1
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Novak JK, Gardner JG. Current models in bacterial hemicellulase-encoding gene regulation. Appl Microbiol Biotechnol 2024; 108:39. [PMID: 38175245 PMCID: PMC10766802 DOI: 10.1007/s00253-023-12977-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
The discovery and characterization of bacterial carbohydrate-active enzymes is a fundamental component of biotechnology innovation, particularly for renewable fuels and chemicals; however, these studies have increasingly transitioned to exploring the complex regulation required for recalcitrant polysaccharide utilization. This pivot is largely due to the current need to engineer and optimize enzymes for maximal degradation in industrial or biomedical applications. Given the structural simplicity of a single cellulose polymer, and the relatively few enzyme classes required for complete bioconversion, the regulation of cellulases in bacteria has been thoroughly discussed in the literature. However, the diversity of hemicelluloses found in plant biomass and the multitude of carbohydrate-active enzymes required for their deconstruction has resulted in a less comprehensive understanding of bacterial hemicellulase-encoding gene regulation. Here we review the mechanisms of this process and common themes found in the transcriptomic response during plant biomass utilization. By comparing regulatory systems from both Gram-negative and Gram-positive bacteria, as well as drawing parallels to cellulase regulation, our goals are to highlight the shared and distinct features of bacterial hemicellulase-encoding gene regulation and provide a set of guiding questions to improve our understanding of bacterial lignocellulose utilization. KEY POINTS: • Canonical regulatory mechanisms for bacterial hemicellulase-encoding gene expression include hybrid two-component systems (HTCS), extracytoplasmic function (ECF)-σ/anti-σ systems, and carbon catabolite repression (CCR). • Current transcriptomic approaches are increasingly being used to identify hemicellulase-encoding gene regulatory patterns coupled with computational predictions for transcriptional regulators. • Future work should emphasize genetic approaches to improve systems biology tools available for model bacterial systems and emerging microbes with biotechnology potential. Specifically, optimization of Gram-positive systems will require integration of degradative and fermentative capabilities, while optimization of Gram-negative systems will require bolstering the potency of lignocellulolytic capabilities.
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Affiliation(s)
- Jessica K Novak
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA
| | - Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA.
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2
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Basu A, Adams AND, Degnan PH, Vanderpool CK. Determinants of raffinose family oligosaccharide use in Bacteroides species. J Bacteriol 2024:e0023524. [PMID: 39330254 DOI: 10.1128/jb.00235-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 09/06/2024] [Indexed: 09/28/2024] Open
Abstract
Bacteroides species are successful colonizers of the human colon and can utilize a wide variety of complex polysaccharides and oligosaccharides that are indigestible by the host. To do this, they use enzymes encoded in polysaccharide utilization loci (PULs). While recent work has uncovered the PULs required for the use of some polysaccharides, how Bacteroides utilize smaller oligosaccharides is less well studied. Raffinose family oligosaccharides (RFOs) are abundant in plants, especially legumes, and consist of variable units of galactose linked by α-1,6 bonds to a sucrose (glucose α-1-β-2 fructose) moiety. Previous work showed that an α-galactosidase, BT1871, is required for RFO utilization in Bacteroides thetaiotaomicron. Here, we identify two different types of mutations that increase BT1871 mRNA levels and improve B. thetaiotaomicron growth on RFOs. First, a novel spontaneous duplication of BT1872 and BT1871 places these genes under the control of a ribosomal promoter, driving high BT1871 transcription. Second, nonsense mutations in a gene encoding the PUL24 anti-sigma factor likewise increase BT1871 transcription. We then show that hydrolases from PUL22 work together with BT1871 to break down the sucrose moiety of RFOs and determine that the master regulator of carbohydrate utilization (BT4338) plays a role in RFO utilization in B. thetaiotaomicron. Examining the genomes of other Bacteroides species, we found homologs of BT1871 in a subset and showed that representative strains of species with a BT1871 homolog grew better on melibiose than species that lack a BT1871 homolog. Altogether, our findings shed light on how an important gut commensal utilizes an abundant dietary oligosaccharide. IMPORTANCE The gut microbiome is important in health and disease. The diverse and densely populated environment of the gut makes competition for resources fierce. Hence, it is important to study the strategies employed by microbes for resource usage. Raffinose family oligosaccharides are abundant in plants and are a major source of nutrition for the microbiota in the colon since they remain undigested by the host. Here, we study how the model commensal organism, Bacteroides thetaiotaomicron utilizes raffinose family oligosaccharides. This work highlights how an important member of the microbiota uses an abundant dietary resource.
