of faecal microbiota trapoinsplantation. While diabetes and hypertension as well as BKV and CMV viremia are common and important complications of transplantation, both worsening the graft function and causing systemic injuries, it opens up potential clinical treatment options. As has been also suggested in the current review, some bacterial subsets exhibit protective properties. However, currently, there is a lack of evidence on pro- and prebiotic supplementation in kidney transplant patients. In the current review, we describe the effect of the microbiota on the transplanted kidney in renal transplant recipients.

Isomaltooligosaccharides Sustain the Growth of Prevotella Both In Vitro and in Animal Models

The human digestive tract is colonized by trillions of bacterial cells that play important roles in human health and diseases. It is well known that dietary habits are associated with human microbiota enterotypes. However, the factors that determine the enterotype still remain elusive. In this study, it was first examined, via in vitro batch fermentation, how different carbohydrates affect the Bacteroides and Prevotella enterotypes. Among the 11 substrates (fructo-, galacto-, xylo-, manno-, and isomalto-oligosaccharides [IMO] and lactulose, raffinose, starch, inulin [INU], mannitol, and xylitol) tested, IMO, INU, and starch were found to sustain the growth of Prevotella through batch fermentation. The development of the Prevotella and Bacteroides enterotypes was further simulated in chemostats using fecal samples. IMO coupled with faster dilution rates and lower pH were required to sustain the growth of Prevotella copri in the chemostat based on 16S rRNA gene and metagenomic sequencing. Meanwhile, starch with relatively lower dilution rates and higher pH was required to support the development of the Bacteroides enterotype. Amylo-α-1,6-glucosidase, pectin, and xylan lyases were the carbohydrate-active enzymes associated with the Prevotella enterotype. The Bacteroides enterotype was associated with more diversified carbohydrate-active enzymes. Consistently, since honey contains high isomaltose content, mice fed IMO and honey displayed an increased relative abundance of Prevotella in the colon. In conclusion, both in vitro systems and a mouse model were used to demonstrate that IMO maintains the Prevotella enterotype. This result provides insight into the nutritional requirements underlying gut enterotype formation. IMPORTANCE The Prevotella enterotype type is a human traditional enterotype with high dietary fiber intake, which is related to healthy ageing and Parkinson's disease development. Manipulations of the dwelled gut microbes by dietary isomalto-oligosaccharides efficiently sustained Prevotella type enterotypes, indicating that it can be used in the improvement of elderly health by increasing the gut transit time.

Intermediate role of gut microbiota in vitamin B nutrition and its influences on human health

Vitamin B consists of a group of water-soluble micronutrients that are mainly derived from the daily diet. They serve as cofactors, mediating multiple metabolic pathways in humans. As an integrated part of human health, gut microbiota could produce, consume, and even compete for vitamin B with the host. The interplay between gut microbiota and the host might be a crucial factor affecting the absorbing processes of vitamin B. On the other hand, vitamin B supplementation or deficiency might impact the growth of specific bacteria, resulting in changes in the composition and function of gut microbiota. Together, the interplay between vitamin B and gut microbiota might systemically contribute to human health. In this review, we summarized the interactions between vitamin B and gut microbiota and tried to reveal the underlying mechanism so that we can have a better understanding of its role in human health.

The effects of probiotic administration on patients with prediabetes: a meta-analysis and systematic review

BACKGROUND

This paper aimed to examine the effects of probiotics on eight factors in the prediabetic population by meta-analysis, namely, fasting blood glucose (FBG), glycated haemoglobin A1c (HbA1c), homeostatic model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), and the mechanisms of action are summarized from the existing studies.

METHODS

Seven databases (PubMed, Web of Science, Embase, Cochrane Library, SinoMed, CNKI, and Wanfang Med) were searched until March 2022. Review Manager 5.4 was used for meta-analysis. The data were analysed using weighted mean differences (WMDs) or standardized mean differences (SMDs) under a fixed effect model to observe the efficacy of probiotic supplementation on the included indicators.

