Antioxidants of Fruit Extracts as Antimicrobial Agents against Pathogenic Bacteria.

Fruit is an essential part of the human diet and is of great interest because of its richness in phytochemicals. Various fruit extracts from citrus, berries and pomegranates have been shown to possess a broad spectrum of medicinal properties. Fruit phytochemicals are of considerable interest because of their antioxidant properties involving different mechanisms of action, which can act against different pathogenic bacteria.

Revealing microbial species diversity using sequence capture by hybridization.

Targeting small parts of the 16S rDNA phylogenetic marker by metabarcoding reveals microorganisms of interest but cannot achieve a taxonomic resolution at the species level, precluding further precise characterizations. To identify species behind operational taxonomic units (OTUs) of interest, even in the rare biosphere, we developed an innovative strategy using gene capture by hybridization. From three OTU sequences detected upon polyphenol supplementation and belonging to the rare biosphere of the human gut microbiota, we revealed 59 nearly full-length 16S rRNA genes, highlighting high bacterial diversity hidden behind OTUs while evidencing novel taxa.

Evaluating the role of orange juice, HESPERidin in vascular HEALTH benefits (HESPER-HEALTH study): protocol for a randomised controlled trial.

Introduction: Although epidemiological studies associate the consumption of sugary beverages with adverse health effects, human experimental studies have demonstrated substantially different metabolic responses when 100% fruit juices are compared with artificial beverages. Fruit juices do not just provide sugars and associated calories, but they are also rich in bioactive compounds. Flavanones are bioactives specifically and abundantly found in citrus foods, with hesperidin as the major representative in sweet oranges.

Competitions between Fibrobacter succinogenes, Ruminococcus flavefaciens, and Ruminoccus albus in a Gnotobiotic Sheep Model Revealed by Multi-Omic Analyses.

, , and are the three predominant cellulolytic bacterial species found in the rumen. studies have shown that these species compete for adherence to, and growth upon, cellulosic biomass. Yet their molecular interactions have not heretofore been examined.

Tripartite relationship between gut microbiota, intestinal mucus and dietary fibers: towards preventive strategies against enteric infections.

The human gut is inhabited by a large variety of microorganims involved in many physiological processes and collectively referred as to gut microbiota. Disrupted microbiome has been associated with negative health outcomes and especially could promote the onset of enteric infections. To sustain their growth and persistence within the human digestive tract, gut microbes and enteric pathogens rely on two main polysaccharide compartments, namely dietary fibers and mucus carbohydrates.

Procyanidin-Cell Wall Interactions within Apple Matrices Decrease the Metabolization of Procyanidins by the Human Gut Microbiota and the Anti-Inflammatory Effect of the Resulting Microbial Metabolome In Vitro.

B-type oligomeric procyanidins in apples constitute an important source of polyphenols in the human diet. Their role in health is not known, although it is suggested that they generate beneficial bioactive compounds upon metabolization by the gut microbiota. During apple processing, procyanidins interact with cell-wall polysaccharides and form stable complexes.

Food Chemicals Disrupt Human Gut Microbiota Activity And Impact Intestinal Homeostasis As Revealed By In Vitro Systems.

Growing evidence indicates that the human gut microbiota interacts with xenobiotics, including persistent organic pollutants and foodborne chemicals. The toxicological relevance of the gut microbiota-pollutant interplay is of great concern since chemicals may disrupt gut microbiota functions, with a potential impairment of host homeostasis. Herein we report within batch fermentation systems the impact of food contaminants (polycyclic aromatic hydrocarbons, polychlorobiphenyls, brominated flame retardants, dioxins, pesticides and heterocyclic amines) on the human gut microbiota by metatranscriptome and volatolome i.

FibroChip, a Functional DNA Microarray to Monitor Cellulolytic and Hemicellulolytic Activities of Rumen Microbiota.

Ruminants fulfill their energy needs for growth primarily through microbial breakdown of plant biomass in the rumen. Several biotic and abiotic factors influence the efficiency of fiber degradation, which can ultimately impact animal productivity and health. To provide more insight into mechanisms involved in the modulation of fibrolytic activity, a functional DNA microarray targeting genes encoding key enzymes involved in cellulose and hemicellulose degradation by rumen microbiota was designed.

Metatranscriptomics Reveals the Active Bacterial and Eukaryotic Fibrolytic Communities in the Rumen of Dairy Cow Fed a Mixed Diet.