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Affiliation(s)
- Anubhav Basu
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Amanda N D Adams
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Patrick H Degnan
- Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, California, USA
| | - Carin K Vanderpool
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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3
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Rong X, Shen C, Shu Q. Interplay between traditional Chinese medicine polysaccharides and gut microbiota: The elusive "polysaccharides-bond-bacteria-enzyme" equation. Phytother Res 2024. [PMID: 39120443 DOI: 10.1002/ptr.8284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 06/09/2024] [Accepted: 06/13/2024] [Indexed: 08/10/2024]
Abstract
Polysaccharides are one of the most important components of traditional Chinese medicine (TCM) and have been extensively studied for their immunomodulatory properties. The functions and effects of TCM polysaccharides are closely related to the gut microbiota, making the study of their interaction a hot topic in the field of TCM metabolism. This review follows two main inquiries: first, how the gut microbiota breaks down TCM polysaccharides to produce bioactive metabolites; and second, how TCM polysaccharides reshape the gut microbiota as a carbon source. Understanding the interaction mechanism involves a challenging equation of the structural association of TCM polysaccharides with the metabolic activities of the microbiota. This review has meticulously searched, partially organized literature spanning the past decade, that delves into the interaction mechanism between TCM polysaccharides and gut microbiota. It also gives an overview of the complex factors of the elusive "polysaccharides-bond-bacteria-enzyme" equation: the complexity of polysaccharide structures, the diversity of glycosidic bond types, the communal nature of metabolizing microbiota, the enzymes involved in functional degradation by microbiota, and the hierarchical roles of polysaccharide utilization locus and gram-positive PULs. Finally, this review aims to facilitate discussion among peers in the field of TCM microbiota and offers prospects for research in related fields, paving the way for pharmacological studies on TCM polysaccharides and gut microbiota therapeutics, and providing a reference point for further clinical research.
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Affiliation(s)
- XinQian Rong
- Jiangxi University of Chinese Medicine, Nanchang, China
| | - CanTing Shen
- Jiangxi University of Chinese Medicine, Nanchang, China
| | - QingLong Shu
- Jiangxi University of Chinese Medicine, Nanchang, China
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4
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Gao R, Wu T, Stock AM. A conserved inhibitory interdomain interaction regulates DNA-binding activities of hybrid two-component systems in Bacteroides. mBio 2024; 15:e0122024. [PMID: 38842315 PMCID: PMC11253607 DOI: 10.1128/mbio.01220-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 05/02/2024] [Indexed: 06/07/2024] Open
Abstract
Hybrid two-component systems (HTCSs) comprise a major class of transcription regulators of polysaccharide utilization genes in Bacteroides. Distinct from classical two-component systems in which signal transduction is carried out by intermolecular phosphotransfer between a histidine kinase (HK) and a cognate response regulator (RR), HTCSs contain the membrane sensor HK and the RR transcriptional regulator within a single polypeptide chain. Tethering the DNA-binding domain (DBD) of the RR with the dimeric HK domain in an HTCS could potentially promote dimerization of the DBDs and would thus require a mechanism to suppress DNA-binding activity in the absence of stimulus. Analysis of phosphorylation and DNA-binding activities of several HTCSs from Bacteroides thetaiotaomicron revealed a DBD suppression mechanism in which an inhibitory interaction between the DBD and the phosphoryl group-accepting receiver domain (REC) decreases autophosphorylation rates of HTCS-RECs and represses DNA-binding activities in the absence of phosphorylation. Sequence analyses and structure predictions identified a highly conserved sequence motif correlated with a conserved inhibitory domain arrangement of REC and DBD. The presence of the motif, as in most HTCSs, or its absence, in a small subset of HTCSs, is likely predictive of two distinct regulatory mechanisms evolved for different glycans. Substitutions within the conserved motif relieve the inhibitory interaction and result in elevated DNA-binding activities in the absence of phosphorylation. Our data suggest a fundamental regulatory mechanism shared by most HTCSs to suppress DBD activities using a conserved inhibitory interdomain arrangement to overcome the challenge of the fused HK and RR components. IMPORTANCE Different dietary and host-derived complex carbohydrates shape the gut microbial community and impact human health. In Bacteroides, the prevalent gut bacteria genus, utilization of these diverse carbohydrates relies on different gene clusters that are under sophisticated control by various signaling systems, including the hybrid two-component systems (HTCSs). We have uncovered a highly conserved regulatory mechanism in which the output DNA-binding activity of HTCSs is suppressed by interdomain interactions in the absence of stimulating phosphorylation. A consensus amino acid motif is found to correlate with the inhibitory interaction surface while deviations from the consensus can lead to constitutive activation. Understanding of such conserved HTCS features will be important to make regulatory predictions for individual systems as well as to engineer novel systems with substitutions in the consensus to explore the glycan regulation landscape in Bacteroides.
