Proteomics,human gut microbiota and probiotics

The various bacterial communities associated with humans have many functions and the gut microbiota has a major role in the host. Bacterial imbalance in the gut, known as dysbiosis, has therefore been linked to several diseases. Probiotics, that is, microbial strains that have beneficial effects on the host, are thought to benefit this intestinal ecosystem. Hence, knowledge of the gut microbiota composition and an understanding of its functionalities are of interest. Recently, efforts have focused on developing new high-throughput techniques for studying microbial cells and complex communities. Among them, proteomics is increasingly being used. The purpose of this article is to focus on the recent development of this technology and its usefulness in analyzing the human gut ecosystem and probiotic strains.     

Probiotic Bifidobacterium bifidum G9‐1 ameliorates phytohemagglutinin‐induced diarrhea caused by intestinal dysbiosis

Diarrhea is largely caused by dysbiosis accompanying the hyperproliferation of Escherichia coli (E. coli). While current treatments can resolve the symptoms, they cannot suppress the proliferation of pathogenic bacteria in the intestine. Probiotics have numerous beneficial effects on host health, including restoring the balance of the intestinal microbiota. This study investigated the effect of the probiotic Bifidobacterium bifidum G9‐1 (BBG9‐1), which is active in intestinal dysbiosis, in the incidence of diarrhea, in the composition of the intestinal microbiota, and in the intestinal tissue of a rat model of phytohemagglutinin (PHA)‐induced diarrhea. The rats were treated with PHA, with and without BBG9‐1, and the microbiota composition throughout the intestine and stool was examined using high‐throughput 16S rRNA sequencing. In line with previous reports, PHA administration caused diarrhea as well as dysbiosis due to E. coli hyperproliferation. Histological findings indicated that the jejunal villus length was shortened. Rats that received BBG9‐1 showed clear improvements in dysbiosis, diarrhea symptoms, and jejunal villus length. Principal coordinates analysis demonstrated the microbiota profile to be more similar between the BBG9‐1 and normal groups than between the PHA and normal groups. These results indicated that BBG9‐1 suppresses the hyperproliferation of E. coli and restores the jejunal villus length, thereby improving dysbiosis, and in turn, alleviating the symptoms of diarrhea.     

Proteomics, human gut microbiota and probiotics

The various bacterial communities associated with humans have many functions and the gut microbiota has a major role in the host. Bacterial imbalance in the gut, known as dysbiosis, has therefore been linked to several diseases. Probiotics, that is, microbial strains that have beneficial effects on the host, are thought to benefit this intestinal ecosystem. Hence, knowledge of the gut microbiota composition and an understanding of its functionalities are of interest. Recently, efforts have focused on developing new high-throughput techniques for studying microbial cells and complex communities. Among them, proteomics is increasingly being used. The purpose of this article is to focus on the recent development of this technology and its usefulness in analyzing the human gut ecosystem and probiotic strains.     

Cervicovaginal microbiome dynamics after taking oral probiotics

The vaginal microbiota is less complex than the gut microbiota, and the colonization of Lactobacillus in the female vagina is considered to be critical for reproductive health. Oral probiotics have been suggested as promising means to modulate vaginal homeostasis in the general population. In this study, 60 Chinese women were followed for over a year before, during, and after treatment with the probiotics Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14. Shotgun metagenomic data of 1334 samples from multiple body sites did not support a colonization route of the probiotics from the oral cavity to the intestinal tract and then to the vagina. Our analyses enable the classification of the cervicovaginal microbiome into a stable state and a state of dysbiosis. The microbiome in the stable group steadily maintained a relatively high abundance of Lactobacilli over one year, which was not affected by probiotic intake, whereas in the dysbiosis group, the microbiota was more diverse and changed markedly over time. Data from a subset of the dysbiosis group suggests this subgroup possibly benefited from supplementation with the probiotics,indicating that probiotics supplementation can be prescribed for women in a subclinical microbiome setting of dysbiosis, providing opportunities for targeted and personalized microbiome reconstitution.     

