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Scientific Reports Dec 2022Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children and adolescents. The gut microbiota plays an important role in the...
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children and adolescents. The gut microbiota plays an important role in the pathophysiology of NAFLD through the gut-liver axis. Therefore, we aimed to investigate the genus and species of gut microbiota and their functions in children and adolescents with NAFLD. From May 2017 to July 2018, a total of 58 children and adolescents, including 27 abnormal weight (AW) (obese) NAFLD patients, 16 AW non-NAFLD children, and 15 healthy children, were enrolled in this study at Shenzhen Children's Hospital. All of them underwent magnetic resonance spectroscopy (MRS) to quantify the liver fat fraction. Stool samples were collected and analysed with metagenomics. According to body mass index (BMI) and MRS proton density fat fraction (MRS-PDFF), we divided the participants into BMI groups, including the AW group (n = 43) and the Lean group (n = 15); MRS groups, including the NAFLD group (n = 27) and the Control group (n = 31); and BMI-MRS 3 groups, including NAFLD_AW (AW children with NAFLD) (n = 27), Ctrl_AW (n = 16) (AW children without NAFLD) and Ctrl_Lean (n = 15). There was no difference in sex or age among those groups (p > 0.05). In the BMI groups, at the genus level, Dialister, Akkermansia, Odoribacter, and Alistipes exhibited a significant decrease in AW children compared with the Lean group. At the species level, Megamonas hypermegale was increased in the AW group, while Akkermansia muciniphila, Dialister invisus, Alistipes putredinis, Bacteroides massiliensis, Odoribacter splanchnicus, and Bacteroides thetaiotaomicron were decreased in AW children, compared to the Lean group. Compared with the Control group, the genus Megamonas, the species of Megamonas hypermegale and Megamonas rupellensis, increased in the NAFLD group. Furthermore, the genus Megamonas was enriched in the NAFLD_AW group, while Odoribacter, Alistipes, Dialister, and Akkermansia were depleted compared with the Ctrl_Lean or Ctrl_AW group at the genus level. Megamonas hypermegale and Megamonas rupellensis exhibited a significant increase in NAFLD_AW children compared with the Ctrl_Lean or Ctrl_AW group at the species level. Compared with healthy children, the pathways of P461-PWY contributed by the genus Megamonas were significantly increased in NAFLD_AW. We found that compared to healthy children, the genus Megamonas was enriched, while Megamonas hypermegale and Megamonas rupellensis were enriched at the species level in children and adolescents with NAFLD. This indicates that the NAFLD status and/or diet associated with NAFLD patients might lead to the enrichment of the genus Megamonas or Megamonas species.
Topics: Humans; Adolescent; Child; Non-alcoholic Fatty Liver Disease; Gastrointestinal Microbiome; Firmicutes; Liver
PubMed: 36539432
DOI: 10.1038/s41598-022-25140-2 -
Clinical Rheumatology May 2019We have previously demonstrated that the phylum Actinobacteria, the family Lactobacillaceae, and the genus Bifidobacterium increased in relative abundance of gut...
Relative abundance of Megamonas hypermegale and Butyrivibrio species decreased in the intestine and its possible association with the T cell aberration by metabolite alteration in patients with Behcet's disease (210 characters).
OBJECTIVES
We have previously demonstrated that the phylum Actinobacteria, the family Lactobacillaceae, and the genus Bifidobacterium increased in relative abundance of gut microbiota in patients with Behcet's disease (BD). The phylum Firmicutes and the class Clostridia were predominant in the feces of normal individuals. The class Clostridia includes short-chain fatty acid-producing bacteria, important for the balance between regulatory T cells and helper T type 17 (Th17) cells. It is possible that the bacterial compositional alteration causes low intestinal short-chain fatty acid concentrations, leading to skewed immune functions in patients with BD.
METHODS
To test the hypothesis, we examined species composition and gene functions from the 16S rRNA data by utilizing PICRUSt software.
RESULTS
We have shown that relative abundance of Eggerthella lenta, Acidaminococcus species, Lactobacillus mucosae, Bifidobacterium bifidum, Lactobacillus iners, Streptococcus species, and Lactobacillus salivarius increased significantly in patients with BD. Relative abundance of Megamonas hypermegale, Butyrivibrio species, Streptococcus infantis, and Filifactor species increased significantly in normal individuals compared with BD patients. In the functional annotation analysis by PICRUSt, we found prevalent gene functions of the pentose phosphate pathway and the inosine monophosphate biosynthesis in patients with BD. The data suggested that BD gut microbes altered nucleic acid and fatty acid synthesis.
