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Nature Oct 2022Tobacco smoking is positively correlated with non-alcoholic fatty liver disease (NAFLD), but the underlying mechanism for this association is unclear. Here we report...
Tobacco smoking is positively correlated with non-alcoholic fatty liver disease (NAFLD), but the underlying mechanism for this association is unclear. Here we report that nicotine accumulates in the intestine during tobacco smoking and activates intestinal AMPKα. We identify the gut bacterium Bacteroides xylanisolvens as an effective nicotine degrader. Colonization of B. xylanisolvens reduces intestinal nicotine concentrations in nicotine-exposed mice, and it improves nicotine-exacerbated NAFLD progression. Mechanistically, AMPKα promotes the phosphorylation of sphingomyelin phosphodiesterase 3 (SMPD3), stabilizing the latter and therefore increasing intestinal ceramide formation, which contributes to NAFLD progression to non-alcoholic steatohepatitis (NASH). Our results establish a role for intestinal nicotine accumulation in NAFLD progression and reveal an endogenous bacterium in the human intestine with the ability to metabolize nicotine. These findings suggest a possible route to reduce tobacco smoking-exacerbated NAFLD progression.
Topics: Animals; Humans; Mice; Bacteria; Ceramides; Nicotine; Non-alcoholic Fatty Liver Disease; Sphingomyelin Phosphodiesterase; Tobacco Smoking; Intestines; AMP-Activated Protein Kinases; Disease Progression
PubMed: 36261549
DOI: 10.1038/s41586-022-05299-4 -
Carbohydrate Polymers Sep 2023Although many polysaccharides utilization loci (PULs) have been investigated by genomics and transcriptomics, the detailed functional characterization lags severely...
Although many polysaccharides utilization loci (PULs) have been investigated by genomics and transcriptomics, the detailed functional characterization lags severely behind. We hypothesize that PULs on the genome of Bacteroides xylanisolvens XB1A (BX) dictate the degradation of complex xylan. To address, xylan S32 isolated from Dendrobium officinale was employed as a sample polysaccharide. We firstly showed that xylan S32 promoted the growth of BX which might degrade xylan S32 into monosaccharides and oligosaccharides. We further showed that this degradation was performed mainly via two discrete PULs in the genome of BX. Briefly, a new surface glycan binding protein (SGBP) BX_29290 was identified, and shown to be essential for the growth of BX on xylan S32. Two cell surface endo-xylanases Xyn10A and Xyn10B cooperated to deconstruct the xylan S32. Intriguingly, genes encoding Xyn10A and Xyn10B were mainly distributed in the genome of Bacteroides spp. In addition, BX metabolized xylan S32 to produce short chain fatty acids (SCFAs) and folate. Taken together, these findings provide new evidence to understand the food source of BX and the BX-directed intervention strategy by xylan.
Topics: Humans; Xylans; Polysaccharides; Bacteroides; Gene Expression Profiling
PubMed: 37230606
DOI: 10.1016/j.carbpol.2023.121005 -
Clinical Nutrition (Edinburgh, Scotland) Nov 2022Advancing age coincides with changes in the gut microbiome and a decline in cognitive ability. Psychobiotics are microbiota-targeted interventions that can result in... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Advancing age coincides with changes in the gut microbiome and a decline in cognitive ability. Psychobiotics are microbiota-targeted interventions that can result in mental health benefits and protect the aging brain. This study investigated the gut microbiome composition and predicted microbial functional pathways of middle-aged and older adults that met criteria for mild cognitive impairment (MCI), compared to neurologically healthy individuals, and investigated the impact of probiotic Lactobacillus rhamnosus GG (LGG) in a double-blind, placebo-controlled, randomized clinical trial. A total of 169 community-dwelling middle-aged (52-59 years) and older adults (60-75 years) received a three-month intervention and were randomized to probiotic and placebo groups. Participants were further subdivided based on cognitive status into groups with intact or impaired cognition and samples were collected at baseline and post supplementation.
RESULTS
Microbiome analysis identified Prevotella ruminicola, Bacteroides thetaiotaomicron, and Bacteroides xylanisolvens as taxa correlated with MCI. Differential abundance analysis at baseline identified Prevotella as significantly more prevalent in MCI subjects compared to cognitively intact subjects (ALDEx2 P = 0.0017, ANCOM-BC P = 0.0004). A decrease in the relative abundance of the genus Prevotella and Dehalobacterium in response to LGG supplementation in the MCI group was correlated with an improved cognitive score.
CONCLUSIONS
Our study points to specific members of the gut microbiota correlated with cognitive performance in middle-aged and older adults. Should findings be replicated, these taxa could be used as key early indicators of MCI and manipulated by probiotics, prebiotics, and symbiotics to promote successful cognitive aging. Registered under ClinicalTrials.gov Identifier no. NCT03080818.