Ruminants have a unique ability to derive energy from the degradation of plant polysaccharides through the activity of the rumen microbiota. Although this process is well studied , knowledge gaps remain regarding the relative contribution of the microbiota members and enzymes . The present study used RNA-sequencing to reveal both the expression of genes encoding carbohydrate-active enzymes (CAZymes) by the rumen microbiota of a lactating dairy cow and the microorganisms forming the fiber-degrading community.

Mannoside recognition and degradation by bacteria.

Mannosides constitute a vast group of glycans widely distributed in nature. Produced by almost all organisms, these carbohydrates are involved in numerous cellular processes, such as cell structuration, protein maturation and signalling, mediation of protein-protein interactions and cell recognition. The ubiquitous presence of mannosides in the environment means they are a reliable source of carbon and energy for bacteria, which have developed complex strategies to harvest them.

Xylan degradation by the human gut Bacteroides xylanisolvens XB1A(T) involves two distinct gene clusters that are linked at the transcriptional level.

Background: Plant cell wall (PCW) polysaccharides and especially xylans constitute an important part of human diet. Xylans are not degraded by human digestive enzymes in the upper digestive tract and therefore reach the colon where they are subjected to extensive degradation by some members of the symbiotic microbiota. Xylanolytic bacteria are the first degraders of these complex polysaccharides and they release breakdown products that can have beneficial effects on human health.

Increasing linseed supply in dairy cow diets based on hay or corn silage: Effect on enteric methane emission, rumen microbial fermentation, and digestion.

We investigated the effects of increasing extruded linseed supply in diets based on hay (H; experiment 1) or corn silage (CS; experiment 2) on enteric methane (CH4) emission, rumen microbial and fermentation parameters, and rumen and total-tract digestibility. In each experiment, 4 lactating Holstein cows fitted with cannulas at the rumen and proximal duodenum were used in a 4×4 Latin square design (28-d periods). Cows were fed ad libitum a diet [50:50 and 60:40 forage:concentrate on a dry matter (DM) basis for experiments 1 and 2, respectively] without supplementation (H0, CS0) or supplemented with extruded linseed at 5% (H5, CS5), 10% (H10, CS10), and 15% (H15, CS15) of dietary DM (i.

Unraveling the pectinolytic function of Bacteroides xylanisolvens using a RNA-seq approach and mutagenesis.

Background: Diet and particularly dietary fibres have an impact on the gut microbiome and play an important role in human health and disease. Pectin is a highly consumed dietary fibre found in fruits and vegetables and is also a widely used additive in the food industry. Yet there is no information on the effect of pectin on the human gut microbiome.

Live yeasts enhance fibre degradation in the cow rumen through an increase in plant substrate colonization by fibrolytic bacteria and fungi.

Aims: To monitor the effect of a live yeast additive on feedstuff colonization by targeted fibrolytic micro-organisms and fibre degradation in the cow rumen.

Methods And Results: Abundance of adhering fibrolytic bacteria and fungi on feedstuffs incubated in sacco in the cow rumen was quantified by qPCR and neutral detergent fibre (NDF) degradation was measured. Saccharomyces cerevisiae I-1077 (SC) increased the abundance of fibre-associated Fibrobacter succinogenes on wheat bran (WB) and that of Ruminococcus flavefaciens on alfalfa hay (AH) and wheat silage (WS).

Rumen cellulosomics: divergent fiber-degrading strategies revealed by comparative genome-wide analysis of six ruminococcal strains.

Background: A complex community of microorganisms is responsible for efficient plant cell wall digestion by many herbivores, notably the ruminants. Understanding the different fibrolytic mechanisms utilized by these bacteria has been of great interest in agricultural and technological fields, reinforced more recently by current efforts to convert cellulosic biomass to biofuels.

Methodology/principal Findings: Here, we have used a bioinformatics-based approach to explore the cellulosome-related components of six genomes from two of the primary fiber-degrading bacteria in the rumen: Ruminococcus flavefaciens (strains FD-1, 007c and 17) and Ruminococcus albus (strains 7, 8 and SY3).

Repeated acidosis challenges and live yeast supplementation shape rumen microbiota and fermentations and modulate inflammatory status in sheep.