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Affiliation(s)
- Rong Gao
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Ti Wu
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Ann M. Stock
- Center for Advanced Biotechnology and Medicine, Department of Biochemistry and Molecular Biology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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5
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Basu A, Adams AN, Degnan PH, Vanderpool CK. Determinants of raffinose family oligosaccharide use in Bacteroides species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597959. [PMID: 38895307 PMCID: PMC11185731 DOI: 10.1101/2024.06.07.597959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Bacteroides species are successful colonizers of the human gut and can utilize a wide variety of complex polysaccharides and oligosaccharides that are indigestible by the host. To do this, they use enzymes encoded in Polysaccharide Utilization Loci (PULs). While recent work has uncovered the PULs required for use of some polysaccharides, how Bacteroides utilize smaller oligosaccharides is less well studied. Raffinose family oligosaccharides (RFOs) are abundant in plants, especially legumes, and consist of variable units of galactose linked by α-1,6 bonds to a sucrose (glucose α-1-β-2 fructose) moiety. Previous work showed that an α-galactosidase, BT1871, is required for RFO utilization in Bacteroides thetaiotaomicron. Here, we identify two different types of mutations that increase BT1871 mRNA levels and improve B. thetaiotaomicron growth on RFOs. First, a novel spontaneous duplication of BT1872 and BT1871 places these genes under control of a ribosomal promoter, driving high BT1871 transcription. Second, nonsense mutations in a gene encoding the PUL24 anti-sigma factor likewise increase BT1871 transcription. We then show that hydrolases from PUL22 work together with BT1871 to break down the sucrose moiety of RFOs and determine that the master regulator of carbohydrate utilization (BT4338) plays a role in RFO utilization in B. thetaiotaomicron. Examining the genomes of other Bacteroides species, we found homologs of BT1871 in subset and show that representative strains of species containing a BT1871 homolog grew better on melibiose than species that lack a BT1871 homolog. Altogether, our findings shed light on how an important gut commensal utilizes an abundant dietary oligosaccharide.
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Affiliation(s)
- Anubhav Basu
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Amanda N.D. Adams
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Patrick H. Degnan
- Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, California, USA
| | - Carin K. Vanderpool
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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6
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Murovec U, Accetto T. Transcriptomic analysis of polysaccharide utilization loci reveals substrate preferences in ruminal generalists Segatella bryantii TF1-3 and Xylanibacter ruminicola KHP1. BMC Genomics 2024; 25:495. [PMID: 38769483 PMCID: PMC11107044 DOI: 10.1186/s12864-024-10421-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 05/15/2024] [Indexed: 05/22/2024] Open
Abstract
Bacteria of the genera Xylanibacter and Segatella are among the most dominant groups in the rumen microbiota. They are characterized by the ability to utilize different hemicelluloses and pectin of plant cell-wall as well as plant energy storage polysaccharides. The degradation is possible with the use of cell envelope bound multiprotein apparatuses coded in polysaccharide utilization loci (PULs), which have been shown to be substrate specific. The knowledge of PUL presence in rumen Xylanibacter and Segatella based on bioinformatic analyses is already established and transcriptomic and genetic approaches confirmed predicted PULs for a limited number of substrates. In this study, we transcriptomically identified additional different PULs in Xylanibacter ruminicola KHP1 and Segatella bryantii TF1-3. We also identified substrate preferences and found that specific growth rate and extent of growth impacted the choice of substrates preferentially used for degradation. These preferred substrates were used by both strains simultaneously as judged by their PUL upregulation. Lastly, β-glucan and xyloglucan were used by these strains in the absence of bioinformatically and transcriptomically identifiable PUL systems.
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Affiliation(s)
- Urška Murovec
- Department of microbiology, Biotechnical faculty, University of Ljubljana, Groblje 3, 1230, Domžale, Slovenia
| | - Tomaž Accetto
- Department of microbiology, Biotechnical faculty, University of Ljubljana, Groblje 3, 1230, Domžale, Slovenia.
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7
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Dong J, Cui Y, Qu X. Metabolism mechanism of glycosaminoglycans by the gut microbiota: Bacteroides and lactic acid bacteria: A review. Carbohydr Polym 2024; 332:121905. [PMID: 38431412 DOI: 10.1016/j.carbpol.2024.121905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/19/2024] [Accepted: 01/30/2024] [Indexed: 03/05/2024]
Abstract
Glycosaminoglycans (GAGs), as a class of biopolymers, play pivotal roles in various biological metabolisms such as cell signaling, tissue development, cell apoptosis, immune modulation, and growth factor activity. They are mainly present in the colon in free forms, which are essential for maintaining the host's health by regulating the colonization and proliferation of gut microbiota. Therefore, it is important to explain the specific members of the gut microbiota for GAGs' degradation and their enzymatic machinery in vivo. This review provides an outline of GAGs-utilizing entities in the Bacteroides, highlighting their polysaccharide utilization loci (PULs) and the enzymatic machinery involved in chondroitin sulfate (CS) and heparin (Hep)/heparan sulfate (HS). While there are some variations in GAGs' degradation among different genera, we analyze the reputed GAGs' utilization clusters in lactic acid bacteria (LAB), based on recent studies on GAGs' degradation. The enzymatic machinery involved in Hep/HS and CS metabolism within LAB is also discussed. Thus, to elucidate the precise mechanisms utilizing GAGs by diverse gut microbiota will augment our understanding of their effects on human health and contribute to potential therapeutic strategies for diseases.