RESULTS

Seven publications with a total of 460 patients were included. According to the meta-analysis, probiotics were able to significantly decrease the levels of HbA1c (WMD, -0.07; 95% CI -0.11, -0.03; P = 0.001), QUICKI (WMD, 0.01; 95% CI 0.00, 0.02; P = 0.04), TC (SMD, -0.28; 95% CI -0.53, -0.22; P = 0.03), TG (SMD, -0.26; 95% CI -0.52, -0.01; P = 0.04), and LDL-C (WMD, -8.94; 95% CI -14.91, -2.97; P = 0.003) compared to levels in the placebo group. The effects on FBG (WMD, -0.53; 95% CI -2.31, 1.25; P = 0.56), HOMA-IR (WMD, -0.21; 95% CI -0.45, 0.04; P = 0.10), and HDL-C (WMD, 2.05; 95% CI -0.28, 4.38; P = 0.08) were not different from those of the placebo group.

CONCLUSION

The present study clearly indicated that probiotics may fulfil an important role in the regulation of HbA1c, QUICKI, TC, TG and LDL-C in patients with prediabetes. In addition, based on existing studies, we concluded that probiotics may regulate blood glucose homeostasis in a variety of ways.

TRIAL REGISTRATION

This meta-analysis has been registered at PROSPERO with ID: CRD42022321995.

Microbial dysbiosis and epigenetics modulation in cancer development - A chemopreventive approach

An overwhelming number of research articles have reported a strong relationship of the microbiome with cancer. Microbes have been observed more commonly in the body fluids like urine, stool, mucus of people with cancer compared to the healthy controls. The microbiota is responsible for both progression and suppression activities of various diseases. Thus, to maintain healthy human physiology, host and microbiota relationship should be in a balanced state. Any disturbance in this equilibrium, referred as microbiome dysbiosis becomes a prime cause for the human body to become more prone to immunodeficiency and cancer. It is well established that some of these microbes are the causative agents, whereas others may encourage the formation of tumours, but very little is known about how these microbial communications causing change at gene and epigenome level and trigger as well as encourage the tumour growth. Various studies have reported that microbes in the gut influence DNA methylation, DNA repair and DNA damage. The genes and pathways that are altered by gut microbes are also associated with cancer advancement, predominantly those implicated in cell growth and cell signalling pathways. This study exhaustively reviews the current research advancements in understanding of dysbiosis linked with colon, lung, ovarian, breast cancers and insights into the potential molecular targets of the microbiome promoting carcinogenesis, the epigenetic alterations of various potential targets by altered microbiota, as well as the role of various chemopreventive agents for timely prevention and customized treatment against various types of cancers.

Transcriptional Changes in Bifidobacterium bifidum Involved in Synergistic Multispecies Biofilms

Bifidobacterium bifidum is part of the core microbiota of healthy infant guts where it may form biofilms on epithelial cells, mucosa, and food particles in the gut lumen. Little is known about transcriptional changes in B. bifidum engaged in synergistic multispecies biofilms with ecologically relevant species of the human gut. Recently, we reported prevalence of synergism in mixed-species biofilms formed by the human gut microbiota. This study represents a comparative gene expression analysis of B. bifidum when grown in a single-species biofilm and in two multispecies biofilm consortia with Bifidobacterium longum subsp. infantis, Bacteroides ovatus, and Parabacteroides distasonis in order to identify genes involved in this adaptive process in mixed biofilms and the influence on its metabolic and functional traits. Changes up to 58% and 43% in its genome were found when it grew in three- and four-species biofilm consortia, respectively. Upregulation of genes of B. bifidum involved in carbohydrate metabolism (particularly the galE gene), quorum sensing (luxS and pfs), and amino acid metabolism (especially branched chain amino acids) in both multispecies biofilms, compared to single-species biofilms, suggest that they may be contributing factors for the observed synergistic biofilm production when B. bifidum coexists with other species in a biofilm.

