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MSystems Feb 2023Previous study found that appropriate high-fiber diet (containing 19.10% total dietary fiber [TDF], treatment II) did not reduce apparent fiber digestibility of Chinese...
Previous study found that appropriate high-fiber diet (containing 19.10% total dietary fiber [TDF], treatment II) did not reduce apparent fiber digestibility of Chinese Suhuai finishing pigs and increased the yield of short-chain fatty acids (SCFAs), but too high-fiber diet (containing 24.11% TDF, treatment IV) significantly reduced apparent fiber digestibility compared with normal diet (containing 16.70% TDF, control group). However, characteristics of microbiota at the species level and histological structure in pigs with the ability to digest appropriate high-fiber diets were still unknown. This study conducted comparative analysis of cecal physiology and microbial populations colonizing cecal mucosa. The results showed intestinal development indexes including cecum length, densities of cecal goblet cells, and renewal of cecal epithelial cells in treatment II and IV had better performance than those in the control. Paludibacter jiangxiensis, Coprobacter fastidiosus, Bacteroides coprocola CAG:162, Bacteroides barnesiae, and Parabacteroides merdae enriched in treatment II expressed large number of glycoside hydrolase (GH)-encoding genes and had the largest number of GH families. In addition, pathogenic bacteria (Shigella sonnei, Mannheimia haemolytica, and Helicobacter felis) were enriched in treatment IV. Correlation analysis revealed that the intestinal development index positively correlated with the relative abundance of cecal mucosal microbiota and the amount of digested fiber. These results indicated that increased proportions of fiber-degrading microbes and enhanced intestinal development jointly promote the host to digest an appropriate high-fiber diet. However, although too-high fiber levels in diet could maintain the adaptive development of cecal epithelium, the proportions of pathogenic bacteria increased, which might lead to a decrease of fiber digestion in pigs. Although studies about the effects of dietary fiber on fiber digestion and intestinal microbiota of pigs were widely in progress, few studies have been conducted on the dynamic response of intestinal microbiota to dietary fiber levels, and the characteristics of intestinal microbiota and intestinal epithelial development adapted to high-fiber diet s were still unclear. Appropriate high fiber promoted the thickness of large intestine wall, increased the density of cecal goblet cells, and promoted the renewal of cecal epithelial cells. In addition, appropriate high fiber improves the microbial abundance with fiber-digesting potential. However, excessive dietary fiber caused an increase in the abundance of pathogenic bacteria. These results indicated that an increased proportion of fiber-degrading microbes and enhanced intestinal development jointly promote host to digest appropriate high-fiber diets. However, although too-high fiber levels in diet could maintain the adaptive development of cecal epithelium, the proportions of pathogenic bacteria increased, which might lead to a decrease of fiber digestion in pigs. Our data provided a theoretical basis for rational and efficient utilization of unconventional feed resources in pig production.
Topics: Swine; Animals; Digestion; Cecum; Diet; Dietary Fiber; Intestinal Mucosa
PubMed: 36511688
DOI: 10.1128/msystems.00937-22 -
Microbiological Research Jun 2024As the most abundant gram-negative bacterial order in the gastrointestinal tract, Bacteroidales bacteria have been extensively studied for their contribution to various...
As the most abundant gram-negative bacterial order in the gastrointestinal tract, Bacteroidales bacteria have been extensively studied for their contribution to various aspects of gut health. These bacteria are renowned for their involvement in immunomodulation and their remarkable capacity to break down complex carbohydrates and fibers. However, the human gut microbiota is known to produce many metabolites that ultimately mediate important microbe-host and microbe-microbe interactions. To gain further insights into the metabolites produced by the gut commensal strains of this order, we examined the metabolite composition of their bacterial cell cultures in the stationary phase. Based on their abundance in the gastrointestinal tract and their relevance in health and disease, we selected a total of six bacterial strains from the relevant genera Bacteroides, Phocaeicola, Parabacteroides, and Segatella. We grew these strains in modified Gifu anaerobic medium (mGAM) supplemented with mucin, which resembles the gut microbiota's natural environment. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolite profiling revealed 179 annotated metabolites that had significantly differential abundances between the studied bacterial strains and the control growth medium. Most of them belonged to classes such as amino acids and derivatives, organic acids, and nucleot(s)ides. Of particular interest, Segatella copri DSM 18205 (previously referred to as Prevotella copri) produced substantial quantities of the bioactive metabolites phenylethylamine, tyramine, tryptamine, and ornithine. Parabacteroides merdae CL03T12C32 stood out due to its ability to produce cadaverine, histamine, acetylputrescine, and deoxycarnitine. In addition, we found that strains of the genera Bacteroides, Phocaeicola, and Parabacteroides accumulated considerable amounts of proline-hydroxyproline, a collagen-derived bioactive dipeptide. Collectively, these findings offer a more detailed comprehension of the metabolic potential of these Bacteroidales strains, contributing to a better understanding of their role within the human gut microbiome in health and disease.