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Affiliation(s)
- Jiahuan Dong
- Department of Food Nutrition and Health, School of Medicine and Health, Harbin Institute of Technology, Harbin 150090, China
| | - Yanhua Cui
- Department of Food Nutrition and Health, School of Medicine and Health, Harbin Institute of Technology, Harbin 150090, China.
| | - Xiaojun Qu
- Institute of Microbiology, Heilongjiang Academy of Sciences, Harbin 150010, China
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8
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Ontai-Brenning A, Hamchand R, Crawford JM, Goodman AL. Gut microbes modulate (p)ppGpp during a time-restricted feeding regimen. mBio 2023; 14:e0190723. [PMID: 37971266 PMCID: PMC10746209 DOI: 10.1128/mbio.01907-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/09/2023] [Indexed: 11/19/2023] Open
Abstract
IMPORTANCE Mammals do not eat continuously, instead concentrating their feeding to a restricted portion of the day. This behavior presents the mammalian gut microbiota with a fluctuating environment with consequences for host-microbiome interaction, infection risk, immune response, drug metabolism, and other aspects of health. We demonstrate that in mice, gut microbes elevate levels of an intracellular signaling molecule, (p)ppGpp, during the fasting phase of a time-restricted feeding regimen. Disabling this response in a representative human gut commensal species significantly reduces colonization during this host-fasting phase. This response appears to be general across species and conserved across mammalian gut communities, highlighting a pathway that allows healthy gut microbiomes to maintain stability in an unstable environment.
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Affiliation(s)
- Amy Ontai-Brenning
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Randy Hamchand
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Jason M. Crawford
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Institute of Biomolecular Design & Discovery, Yale University, West Haven, Connecticut, USA
| | - Andrew L. Goodman
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
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9
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Beller ZW, Wesener DA, Seebeck TR, Guruge JL, Byrne AE, Henrissat S, Terrapon N, Henrissat B, Rodionov DA, Osterman AL, Suarez C, Bacalzo NP, Chen Y, Couture G, Lebrilla CB, Zhang Z, Eastlund ER, McCann CH, Davis GD, Gordon JI. Inducible CRISPR-targeted "knockdown" of human gut Bacteroides in gnotobiotic mice discloses glycan utilization strategies. Proc Natl Acad Sci U S A 2023; 120:e2311422120. [PMID: 37733741 PMCID: PMC10523453 DOI: 10.1073/pnas.2311422120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/08/2023] [Indexed: 09/23/2023] Open
Abstract
Understanding how members of the human gut microbiota prioritize nutrient resources is one component of a larger effort to decipher the mechanisms defining microbial community robustness and resiliency in health and disease. This knowledge is foundational for development of microbiota-directed therapeutics. To model how bacteria prioritize glycans in the gut, germfree mice were colonized with 13 human gut bacterial strains, including seven saccharolytic Bacteroidaceae species. Animals were fed a Western diet supplemented with pea fiber. After community assembly, an inducible CRISPR-based system was used to selectively and temporarily reduce the absolute abundance of Bacteroides thetaiotaomicron or B. cellulosilyticus by 10- to 60-fold. Each knockdown resulted in specific, reproducible increases in the abundances of other Bacteroidaceae and dynamic alterations in their expression of genes involved in glycan utilization. Emergence of these "alternate consumers" was associated with preservation of community saccharolytic activity. Using an inducible system for CRISPR base editing in vitro, we disrupted translation of transporters critical for utilizing dietary polysaccharides in Phocaeicola vulgatus, a B. cellulosilyticus knockdown-responsive taxon. In vitro and in vivo tests of the resulting P. vulgatus mutants allowed us to further characterize mechanisms associated with its increased fitness after knockdown. In principle, the approach described can be applied to study utilization of a range of nutrients and to preclinical efforts designed to develop therapeutic strategies for precision manipulation of microbial communities.
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Affiliation(s)
- Zachary W. Beller
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
| | - Darryl A. Wesener
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
| | - Timothy R. Seebeck
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
- Genome Engineering R&D, MilliporeSigma, the Life Science business Merck KGaA, Darmstadt, Germany, St. Louis, MO63103
| | - Janaki L. Guruge
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
| | - Alexandra E. Byrne
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
| | - Suzanne Henrissat
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique and Aix-Marseille University, 13288Marseille, France
| | - Nicolas Terrapon
- Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique and Aix-Marseille University, 13288Marseille, France
| | - Bernard Henrissat
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. LyngbyDK-2800, Denmark
- Department of Biological Sciences, King Abdulaziz University, Jeddah21589, Saudi Arabia
| | - Dmitry A. Rodionov
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA92037
| | - Andrei L. Osterman
- Infectious and Inflammatory Disease Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA92037
| | - Chris Suarez
- Department of Chemistry, University of California, Davis, CA95616
| | | | - Ye Chen
- Department of Chemistry, University of California, Davis, CA95616
| | - Garret Couture
- Department of Chemistry, University of California, Davis, CA95616
| | | | - Zhigang Zhang
