Frontiers in Microbiology
·
2024
·
IF 4
Shuo Xie,Junze Ma,Zheng Lu
This study probes into the unique metabolic responses of Bacteroides thetaiotaomicron (B. thetaiotaomicron), a key player in the gut microbiota, when it metabolizes rhamnose rather than typical carbohydrates. Known for its predominant role in the Bacteroidetes phylum, B. thetaiotaomicron efficiently breaks down poly- and mono-saccharides into beneficial short-chain fatty acids (SCFAs), crucial for both host health and microbial ecology balance. Our research focused on how this bacterium’s SCFA production differ when utilizing various monosaccharides, with an emphasis on the oxidative stress responses triggered by rhamnose consumption. Notably, rhamnose use results in unique metabolic byproducts, including substantial quantities of 1,2-propanediol, which differs significantly from those produced during glucose metabolism. Our research reveals that rhamnose consumption is associated with a reduction in reactive oxygen species (ROS), signifying improved resistance to oxidative stress compared to other sugars. This effect is attributed to specific gene expressions within the rhamnose metabolic pathway. Notably, overexpression of the rhamnose metabolism regulator RhaR in B. thetaiotaomicron enhances its survival in oxygen-rich conditions by reducing hydrogen peroxide production. This reduction is linked to decreased expression of pyruvate:ferredoxin oxidoreductase (PFOR). In contrast, experiments with a rhaR-deficient strain demonstrated that the absence of RhaR causes B. thetaiotaomicron cells growing on rhamnose to produce ROS at rates comparable to cells grown on glucose, therefore, losing their advantage in oxidative resistance. Concurrently, the expression of PFOR is no longer suppressed. These results indicate that when B. thetaiotaomicron is cultured in a rhamnose-based medium, RhaR can restrain the expression of PFOR. Although PFOR is not a primary contributor to intracellular ROS production, its sufficient inhibition does reduce ROS levels to certain extent, consequently improving the bacterium’s resistance to oxidative stress. It highlights the metabolic flexibility and robustness of microbes in handling diverse metabolic challenges and oxidative stress in gut niches through the consumption of alternative carbohydrates.
研究领域:
微生物学
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代谢组学
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肠道健康
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PubMed
高影响因子
Food Frontiers
·
2021
·Vol. 2
·期 2
·218-231
·
IF 0
Song Li,Baojie Zhang,Jielun Hu,Yadong Zhong,Yonggan Sun,Shaoping Nie
The interaction between gut microbiota and polysaccharide is being paid more and more attention. Galactan is a kind of polysaccharide mainly composed of galactose, and it has been shown to play a significant role in regulating gut microbiota. Bacteroides thetaiotaomicron is considered as the best degrader of polysaccharides. The purpose of this paper was to investigate the utilization of four different galactans, including agarose, carrageenan, arabinogalactan, and glucofucogalactan, by our own isolated B. thetaiotaomicron A4. Samples of cultures grown on either four galactans groups or control groups were collected. The change of OD 600 , pH, and short-chain fatty acids (SCFAs) during fermentation were determined, and growth curve and transcriptome of B. thetaiotaomicron A4 were studied. B. thetaiotaomicron A4 could utilize the four galactans and grew well on them, with carrageenan being most utilized, followed by arabinogalactan, glucofucogalactan, and agarose. SCFAs (mainly acetic acid and propionic acid) produced along with the decreased pH during fermentation. A large number of genes of B. thetaiotaomicron A4 were upregulated and functioned in different pathways during the degradation of the four galactans. The carbohydrate metabolism-related pathways of B. thetaiotaomicron A4 were enriched after feeding the four galactans, although the specific pathways were different among four galactans groups. The different structural characteristics of four galactans required that B. thetaiotaomicron A4 could excrete corresponding enzymes to degrade them. These results help to understand the interaction between galactans and gut microbe.