Topics: Humans; Chromatography, Liquid; Liquid Chromatography-Mass Spectrometry; Tandem Mass Spectrometry; Bacteria; Gastrointestinal Microbiome
PubMed: 38518452
DOI: 10.1016/j.micres.2024.127700 -
Bioscience of Microbiota, Food and... 2022Chronic inflammation caused by gut dysbiosis is associated with the pathophysiology of metabolic disease. Synbiotics are useful for ameliorating gut dysbiosis; however,...
Chronic inflammation caused by gut dysbiosis is associated with the pathophysiology of metabolic disease. Synbiotics are useful for ameliorating gut dysbiosis; however, it remains unclear what types of bacteria act as key markers for synbiotic-driven improvement of chronic inflammation. Here, we performed a post hoc analysis of a 24-week randomized controlled study using synbiotics to investigate the association between gut microbiota and inflammatory markers. We characterized the responders who showed lower interleukin-6 (IL-6) levels in response to synbiotic supplementation among 86 obese patients with type 2 diabetes mellitus. In our baseline analysis, the relative abundances of and correlated positively with IL-6, lipopolysaccharide binding protein (LBP), and high-sensitivity C-reactive protein (Hs-CRP) levels. The relative abundance of correlated positively with LBP and Hs-CRP levels, and that of correlated positively with LBP levels. Based on our responder analysis, patients with higher body mass indices (over 30 kg/m on average), low abundances of and at baseline and 24 weeks, and minimal changes in the relative abundance of and Shannon index from baseline showed decreased IL-6 levels compared with baseline. However, glycemic control in responders was unchanged. In conclusion, we identified four bacterial species (, , , ) related to chronic inflammation and predictive markers ( and severity of obesity) in responders to synbiotic supplementation among obese patients with type 2 diabetes.
PubMed: 35854696
DOI: 10.12938/bmfh.2021-081 -
Fertility and Sterility Jun 2020To identify different microbial species in women with polycystic ovary syndrome (PCOS) and reveal a possible relationship between gut dysbiosis and pathological changes.
OBJECTIVE
To identify different microbial species in women with polycystic ovary syndrome (PCOS) and reveal a possible relationship between gut dysbiosis and pathological changes.
DESIGN
Cross-sectional study.
SETTING
Academic institution.
PATIENT(S)
Reproductive-aged women with PCOS (n = 14) and controls (n = 14) from the Centre for Reproductive Medicine.
INTERVENTION(S)
Shotgun metagenomic sequencing on fecal samples from patients, and clinical parameters (including body mass index, endocrine hormone levels, and glycemia level) gathered for correlation analysis.
MAIN OUTCOME MEASURE(S)
Identification of different gut microbial strains and relativity between microbiota and clinical parameters.
RESULT(S)
We found several microbial strains were statistically significantly more abundant in the PCOS group, including Parabacteroides merdae, Bacteroides fragilis, and strains of Escherichia and Shigella, whereas Faecalibacterium prausnitzii was enriched in the control group. Metagenomic species (MGS) analysis revealed that the microbes of the PCOS group were negatively correlated with those of the control group. Of note, we observed a positive correlation between MGS relevant to PCOS and endocrine disorders, including body mass index and elevated levels of serum testosterone, luteinizing hormone, and antimüllerian hormone. Functional alterations, reflected by Kyoto Encyclopedia of Genes and Genomes orthologues, could imply potential mechanisms of microbial involvement in the developmental progress of PCOS.
CONCLUSION(S)
Our findings suggest an intimate association and potential mechanisms linking microbial dysbiosis and the pathophysiologic changes of PCOS. We address the importance of monitoring and modulating microbial composition and functional shifts in future clinical practice.
Topics: Adult; Bacteria; Case-Control Studies; Cross-Sectional Studies; Dysbiosis; Feces; Female; Gastrointestinal Microbiome; Humans; Intestines; Metagenomics; Polycystic Ovary Syndrome; Young Adult
PubMed: 32482258
DOI: 10.1016/j.fertnstert.2020.01.027 -
Frontiers in Nutrition 2023The aim of the study was to evaluate the effects of Active or Sedentary lifestyle on saliva microbiota composition in Italian schoolchildren.