Probiotic treatment of inflammatory bowel disease: Its extent and intensity

Free radicals (reactive oxygen species, superoxides and hydroxyl radicals) lead to the development of oxidative stress because of imbalance in the amount of antioxidants. Continued development of oxidative stress leads to chronic diseases in humans. The instability in the antioxidant activities and accumulation of oxidative stress due to free radicals may occur in diseases like inflammatory bowel disease (IBD). Antioxidants are substances that inhibit or delay the mechanism of oxidation of molecules mediated by free radicals and also transform into lesser-active derivatives. Probiotics are defined as live microorganisms that show beneficial effects on inflamed intestine and balance the inflammatory immune responses in the gut. Probiotic strains have been reported to scavenge hydroxyl radicals and superoxide anions that are abundantly produced during oxidative stress. The most widely studied probiotic strains are Streptococcus, Bifidobacterium and Lactobacillus. Probiotics cultured in broth have shown some amount of antioxidant activities. Fermented milk and soy milk, which possess starter microorganisms (probiotics), tends to increase the antioxidant activities many-fold. This review aims to discuss the in vivo and in vitro antioxidant activities of specific probiotics with various assays with respect to IBD.

Deoxynivalenol damages the intestinal barrier and biota of the broiler chickens

Background

In the livestock feed industry, feed and feed raw materials are extremely susceptible to mycotoxin contamination. Deoxynivalenol (DON) is one of the main risk factors for mycotoxin contamination in broiler feed and feedstuff, however, there is still little knowledge about this. Hence, the purpose of this study was to explore the toxicity effect of DON on the intestinal barrier and the microecological balance of the biota in broiler chickens.

Results

In our present study, we compared the pathological scores of the small intestines of broilers on the 5^th, 7^th, and 10^th day, and chose the 7^th day to analyze the small intestine histomorphology, tight junctions, and cecal biota of the broilers. The results showed the damage to the small intestine worsened over time, the small intestinal villi of broilers were breakage, the tight junctions of the small intestine were destroyed, the cecal biota was unbalanced, and the growth performance of broilers was reduced on the 7^th day.

Conclusions

DON could damage the functional and structural completeness of the intestinal tract, disorder the Intestinal biota, and finally lead to declined broiler performance. Our study provided a basis for the prevention and treatment of DON in broiler production.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03392-4.

Prebiotics, Probiotics, and Postbiotics in the Prevention and Treatment of Anemia

Iron deficiency anemia (IDA) is very common and affects approximately 1/3 of the world’s human population. There are strong research data that some probiotics, such as Lactobacillus acidophilus and Bifidobacterium longum improve iron absorption and influence the course of anemia. Furthermore, prebiotics, including galactooligosaccharides (GOS) and fructooligosaccharides (FOS), increase iron bioavailability and decrease its destructive effect on the intestinal microbiota. In addition, multiple postbiotics, which are probiotic metabolites, including vitamins, short-chain fatty acids (SCFA), and tryptophan, are involved in the regulation of intestinal absorption and may influence iron status in humans. This review presents the actual data from research studies on the influence of probiotics, prebiotics, and postbiotics on the prevention and therapy of IDA and the latest findings regarding their mechanisms of action. A comparison of the latest research data and theories regarding the role of pre-, post-, and probiotics and the mechanism of their action in anemias is also presented and discussed.

Postbiotics as potential new therapeutic agents for metabolic disorders management

The prevalence of obesity, diabetes, non-alcoholic fatty liver disease, and related metabolic disorders has been steadily increasing in the past few decades. Apart from the establishment of caloric restrictions in combination with improved physical activity, there are no effective pharmacological treatments for most metabolic disorders. Many scientific-studies have described various beneficial effects of probiotics in regulating metabolism but others questioned their effectiveness and safety. Postbiotics are defined as preparation of inanimate microorganisms, and/or their components, which determine their safety of use and confers a health benefit to the host. Additionally, unlike probiotics postbiotics do not require stringent production/storage conditions. Recently, many lines of evidence demonstrated that postbiotics may be beneficial in metabolic disorders management via several potential effects including anti-inflammatory, antibacterial, immunomodulatory, anti-carcinogenic, antioxidant, antihypertensive, anti-proliferative, and hypocholesterolaemia properties that enhance both the immune system and intestinal barrier functions by acting directly on specific tissues of the intestinal epithelium, but also on various organs or tissues. In view of the many reports that demonstrated the high biological activity and safety of postbiotics, we summarized in the present review the current findings reporting the beneficial effects of various probiotics derivatives for the management of metabolic disorders and related alterations.

