Beneficial microbes最新文献

Probiotics are widely used for their health promoting effects, though a lot remain to be discovered, particularly on their mechanisms of action at the molecular level. The functional genomic approach is an appropriate method to decipher how probiotics may influence human cell fate and therefore contribute to their health benefit. In the present work, we focused on Shouchella clausii (formerly named Bacillus then Alkalihalobacillus clausii), a spore-forming bacterium that is commercially available as a probiotic for the prevention and the treatment of intestinal dysbiosis and related gastrointestinal disorders, such as diarrhoea. Several studies have demonstrated that S. clausii treatment modulated inflammatory and immune responses, as well as gut barrier functions. A functional genomic strategy was implemented to decipher the mechanisms by which S. clausii exerts its probiotic effects on human intestinal epithelial cells. To do so, a large genomic DNA fragment library was constructed for each of the four strains: O/C, N/R, SIN and T. A high throughput in vitro screening in human epithelial cells was then conducted, using the reporter gene strategy, targeting the nuclear factor kappa B (NF-κB) pathway and interleukin-10 (IL-10) gene expression. After an exhaustive in vitro screening of approximately a thousand clones per library, several clones modulating the NF-κB pathway in the HT-29 reporter cell line were identified. Among clone lysates, 1.1% (O/C), 1.4% (N/R), 2.0% (SIN), and 1.2% (T) were identified as biologically active on immune reporter systems (NF-κB and IL-10 expression). After transposon mutagenesis and a new set of screening and sequencing, 23 coding sequences (CDS) were identified, including one encoding for the glutamine synthetase, associated with NF-κB modulation, and six CDS for IL-10 modulation. The functional genomic strategy that was applied to S. clausii was an original approach to identify gene candidates that may explain the mechanisms of action of probiotics. However, further work is needed to validate the identified leads.

Imbalances in the gut microbiome have emerged as an important factor in endothelial dysfunction, a significant risk factor for cardiovascular disease. Thus, interventions targeting the microbiome may prove helpful in preventing or reversing this impairment. We previously reported that spore-forming Bacillus subtilis DE111 improved endothelial function in a cohort of healthy, non-obese humans after a four-week intervention. Building on these promising results, the present study sought to investigate whether administering B. subtilis DE111 could reverse endothelial dysfunction in mice with diet-induced obesity. Male C57BL/6J mice were fed a Western diet (WD; n = 24) or standard diet (SD; n = 24) for ten weeks to induce endothelial dysfunction, after which half of the animals in each group (n = 12) were allocated to receive B. subtilis DE111 (hereafter, PB) formulated into the diet for an additional eight weeks. Outcomes included endothelial-dependent arterial dilation, glucose tolerance, body weight changes, microbiota profiles, and assessments of intestinal permeability and mucosal immunity markers. Furthermore, a cell culture model of gut barrier function was used to assess the effects of PB on gut barrier integrity. PB treatment significantly attenuated WD-induced mesenteric endothelial-dependent arterial dilation, independent of changes in other cardiometabolic parameters or changes in gut barrier function. In vitro trans-epithelial electrical resistance of the Caco-2 cell culture confirmed that neither PB-conditioned media nor faecal waters from B. subtilis-treated human stool resulted in gut barrier improvements, nor did they protect against inflammation-associated barrier disruptions. Unsurprisingly, microbiota analysis revealed significant differences in Shannon's alpha diversity of WD-fed animals compared to SD. These data suggest that PB consumption significantly attenuated WD diet-induced endothelial dysfunction; however, the underlying mechanisms of this protection were not determined. Improvement in endothelial function was independent of PB-mediated changes to body weight or gut barrier function. Further studies should explore B. subtilis-mediated immune responses or metabolite production as mechanisms underlying these endothelial protective effects.