CONCLUSIONS
These compositional and functional alterations of gut microbes may accompany unfavorable molecular exchanges between intestinal immunocompetent cells and gut microbes, and these interactions may have an association with the immune aberration in patients with BD.
Topics: Behcet Syndrome; Butyrivibrio; Female; Firmicutes; Gastrointestinal Microbiome; Humans; Intestines; Male; Middle Aged; RNA, Ribosomal, 16S
PubMed: 30628011
DOI: 10.1007/s10067-018-04419-8 -
International Journal of Systematic and... Dec 2008We report here the identification, characterization and culture of a Gram-negative to Gram-variable, rod-shaped, non-spore-forming anaerobic bacterium (strain FM1025(T))...
We report here the identification, characterization and culture of a Gram-negative to Gram-variable, rod-shaped, non-spore-forming anaerobic bacterium (strain FM1025(T)) isolated from the caecum of a duck. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that this strain clustered with species of the family 'Acidaminococcaceae', with 94.9 % similarity to Megamonas hypermegale DSM 1672(T) and less than 91 % similarity with type strains of Pectinatus species. Sequence similarities of at least 98-99 % were observed with numerous sequences deposited in GenBank of uncultured strains from human and chicken caecal contents, but this strain is the first isolate of this taxon to be cultivated and described. On the basis of morphological, physiological and phylogenetic features, this strain should be assigned to a novel species in the genus Megamonas, for which the name Megamonas rupellensis sp. nov. is proposed. The type strain is strain FM1025(T) (=DSM 19944(T) =CIP 109788(T)).
Topics: Anaerobiosis; Animals; Cecum; Ducks; Microscopy, Electron, Scanning; Molecular Sequence Data; Phylogeny; RNA, Ribosomal, 16S; Species Specificity; Veillonellaceae
PubMed: 19060083
DOI: 10.1099/ijs.0.2008/001297-0 -
Journal of Neuro-ophthalmology : the... Mar 2022Idiopathic intracranial hypertension syndrome (IIH) is most common among obese women. Weight loss is an important factor in improving papilledema. Over the last decade,...
BACKGROUND
Idiopathic intracranial hypertension syndrome (IIH) is most common among obese women. Weight loss is an important factor in improving papilledema. Over the last decade, growing evidence has identified gut microbiota as a potential factor in the pathophysiology of obesity. Accordingly, we investigated whether the gut microbiome is modified in IIH patients compared with healthy controls, and provide possible new treatment venues.
METHODS
Shotgun metagenomic sequencing of the gut microbiome of 25 cases of IIH patients (according to the modified Dandy criteria) and 20 healthy controls. Participants were further stratified according to their body mass index. The total DNA from each sample was extracted using the PureLink Microbiome DNA Purification Kit A29789 (Invitrogen, Thermo Fisher Scientific, US). Library preparation was performed using the Nextera DNA Flex Library Prep Kit. Samples were sequenced on the Illumina Novaseq 6000 device. A list of bacterial species that significantly differed between the IIH patients and healthy controls was produced in addition to species diversity. In addition, patients' cohort alone was analyzed, (excluding the healthy controls), and the effect of acetazolamide treatment on their gut microbiota was analyzed.
RESULTS
IIH patients have a lower diversity of bacterial species compared with healthy individuals. These bacteria, that is, Lactobacillus ruminis (L. ruminis) (p<6.95E-08), Atopobium parvulum (p<3.9E-03), Megamonas hypermegale (p<5.61E-03), Ruminococcus gnavus (p<1.29E-02), MEL.A1 (p<3.04E-02), and Streptococcus sp. I-G2 (p<3.04E-02), were previously characterized with beneficial health effects. Moreover, we found that Lactobacillus brevis, a beneficial bacterium as well, is more abundant in acetazolamide treated patients (p<7.07E-06).
CONCLUSIONS
Gut microbiota plays a potential role in IIH etiology and therefore, can provide a promising new treatment approach for this disease.