UNLABELLED
The aim of the study was to evaluate the effects of Active or Sedentary lifestyle on saliva microbiota composition in Italian schoolchildren.
METHODS
Male (114) and female children (8-10 years) belonging to five primary schools in the neighborhoods of Turin were classified as active (A) or sedentary (S) based on PAQ-C-It questionnaire. PCR amplification of salivary DNA targeted the hypervariable V3-V4 regions of the 16S rRNA bacterial genes. DADA2 workflow was used to infer the Amplicon Sequence Variants and the taxonomic assignments; the beta-diversity was obtained by PCoA with the UniFrac method; LEfSe algorithm, threshold at 5%, and Log LDA cutoff at ±0.5 were used to identify differently abundant species in A compared to S saliva sample. Daily food intake was assessed by 3-Days food record. The metabolic potential of microbial communities was assessed by PICRUSt.
RESULTS
No significant differences were found in individual's gender distribution ( = 0.411), anthropometry, BMI ( > 0.05), and all diet composition between A and S groups ( > 0.05). Eight species were differently abundant: (LDA score = -3.76; FDR = 1.5×10-03), (LDA score = -3.17; FDR = 7.45×10-03), (LDA score = -2.96; FDR = 2.76×10-05), (LDA score = -2.43; FDR = 1.3×10-02) are enriched in the A group; , (LDA score = -3.9; FDR = 5.27×10-04), (LDA score = 4.23; FDR = 1.93×10-02), (LDA score = 4.43; FDR = 1.31×10-02; LDA score = 2.94; FDR = 7.45×10-03) are enriched in the S group. A prevalence of superpathway of fatty acid biosynthesis initiation () and catechol degradation II (meta-cleavage pathway) was found in saliva from A compared to S children.
CONCLUSION
Our results showed that active children had an enrichment of species and genera mainly associated with a healthier profile. By contrast, the genera and the species enriched in the sedentary group could be linked to human diseases.
PubMed: 37671197
DOI: 10.3389/fnut.2023.1226891 -
Journal of Cachexia, Sarcopenia and... Aug 2022Older adults are particularly prone to the development of poor appetite and undernutrition. Possibly, this is partly due to the aged gut microbiota. We aimed to evaluate...
BACKGROUND
Older adults are particularly prone to the development of poor appetite and undernutrition. Possibly, this is partly due to the aged gut microbiota. We aimed to evaluate the gut microbiota in relation to both poor appetite and undernutrition in community-dwelling older adults. Furthermore, we studied the causal effects of the microbiota on body weight and body composition by transferring faecal microbiota from cohort participants into germ-free mice.
METHODS
First, we conducted a cross-sectional cohort study of 358 well-phenotyped Dutch community-dwelling older adults from the Longitudinal Aging Study Amsterdam. Data collection included body measurements, a faecal and blood sample, as well as extensive questionnaires on appetite, dietary intake, and nutritional status. Appetite was assessed by the Council of Nutrition Appetite Questionnaire (CNAQ) and undernutrition was defined by either a low body mass index (BMI) (BMI < 20 kg/m if <70 years or BMI < 22 kg/m if ≥70 years) or >5% body weight loss averaged over the last 2 years. Gut microbiota composition was determined with 16S rRNA sequencing. Next, we transferred faecal microbiota from 12 cohort participants with and without low BMI or recent weight loss into a total of 41 germ-free mice to study the potential causal effects of the gut microbiota on host BMI and body composition.
RESULTS
The mean age (range) of our cohort was 73 (65-93); 58.4% was male. Seventy-seven participants were undernourished and 21 participants had poor appetite (CNAQ < 28). A lower abundance of the genus Blautia was associated with undernutrition (log2 fold change = -0.57, Benjamini-Hochberg-adjusted P = 0.008), whereas higher abundances of taxa from Lachnospiraceae, Ruminococcaceae UCG-002, Parabacteroides merdae, and Dorea formicigenerans were associated with poor appetite. Furthermore, participants with poor appetite or undernutrition had reduced levels of faecal acetate (P = 0.006 and 0.026, respectively). Finally, there was a trend for the mice that received faecal microbiota from older adults with low BMI to weigh 1.26 g less after 3 weeks (P = 0.086) and have 6.13% more lean mass (in % body weight, P = 0.067) than the mice that received faecal microbiota from older adults without low BMI or recent weight loss.
CONCLUSIONS
This study demonstrates several associations of the gut microbiota with both poor appetite and undernutrition in older adults. Moreover, it is the first to explore a causal relation between the aged gut microbiota and body weight and body composition in the host. Possibly, microbiota-manipulating strategies will benefit older adults prone to undernutrition.