Prenatal stress (PNS) has widespread effects on offspring, including aberrant immune development and behavioural deficits. The microbiome is a mediator of the dissemination of stress effects to the offspring through immunomodulation and metabolite production. Metabolites derived from the mother and their gut microbiota pass to the foetus and can affect immune and nervous development. Stress affects the abundance of such metabolites, including the tryptophan (Trp) pathway, which are involved in immune and nervous system function. We hypothesized that the PNS is associated with dysregulation of Trp metabolism. We further posited that treatment with a Trp-metaboliser Parasutterella excrementihominis would abrogate PNS-associated deleterious effects on offspring development. To test this hypothesis, pregnant mice were exposed to restraint stress and administered P. excrementihominis (Dam n = 3-9; Offspring n = 5-10). PNS increased maternal gut Trp and both maternal and offspring inflammation. P. excrementihominis treatment reduced the PNS-induced excess pool of maternal gut Trp. Some PNS effects on foetal neuroinflammation were reduced in severity due to handling effects from bacterial gavage. However, P. excrementihominis was anti-inflammatory in dam and offspring and anxiolytic in offspring of Pe-treated dams. These data illustrate that elevated Trp levels are associated PNS and its downstream deleterious offspring inflammatory and behavioural outcomes while P. excrementihominis, a Trp-metabolizer, can ameliorate these effects and improve offspring outcomes.

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit to the host. The selection criteria for probiotics include strain safety, viability, tolerance, metabolite production and/or the ability to modulate the immune system. Probiotics are commonly used in industries, such as food, agriculture, medicine, biotechnology, pharmaceuticals, and aquaculture. Recently, the medicinal applications of probiotics have gained attention and are being explored for the prevention and treatment of various diseases. One emerging area of interest is their potential role in psychological disorders. Mental illnesses, characterised by disturbances in behaviour, mood, thinking, and emotions, affect over one billion people globally. While various preventive and treatment options for mental disorders exists, each is associated with certain limitations. A new avenue being explored is the gut-brain axis, a complex bi-directional communication between the gut and the brain, that is facilitated by hormonal, neuronal, humoral, and immunological pathways. This system plays an important role in mental health. Probiotics, as a key modulator of the gut microbiome, could play a vital role in this communication. However, the underlying mechanisms remain to be explored. Probiotics may act through the production of metabolites and neuroactive substances, as well as through immunomodulation and cytokine production. Current data shows promising effects on stress, mood, and depression, presenting probiotics as a potential natural treatment option for psychological disorders. Nevertheless, major limitations in the existing research include insufficient clinical outcomes, limited sample sizes, and variable dosing. Future advancements may be achieved through stratifications based on gut microbiota, the use of next-generation probiotic strains, and the conduct of comprehensive validation studies.

Maternal separation (MS) in mice results in behavioral deficits and gut microbiota dysbiosis that all persist into adulthood. Limosilactobacillus reuteri DSM 17938 modulates gut microbiota, alters systemic metabolites, and facilitates immune regulation. To assess the effect of DSM 17938 on biochemical and behavioural stress-associated changes, newborn mice were exposed to unpredictable MS (MSU) daily from day 7 to day 20 of life, with intragastric administration of DSM 17938 or PBS as control. Body weight, brain levels of cholecystokinin (CCK), glial fibrillary acidic protein (GFAP), corticosterone, and stool microbiota were assessed at day 21. Behaviour tests including Y-maze (YMT), Tail Suspension (TST), and Open Field (OFT) were evaluated in adult mice. MSU resulted in a decrease in early postnatal growth, which improved with DSM 17938. Reduced CCK and increased corticosterone brain levels due to MSU were reversed by DSM 17938. GFAP levels increased with MSU, indicating that the decreased brain CCK was likely secondary to neuronal damage. DSM 17938 treated offspring demonstrated better cognitive function and less anxious behaviour in adult behaviour tests. DSM 17398 corrected stress related gut microbial dysbiosis. In conclusion, early life modulation of gut microbiota by DSM 17938 had beneficial effects on stress-associated physical and biochemical changes caused by MS in neonates and on subsequent adult behaviour.

