in the Human Gut: Dynamics and Ecological Roles in Health and Disease.

The human gut microbiota plays a crucial role in maintaining host health. Our review explores the prevalence and dynamics of , a bacterial family within the Proteobacteria phylum, in the human gut which represents a small fraction of the gut microbiota in healthy conditions. Even though their roles are not yet fully understood, and especially () play a part in creating an anaerobic environment, producing vitamins and protecting against pathogenic infections.

Design and validation of a dual-fluorescence reporter system to monitor bacterial gene expression in the gut environment.

Fluorescence-based reporter systems are valuable tools for studying gene expression dynamics in living cells. However, available strategies to follow gene expression in bacteria within their natural ecosystem that can be typically rich and complex are scarce. In this work, we designed a plasmid-based tool ensuring both the identification of a strain of interest in complex environments and the monitoring of gene expression through the combination of two distinct fluorescent proteins as reporter genes.

A proof of concept infant-microbiota associated rat model for studying the role of gut microbiota and alleviation potential of in infant colic.

Establishing the relationship between gut microbiota and host health has become a main target of research in the last decade. Human gut microbiota-associated animal models represent one alternative to human research, allowing for intervention studies to investigate causality. Recent cohort and studies proposed an altered gut microbiota and lactate metabolism with excessive H production as the main causes of infant colic.

Diversity of ethanolamine utilization by human commensal Escherichiacoli.

Ethanolamine (EA) is a substrate naturally present in the human gut and its catabolism by bacteria relies on the presence of eut genes encoding specific metabolic enzymes and accessory proteins. To date, EA utilization has been mostly investigated in gut bacterial pathogens. The aim of this study was to evaluate the ability of human gut commensal Escherichia coli isolates to utilize EA as a nitrogen and/or carbon sources.

Milk polar lipids favorably alter circulating and intestinal ceramide and sphingomyelin species in postmenopausal women.

BACKGROUNDHigh circulating levels of ceramides (Cer) and sphingomyelins (SM) are associated with cardiometabolic diseases. The consumption of whole fat dairy products, naturally containing such polar lipids (PL), is associated with health benefits, but the impact on sphingolipidome remains unknown.METHODSIn a 4-week randomized controlled trial, 58 postmenopausal women daily consumed milk PL-enriched cream cheese (0, 3, or 5 g of milk PL).

Characterisation of microbiota in saliva, bronchoalveolar lavage fluid, non-malignant, peritumoural and tumour tissue in non-small cell lung cancer patients: a cross-sectional clinical trial.

Background: While well-characterised on its molecular base, non-small cell lung cancer (NSCLC) and its interaction with local microbiota remains scarcely explored. Moreover, current studies vary in source of lung microbiota, from bronchoalveolar lavage fluid (BAL) to tissue, introducing potentially differing results. Therefore, the objective of this study was to provide detailed characterisation of the oral and multi-source lung microbiota of direct interest in lung cancer research.

Milk polar lipids reduce lipid cardiovascular risk factors in overweight postmenopausal women: towards a gut sphingomyelin-cholesterol interplay.

Objective: To investigate whether milk polar lipids (PL) impact human intestinal lipid absorption, metabolism, microbiota and associated markers of cardiometabolic health.

Design: A double-blind, randomised controlled 4-week study involving 58 postmenopausal women was used to assess the chronic effects of milk PL consumption (0, 3 or 5 g-PL/day) on lipid metabolism and gut microbiota. The acute effects of milk PL on intestinal absorption and metabolism of cholesterol were assessed in a randomised controlled crossover study using tracers in ileostomy patients.

Characterisation of gut, lung, and upper airways microbiota in patients with non-small cell lung carcinoma: Study protocol for case-control observational trial.

Background: Several studies have confirmed the important role of the gut microbiota in the regulation of immune functions and its correlation with different diseases, including cancer. While brain-gut and liver-gut axes have already been demonstrated, the existence of a lung-gut axis has been suggested more recently, with the idea that changes in the gut microbiota could affect the lung microbiota, and vice versa. Likewise, the close connection between gut microbiota and cancer of proximal sites (intestines, kidneys, liver, etc.

Mixed mucosal-parenteral immunizations with the broadly conserved pathogenic Escherichia coli antigen SslE induce a robust mucosal and systemic immunity without affecting the murine intestinal microbiota.