益生菌以及益生元在肥胖及其代谢综合征中的潜在作用

肥胖以及相关的代谢综合征已经成为全球性的公共健康问题。大量的研究表明,肥胖形成以及减肥过程均与肠道菌群密切相关且相互影响。肠道菌群以及弱炎症反应成为肥胖以及相关代谢综合征的两大重要影响因素。本文综述了近几年来,肠道菌群失调对宿主能量储存以及新陈代谢的影响,以及弱炎症反应对肥胖引起的代谢综合征的影响。大量的研究证明,益生元有助于益生菌的生长,而益生菌可以调节肠道菌群以及改善肠道内弱炎症反应,借助于益生菌以及益生元的方法也许能为由肠道菌群失调以及弱炎症反应引起的肥胖及其代谢综合征提供一种新的治疗方法。     

Probiotic and other functional microbes: from markets to mechanisms

Insight into the diversity and function of the human intestinal microbiota has been stimulated by clinical studies with bacteria that exhibit specific functions and which are marketed as probiotics to positively affect our health. Initial efforts concentrated on establishing sound scientific support for the efficacy of these probiotic bacteria, which mainly include Lactobacillus and Bifidobacterium species. Following these evidence-based functional approaches, considerable research is now focused on the mechanisms of action of probiotic bacteria. The mechanisms identified to date mainly relate to the stimulation of host defence systems, immune modulation and the competitive exclusion of pathogens. Recent efficacy, molecular and genomics-based studies have also been reported for some probiotic strains that have found their position in the market place.     

Intestinal anti-inflammatory effect of the probiotic Saccharomyces boulardii in DSS-induced colitis in mice: Impact on microRNAs expression and gut microbiota composition

The beneficial effects exerted by probiotics in inflammatory bowel disease (IBD) are well known, although their exact mechanisms have not been fully elucidated, and only few studies have focused on their impact on selected miRNAs and the gut microbiota composition. Therefore, our aim was to correlate the intestinal anti-inflammatory activity of the probiotic Saccharomyces boulardii in the dextran sodium sulphate (DSS) model of mouse colitis and the changes induced in miRNA expression and gut microbiota populations. Probiotic was given orally (5×10⁹ CFU) to C57BL/6 mice for 26 days. After 2 weeks, the colitis was induced adding DSS to the drinking water. Mice were scored daily using a Disease Activity Index (DAI). After sacrifice, the colonic specimens were evaluated by determining the expression of inflammatory markers and micro-RNAs by qRT-PCR. Moreover, changes in microbiota populations were evaluated by pyrosequencing. Probiotic ameliorated the colonic damage induced by DSS, as evidenced by lower DAI values and colonic weight/length compared with untreated mice. The treatment modified the colonic expression of different inflammatory markers and the epithelial integrity proteins, and induced changes in micro-RNAs expression. Moreover, microbiota characterization showed that probiotic treatment increased bacterial diversity, thus ameliorating the dysbiosis produced by DSS-colitis. Saccharomyces boulardii exerted intestinal anti-inflammatory effects in DSS-mouse colitis, through the modulation in the immune response, involving modification of altered miRNA expression, being associated to the improvement of the inflammation-associated dysbiosis in the intestinal lumen, which could be of great interest to control the complex pathogenesis of IBD.     

Role of commercial probiotic strains against human pathogen adhesion to intestinal mucus

AIMS: The aims of this study present were to assess and to evaluate in vitro the abilities of commercial probiotic strains derived from fermented milk products and related sources currently marketed in European countries, to inhibit, compete and displace the adhesion of selected potential pathogens to immobilized human mucus. METHODS AND RESULTS: The adhesion was assessed by measuring the radioactivity of bacteria adhered to the human mucus. We tested 12 probiotic strains against eight selected pathogens. All strains tested were able to adhere to mucus. All probiotic strains tested were able to inhibit and displace (P<0.05) the adhesion of Bacteroides, Clostridium, Staphylococcus and Enterobacter. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting that several complementary mechanisms are implied in the processes. CONCLUSIONS: Our results indicate the need for a case-by-case assessment in order to select strains with the ability to inhibit or displace a specific pathogen. Probiotics could be useful to correct deviations observed in intestinal microbiota associated with specific diseases and also, to prevent pathogen infections. SIGNIFICANCE AND IMPACT OF THE STUDY: The competitive exclusion properties of probiotics as well as their ability to displace and inhibit pathogens are the most importance for therapeutic manipulation of the enteric microbiota. The application of such strategies could contribute to expand the beneficial properties on human health against pathogen infection.     