Topics: Acetazolamide; Brain; Female; Gastrointestinal Microbiome; Humans; Obesity; Papilledema; Pseudotumor Cerebri
PubMed: 34270519
DOI: 10.1097/WNO.0000000000001330 -
International Journal of Systematic and... Jul 2007Megamonas hypermegale is the sole species of the genus Megamonas included in the List of Prokaryotic Names with Standing in Nomenclature and in the databases of DDBJ,...
Megamonas hypermegale is the sole species of the genus Megamonas included in the List of Prokaryotic Names with Standing in Nomenclature and in the databases of DDBJ, EBI/EMBL and NCBI/GenBank it is placed in the lineage of Bacteroidetes; Bacteroidetes (class); 'Bacteroidales'; Bacteroidaceae; Megamonas. Phylogenetic analysis based on comparative 16S rRNA gene sequencing showed that this species clustered with species of the family 'Acidaminococcaceae' but not with those of the Bacteroidaceae. The genus Megamonas should be placed in the lineage of Firmicutes; Clostridia; Clostridiales; 'Acidaminococcaceae'; Megamonas.
Topics: Bacteroidaceae; DNA, Bacterial; DNA, Ribosomal; Phylogeny; RNA, Ribosomal, 16S; Sequence Homology, Nucleic Acid; Veillonellaceae
PubMed: 17625216
DOI: 10.1099/ijs.0.65150-0 -
Frontiers in Cellular and Infection... 2022It is predicted that by 2035, metabolic syndrome (MS) will be found in nearly more than half of our adult population, seriously affecting the health of our body. MS is...
It is predicted that by 2035, metabolic syndrome (MS) will be found in nearly more than half of our adult population, seriously affecting the health of our body. MS is usually accompanied by the occurrence of abnormal liver enzymes, such as elevated gamma-glutamyl transpeptidase (GGT). More and more studies have shown that the gut microbiota is involved in MS; however, the correlation between gut microbiota and MS with elevated GGT has not been studied comprehensively. Especially, there are few reports about its role in the physical examination of the population of men with MS and elevated GGT. By using the whole-genome shotgun sequencing technology, we conducted a genome-wide association study of the gut microbiome in 66 participants diagnosed as having MS accompanied by high levels of GGT (case group) and 66 participants with only MS and normal GGT level (control group). We found that the number of gut microbial species was reduced in participants in the case group compared to that of the control group. The overall microbial composition between the two groups is of significant difference. The gut microbiota in the case group is characterized by increased levels of "harmful bacteria" such as , , unclassified, , and and decreased levels of "beneficial bacteria" such as , , , , , and . Moreover, the pathways of POLYAMSYN-PWY, ARG+POLYAMINE-SYN, PWY-6305, and GOLPDLCAT-PWY were also increased in the case group, which may play a role in the elevation of GGT by producing amine, polyamine, putrescine, and endogenous alcohol. Taken together, there are apparent changes in the composition of the gut microbiome in men with MS and abnormal GGT levels, and it is high time to discover specific gut microbiome as a potential therapeutic target in that population. More in-depth studies of relevant mechanism could offer some new methods for the treatment of MS with elevated GGT.
Topics: Adult; Gastrointestinal Microbiome; Genome-Wide Association Study; Humans; Male; Metabolic Syndrome; Polyamines; gamma-Glutamyltransferase
PubMed: 35967853
DOI: 10.3389/fcimb.2022.946757 -
BMC Medicine Jul 2021Myasthenia gravis (MG) is an acquired immune-mediated disorder of the neuromuscular junction that causes fluctuating skeletal muscle weakness and fatigue. Pediatric MG...
BACKGROUND
Myasthenia gravis (MG) is an acquired immune-mediated disorder of the neuromuscular junction that causes fluctuating skeletal muscle weakness and fatigue. Pediatric MG and adult MG have many different characteristics, and current MG diagnostic methods for children are not quite fit. Previous studies indicate that alterations in the gut microbiota may be associated with adult MG. However, it has not been determined whether the gut microbiota are altered in pediatric MG patients.
METHODS
Our study recruited 53 pediatric MG patients and 46 age- and gender-matched healthy controls (HC). We sequenced the fecal samples of recruited individuals using whole-genome shotgun sequencing and analyzed the data with in-house bioinformatics pipeline.