The current approaches for detecting most colorectal polyps and early neoplasms lack sufficient sensitivity and specificity, potentially hindering treatment and ultimately reducing survival rates. Here, we performed a metagenomic analysis to identify microbiome markers in stool samples from patients with early-stage colorectal cancer (CRC). We compared the composition of gut microbiota between patients with CRC and healthy individuals, specifically focusing on patients with early-stage CRC, defined as those without core mutations (KRAS, BRAF) for CRC diagnosis, stable microsatellite instability, and distant metastasis. The aim of our study is to identify potential biomarkers from gut microbiota at different cancer stages in colorectal cancer (CRC) patients through 16S rRNA amplicon sequencing, thereby proposing a novel non-invasive method for the early diagnosis of CRC. Specific microbes were detected from groups divided based on the TNM criteria, with one group classified by tumour size only (named the T group) and another group with lymph node metastasis (named the TN group). Aerobic bacteria, such as Delftia, Stenotrophomonas, Sphingobacterium, Rhodococcus, Devosia, Ensifer, and Psychrobacter were predominantly detected in patients with CRC without lymph node metastasis. The diagnostic prediction was evaluated using the CatBoost algorithm; these microbes presented high diagnostic accuracy with a receiver operating characteristics-area under curve of 0.8, which was validated using qPCR. In conclusion, this study identified specific aerobic microbial groups as non-invasive biomarkers for early diagnosis in patients with CRC without genetic or environmental factors.

Perinatal antibiotic exposure potentially leads to gut microbiota dysbiosis, which is associated with functional gastrointestinal disorders (FGIDs). We aimed to investigate the effects of Limosilactobacillus reuteri DSM 17938 supplementation on the development of FGIDs, crying and sleep duration, and the gut microbial composition in infants exposed to antibiotics during the neonatal period. In this randomised, double-blind, placebo-controlled study, we included 89 term neonates treated with antibiotics. Neonates received the study product for six weeks. FGIDs, assessed by the Infant Gastrointestinal Symptom Questionnaire, crying and sleep duration were assessed at four and eight weeks, and six months after enrolment. Faecal samples were collected six weeks and twelve months after enrolment. The gut microbial community composition was analysed using 16S amplicon sequencing and qPCR. The proportion of infants with FGIDs was greater in the control group, although the difference between the groups was significant only six months after enrolment. At all time points, the probiotic group presented a longer sleep duration and shorter crying time than the control group, but the difference was not statistically significant. Probiotic consumption had no significant effect on the gut microbiota composition except for increased L. reuteri DSM 17938 abundance in the probiotic group at six weeks after enrolment. At specific time points after supplementation with L. reuteri DSM 17938, a reduction in the prevalence of FGIDs was observed in the probiotic group. However, no observable effect on the gut microbiota was detected during the intervention. We believe that probiotic supplementation in neonates during and after antibiotic treatment to minimise the negative effects of antibiotics on gut function during this vulnerable period of human development warrants further investigation. The trial is registered at ClinicalTrials.gov (NCT02865564).

Colon target delivery of active ingredients is frequently applied in pharmaceutical products. However, in functional food and beverage applications, dietary supplements, and medical nutrition, formats targeting colonic delivery to improve human health are rare. Nevertheless, there is emerging evidence for beneficial effects of colonic delivered nutrients on gut microbiota and host health which increases the demand for sustainable food grade materials that are regulatory approved for application. In this paper, we describe a double layer coated multi-unit particle system (MUPS) with a diameter of approximately 730 microns consisting of food grade materials: shellac as outer layer, alginate as inner layer, cellulose as a core and riboflavin as active ingredient. The suitability of the MUPS for colonic delivery was tested in three well-established in vitro digestion and fermentation models: the USP Apparatus 3 and the TNO Intestinal Models 1 and 2 (TIM-1 and TIM-2). All systems confirmed the integrity of the MUPS under simulated upper gastrointestinal tract conditions with approximately 90% of the active ingredient being released under simulated ileal-colonic conditions. The TIM-2 model also showed the effects of riboflavin loaded MUPS on the microbiome composition with an increase in the production of short-chain fatty acids, acetate and butyrate. The results of these experiments provide a reliable basis for validation of this vitamin-loaded food grade MUPS in future human clinical trials. In addition, following the recent announcement of the European Commission to restrict intentionally added microplastics to products, the materials used in the described formulation offer an environmentally friendly alternative to often applied methyl acrylate based coatings.