- Genome Engineering R&D, MilliporeSigma, the Life Science business Merck KGaA, Darmstadt, Germany, St. Louis, MO63103
| | - Erik R. Eastlund
- Genome Engineering R&D, MilliporeSigma, the Life Science business Merck KGaA, Darmstadt, Germany, St. Louis, MO63103
| | - Caitlin H. McCann
- Genome Engineering R&D, MilliporeSigma, the Life Science business Merck KGaA, Darmstadt, Germany, St. Louis, MO63103
| | - Gregory D. Davis
- Genome Engineering R&D, MilliporeSigma, the Life Science business Merck KGaA, Darmstadt, Germany, St. Louis, MO63103
| | - Jeffrey I. Gordon
- Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO63110
- Center for Gut Microbiome and Nutrition Research, Washington University School of Medicine, St. Louis, MO63110
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10
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Xu Y, Wang F, Mi K, Wang X, Wang D, Zhao Q, Wang J, Liu Z, Zhang Q, Liu Y, Zhang X, Liu X. Biglycan regulated colorectal cancer progress by modulating enteric neuron-derived IL-10 and abundance of Bacteroides thetaiotaomicron. iScience 2023; 26:107515. [PMID: 37664615 PMCID: PMC10469580 DOI: 10.1016/j.isci.2023.107515] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/01/2022] [Accepted: 07/27/2023] [Indexed: 09/05/2023] Open
Abstract
Biglycan (BGN) is a proteoglycan with branch chains and highly expressed in enteric neurons in the tumor tissue of colorectal cancer (CRC), which is negatively associated with survival rates in patients with CRC. However, how the proteoglycan promotes the progress of CRC through interacting with bacteria and regulating the immune response of enteric neurons remains largely unknown. In the present study, we found that biglycan deficiency changed tumor distribution in a colitis-associated colon cancer model. Furthermore, we revealed that BGN deficiency inhibits tumor growth in an allograft tumor model and the migration of cancer cell by upregulating interleukin-10 expression in enteric neurons. Significantly, we demonstrated that biglycan deficiency enriched the abundance of Bacteroides thetaiotaomicron through competing with it for chondroitin sulfate to inhibit CRC progress. Our work provided new insights into the interaction between host proteoglycan and gut microbiota as well as the role of enteric neurons in the tumor microenvironment.
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Affiliation(s)
- Yuyu Xu
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Fei Wang
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
- The Affiliated Mental Health Center of Jiangnan University, Wuxi Central Rehabilitation Hospital, Wuxi, Jiangsu 214151, China
| | - Kai Mi
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Xinyuan Wang
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Danlei Wang
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Qing Zhao
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Jingjing Wang
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Zhi Liu
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Qingqing Zhang
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Yang Liu
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Xuemei Zhang
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
| | - Xingyin Liu
- Department of Pathogen Biology-Microbiology Division, State Key Laboratory of Reproductive Medicine and Offspring Health, Key Laboratory of Pathogen of Jiangsu Province, Key Laboratory of Human Functional Genomics of Jiangsu Province, Center of Global Health, Nanjing Medical University, Nanjing 211166, China
- The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Nanjing, China
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11
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Hu G, Wang Y, Xue R, Liu T, Zhou Z, Yang Z. Effects of the Exopolysaccharide from Lactiplantibacillus plantarum HMX2 on the Growth Performance, Immune Response, and Intestinal Microbiota of Juvenile Turbot, Scophthalmus maximus. Foods 2023; 12:2051. [PMID: 37238869 PMCID: PMC10217481 DOI: 10.3390/foods12102051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/08/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
In this study, the exopolysaccharide (EPS) from Lactiplantibacillus plantarum (HMX2) was isolated from Chinese Northeast Sauerkraut. Its effects on juvenile turbot were investigated by adding different concentrations of HMX2-EPS (C: 0 mg/kg, H1: 100 mg/kg, H2: 500 mg/kg) to the feed. Compared with the control group, HMX2-EPS significantly improved the growth performance of juvenile turbot. The activities of antioxidant enzymes, digestive enzymes, and immune-related enzymes were significantly increased. HMX2-EPS could also increase the secretion of inflammatory factors and enhance the immune response of turbot by regulating the IFN signal transduction pathway and exhibit stronger survival rates after the A. hydrophila challenge. Moreover, HMX2-EPS could improve the diversity of intestinal microbiota in juvenile fish, increase the abundance of potential probiotics, and reduce the abundance of pathogenic bacteria. The function of gut microbes in metabolism and the immune system could also be improved. All results showed better effects with high concentrations of HMX2-EPS. These results indicated that HMX2-EPS supplementation in the diet could promote growth, improve antioxidant activity, digestive capacity, and immunity capacity, and actively regulate the intestinal microbiota of juvenile turbot. In conclusion, this study might provide basic technical and scientific support for the application of L. plantarum in aquatic feed.
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Affiliation(s)
| | | | | | | | | | - Zhennai Yang
- Key Laboratory of Geriatric Nutrition and Health of Ministry of Education, Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology and Business University, No. 11 Fu-Cheng Road, Hai-Dian District, Beijing 100048, China; (G.H.); (Y.W.); (R.X.); (T.L.); (Z.Z.)