Caproic Acid-Producing Bacteria in Chinese Baijiu Brewing

Caproic acid can be used as spices, preservatives, animal feed additives, and biofuels. At the same time, caproic acid plays an important role in Chinese Baijiu. It is the precursor substance for the synthesis of ethyl caproate, which directly affects the quality of Chinese Baijiu. Caproic acid-producing bacteria are the main microorganisms that synthesize caproic acid in Chinese Baijiu, and the most common strain is Clostridium kluyveri. Caproic acid-producing bacteria synthesize n-caproic acid through reverse β-oxidation to extend the carboxylic acid chain. This method mainly uses ethanol and lactic acid as substrates. Ethanol and lactic acid are converted into acetyl-CoA, and acetyl-CoA undergoes a series of condensation, dehydrogenation, dehydration, and reduction to extend the carboxylic acid chain. This review addresses the important issues of caproic acid-producing bacteria in the brewing process of Baijiu: the common caproic acid-producing bacteria that have been reported metabolic pathways, factors affecting acid production, biological competition pathways, and the effect of mixed bacteria fermentation on acid production. It is hoped that this will provide new ideas for the study of caproic acid-producing bacteria in Chinese Baijiu.

Mapping the Influence of the Gut Microbiota on Small Molecules across the Microbiome Gut Brain Axis

Microbes exert influence across the microbiome-gut-brain axis through neurotransmitter production, induction of host immunomodulators, or the release or induction of other microbial or host molecules. Here, we used mass spectrometry imaging (MSI), a label-free imaging tool, to map molecular changes in the gut and brain in germ-free, antibiotic-treated and control mice. We determined spatial distribution and relative quantification of neurotransmitters and their precursors in response to the microbiome. Using untargeted MSI, we detected a significant change in the levels of four identified small molecules in the brains of germ-free animals compared to controls. However, antibiotic treatment induced no significant changes in these same metabolites in the brain after 1 week of treatment. This work exemplifies the utility of MSI as a tool for the study of known and discovery of novel, mediators of microbiome-gut-brain axis communication.

Are Metabolites From the Gut Microbiota Capable of Regulating Epigenetic Mechanisms in the Human Parasite Entamoeba histolytica?

The unicellular parasite Entamoeba histolytica inhabits the human gut. It has to adapt to a complex environment that consists of the host microbiota, nutritional stress, oxidative stress, and nitrosative stress. Adaptation to this complex environment is vital for the survival of this parasite. Studies have shown that the host microbiota shapes virulence and stress adaptation in E. histolytica. Increasing evidence suggests that metabolites from the microbiota mediate communication between the parasite and microbiota. In this review, we discuss the bacterial metabolites that regulate epigenetic processes in E. histolytica and the implications that this knowledge may have for the development of new anti-amebic strategies.

Dietary Intake Is Unlikely to Explain Symptom Severity and Syndrome-Specific Microbiome Alterations in a Cohort of Women with Fibromyalgia

BACKGROUND

Significant alterations were recently identified in the composition and putative function of the gut microbiome in women with fibromyalgia. As diet can influence the composition of the gut microbiome, differences in nutritional intake could, in theory, account for some of these specific fibromyalgia microbiome alterations. The current study aims to compare the diet of women with fibromyalgia to that of controls in order to explore possible associations between the intake of certain nutrients, symptom severity and gut microbiome composition.

METHODS

The study population was comprised of 56 women with fibromyalgia and 68 controls. Dietary intake was assessed using the NIH Automated Self-Administered 24 h recall, following dietitian's instructions and the completion of a three-day dietary recall. The gut microbiome was assessed by 16S ribosomal RNA gene sequencing of stool samples.

RESULTS

Most demographic and anthropometric characteristics were comparable between groups. The average energy and macronutrient intake (total and relative) and overall diet quality score were not different between patients and controls, nor were the main vitamins, minerals, fatty acids, alcohol, caffeine, sugar or fiber intakes. The daily intake of micronutrients and normalized macronutrients in women with fibromyalgia was largely not correlated with disease-specific measures, including pain intensity, fatigue, cognitive symptoms and quality of sleep, or with the relative quantity of almost any of the gut microbiome bacterial taxa differentially abundant in fibromyalgia.

CONCLUSION

These data demonstrate that dietary intakes, as evaluated by self-reported questionnaires, probably cannot explain the syndrome-specific differences in gut microbiome or the clinical phenotype of fibromyalgia.