This study aimed to investigate the impact of repeated acidosis challenges (ACs) and the effect of live yeast supplementation (Saccharomyces cerevisiae I-1077, SC) on rumen fermentation, microbial ecosystem and inflammatory response. The experimental design involved two groups (SC, n=6; Control, n=6) of rumen fistulated wethers that were successively exposed to three ACs of 5 days each, preceded and followed by resting periods (RPs) of 23 days. AC diets consisted of 60% wheat-based concentrate and 40% hay, whereas RPs diets consisted of 20% concentrate and 80% hay.

Methanogen colonisation does not significantly alter acetogen diversity in lambs isolated 17 h after birth and raised aseptically.

Reductive acetogenesis is not competitive with methanogenesis in adult ruminants, whereas acetogenic bacteria are the dominant hydrogenotrophs in the early rumen microbiota. The ecology of hydrogenotrophs in the developing rumen was investigated using young lambs, raised in sterile isolators, and conventional adult sheep. Two lambs were born naturally, left with their dams for 17 h and then placed into a sterile isolator and reared aseptically.

Long-term defaunation increases the abundance of cellulolytic ruminococci and methanogens but does not affect the bacterial and methanogen diversity in the rumen of sheep.

Protozoa are commensal eukaryotes in the rumen of herbivores. Protozoa are large producers of hydrogen, which is utilized by methanogenic archaea to produce methane, a greenhouse gas. The removal of protozoa from the rumen (defaunation) decreases methanogenesis, but also negatively affects fiber digestion, which is the main function of the rumen.

Characterization of Xyn10A, a highly active xylanase from the human gut bacterium Bacteroides xylanisolvens XB1A.

A xylanase gene xyn10A was isolated from the human gut bacterium Bacteroides xylanisolvens XB1A and the gene product was characterized. Xyn10A is a 40-kDa xylanase composed of a glycoside hydrolase family 10 catalytic domain with a signal peptide. A recombinant His-tagged Xyn10A was produced in Escherichia coli and purified.

Differential translocation of green fluorescent protein fused to signal sequences of Ruminococcus albus cellulases by the Tat and Sec pathways of Escherichia coli.

Ruminococcus albus is a Gram-positive bacterium that degrades plant cell walls in the rumen of herbivores. It was described to synthesize two major glycoside-hydrolases (Cel9B and Cel48A), which are exported and anchored at the cell surface. In bacteria, proteins destined to cross the cytoplasmic membrane are synthesized as precursors and possess a signal sequence (SS) directing them to the 'Sec' (general secretory) or 'Tat' (twin arginine translocation) pathway.

Development of a RT-qPCR method for the quantification of Fibrobacter succinogenes S85 glycoside hydrolase transcripts in the rumen content of gnotobiotic and conventional sheep.

An improved RNA isolation method based on the acid guanidinium-phenol-chloroform (AGPC) procedure using saline precipitation but no column purification was evaluated for quantifying microbial gene expression using reverse transcription quantitative PCR (RT-qPCR) in rumen contents. The method provided good RNA integrity and quantity extracts. The transcript levels of eight glycoside hydrolase (GH) genes of the major rumen fibrolytic bacterium Fibrobacter succinogenes were quantified in the complex microbiota of a conventional sheep and in a gnotobiotic lamb harboring a microflora containing F.

Proteomic identification of CBM37-containing cellulases produced by the rumen cellulolytic bacterium Ruminococcus albus 20 and their putative involvement in bacterial adhesion to cellulose.

The objective of this study was to identify and characterize other proteins than fimbrial proteins potentially involved in R. albus 20 adhesion to cellulose using an adhesion-related antiserum preparation (i.e.

Quantification by real-time PCR of cellulolytic bacteria in the rumen of sheep after supplementation of a forage diet with readily fermentable carbohydrates: effect of a yeast additive.

Aim: To examine the effect of concentrate and yeast additive on the number of cellulolytic bacteria in the rumen of sheep.

Methods And Results: Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens were quantified using real-time PCR (targeting 16S rDNA) in parallel to cellulolytic flora enumeration with cultural techniques. Whatever the conditions tested, R.

The Ruminococcus albus pilA1-pilA2 locus: expression and putative role of two adjacent pil genes in pilus formation and bacterial adhesion to cellulose.

Ruminococcus albus produces fimbria-like structures that are involved with the bacterium's adhesion to cellulose. The subunit protein has been identified in strain 8 (CbpC) and strain 20 (GP25) and both are type IV fimbrial (Pil) proteins. The presence of a pil locus that is organized similarly in both strains is reported here together with the results of an initial examination of a second Pil protein.