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12
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Wu CM, Wheeler KM, Cárcamo-Oyarce G, Aoki K, McShane A, Datta SS, Mark Welch JL, Tiemeyer M, Griffen AL, Ribbeck K. Mucin glycans drive oral microbial community composition and function. NPJ Biofilms Microbiomes 2023; 9:11. [PMID: 36959210 PMCID: PMC10036478 DOI: 10.1038/s41522-023-00378-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 02/20/2023] [Indexed: 03/25/2023] Open
Abstract
Human microbiome composition is closely tied to health, but how the host manages its microbial inhabitants remains unclear. One important, but understudied, factor is the natural host environment: mucus, which contains gel-forming glycoproteins (mucins) that display hundreds of glycan structures with potential regulatory function. Leveraging a tractable culture-based system to study how mucins influence oral microbial communities, we found that mucin glycans enable the coexistence of diverse microbes, while resisting disease-associated compositional shifts. Mucins from tissues with unique glycosylation differentially tuned microbial composition, as did isolated mucin glycan libraries, uncovering the importance of specific glycan patterns in microbiome modulation. We found that mucins shape microbial communities in several ways: serving as nutrients to support metabolic diversity, organizing spatial structure through reduced aggregation, and possibly limiting antagonism between competing taxa. Overall, this work identifies mucin glycans as a natural host mechanism and potential therapeutic intervention to maintain healthy microbial communities.
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Affiliation(s)
- Chloe M Wu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kelsey M Wheeler
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gerardo Cárcamo-Oyarce
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Abigail McShane
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sujit S Datta
- Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | | | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Ann L Griffen
- Department of Dentistry, Nationwide Children's Hospital, Columbus, OH, USA
- Divisions of Biosciences and Pediatric Dentistry, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Katharina Ribbeck
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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13
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Modesto JL, Pearce VH, Townsend GE. Harnessing gut microbes for glycan detection and quantification. Nat Commun 2023; 14:275. [PMID: 36650134 PMCID: PMC9845299 DOI: 10.1038/s41467-022-35626-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 12/13/2022] [Indexed: 01/19/2023] Open
Abstract
Glycans facilitate critical biological functions and control the mammalian gut microbiota composition by supplying differentially accessible nutrients to distinct microbial subsets. Therefore, identifying unique glycan substrates that support defined microbial populations could inform therapeutic avenues to treat diseases via modulation of the gut microbiota composition and metabolism. However, examining heterogeneous glycan mixtures for individual microbial substrates is hindered by glycan structural complexity and diversity, which presents substantial challenges to glycomics approaches. Fortuitously, gut microbes encode specialized sensor proteins that recognize unique glycan structures and in-turn activate predictable, specific, and dynamic transcriptional responses. Here, we harness this microbial machinery to indicate the presence and abundance of compositionally similar, yet structurally distinct glycans, using a transcriptional reporter we develop. We implement these tools to examine glycan mixtures, isolate target molecules for downstream characterization, and quantify the recovered products. We assert that this toolkit could dramatically enhance our understanding of the mammalian intestinal environment and identify host-microbial interactions critical for human health.
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Affiliation(s)
- Jennifer L Modesto
- Department of Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, 17033, USA.,Penn State Microbiome Center, The Pennsylvania State University, State College, PA, 16802, USA.,Center for Molecular Carcinogenesis and Toxicology, The Pennsylvania State University, State College, PA, 16802, USA
| | - Victoria H Pearce
- Department of Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, 17033, USA.,Penn State Microbiome Center, The Pennsylvania State University, State College, PA, 16802, USA.,Center for Molecular Carcinogenesis and Toxicology, The Pennsylvania State University, State College, PA, 16802, USA
| | - Guy E Townsend
- Department of Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, 17033, USA. .,Penn State Microbiome Center, The Pennsylvania State University, State College, PA, 16802, USA. .,Center for Molecular Carcinogenesis and Toxicology, The Pennsylvania State University, State College, PA, 16802, USA.
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14
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Pearce VH, Groisman EA, Townsend GE. Dietary sugars silence the master regulator of carbohydrate utilization in human gut Bacteroides species. Gut Microbes 2023; 15:2221484. [PMID: 37358144 PMCID: PMC10294740 DOI: 10.1080/19490976.2023.2221484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/08/2023] [Indexed: 06/27/2023] Open
Abstract
The mammalian gut microbiota is a critical human health determinant with therapeutic potential for remediation of many diseases. The host diet is a key factor governing the gut microbiota composition by altering nutrient availability and supporting the expansion of distinct microbial populations. Diets rich in simple sugars modify the abundance of microbial subsets, enriching for microbiotas that elicit pathogenic outcomes. We previously demonstrated that diets rich in fructose and glucose can reduce the fitness and abundance of a human gut symbiont, Bacteroides thetaiotaomicron, by silencing the production of a critical intestinal colonization protein, called Roc, via its mRNA leader through an unknown mechanism. We have now determined that dietary sugars silence Roc by reducing the activity of BT4338, a master regulator of carbohydrate utilization. Here, we demonstrate that BT4338 is required for Roc synthesis, and that BT4338 activity is silenced by glucose or fructose. We show that the consequences of glucose and fructose on orthologous transcription factors are conserved across human intestinal Bacteroides species. This work identifies a molecular pathway by which a common dietary additive alters microbial gene expression in the gut that could be harnessed to modulate targeted microbial populations for future therapeutic interventions.