Functional bacterial cultures for dairy applications: towards improving safety, quality, nutritional and health benefit aspects

Traditionally, fermentation was used to preserve the shelf life of food. Currently, in addition to favouring food preservation, well standardized and controlled industrial processes are also aimed at improving the functional characteristics of the final product. In this regard, starter cultures have become an essential cornerstone of food production. The selection of robust microorganisms, well adapted to the food environment, has been followed by the development of microbial consortia that provide some functional characteristics, beyond their acidifying capacity, achieving safer, high‐quality foods with improved nutritional and health‐promoting properties. In addition to starters, adjunct cultures and probiotics, which normally do not have a relevant role in fermentation, are added to the food in order to provide some beneficial characteristics. This review focuses on highlighting the functional characteristics of food starters, as well as adjunct and probiotic cultures (mainly lactic acid bacteria and bifidobacteria), with a specific focus on the synthesis of metabolites for preservation and safety aspects (e.g. bacteriocins), organoleptic properties (e.g. exopolysaccharides), nutritional (e.g. vitamins) and health improvement (e.g. neuroactive molecules). Literature reporting the application of these functional cultures in the manufacture of foods, mainly those related to dairy production, such as cheeses and fermented milks, has also been updated.

The Combination of In Vitro Assessment of Stress Tolerance Ability, Autoaggregation, and Vitamin B-Producing Ability for New Probiotic Strain Introduction

The health benefits of probiotics are beyond doubt. The positive effects of lactobacilli and bifidobacteria on the function of many body systems have been repeatedly proven by various studies. To completely realize the potential of probiotic microorganisms, the strains should be tested by the greatest combination of characteristics that contribute to the wellness of the host. In this work, for the first time, a combined assessment of the probiotic properties and vitamin B-producing potential of various species and strains of bifidobacteria and lactobacilli was carried out. The presence of an additional advantage, such as vitamin-producing ability, can prevent vitamin deficiency both at the level of the consumption of fermented foods, when the enrichment will occur naturally on the spot, and during colonization by these intestinal strains, when synthesis will occur in vivo. To select potential probiotics, the stress tolerance ability of 16 lactic acid bacteria and bifidobacteria strains to low pH values, bile, and proteolytic enzymes, as well as their ability to autoaggregate, were studied under conditions of modeling the gastrointestinal tract in vitro. The ability of the strains to extracellularly accumulate water-soluble B vitamins was evaluated by capillary electrophoresis. Among the tested strains of bifidobacteria, B. adolescentis VKPM AC-1662 is of interest; it was characterized by the greatest stress tolerance ability and the ability to autoaggregate, in addition to the extracellular synthesis of riboflavin and pyridoxine. Among lactic acid bacteria, L. sakei VKPM B-8936 demonstrated the greatest tolerance to low pH, L. plantarum VKPM B–11007 to duodenal conditions, L. acidophilus VKPM B-2213 to pepsin, and L. salivarius VKPM B–2214 to pancreatin. The highest percentage of autoaggregation was observed in L. salivarius VKPM B-2214, which also accumulated the largest amount of pantothenic acid, but it was sensitive to stress conditions. The obtained results could be used to create new products enriched with probiotics and B vitamins.

Gut microbiota and vitamin status in persons with obesity: A key interplay

There are numerous factors involved in obesity progression and maintenance including systemic low-grade inflammation, adipose tissue dysfunction, or gut microbiota dysbiosis. Recently, a growing interest has arisen for vitamins' role in obesity and related disorders, both at the host and gut bacterial level. Indeed, vitamins are provided mostly by food, but some, from the B and K groups in particular, can be synthesized by the gut bacterial ecosystem and absorbed in the colon. Knowing that vitamin deficiency can alter many important cellular functions and lead to serious health issues, it is important to carefully monitor the vitamin status of patients with obesity and potentially already existing comorbidities as well as to examine the dysbiotic gut microbiota and thus potentially altered bacterial metabolism of vitamins. In this review, we examined both murine and human studies, to assess the prevalence of sub-optimal levels of several vitamins in obesity and metabolic alterations. This review also examines the relationship between vitamins and the gut microbiota in terms of vitamin production and the modulation of the gut bacterial ecosystem in conditions of vitamin shortage or supplementation. Furthermore, some strategies to improve vitamin status of patients with severe obesity are proposed within this review.