研究领域:
微生物学
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分子生物学
·
肠道微生物
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DOI
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2025
·
IF 6.2
Shanshan Zhang,Yonggan Sun,Xinyu Bian,Fangwei Liu,Shaoping Nie
Inflammatory bowel disease (IBD) is linked to gut microbiota dysbiosis, and modulating microbiota through diet is a promising IBD management strategy. Larch arabinogalactan (AG) is a natural polysaccharide with potential prebiotic effects; however, its regulatory effects on gut microbiota and the underlying anti-inflammatory mechanisms remain unclear. Here, we demonstrated that AG improves gut homeostasis in dextran sulfate sodium-induced colitis mice, with effects depend on the gut microbiota. Further analysis revealed that AG notably enriched the Bacteroides, particularly Bacteroides thetaiotaomicron. Specifically, B. thetaiotaomicron exhibited anti-inflammatory activity, producing propionate and upregulating colonic G-protein-coupled receptor 41 (GPR41) expression, effects also observed in AG-treated mice. Collectively, our findings reveal the targeted regulatory effects of AG on gut microbiota and demonstrate that the B. thetaiotaomicron-propionate-GPR41 axis contributes to the amelioration of colitis by AG. These results provide new scientific evidence for the application of AG in health foods and offer novel insights for microbiota-targeted nutritional intervention.
研究领域:
微生物学
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免疫学
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营养科学
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胃肠病学
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分子生物学
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DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2026
·Vol. 74
·期 33
·26290-26302
·
IF 6.7
He Ying,Yu Ziyang,Li Qiqiong,Tao Ze,Xu Yushan,Xie Junhua,Nie Shaoping
Bacteroides thetaiotaomicron (Bt)
degrades dietary glycans via carbohydrate-active enzymes (CAZymes),
but their spatial distribution and functional coordination remain
unclear. In this study, we characterized the “labor division”
during glycan degradation across four bacterial fractions: cytoplasm,
outer membrane, extracellular vesicles, and supernatant. All fractions
displayed hydrolytic activity. Proteomic analysis identified abundant
glycoside hydrolases, mainly GH32 enzymes encoded by PUL22, and their
components varied greatly. Untargeted metabolomics identified 45 shared
differential metabolites (e.g., carbohydrates and short-chain fatty
acids), indicating distinct hydrolytic capacities among fractions.
Notably, cross-feeding experiments confirmed that Bt EVs-mediated
degradation can support the growth of recipient bacteria. Collectively,
our results reveal a synergistic multicomponent strategy for glycan
degradation in Bacteroides , offering new insights
into glycan utilization and laying a foundation for developing postbiotics
and functional microbial products.
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PubMed
高影响因子
Nature Microbiology
·
2026
·
IF 18.7
Ye Meng,Liu Xinyu,Peng Zhengxiong,Li Shuaichao,Jia Xiaoyu,Yang Xiyuchen,Jiang Shan,Wang Feng,Yang Xiaobing,Yu Juping,Liu Wei,Gao Xiangdong
Engineered therapeutic microbes for intestinal inflammation must be capable of gut colonization, sensitive detection of disease-associated biomarkers and targeted delivery of therapeutic molecules. Examples of microbes displaying all three characteristics are limited. Here we engineered Bacteroides thetaiotaomicron , a human gut commensal bacterium with colonization ability, colonic tropism and innate anti-inflammatory properties, as a chassis to create programmable bacterial strains termed Btbots. We developed genetic circuits that were integrated into the bacterial chromosome to sense two intestinal inflammation biomarkers, deoxycholic acid (DCA) and nitric oxide (NO), and to enhance surface display and secretion of therapeutic molecules in response. Btbots with these biosensors were developed that either display trefoil factor-3 to facilitate mucosal repair or secrete interleukin-35 to suppress inflammation. These Btbots sensed DCA and NO biomarkers and released therapeutic agents, alleviating colitis and modulating the gut microenvironment and microbiota in mouse models. This work establishes a proof of concept for localized sensing and consequent therapeutic molecule release for gastrointestinal applications, whose clinical potential awaits further investigation.