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Affiliation(s)
- Victoria H. Pearce
- Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
- Penn State Microbiome Center, Pennsylvania State University, State College, PA, USA
- Center for Molecular Carcinogenesis and Toxicology, Pennsylvania State University, State College, PA, USA
| | - Eduardo A. Groisman
- Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, USA
- Microbial Sciences Institute, Yale University, New Haven, CT, USA
| | - Guy E. Townsend
- Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
- Penn State Microbiome Center, Pennsylvania State University, State College, PA, USA
- Center for Molecular Carcinogenesis and Toxicology, Pennsylvania State University, State College, PA, USA
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15
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Geffroy L, Brown HA, DeVeaux AL, Koropatkin NM, Biteen JS. Single-molecule dynamics of surface lipoproteins in bacteroides indicate similarities and cooperativity. Biophys J 2022; 121:4644-4655. [PMID: 36266970 PMCID: PMC9748367 DOI: 10.1016/j.bpj.2022.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 12/15/2022] Open
Abstract
The gut microbiota comprises hundreds of species with a composition shaped by the available glycans. The well-studied starch utilization system (Sus) is a prototype for glycan uptake in the human gut bacterium Bacteroides thetaiotaomicron (Bt). Each Sus-like system includes outer-membrane proteins, which translocate glycan into the periplasm, and one or more cell-surface glycoside hydrolases, which break down a specific (cognate) polymer substrate. Although the molecular mechanisms of the Sus system are known, how the Sus and Sus-like proteins cooperate remains elusive. Previously, we used single-molecule and super-resolution fluorescence microscopy to show that SusG is mobile on the outer membrane and slows down in the presence of starch. Here, we compare the dynamics of three glycoside hydrolases: SusG, Bt4668, and Bt1760, which target starch, galactan, and levan, respectively. We characterized the diffusion of each surface hydrolase in the presence of its cognate glycan and found that all three enzymes are mostly immobile in the presence of the polysaccharide, consistent with carbohydrate binding. Moreover, experiments in glucose versus oligosaccharides suggest that the enzyme dynamics depend on their expression level. Furthermore, we characterized enzyme diffusion in a mixture of glycans and found that noncognate polysaccharides modify the dynamics of SusG and Bt1760 but not Bt4668. We investigated these systems with polysaccharide mixtures and genetic knockouts and found that noncognate polysaccharides modify hydrolase dynamics through some combination of nonspecific protein interactions and downregulation of the hydrolase. Overall, these experiments extend our understanding of how Sus-like lipoprotein dynamics can be modified by changing carbohydrate conditions and the expression level of the enzyme.
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Affiliation(s)
- Laurent Geffroy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan
| | - Haley A Brown
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Anna L DeVeaux
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan.
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16
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Cheng J, Hu J, Geng F, Nie S. Bacteroides utilization for dietary polysaccharides and their beneficial effects on gut health. FOOD SCIENCE AND HUMAN WELLNESS 2022. [DOI: 10.1016/j.fshw.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Loktionov A. Colon mucus in colorectal neoplasia and beyond. World J Gastroenterol 2022; 28:4475-4492. [PMID: 36157924 PMCID: PMC9476883 DOI: 10.3748/wjg.v28.i32.4475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/23/2022] [Accepted: 08/06/2022] [Indexed: 02/06/2023] Open
Abstract
Little was known about mammalian colon mucus (CM) until the beginning of the 21st century. Since that time considerable progress has been made in basic research addressing CM structure and functions. Human CM is formed by two distinct layers composed of gel-forming glycosylated mucins that are permanently secreted by goblet cells of the colonic epithelium. The inner layer is dense and impenetrable for bacteria, whereas the loose outer layer provides a habitat for abundant commensal microbiota. Mucus barrier integrity is essential for preventing bacterial contact with the mucosal epithelium and maintaining homeostasis in the gut, but it can be impaired by a variety of factors, including CM-damaging switch of commensal bacteria to mucin glycan consumption due to dietary fiber deficiency. It is proven that impairments in CM structure and function can lead to colonic barrier deterioration that opens direct bacterial access to the epithelium. Bacteria-induced damage dysregulates epithelial proliferation and causes mucosal inflammatory responses that may expand to the loosened CM and eventually result in severe disorders, including colitis and neoplastic growth. Recently described formation of bacterial biofilms within the inner CM layer was shown to be associated with both inflammation and cancer. Although obvious gaps in our knowledge of human CM remain, its importance for the pathogenesis of major colorectal diseases, comprising inflammatory bowel disease and colorectal cancer, is already recognized. Continuing progress in CM exploration is likely to result in the development of a range of new useful clinical applications addressing colorectal disease diagnosis, prevention and therapy.
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18
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Rawat PS, Seyed Hameed AS, Meng X, Liu W. Utilization of glycosaminoglycans by the human gut microbiota: participating bacteria and their enzymatic machineries. Gut Microbes 2022; 14:2068367. [PMID: 35482895 PMCID: PMC9067506 DOI: 10.1080/19490976.2022.2068367] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Glycosaminoglycans (GAGs) are consistently present in the human colon in free forms and as part of proteoglycans. Their utilization is critical for the colonization and proliferation of gut bacteria and also the health of hosts. Hence, it is essential to determine the GAG-degrading members of the gut bacteria and their enzymatic machinery for GAG depolymerization. In this review, we have summarized the reported GAG utilizers from Bacteroides and presented their polysaccharide utilization loci (PUL) and related enzymatic machineries for the degradation of chondroitin and heparin/heparan sulfate. Although similar comprehensive knowledge of GAG degradation is not available for other gut phyla, we have specified recently isolated GAG degraders from gut Firmicutes and Proteobacteria, and analyzed their genomes for the presence of putative GAG PULs. Deciphering the precise GAG utilization mechanism for various phyla will augment our understanding of their effects on human health.