Emergence and dissemination of multidrug resistance among pathogenic Escherichia coli have posed a serious threat to public health across developing and developed countries. In combination with a flexible repertoire of virulence mechanisms, E. coli can cause a vast range of intestinal (InPEC) and extraintestinal (ExPEC) diseases but only a very limited number of antibiotics still remains effective against this pathogen.

Desired Turbulence? Gut-Lung Axis, Immunity, and Lung Cancer.

The microbiota includes different microorganisms consisting of bacteria, fungi, viruses, and protozoa distributed over many human body surfaces including the skin, vagina, gut, and airways, with the highest density found in the intestine. The gut microbiota strongly influences our metabolic, endocrine, and immune systems, as well as both the peripheral and central nervous systems. Recently, a dialogue between the gut and lung microbiota has been discovered, suggesting that changes in one compartment could impact the other compartment, whether in relation to microbial composition or function.

Polysaccharide utilization loci and nutritional specialization in a dominant group of butyrate-producing human colonic .

and are the predominant bacterial phyla colonizing the healthy human large intestine. Whilst both ferment dietary fibre, genes responsible for this important activity have been analysed only in the , with very little known about the . This work investigates the carbohydrate-active enzymes (CAZymes) in a group of , spp.

The human intestinal microbiota of constipated-predominant irritable bowel syndrome patients exhibits anti-inflammatory properties.

The intestinal microbiota of patients with constipated-predominant irritable bowel syndrome (C-IBS) displays chronic dysbiosis. Our aim was to determine whether this microbial imbalance instigates perturbation of the host intestinal mucosal immune response, using a model of human microbiota-associated rats (HMAR) and dextran sulfate sodium (DSS)-induced experimental colitis. The analysis of the microbiota composition revealed a decrease of the relative abundance of Bacteroides, Roseburia-Eubacterium rectale and Bifidobacterium and an increase of Enterobacteriaceae, Desulfovibrio sp.

Metabolic adaptations to HFHS overfeeding: how whole body and tissues postprandial metabolic flexibility adapt in Yucatan mini-pigs.

Purpose: In the present study, we aimed to metabolically characterize the postprandial adaptations of the major tissues involved in energy, lipids and amino acids metabolisms in mini-pigs.

Method: Mini-pigs were fed on high-fat-high-sucrose (HFHS) diet for 2 months and several tissues explored for metabolic analyses. Further, the urine metabolome was followed over the time to picture the metabolic adaptations occurring at the whole body level following overfeeding.

Effects of scFOS on the composition of fecal microbiota and anxiety in patients with irritable bowel syndrome: a randomized, double blind, placebo controlled study.

Background: Short-chain fructooligosaccharides (scFOS) have beneficial effects in subjects with minor digestive complaints, but the potential mechanisms involved have not been elucidated. The aim of the study was to evaluate changes in rectal sensitivity related to the clinical effects of scFOS in a selected group of patients with irritable bowel syndrome (IBS) and rectal hypersensitivity.

Methods: In 79 IBS patients (defined by Rome III criteria) with rectal hypersensitivity (defined as discomfort threshold ≤44 g) a parallel, placebo-controlled, randomized, and double-blind study was performed to assess the effects of dietary supplementation (5 g d ) with scFOS vs placebo for 4 weeks on rectal sensitivity (primary outcome: tolerance to increasing wall tension applied by a tensostat), clinical outcomes (IBS, anxiety/depression and quality of life scores) and composition of fecal microbiota.

Western diet induces a shift in microbiota composition enhancing susceptibility to Adherent-Invasive E. coli infection and intestinal inflammation.

Recent advances have shown that the abnormal inflammatory response observed in CD involves an interplay among intestinal microbiota, host genetics and environmental factors. The escalating consumption of fat and sugar in Western countries parallels an increased incidence of CD during the latter 20(th) century. The impact of a HF/HS diet in mice was evaluated for the gut micro-inflammation, intestinal microbiota composition, function and selection of an E.

Effect of Bifidobacterium thermophilum RBL67 and fructo-oligosaccharides on the gut microbiota in Göttingen minipigs.

Modulating the gut microbiota via dietary interventions is a common strategy to enhance the natural defence mechanisms of the host. Several in vitro studies have highlighted the probiotic potential of Bifidobacterium thermophilum RBL67 (RBL67) selected for its anti-Salmonella effects. The present study aimed to investigate the impact of RBL67 alone and combined with fructo-oligosaccharides (FOS) on the gut microbiota of Göttingen minipigs.