Topics: Middle Aged; Humans; Aged; Gastrointestinal Microbiome; Prebiotics; Probiotics; Lacticaseibacillus rhamnosus; Cognitive Dysfunction; Prevotella
PubMed: 36228569
DOI: 10.1016/j.clnu.2022.09.012 -
Frontiers in Microbiology 2023Hyperuricemia is widespread in humans and birds which is a necessary physiological factor leading to gout. Studies have shown an inextricable relationship between gut...
INTRODUCTION
Hyperuricemia is widespread in humans and birds which is a necessary physiological factor leading to gout. Studies have shown an inextricable relationship between gut microbiota and hyperuricemia. This study explored the association between intestinal flora and hyperuricemia in Goslings.
METHODS AND RESULTS
The hyperuricemia model was established in gosling by a high protein diet (HPD). 16S rDNA sequencing showed that the cecal microbiota differed significantly between the HPD and control groups (fed with the normal protein). The abundance of was higher in the HPD group, while the were lower than in controls. To investigate the role of intestinal flora in hyperuricemia, the cecum microbiotas from the HPD group and the control group were transplanted to the newly born goslings by gavage. The serum uric acid levels of the goslings that transplanted the cecal microbiota of the HPD group were significantly higher than the goslings that transplanted the cecal microbiota of the controls. Furthermore, the transplantation of cecal microbiota also affects the production and excretion of uric acid in goslings. Then we identify the gut bacterium as an effective anti-hyperuricemia in the Goslings. reduces serum uric acid concentrations in hyperuricemia in the Goslings' model, and it can up-regulation ABCG2 mRNA expression in the kidney and down-regulation XDH mRNA expression in the liver.
DISCUSSION
The intestinal flora acts as a novel target for the therapeutic approach to hyperuricemia and gout, suggest is a possible route to therapy for hyperuricemia and gout in goslings.
PubMed: 37455728
DOI: 10.3389/fmicb.2023.1173856 -
Chinese Journal of Natural Medicines Feb 2023
Topics: Humans; Nicotine; Non-alcoholic Fatty Liver Disease; Bacteroides
PubMed: 36871984
DOI: 10.1016/S1875-5364(23)60387-5 -
The Journal of Antimicrobial... May 2022We sought to characterize the carbapenem resistance mechanism of Bacteroides xylanisolvens 14880, an imipenem-resistant strain from Germany, and assess its prevalence.
OBJECTIVES
We sought to characterize the carbapenem resistance mechanism of Bacteroides xylanisolvens 14880, an imipenem-resistant strain from Germany, and assess its prevalence.
METHODS
Antimicrobial susceptibilities were determined using agar dilution or Etest methodology and specific imipenemase activity was detected. The genomic sequence of B. xylanisolvens 14880 was determined and analysed for antibiotic resistance genes and genomic islands. We also used gene transfer to a carbapenem susceptible host, along with 5'-RACE, conventional PCR with capillary sequencing and RT-PCR-based screening.
RESULTS
B. xylanisolvens 14880 displayed resistance to carbapenems and produced high specific imipenemase activity. Its genomic sequence was 6.1 Mbp and a class B1 β-lactamase gene (termed crxA) was detected in it. crxA was carried on a putative genomic island with insertion sequence (IS) elements and a putative GNAT (Gcn5-like acetyltransferase) toxin gene. Promoter localization by 5'-RACE and gene targeting to an imipenem-susceptible Bacteroides host indicated that it is activated by an IS1380-like IS element and it can confer carbapenem resistance. The PCR screening of Bacteroides strains showed that crxA was specific to B. xylanisolvens with a carriage rate of 16.7%.
CONCLUSIONS
B. xylanisolvens strains can harbour a carbapenem resistance gene, which has many similarities to the 'cfiA system': metallo-β-lactamase (MBL), IS element activation, carriage of a GNAT toxin gene, specific for a unique Bacteroides species with a significant prevalence.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Bacteroides; Bacteroides fragilis; Carbapenems; DNA Transposable Elements; Genomics; Imipenem; Microbial Sensitivity Tests; beta-Lactamases
PubMed: 35296904
DOI: 10.1093/jac/dkac088 -
Food Research International (Ottawa,... Feb 2019Probiotics play important roles on sustaining or reconstructing the homeostasis of intestinal microbiota, which is one of the key factors in alleviating diseases and... (Review)
Review
Probiotics play important roles on sustaining or reconstructing the homeostasis of intestinal microbiota, which is one of the key factors in alleviating diseases and maintaining the healthy condition of the host. Preclinical trials indicate that Bacteroides genus is widely considered as source of novel beneficial candidates for attenuating inflammation by regulating lymphocytes and cytokine expression, controlling metabolism and preventing cancer. Furthermore, the first case of authorization of Bacteroides xylanisolvens in food by the European Commission opens the gate for further investigation and application of this promising community. With this paper, we summarized current investigations of discovering beneficial Bacteroides strains, exploring their interaction mechanisms with the host, and evaluating the potential safety risks during commercialization.