PCR and real-time PCR primers developed for detection and identification of <Emphasis Type="Italic">Bifidobacterium thermophilum</Emphasis>in faeces

Background  

Culture-independent methods based on the 16S ribosomal RNA molecule are nowadays widely used for assessment of the composition of the intestinal microbiota, in relation to host health or probiotic efficacy. Because Bifidobacterium thermophilum was only recently isolated from human faeces until now, no specific real-time PCR (qPCR) assay has been developed for detection of this species as component of the bifidobacterial community of the human intestinal flora.     

益生菌在血糖调控中的研究进展

随着经济的快速发展和人们生活方式的改变,糖尿病等代谢性疾病的发病率在全球范围急剧上升,特别是在我国形势尤其严峻。以往研究结果表明,肠道微生物与人体健康密切相关,糖尿病患者的菌群结构与健康人群存在显著差别。益生菌疗法由于具有低成本、高安全性和高可靠性的特点,在疾病预防和重塑肠道微生态健康方面具有良好的应用前景,逐渐成为糖尿病防治的研究热点。本文系统地阐述了血糖调控益生菌的基础研究和应用开发进展,为血糖调控益生菌制剂及相关功能性食品的开发提供理论参考和指导依据。     

肠道菌群失衡与乳糜泻:重要性及可能机制

乳糜泻(Celiac disease,CeD)是基因易感人群摄入麸质后所发生的一种自身免疫性肠道疾病.越来越多证据表明,"第二人类基因组"——肠道菌群参与了CeD的发生与发展.相对于健康人群,CeD患者的肠道菌群多样性虽然增高,但有益菌减少,促炎细菌增多,并伴随菌群功能及代谢状态的改变.然而,这种菌群失衡是如何发生的,...     

The potential for probiotic manipulation of the gastrointestinal microbiome

Multiple internal and external sites of the healthy human body are colonized by a diversity of symbiotic microbes. The microbial assemblages found in the intestine represent some of the most dense and diverse of these human-associated ecosystems. Unsurprisingly, the enteric microbiome, that is the totality of microbes, their combined genomes, and their interactions with the human body, has a profound impact on physiological aspects of mammalian function, not least, host immune response. Lack of early-life exposure to certain microbes, or shifts in the composition of the gastrointestinal microbiome have been linked to the development and progression of several intestinal and extra-intestinal diseases, including childhood asthma development and inflammatory bowel disease. Modulating microbial exposure through probiotic supplementation represents a long-held strategy towards ameliorating disease via intestinal microbial community restructuring. This field has experienced somewhat of a resurgence over the past few years, primarily due to the exponential increase in human microbiome studies and a growing appreciation of our dependence on resident microbiota to modulate human health. This review aims to review recent regulatory aspects related to probiotics in food. It also summarizes what is known to date with respect to human gastrointestinal microbiota - the niche which has been most extensively studied in the human system - and the evidence for probiotic supplementation as a viable therapeutic strategy for modulating this consortium.     

The Yin and Yang of Bacterial Resilience in the Human Gut Microbiota

The human gut is home to trillions of microbes that form a symbiotic relationship with the human host. During health, the intestinal microbiota provides many benefits to the host and is generally resistant to colonization by new species; however, disruption of this complex community can lead to pathogen invasion, inflammation, and disease. Restoration and maintenance of a healthy gut microbiota composition requires effective therapies to reduce and prevent colonization of harmful bacteria (pathogens) while simultaneously promoting growth of beneficial bacteria (probiotics). Here we review the mechanisms by which the host modulates the gut community composition during health and disease, and we discuss prospects for antibiotic and probiotic therapy for restoration of a healthy intestinal community following disruption.     