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高影响因子
Frontiers in Microbiology
·
2024
·
IF 4
Yu Biao,Lu Zheng,Zhong Saiyi,Cheong Kit-Leong
Introduction: Research on the mechanism of marine polysaccharide utilization by Bacteroides thetaiotaomicron has drawn substantial attention in recent years. Derived from marine algae, the marine algae polysaccharides could serve as prebiotics to facilitate intestinal microecological balance and alleviate colonic diseases. Bacteroides thetaiotaomicron, considered the most efficient degrader of polysaccharides, relates to its capacity to degrade an extensive spectrum of complex polysaccharides. Polysaccharide utilization loci (PULs), a specialized organization of a collection of genes-encoded enzymes engaged in the breakdown and utilization of polysaccharides, make it possible for Bacteroides thetaiotaomicron to metabolize various polysaccharides. However, there is still a paucity of comprehensive studies on the procedure of polysaccharide degradation by Bacteroides thetaiotaomicron.Methods: In the current study, the degradation of four kinds of marine algae polysaccharides, including sodium alginate, fucoidan, laminarin, and Pyropia haitanensis polysaccharides, and the underlying mechanism by Bacteroides thetaiotaomicron G4 were investigated. Pure culture of Bacteroides thetaiotaomicron G4 in a substrate supplemented with these polysaccharides were performed. The change of OD600, total carbohydrate contents, and molecular weight during this fermentation were determined. Genomic sequencing and bioinformatic analysis were further performed to elucidate the mechanisms involved. Specifically, Gene Ontology (GO) annotation, Clusters of Orthologous Groups (COG) annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were utilized to identify potential target genes and pathways.Results: Underlying target genes and pathways were recognized by employing bioinformatic analysis. Several PULs were found that are anticipated to participate in the breakdown of these four polysaccharides. These findings may help to understand the interactions between these marine seaweed polysaccharides and gut microorganisms.Discussion: The elucidation of polysaccharide degradation mechanisms by Bacteroides thetaiotaomicron provides valuable insights into the utilization of marine polysaccharides as prebiotics and their potential impact on gut health. Further studies are warranted to explore the specific roles of individual PULs and their contributions to polysaccharide metabolism in the gut microbiota.
研究领域:
微生物学
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分子生物学
·
基因组学
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生物信息学
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营养科学
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胃肠病学
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DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2025
·
IF 9.8
Zi Ye,Leilei Yu,Chuan Zhang,Xiaojing Wei,Jianxin Zhao,Wei Chen,Qixiao Zhai,Fengwei Tian
Volvaria volvacea polysaccharides (VVP) possess diverse bioactivities with promising applications in biomedicine and functional foods. This study investigated the metabolic fate of VVP in human gut microbiota and uncovered the pivotal role of Bacteroides thetaiotaomicron using in vitro fecal fermentation models. VVP selectively promoted B. thetaiotaomicron proliferation, establishing it as a central hub in microbial interaction networks. Metabolomic profiling revealed significant increases in short-chain fatty acids (SCFAs) and adenosine during VVP fermentation. KEGG pathway enrichment demonstrated activation of starch and sucrose metabolism and histidine biosynthesis, consistent with PICRUSt functional predictions. Network correlation and sole‑carbon source assays confirmed B. thetaiotaomicron as a key VVP degrader. These findings establish B. thetaiotaomicron as a dual-function mediator that orchestrates VVP bioconversion into bioactive metabolites and reshapes gut microenvironment. This mechanistic framework supports the development of VVP-based, microbiota-targeted interventions to enhance gut health.
研究领域:
微生物学
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糖生物学
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代谢组学
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功能性食品
·
生物医学
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DOI
PubMed
高影响因子
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