A Comprehensive Review on the Role of the Gut Microbiome in Human Neurological Disorders

The human body is full of an extensive number of commensal microbes, consisting of bacteria, viruses, and fungi, collectively termed the human microbiome. The initial acquisition of microbiota occurs from both the external and maternal environments, and the vast majority of them colonize the gastrointestinal tract (GIT). These microbial communities play a central role in the maturation and development of the immune system, the central nervous system, and the GIT system and are also responsible for essential metabolic pathways. Various factors, including host genetic predisposition, environmental factors, lifestyle, diet, antibiotic or nonantibiotic drug use, etc., affect the composition of the gut microbiota. Recent publications have highlighted that an imbalance in the gut microflora, known as dysbiosis, is associated with the onset and progression of neurological disorders. Moreover, characterization of the microbiome-host cross talk pathways provides insight into novel therapeutic strategies. Novel preclinical and clinical research on interventions related to the gut microbiome for treating neurological conditions, including autism spectrum disorders, Parkinson's disease, schizophrenia, multiple sclerosis, Alzheimer's disease, epilepsy, and stroke, hold significant promise. This review aims to present a comprehensive overview of the potential involvement of the human gut microbiome in the pathogenesis of neurological disorders, with a particular emphasis on the potential of microbe-based therapies and/or diagnostic microbial biomarkers. This review also discusses the potential health benefits of the administration of probiotics, prebiotics, postbiotics, and synbiotics and fecal microbiota transplantation in neurological disorders.

Suppression of high-fat-diet-induced obesity in mice by dietary folic acid supplementation is linked to changes in gut microbiota

PURPOSE

To investigate whether the effects of dietary folic acid supplementation on body weight gain are mediated by gut microbiota in obesity.

METHODS

Male C57 BL/6J conventional (CV) and germ-free (GF) mice both aged three to four weeks were fed a high-fat diet (HD), folic acid-deficient HD (FD-HD), folic acid-supplement HD (FS-HD) and a normal-fat diet (ND) for 25 weeks. Faecal microbiota were analyzed by 16S rRNA high-throughput sequencing, and the mRNA expression of genes was determined by the real-time RT-PCR. Short-chain fatty acids (SCFAs) in faeces and plasma were measured using gas chromatography-mass spectrometry.

RESULTS

In CV mice, HD-induced body weight gain was inhibited by FS-HD, accompanied by declined energy intake, smaller white adipocyte size, and less whitening of brown adipose tissue. Meanwhile, the HD-induced disturbance in the expression of fat and energy metabolism-associated genes (Fas, Atgl, Hsl, Ppar-α, adiponectin, resistin, Ucp2, etc.) in epididymal fat was diminished, and the dysbiosis in faecal microbiota was lessened, by FS-HD. However, in GF mice with HD feeding, dietary folic acid supplementation had almost no effect on body weight gain and the expression of fat- and energy-associated genes. Faecal or plasma SCFA concentrations in CV and GF mice were not altered by either FD-HD or FS-HD feeding.

CONCLUSION

Dietary folic acid supplementation differently affected body weight gain and associated genes' expression under HD feeding between CV and GF mice, suggesting that gut bacteria might partially share the responsibility for beneficial effects of dietary folate on obesity.

An Update on the Effectiveness of Probiotics in the Prevention and Treatment of Cancer

Probiotics are living microbes that play a significant role in protecting the host in various ways. Gut microbiota is one of the key players in maintaining homeostasis. Cancer is considered one of the most significant causes of death worldwide. Although cancer treatment has received much attention in recent years, the number of people suffering from neoplastic syndrome continues to increase. Despite notable improvements in the field of cancer therapy, tackling cancer has been challenging due to the multiple properties of cancer cells and their ability to evade the immune system. Probiotics alter the immunological and cellular responses by enhancing the epithelial barrier and stimulating the production of anti-inflammatory, antioxidant, and anticarcinogenic compounds, thereby reducing cancer burden and growth. The present review focuses on the various mechanisms underlying the role of probiotics in the prevention and treatment of cancer.