Ruminococcal cellulosome systems from rumen to human.

A cellulolytic fiber-degrading bacterium, Ruminococcus champanellensis, was isolated from human faecal samples, and its genome was recently sequenced. Bioinformatic analysis of the R. champanellensis genome revealed numerous cohesin and dockerin modules, the basic elements of the cellulosome, and manual sequencing of partially sequenced genomic segments revealed two large tandem scaffoldin-coding genes that form part of a gene cluster.

Increasing fat content from 20 to 45 wt% in a complex diet induces lower endotoxemia in parallel with an increased number of intestinal goblet cells in mice.

The impacts of high-fat diets (HFDs) on the onset of metabolic endotoxemia and low-grade inflammation are well established in rodent models. However, the dose-effect of dietary lipid intakes on these parameters is not known. We hypothesized that increasing dietary lipid amounts could be linked to parallel increases of endotoxemia, low-grade inflammation, and metabolic and intestinal alterations.

Transcriptome analysis of Escherichia coli O157:H7 grown in vitro in the sterile-filtrated cecal content of human gut microbiota associated rats reveals an adaptive expression of metabolic and virulence genes.

In developed countries, enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a leading cause of bloody diarrhea and renal failures in human. Understanding strategies employed by EHEC to colonize the intestine is of major importance since to date no cure exists to eradicate the pathogen. In this study, the adaptive response of EHEC to the intestinal milieu conditioned by a human microbiota was examined.

Iron supplementation promotes gut microbiota metabolic activity but not colitis markers in human gut microbiota-associated rats.

The global prevalence of Fe deficiency is high and a common corrective strategy is oral Fe supplementation, which may affect the commensal gut microbiota and gastrointestinal health. The aim of the present study was to investigate the impact of different dietary Fe concentrations on the gut microbiota and gut health of rats inoculated with human faecal microbiota. Rats (8 weeks old, n 40) were divided into five (n 8 each) groups and fed diets differing only in Fe concentration during an Fe-depletion period (12 weeks) and an Fe-repletion period (4 weeks) as follows: (1) Fe-sufficient diet throughout the study period; (2) Fe-sufficient diet followed by 70 mg Fe/kg diet; (3) Fe-depleted diet throughout the study period; (4) Fe-depleted diet followed by 35 mg Fe/kg diet; (5) Fe-depleted diet followed by 70 mg Fe/kg diet.

The hypersensitivity to colonic distension of IBS patients can be transferred to rats through their fecal microbiota.

Background: Alterations of intestinal microbiota and hypersensitivity to colonic distension are two features of the irritable bowel syndrome (IBS). However, the role of intestinal microbiota in visceral hypersensitivity of IBS patients is far to be established. The aim of our study was to determine whether the intestinal microbiota is involved in the visceral hypersensitivity in IBS.

Efficacy and safety profile of LCR35 complete freeze-dried culture in irritable bowel syndrome: a randomized, double-blind study.

Aim: To assess the effects and safety of Lactobacillus casei rhamnosus LCR35 complete freeze-dried culture (LCR35) in patients suffering from irritable bowel syndrome (IBS).

Methods: A randomized, double-blind pilot study was performed in 50 patients complaining of IBS symptoms complying with Rome III criteria. Patients were allocated to receive either LCR35 (n = 25) at a minimum daily dose of 6 × 10(8) colony forming units or placebo (n = 25) for 4 wk.

Functional dysbiosis within the gut microbiota of patients with constipated-irritable bowel syndrome.

Background: The role of the gut microbiota in patho-physiology of irritable bowel syndrome (IBS) is suggested by several studies. However, standard cultural and molecular methods used to date have not revealed specific and consistent IBS-related groups of microbes.

Aim: To explore the constipated-IBS (C-IBS) gut microbiota using a function-based approach.

Ruminococcus champanellensis sp. nov., a cellulose-degrading bacterium from human gut microbiota.

A strictly anaerobic, cellulolytic strain, designated 18P13(T), was isolated from a human faecal sample. Cells were Gram-positive non-motile cocci. Strain 18P13(T) was able to degrade microcrystalline cellulose but the utilization of soluble sugars was restricted to cellobiose.