Effect of Lactobacillus salivarius bacteriocin Abp118 on the mouse and pig intestinal microbiota

Lactobacilli are gram-positive bacteria that are a subdominant element in the human gastrointestinal microbiota, and which are commonly used in the food industry. Some lactobacilli are considered probiotic, and have been associated with health benefits. However, there is very little culture-independent information on how consumed probiotic microorganisms might affect the entire intestinal microbiota. We therefore studied the impact of the administration of Lactobacillus salivarius UCC118, a microorganism well characterized for its probiotic properties, on the composition of the intestinal microbiota in two model animals. UCC118 has anti-infective activity due to production of the bacteriocin Abp118, a broad-spectrum class IIb bacteriocin, which we hypothesized could impact the microbiota. Mice and pigs were administered wild-type (WT) L. salivarius UCC118 cells, or a mutant lacking bacteriocin production. The microbiota composition was determined by pyrosequencing of 16S rRNA gene amplicons from faeces. The data show that L. salivarius UCC118 administration had no significant effect on proportions of major phyla comprising the mouse microbiota, whether the strain was producing bacteriocin or not. However, L. salivarius UCC118 WT administration led to a significant decrease in Spirochaetes levels, the third major phylum in the untreated pig microbiota. In both pigs and mice, L. salivarius UCC118 administration had an effect on Firmicutes genus members. This effect was not observed when the mutant strain was administered, and was thus associated with bacteriocin production. Surprisingly, in both models, L. salivarius UCC118 administration and production of Abp118 had an effect on gram-negative microorganisms, even though Abp118 is normally not active in vitro against this group of microorganisms. Thus L. salivarius UCC118 administration has a significant but subtle impact on mouse and pig microbiota, by a mechanism that seems at least partially bacteriocin-dependent.     

Dairy propionibacteria as probiotics: recent evidences

Nowdays there is evidence that dairy propionibacteria display probiotic properties, which as yet have been underestimated. The aim of this paper is to review the recent highlights of data representing the probiotic potential of dairy propionibacteria, studied both by general selection criteria (useful for all probiotic potentials), and by more specific and innovative approach. Dairy propionibacteria show a robust nature, that makes them able to overcome technological hurdles, allowing their future use in various fermented probiotic foods. In addition to the general selection criteria for probiotics in areas such as food safety, technological and digestive stress tolerance, many potential health benefits have been recently described for dairy propionibacteria, including, production of several active molecules and adhesion capability, that can mean a steady action in modulation of microbiota and of metabolic activity in the gut; their impact on intestinal inflammation, modulation of the immune system, potential modulation of risk factors for cancer development modulation of intestinal absorption.     

Synthetic microbial consortia for the treatment of Clostridioides difficile infection in mice model

Clostridioides difficile infection (CDI) as of recent has become a great concern to the impact on human health due to its high hazardous risk and rate of recurrence. Live bacterial therapeutics is a promising method to treat or prevent CDI. Here, a synthetic microbial consortia (SMC) B10 was constructed using probiotic strains with antibacterial and anti-quorum sensing activities, and the therapeutic effect of SMC B10 against C. difficile infection was evaluated in vitro. Compared to the model group, the treatment of SMC B10 significantly increased the survival rate. The clinical signs of mice were significantly ameliorated, especially the cecum injury, while the secretion of pro-inflammatory associated cytokines such as IL-1α, IL-6, IL-17A and TNF-α was reduced, the expression of TLR4 was inhibited, which alleviated the inflammatory response, and the expression of the tight junction protein Claudin-1 was increased, ultimately promoting the recovery of host health. The treatment of B10 restored gut microbiota dysbiosis and led to a healthy intestinal microbiota structure, significantly improved alpha diversity, suppressing potentially harmful bacteria and restoring other core bacterial species. In conclusion, SMC B10 can effectively treat CDI through modulate gut microbiota and attenuate the inflammatory response.     