Stress significantly affects gastrointestinal and mental health, and the gut microbiota plays a pivotal role in this process. Enterococcus faecalis strain EC-12 (EC-12) is a lactic acid bacterium that has several health benefits. To investigate the impact of oral supplementation with heat-killed EC-12 on the discomfort caused by stress, a randomised, double-blind, placebo-controlled trial was conducted with students under academic stress taking EC-12 (n = 14) or a placebo (n = 13) daily for one week. Improvement in the students' symptoms was assessed using the visual analogue scale. Faecal microbiota was characterised by next-generation sequencing of 16S rRNA genes, and faecal metabolites and short-chain fatty acids were analysed using a GC-MS metabolomics approach. Significant improvements in abdominal pain and rumbling of the stomach were found in the EC-12 group compared to the placebo group, but no changes were observed in mental symptoms or salivary cortisol levels. The relative abundance of E. faecalis significantly increased in the EC-12 group after the trial; however, the composition and diversity of the gut microbiota did not change significantly. Functional analysis of the gut microbiota suggested that EC-12 intake alters specific metabolic pathways. Although the levels of faecal short-chain fatty acids did not change between the groups before and after the trial, EC-12 intake altered the composition of faecal metabolites, with a significant increase in tryptamine levels. The ratio of students with improved symptoms to those with increased tryptamine levels was calculated based on the number of students with elevated faecal tryptamine levels who showed symptomatic improvements. The ratio of improved rumbling stomach was higher than that of other types of digestive discomfort. These results suggest that oral supplementation with EC-12 has a potentially beneficial effect on stress-induced gastrointestinal discomfort, which may occur through alterations in gut microbiota composition and metabolism. This study was registered at the University Hospital Medical Information Network Center (UMIN) under the UMIN ID: UMIN000048184.

Cow's milk protein allergy (CMPA) in infancy is associated with intestinal microbial dysbiosis, characterised by low Bifidobacteriaceae levels. The present study aimed to investigate the impact of two human milk oligosaccharides (HMO), lactose (L), and their combination on the faecal microbiome and metabolome of infants with CMPA. Stool samples of 12 term infants with probable CMPA (mean age 4.3 months) were analysed using a validated intestinal fermentation assay (SIFR® technology). For each substrate (i.e. HMO (2'-fucosyllactose [2'-FL] and lacto-N-neotetraose [LNnT]), L and HMO + L), taxonomic microbiome characterisation and untargeted metabolite profiling were performed at multiple timepoints. At baseline, the tested faecal microbiota overall displayed low abundances of Bifidobacteriaceae. Fermentation with either HMO or lactose significantly enriched Bifidobacterium breve, Bifidobacterium longum, Bifidobacterium pseudocatenulatum and, for HMO + L, also Bifidobacterium bifidum. The increase in HMO-utilising bifidobacteria was associated with a significant rise in levels of short-chain fatty acids, aromatic lactic acids and N-acetylated amino acids, with additive effects being observed for HMO + L. The above data suggest that the combination of 2'-FL, LNnT and lactose helps to alleviate the previously reported CMPA-associated intestinal bacterial dysbiosis and induces the production of several beneficial metabolites. The clinical significance of these findings for infants with CMPA requires further investigation.