RESULTS
We built an MG disease classifier based on the abundance of five species, Fusobacterium mortiferum, Prevotella stercorea, Prevotella copri, Megamonas funiformis, and Megamonas hypermegale. The classifier obtained 94% area under the curve (AUC) in cross-validation and 84% AUC in the independent validation cohort. Gut microbiome analysis revealed the presence of human adenovirus F/D in 10 MG patients. Significantly different pathways and gene families between MG patients and HC belonged to P. copri, Clostridium bartlettii, and Bacteroides massiliensis. Based on functional annotation, we found that the gut microbiome affects the production of short-chain fatty acids (SCFAs), and we confirmed the decrease in SCFA levels in pediatric MG patients via serum tests.
CONCLUSIONS
The study indicated that altered fecal microbiota might play vital roles in pediatric MG's pathogenesis by reducing SCFAs. The microbial markers might serve as novel diagnostic methods for pediatric MG.
Topics: Adult; Bacteroides; Child; Clostridiales; Feces; Firmicutes; Fusobacterium; Gastrointestinal Microbiome; Humans; Metagenome; Myasthenia Gravis; Prevotella; RNA, Ribosomal, 16S
PubMed: 34233671
DOI: 10.1186/s12916-021-02034-0 -
International Journal of Systematic and... Apr 2008Three strains of anaerobic, non-spore-forming, Gram-negative coccobacilli (YIT 11816T, YIT 11817 and YIT 11818) were isolated from human faeces. On the basis of 16S rRNA...
Three strains of anaerobic, non-spore-forming, Gram-negative coccobacilli (YIT 11816T, YIT 11817 and YIT 11818) were isolated from human faeces. On the basis of 16S rRNA gene sequence similarity, these strains were shown to belong to the family Alcaligenaceae and to be related to the type strain of Sutterella stercoricanis (94.9 %) and to Sutterella wadsworthensis WAL 7877 (94.3 %); the similarity to strains of any other species with a validly published name within the family Alcaligenaceae was less than 92 %. Biochemical data supported the affiliation of these strains to the genus Sutterella. These strains therefore represent a novel species, for which the name Sutterella parvirubra sp. nov. is proposed; the type strain is YIT 11816T (=DSM 19354T =JCM 14724T). The cells of another isolate, strain YIT 11815T, were non-spore-forming, Gram-negative, very large rods, 1x5-200 microm in size, with or without a central, subterminal or terminal swelling of 2-4 microm diameter when grown in a broth medium supplemented with glucose. Based on comparative 16S rRNA gene sequencing, this bacterium is a member of the family Acidaminococcaceae, and most closely related to Megamonas hypermegale (95.3 % similarity to the type strain). Interestingly, the 16S rRNA gene sequence of strain YIT 11815T showed 99 % similarity to sequences of uncultured colonic bacteria. A 16S rRNA gene sequence divergence value of >3 % from known cultured species suggested that isolate YIT 11815T represents a novel species, for which the name Megamonas funiformis sp. nov. is proposed; the type strain is YIT 11815T (=DSM 19343T =JCM 14723T).
Topics: Alcaligenaceae; Base Sequence; DNA Primers; DNA, Bacterial; Feces; Genes, Bacterial; Humans; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Molecular Sequence Data; Phenotype; Phylogeny; RNA, Bacterial; RNA, Ribosomal, 16S; Species Specificity; Terminology as Topic; Veillonellaceae
PubMed: 18398204
DOI: 10.1099/ijs.0.65456-0 -
Poultry Science Feb 2023Zoonotic Salmonella infection is a critical and challenging issue for public health. Since human infections are mainly associated with consuming contaminated chicken...