A review on prebiotics and probiotics for the control of dysbiosis: present status and future perspectives

Dysbiosis or dysbacteriosis is defined as a shift in the intestinal microbiota composition resulting in an imbalance between beneficial and harmful bacteria. Since the ban on the use of growth-promoting antibiotics in animal feed in the EU, dysbiosis has emerged as a major problem in intensive animal production. Prebiotics and probiotics are currently under investigation as possible alternatives to growth-promoting antibiotics, as their mode of action is thought to be based largely on a modulation of the composition and function of the intestinal microbiota. In this review, we analyse the currently available data from both animal and human nutrition that document the potential and limitations of prebiotics and probiotics for the control of dysbiosis. An impressive number of empirical feeding trials have been carried out in healthy animals, yielding sometimes contradictory results. More in-depth studies have revealed the complexity of the interactions taking place in the lower intestinal tract, thus illustrating that pre- and probiotics cannot be a simple replacement for growth-promoting antibiotics. Although there are indications that the strategic use of pre- and probiotics can provide major benefits, there is still a lack of basic knowledge on the delicate interactions between the microbiota, the host and the feed components, which hampers the widespread use of these valuable feed additives.     

Current understanding of microbiota- and dietary-therapies for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a result of chronic inflammation caused, in some part, by dysbiosis of intestinal microbiota, mainly commensal bacteria. Gut dysbiosis can be caused by multiple factors, including abnormal immune responses which might be related to genetic susceptibility, infection, western dietary habits, and administration of antibiotics. Consequently, the disease itself is characterized as having multiple causes, etiologies, and severities. Recent studies have identified >200 IBD risk loci in the host. It has been postulated that gut microbiota interact with these risk loci resulting in dysbiosis, and this subsequently leads to the development of IBD. Typical gut microbiota in IBD patients are characterized with decrease in species richness and many of the commensal, and beneficial, fecal bacteria such as Firmicutes and Bacteroidetes and an increase or bloom of Proteobacteria. However, at this time, cause and effect relationships have not been rigorously established. While treatments of IBD usually includes medications such as corticosteroids, 5-aminosalicylates, antibiotics, immunomodulators, and anti-TNF agents, restoration of gut dysbiosis seems to be a safer and more sustainable approach. Bacteriotherapies (now called microbiota therapies) and dietary interventions are effective way to modulate gut microbiota. In this review, we summarize factors involved in IBD and studies attempted to treat IBD with probiotics. We also discuss the potential use of microbiota therapies as one promising approach in treating IBD. As therapies based on the modulation of gut microbiota becomes more common, future studies should include individual gut microbiota differences to develop personalized therapy for IBD.     

肠道真菌研究进展

真菌菌群是肠道菌群的重要组成部分,在肠道微生态稳态的维持和宿主的免疫调节中发挥重要作用。肠道真菌失调通常和肠道疾病甚至肠道外疾病有关。本文就肠道真菌的定殖与组成、真菌菌群对肠道微生态的调控、菌群失调促进疾病的发展机制、基于肠道真菌的治疗策略和肠道真菌的鉴定分析方法等方面的进展进行了综述和展望,旨在系统认识肠道真菌调节宿主健康和促进疾病发生的机制,为相关疾病的诊断和治疗提供重要参考。     

Intratumor microbiota: Occult participants in the microenvironment of multiple myeloma

More recently, microbiota was detected in several tumorous tissues including multiple myeloma (MM), but the roles of which is still under-studied as paucity of research on tumor biology. Moreover, we also detected the presence of microbiota in the bone marrow of patients with MM by 2bRAD-M sequencing technology, which is an incurable hematological malignancy characterized by accumulation of abnormal plasma cells in the bone marrow. However, the roles of intratumor microbiota in tumor disease remains poorly understood. In this review, we critically reviewed recent literature about microbiota in the tumorigenesis and progression of MM. Importantly, we proposed that the emergence of microbiota in the microenvironment of multiple myeloma may be attributed to microbial dysbiosis and impaired intestinal barrier, due to the increased prevalence of MM in patients with obesity and diabetes, of which the characteristic phenotype is gut microbial dysbiosis and impaired intestinal barrier. When the intestinal barrier is damaged, dysbiotic microbiota and their metabolites, as well as dysregulated immune cells, may participate in the reshaping of the local immune microenvironment, and play pivotal roles in the tumorigenesis and development of multiple myeloma, probably by migrating to the bone marrow microenvironment from intestine. We also discuss the emerging microbiological manipulation strategies to improve long-term outcomes of MM, as well as the prospective of the state-of-the-art techniques to advance our knowledge about the biological implication in the microbiome in MM.