Identifying the essential nutritional requirements of the probiotic bacteria Bifidobacterium animalis and Bifidobacterium longum through genome-scale modeling

Although bifidobacteria are widely used as probiotics, their metabolism and physiology remain to be explored in depth. In this work, strain-specific genome-scale metabolic models were developed for two industrially and clinically relevant bifidobacteria, Bifidobacterium animalis subsp. lactis BB-12® and B. longum subsp. longum BB-46, and subjected to iterative cycles of manual curation and experimental validation. A constraint-based modeling framework was used to probe the metabolic landscape of the strains and identify their essential nutritional requirements. Both strains showed an absolute requirement for pantethine as a precursor for coenzyme A biosynthesis. Menaquinone-4 was found to be essential only for BB-46 growth, whereas nicotinic acid was only required by BB-12®. The model-generated insights were used to formulate a chemically defined medium that supports the growth of both strains to the same extent as a complex culture medium. Carbohydrate utilization profiles predicted by the models were experimentally validated. Furthermore, model predictions were quantitatively validated in the newly formulated medium in lab-scale batch fermentations. The models and the formulated medium represent valuable tools to further explore the metabolism and physiology of the two species, investigate the mechanisms underlying their health-promoting effects and guide the optimization of their industrial production processes.

Metagenome-Scale Metabolic Network Suggests Folate Produced by Bifidobacterium longum Might Contribute to High-Fiber-Diet-Induced Weight Loss in a Prader-Willi Syndrome Child

Gut-microbiota-targeted nutrition intervention has achieved success in the management of obesity, but its underlying mechanism still needs extended exploration. An obese Prader-Willi syndrome boy lost 25.8 kg after receiving a high-fiber dietary intervention for 105 days. The fecal microbiome sequencing data taken from the boy on intervention days 0, 15, 30, 45, 60, 75, and 105, along with clinical indexes, were used to construct a metagenome-scale metabolic network. Firstly, the abundances of the microbial strains were obtained by mapping the sequencing reads onto the assembly of gut organisms through use of reconstruction and analysis (AGORA) genomes. The nutritional components of the diet were obtained through the Virtual Metabolic Human database. Then, a community model was simulated using the Microbiome Modeling Toolbox. Finally, the significant Spearman correlations among the metabolites and the clinical indexes were screened and the strains that were producing these metabolites were identified. The high-fiber diet reduced the overall amount of metabolite secretions, but the secretions of folic acid derivatives by Bifidobacterium longum strains were increased and were significantly relevant to the observed weight loss. Reduced metabolites might also have directly contributed to the weight loss or indirectly contribute by enhancing leptin and decreasing adiponectin. Metagenome-scale metabolic network technology provides a cost-efficient solution for screening the functional microbial strains and metabolic pathways that are responding to nutrition therapy.

Does Folic Acid Protect Patients with Inflammatory Bowel Disease from Complications?

Folic acid, referred to as vitamin B9, is a water-soluble substance, which participates in the synthesis of nucleic acids, amino acids, and proteins. Similarly to B12 and B6, vitamin B9 is involved in the metabolism of homocysteine, which is associated with the MTHFR gene. The human body is not able to synthesize folic acid; thus, it must be supplemented with diet. The most common consequence of folic acid deficiency is anemia; however, some studies have also demonstrated the correlation between low bone mineral density, hyperhomocysteinemia, and folic acid deficiency. Patients with inflammatory bowel disease (IBD) frequently suffer from malabsorption and avoid certain products, such as fresh fruits and vegetables, which constitute the main sources of vitamin B9. Additionally, the use of sulfasalazine by patients may result in folic acid deficiency. Therefore, IBD patients present a higher risk of folic acid deficiency and require particular supervision with regard to anemia and osteoporosis prevention, which are common consequences of IBD.

Epigenetic interaction of microbes with their mammalian hosts

The interaction of microbiota with its host has the ability to alter the cellular functions of both, through several mechanisms. Recent work, from many laboratories including our own, has shown that epigenetic mechanisms play an important role in the alteration of these cellular functions. Epigenetics broadly refers to change in the phenotype without a corresponding change in the DNA sequence. This change is usually brought by epigenetic modifications of the DNA itself, the histone proteins associated with the DNA in the chromatin, non-coding RNA or the modifications of the transcribed RNA. These modifications, also known as epigenetic code, do not change the DNA sequence but alter the expression level of specific genes. Microorganisms seem to have learned how to modify the host epigenetic code and modulate the host transcriptome in their favour. In this review, we explore the literature that describes the epigenetic interaction of bacteria, fungi and viruses, with their mammalian hosts.