Zoonotic Salmonella infection is a critical and challenging issue for public health. Since human infections are mainly associated with consuming contaminated chicken products, strategies to reduce Salmonella carriage and shedding are essential. Here we investigate the mechanisms of the live attenuated Salmonella vaccine (AviPro Salmonella Duo) against Salmonella Enteritidis (SE) infection. We focused on inflammatory-related cytokine expressions and cecal microbiota modulations in specific-pathogen-free (SPF) and field layers. Forty-eight 2-day-old SPF layers were randomly allotted into S.SEvc, S.SEc, S.Vc, and S.Ct groups in trial 1. The equal number of filed layers at 25 wk were allocated into SEvc, SEc, Vc, and Ct groups in trial 2. Each group contained 12 layers. Groups were further assigned for vaccination (S.Vc and Vc groups), SE challenge (S.SEc and SEc groups), vaccination and the following SE challenge (S.SEvc and SEvc groups), or the placebo treatment (S.Ct and Ct groups). Cecal tissues and contents of layers on day 14 post-SE-challenges were collected for cytokine mRNA expression and 16S rRNA metagenomic analyses. We found that SE challenges significantly upregulated expressions of IFNγ, IL-1β, IL-12β, and NFκB1A in SPF layers. The vaccine notably counteracted the levels of IFNα, IFNγ, and NFκB1A activated by SE attacks. The vaccination, SE challenge, and their combination did not significantly affect alpha diversities but promoted dissimilarities in microbial communities between groups. Eubacterium_coprostanoligenes and Faecalibacterium_prausnitzii were identified as contributory taxa in the cecal microbiota of SE-challenged and vaccinated SPF layers. A significantly higher abundance of Faecalibacterium_prausnitzii in the ceca further correlated with the vaccination conferred protection against SE infection. In contrast, Oscillibacter_valericigenes and Mediterraneibacter_glycyrrhizinilyticus were featured taxa in Salmonella-infected field layers. Megamonas_hypermegale and Megamonas_rupellensis were identified as featured taxa in vaccinated field layers compared to SE-infected layers. To conclude, applying a dual Salmonella vaccine in this study modulated expressions of inflammatory-related cytokines and the cecal microbiome in layers, contributing to protection against SE infection. The feature microbes are promising for developing predictive indices and as antibiotic alternatives added to feed to reduce the risk of Salmonella shedding and contamination.
Topics: Humans; Animals; Cytokines; Salmonella enteritidis; RNA, Ribosomal, 16S; Chickens; Salmonella Vaccines; Microbiota; Vaccines, Attenuated; Salmonella Infections, Animal; Poultry Diseases
PubMed: 36527813
DOI: 10.1016/j.psj.2022.102373 -
Poultry Science Oct 2015This experiment was conducted to evaluate the effects of feeding dietary fiber on cecal short-chain fatty acid (SCFA) concentration and cecal microbiota of broiler and...
This experiment was conducted to evaluate the effects of feeding dietary fiber on cecal short-chain fatty acid (SCFA) concentration and cecal microbiota of broiler and laying-hen chicks. The lower fiber diet was based on corn-soybean meal (SBM) and the higher fiber diet was formulated using corn-SBM-dried distillers grains with solubles (DDGS) and wheat bran to contain 60.0 g/kg of both DDGS and wheat bran from 1 to 12 d and 80.0 g/kg of both DDGS and wheat bran from 13 to 21 d. Diets were formulated to meet or exceed NRC nutrient requirements. Broiler and laying-hen chicks were randomly assigned to the high and low fiber diets with 11 replicates of 8 chicks for each of the 4 treatments. One cecum from 3 chicks was collected from each replicate: one cecum underwent SCFA concentration analysis, one underwent bacterial DNA isolation for terminal restriction fragment length polymorphism (TRFLP), and the third cecum was used for metagenomics analyses. There were interactions between bird line and dietary fiber for acetic acid (P = 0.04) and total SCFA (P = 0.04) concentration. There was higher concentration of acetic acid (P = 0.02) and propionic acid (P < 0.01) in broiler chicks compared to laying-hen chicks. TRFLP analysis showed that cecal microbiota varied due to diet (P = 0.02) and chicken line (P = 0.03). Metagenomics analyses identified differences in the relative abundance of Helicobacter pullorum and Megamonas hypermegale and the genera Enterobacteriaceae, Campylobacter, Faecalibacterium, and Bacteroides in different treatment groups. These results provide insights into the effect of dietary fiber on SCFA concentration and modulation of cecal microbiota in broiler and laying-hen chicks.
Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Cecum; Chickens; Diet; Dietary Fiber; Digestion; Edible Grain; Fatty Acids, Volatile; Female; Microbiota; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Random Allocation
PubMed: 26316341
DOI: 10.3382/ps/pev242