Topics: Animals; Appetite; Body Weight; Cohort Studies; Cross-Sectional Studies; Gastrointestinal Microbiome; Humans; Male; Malnutrition; Mice; Microbiota; RNA, Ribosomal, 16S; Weight Loss
PubMed: 35698917
DOI: 10.1002/jcsm.13002 -
Gut Feb 2021Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was detected in faeces of patients with COVID-19, the activity and infectivity of the virus in... (Observational Study)
Observational Study
OBJECTIVE
Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was detected in faeces of patients with COVID-19, the activity and infectivity of the virus in the GI tract during disease course is largely unknown. We investigated temporal transcriptional activity of SARS-CoV-2 and its association with longitudinal faecal microbiome alterations in patients with COVID-19.
DESIGN
We performed RNA shotgun metagenomics sequencing on serial faecal viral extractions from 15 hospitalised patients with COVID-19. Sequencing coverage of the SARS-CoV-2 genome was quantified. We assessed faecal microbiome composition and microbiome functionality in association with signatures of faecal SARS-CoV-2 infectivity.
RESULTS
Seven (46.7%) of 15 patients with COVID-19 had stool positivity for SARS-CoV-2 by viral RNA metagenomic sequencing. Even in the absence of GI manifestations, all seven patients showed strikingly higher coverage (p=0.0261) and density (p=0.0094) of the 3' vs 5' end of SARS-CoV-2 genome in their faecal viral metagenome profile. Faecal viral metagenome of three patients continued to display active viral infection signature (higher 3' vs 5' end coverage) up to 6 days after clearance of SARS-CoV-2 from respiratory samples. Faecal samples with signature of high SARS-CoV-2 infectivity had higher abundances of bacterial species , , , , and higher functional capacity for nucleotide de novo biosynthesis, amino acid biosynthesis and glycolysis, whereas faecal samples with signature of low-to-none SARS-CoV-2 infectivity had higher abundances of short-chain fatty acid producing bacteria, , , and .
CONCLUSION
This pilot study provides evidence for active and prolonged 'quiescent' GI infection even in the absence of GI manifestations and after recovery from respiratory infection of SARS-CoV-2. Gut microbiota of patients with active SARS-CoV-2 GI infection was characterised by enrichment of opportunistic pathogens, loss of salutary bacteria and increased functional capacity for nucleotide and amino acid biosynthesis and carbohydrate metabolism.
Topics: Adult; Aged; COVID-19; Feces; Female; Gastrointestinal Microbiome; Hospitalization; Humans; Longitudinal Studies; Male; Middle Aged; Pilot Projects; Prospective Studies; SARS-CoV-2; Young Adult
PubMed: 32690600
DOI: 10.1136/gutjnl-2020-322294 -
PloS One 2019Gut microbiota is closely related to age. Studies from Europe and the U.S. identified featured microbiota in different age groups for the elderly. Asian studies mainly...
BACKGROUND
Gut microbiota is closely related to age. Studies from Europe and the U.S. identified featured microbiota in different age groups for the elderly. Asian studies mainly focused on people living in longevity areas. Featured microbiota for the elderly people of different age groups, especially in the centenarian in the general population, has not been well investigated in China.
METHOD
We conducted a comparative study by including 198 subjects of three age groups (65-70, 90-99, and 100+ years) in East China. Information regarding age, sex, height, weight, waist circumference, hip circumference, food preference, smoking status and alcohol consumption were collected by using a structured questionnaire. Fecal samples for each participant were collected as well. 16S rRNA gene sequencing were employed to analyze the gut microbiota composition. Logistic regression with LASSO feature selection was used to identify featured taxa in different age groups and to assess their potential interactions with other factors such as lifestyle.
RESULT
The gut microbiota of the 90-99 year and 100+ year age groups showed more diversity, robustness, and richness compared with the 65-70 year age group. PCoA analysis showed a clear separation between the 65-70 and 100+ year age groups. At the species level, Bacteroides fragilis, Parabacteroides merdae, Ruminococcus gnavus, Coprococcus and Clostridium perfringens increased, but Bacteroides vulgatus, Ruminococcus sp.5139BFAA and Clostridium sp.AT5 decreased in the 90-99 year age group. The age differences in gut microbiota were similar across the strata of smoking, alcohol consumption status and food preference.
CONCLUSION
Our study demonstrated age differences in many aspects of gut microbiota, such as overall diversity, microbiota structure, and relative abundance of key taxa. Moreover, the gut microbiota of centenarian was significantly different from those of younger age groups of the elderly.