Probiotic Supplementation and Micronutrient Status in Healthy Subjects: A Systematic Review of Clinical Trials

Micronutrient deficiencies are a worldwide public health concern. Emerging evidence supports the ability of probiotics to enhance micronutrient status, which could aid in the prevention of non-communicable disease-associated malnutrition. This systematic review evaluated evidence of the efficacy of probiotic supplementation to improve micronutrient status in healthy subjects. The authors searched for published English language peer-reviewed journal articles in PubMed, Scopus, Embase, and Google Scholar databases from inception to July 2020 using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of eligible studies was assessed using the Revised Cochrane Risk-of-Bias tool (RoB)2 and Risk of Bias in Non-Randomized Studies of Interventions tool (ROBINS-I tool). Fourteen original studies out of 2790 met the inclusion criteria. The results indicated that, despite varying degrees of efficacy, the intake of certain probiotics in healthy subjects was associated with a positive impact on the status of certain micronutrients (vitamin B12, calcium, folate, iron and zinc). A limitation was that studies were widely heterogeneous in terms of participant age, probiotic strain, species, dosage, intervention duration, and form of administration. Additional clinical trials are warranted to determine the most effective strains of probiotics, doses and durations of interventions.

Malnutrition and Gut Microbiota in Children

Malnutrition continues to threaten the lives of millions across the world, with children being hardest hit. Although inadequate access to food and infectious disease are the primary causes of childhood malnutrition, the gut microbiota may also contribute. This review considers the evidence on the role of diet in modifying the gut microbiota, and how the microbiota impacts childhood malnutrition. It is widely understood that the gut microbiota of children is influenced by diet, which, in turn, can impact child nutritional status. Additionally, diarrhoea, a major contributor to malnutrition, is induced by pathogenic elements of the gut microbiota. Diarrhoea leads to malabsorption of essential nutrients and reduced energy availability resulting in weight loss, which can lead to malnutrition. Alterations in gut microbiota of severe acute malnourished (SAM) children include increased Proteobacteria and decreased Bacteroides levels. Additionally, the gut microbiota of SAM children exhibits lower relative diversity compared with healthy children. Thus, the data indicate a link between gut microbiota and malnutrition in children, suggesting that treatment of childhood malnutrition should include measures that support a healthy gut microbiota. This could be of particular relevance in sub-Saharan Africa and Asia where prevalence of malnutrition remains a major threat to the lives of millions.

Folate in Milk Fermented by Lactic Acid Bacteria from Different Food Sources

Folates are essential micronutrients, and folate deficiency still occurs in many countries. Lactic acid bacteria (LAB) are known to be able to synthesize folates during fermentation, but the folate production is strain-dependent and influenced by the fermentation medium, presence of a folate precursor, and fermentation time. This study aimed to screen extracellular folate-producing LAB from local food sources and evaluate the factors influencing their folate biosynthesis during milk fermentation. The selection of folate-producing LAB was based on their ability to grow in folate-free medium (FACM), with folate concentrations quantified by microbiological assay. Growth of the 18 LAB in FACM varied between isolates, with only 8 isolates growing well and able to synthesize extracellular folate at relatively high concentrations (up to 24.27 ng/mL). The isolates with highest extracellular folate levels, Lactobacillus fermentum JK13 from kefir granules, Lactobacillus plantarum 4C261 from salted mustard, and Lactobacillus rhamnosus R23 from breast milk, were applied to milk fermentation. The last two isolates were probiotic candidates. The three isolates consumed folate when it was present in the milk, and its consumption was in line with their growth. The availability of folate precursors affected the amount of folate consumed, but did not lead to increased folate concentrations in the medium after 72 h fermentation. The results of this study indicate that these isolates cannot be utilized for producing folate in folate-containing milk, as it shows feedback inhibition on folate biosynthesis.