Topics: Animals; Bacteroides; Gastrointestinal Microbiome; Host-Pathogen Interactions; Humans; Immune System; Inflammation Mediators; Intestines; Probiotics; Risk Assessment; Risk Factors; Signal Transduction
PubMed: 30716990
DOI: 10.1016/j.foodres.2018.08.088 -
International Journal of Systematic and... Apr 2008During the course of a study on the xylan-degrading community from the human gut, six xylanolytic, Gram-negative, anaerobic rods were isolated from faecal samples. 16S...
During the course of a study on the xylan-degrading community from the human gut, six xylanolytic, Gram-negative, anaerobic rods were isolated from faecal samples. 16S rRNA gene sequence analysis showed that the isolates were closely related to each other (> or =99 % sequence similarity) and that they belonged to the genus Bacteroides. On the basis of 16S rRNA gene sequence similarity, representative strain XB1AT was most closely related to the type strains of Bacteroides ovatus (97.5 %), B. finegoldii (96.5 %) and B. thetaiotaomicron (95.5 %). DNA-DNA hybridization results revealed that strain XB1AT was distinct from its closest relative, B. ovatus. The DNA G+C content of strain XB1AT (42.8 mol%) and major fatty acid composition (anteiso-C15 : 0, 33.8 %) further supported its affiliation to the genus Bacteroides. The novel isolates degraded different types of xylan, and were also able to grow on a variety of carbohydrates. Unlike most other Bacteroides species isolated from the human gut, these isolates were not able to degrade starch. Other biochemical tests further demonstrated that strain XB1AT could be differentiated from the closest related Bacteroides species. Xylan and sugars were converted by strain XB1AT mainly into acetate, propionate and succinate. Based on physiological, phenotypic and phylogenetic data, the six novel strains are considered to represent a novel species of the genus Bacteroides, for which the name Bacteroides xylanisolvens sp. nov. is proposed. The type strain is XB1AT (=DSM 18836T =CCUG 53782T).
Topics: Bacteroides; Base Composition; Base Sequence; Biotransformation; Carbohydrate Metabolism; DNA Primers; DNA, Bacterial; Feces; Genes, Bacterial; Humans; Molecular Sequence Data; Phenotype; Phylogeny; RNA, Bacterial; RNA, Ribosomal, 16S; Species Specificity; Terminology as Topic; Xylans
PubMed: 18398210
DOI: 10.1099/ijs.0.65504-0 -
Anaerobe Dec 2013We present the results from 16S sequencing and phenotypic tests for differentiation of Bacteroides dorei from Bacteroides vulgatus and Bacteroides ovatus from...
We present the results from 16S sequencing and phenotypic tests for differentiation of Bacteroides dorei from Bacteroides vulgatus and Bacteroides ovatus from Bacteroides xylanisolvens, which was not possible with MALDI-TOF MS. Testing with β-glucosidase could differentiate B. dorei from B. vulgatus and a negative catalase reaction could identify B. xylanisolvens.
Topics: Bacterial Typing Techniques; Bacteroides; DNA, Bacterial; DNA, Ribosomal; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; beta-Glucosidase
PubMed: 23994205
DOI: 10.1016/j.anaerobe.2013.08.004 -
Nutrients Mar 2023Alginate has been documented to prevent the development and progression of ulcerative colitis by modulating the gut microbiota. However, the bacterium that may mediate...
Alginate has been documented to prevent the development and progression of ulcerative colitis by modulating the gut microbiota. However, the bacterium that may mediate the anti-colitis effect of alginate has not been fully characterized. We hypothesized that alginate-degrading bacteria might play a role here since these bacteria could utilize alginate as a carbon source. To test this hypothesis, we isolated 296 strains of alginate-degrading bacteria from the human gut. AY11-1 was observed to have the best capability for alginate degradation. The degradation and fermentation of alginate by AY11-1 produced significant amounts of oligosaccharides and short-chain fatty acids. Further studies indicated that AY11-1 could alleviate body weight loss and contraction of colon length, reduce the incidences of bleeding and attenuate mucosal damage in dextran sulfate sodium (DSS)-fed mice. Mechanistically, AY11-1 improved gut dysbiosis and promoted the growth of probiotic bacteria, including spp. And , in diseased mice. Additionally, AY11-1 showed no oral toxicity and was well-tolerated in male and female mice. Altogether, we illustrate for the first time an anti-colitis effect of the alginate-degrading bacterium AY11-1. Our study paves the way for the development of AY11-1 as a next-generation probiotic bacterium.
Topics: Humans; Male; Female; Animals; Mice; Alginates; Gastrointestinal Microbiome; Colitis; Colon; Bacteria; Probiotics; Dextran Sulfate; Mice, Inbred C57BL; Disease Models, Animal
PubMed: 36986080
DOI: 10.3390/nu15061352