Topics: Aged; Aged, 80 and over; Bacteria; China; Europe; Feces; Female; Gastrointestinal Microbiome; Humans; Longevity; Male; RNA, Ribosomal, 16S
PubMed: 31639130
DOI: 10.1371/journal.pone.0222763 -
Gut Microbes 2022Fecal microbiota transplantation (FMT) is currently used for treating infection and explored for other clinical applications in experimental trials. However, the... (Clinical Trial)
Clinical Trial
Fecal microbiota transplantation (FMT) is currently used for treating infection and explored for other clinical applications in experimental trials. However, the effectiveness of this therapy could vary, and partly depend on the donor's bacterial species engraftment, whose evaluation is challenging because there are no cost-effective strategies for accurately tracking the microbe transference. In this regard, the precise identification of bacterial species inhabiting the human gut is essential to define their role in human health unambiguously. We used Nanopore-based device to sequence bacterial operons (16S-ITS-23S) and to reveal species-level abundance changes in the human gut microbiota of a FMT trial. By assessing the donor and recipient microbiota before and after FMT, we further evaluated whether this molecular approach reveals strain-level genetic variation to demonstrate microbe transfer and engraftment. Strict control over sequencing data quality and major microbiota covariates was critical for accurately estimating the changes in gut microbial species abundance in the recipients after FMT. We detected strain-level variation via single-nucleotide variants (SNVs) at regions in a species-specific manner. We showed that it was possible to explore successfully the donor-bacterial strain (e.g., engraftment in recipients of the FMT by assessing the nucleotide frequencies at rrn-associated SNVs. Our findings indicate that the engraftment of donors' microbiota is to some extent correlated with the improvement of metabolic health in recipients and that parameters such as the baseline gut microbiota configuration, sex, and age of donors should be considered to ensure the success of FMT in humans. The study was prospectively registered at the Dutch Trial registry - NTR4488 (https://www.trialregister.nl/trial/4488).
Topics: Bacteria; Fecal Microbiota Transplantation; Feces; Gastrointestinal Microbiome; Humans; Metabolic Syndrome; Nucleotides
PubMed: 35604764
DOI: 10.1080/19490976.2022.2078621 -
ACS Chemical Biology Jun 2017Cysteine proteases are among the most abundant hydrolytic enzymes produced by bacteria, and this diverse family of proteins have significant biological roles in...
Cysteine proteases are among the most abundant hydrolytic enzymes produced by bacteria, and this diverse family of proteins have significant biological roles in bacterial viability and environmental interactions. Members of the clostripain-like (C11) family of cysteine proteases from commensal gut bacterial strains have recently been shown to mediate immune responses by inducing neutrophil phagocytosis and activating bacterial pathogenic toxins. Development of substrates, inhibitors, and probes that target C11 proteases from enteric bacteria will help to establish the role of these proteins at the interface of the host and microbiome in health and disease. We employed a mass spectrometry-based substrate profiling method to identify an optimal peptide substrate of PmC11, a C11 protease secreted by the commensal bacterium Parabacteroides merdae. Using this substrate sequence information, we synthesized a panel of fluorogenic substrates to calculate k and K and to evaluate the importance of the P2 amino acid for substrate turnover. A potent and irreversible tetrapeptide inhibitor with a C-terminal acyloxymethyl ketone warhead, Ac-VLTK-AOMK, was then synthesized. We determined the crystal structure of PmC11 in complex with this inhibitor and uncovered key active-site interactions that govern PmC11 substrate recognition and specificity. This is the first C11 protease structure in complex with a substrate mimetic and is also the highest resolution crystal structure of a C11 protease to date at 1.12 Å resolution. Importantly, subjecting human epithelial cell lysates to PmC11 hydrolysis in combination with subtiligase-based N-terminal labeling and tandem mass spectrometry proteomics complemented the stringent substrate specificity observed in the in vitro substrate profiling experiment. The combination of chemical biological, biophysical, and biochemical techniques presented here to elucidate and characterize PmC11 substrate selectivity can be expanded to other proteases and the development of chemical tools to study these essential proteins in biologically relevant samples, such as the highly complex distal gut microbiome.
Topics: Bacterial Proteins; Crystallography, X-Ray; Cysteine Endopeptidases; Cysteine Proteases; Enterobacteriaceae; Epithelial Cells; Humans; Molecular Structure; Substrate Specificity; Symbiosis
PubMed: 28414448
DOI: 10.1021/acschembio.7b00143