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Affiliation(s)
- Parkash Singh Rawat
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No.72 Binhai Road, Qingdao266237, P. R. China
| | - Ahkam Saddam Seyed Hameed
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No.72 Binhai Road, Qingdao266237, P. R. China
| | - Xiangfeng Meng
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No.72 Binhai Road, Qingdao266237, P. R. China,CONTACT Xiangfeng Meng State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No.72 Binhai Road, Qingdao266237, P. R. China
| | - Weifeng Liu
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, No.72 Binhai Road, Qingdao266237, P. R. China
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19
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Tian X, Jiang H, Cai B, Feng H, Wang X, Yu G. Comparative Proteomic Analysis of Fucosylated Glycoproteins Produced by Bacteroides thetaiotaomicron Under Different Polysaccharide Nutrition Conditions. Front Microbiol 2022; 13:826942. [PMID: 35308349 PMCID: PMC8931616 DOI: 10.3389/fmicb.2022.826942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteroides thetaiotaomicron, one of the most eminent representative gut commensal Bacteroides species, is able to use the L-fucose in host-derived and dietary polysaccharides to modify its capsular polysaccharides and glycoproteins through a mammalian-like salvage metabolic pathway. This process is essential for the colonization of the bacteria and for symbiosis with the host. However, despite the importance of fucosylated proteins (FGPs) in B. thetaiotaomicron, their types, distribution, and functions remain unclear. In this study, the effects of different polysaccharide (corn starch, mucin, and fucoidan) nutrition conditions on newly synthesized FGPs expressions and fucosylation are investigated using a chemical biological method based on metabolic labeling and bioorthogonal reaction. According to the results of label-free quantification, 559 FGPs (205 downregulated and 354 upregulated) are affected by the dietary conditions. Of these differentially expressed proteins, 65 proteins show extremely sensitive to polysaccharide nutrition conditions (FGPs fold change/global protein fold change ≥2.0 or ≤0.5). Specifically, the fucosylation of the chondroitin sulfate ABC enzyme, Sus proteins, and cationic efflux system proteins varies significantly upon the addition of mucin, corn starch, or fucoidan. Moreover, these polysaccharides can trigger an appreciable increase in the fucosylation level of the two-component system and ammonium transport proteins. These results highlight the efficiency of the combined metabolic glycan labeling and bio-orthogonal reaction in enriching the intestinal Bacteroides glycoproteins. Moreover, it emphasizes the sensitivity of Bacteroides fucosylation to polysaccharide nutrition conditions, which allows for the regulation of bacterial growth.
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Affiliation(s)
- Xiao Tian
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Hao Jiang
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Binbin Cai
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Huxin Feng
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Xuan Wang
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Guangli Yu
- Key Laboratory of Marine Drugs of Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
- Laboratory for Marine Drugs and Bioproducts, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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20
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Park SY, Rao C, Coyte KZ, Kuziel GA, Zhang Y, Huang W, Franzosa EA, Weng JK, Huttenhower C, Rakoff-Nahoum S. Strain-level fitness in the gut microbiome is an emergent property of glycans and a single metabolite. Cell 2022; 185:513-529.e21. [PMID: 35120663 PMCID: PMC8896310 DOI: 10.1016/j.cell.2022.01.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/07/2021] [Accepted: 01/05/2022] [Indexed: 02/05/2023]
Abstract
The human gut microbiota resides within a diverse chemical environment challenging our ability to understand the forces shaping this ecosystem. Here, we reveal that fitness of the Bacteroidales, the dominant order of bacteria in the human gut, is an emergent property of glycans and one specific metabolite, butyrate. Distinct sugars serve as strain-variable fitness switches activating context-dependent inhibitory functions of butyrate. Differential fitness effects of butyrate within the Bacteroides are mediated by species-level variation in Acyl-CoA thioesterase activity and nucleotide polymorphisms regulating an Acyl-CoA transferase. Using in vivo multi-omic profiles, we demonstrate Bacteroides fitness in the human gut is associated together, but not independently, with Acyl-CoA transferase expression and butyrate. Our data reveal that each strain of the Bacteroides exists within a unique fitness landscape based on the interaction of chemical components unpredictable by the effect of each part alone mediated by flexibility in the core genome.
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Affiliation(s)
- Sun-Yang Park
- Division of Infectious Diseases and Division of Gastroenterology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Chitong Rao
- Division of Infectious Diseases and Division of Gastroenterology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Katharine Z Coyte
- Division of Infectious Diseases and Division of Gastroenterology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Gavin A Kuziel
- Division of Infectious Diseases and Division of Gastroenterology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Yancong Zhang
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Wentao Huang
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Eric A Franzosa
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jing-Ke Weng
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Seth Rakoff-Nahoum
- Division of Infectious Diseases and Division of Gastroenterology, Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA; Department of Microbiology, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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21
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Gardner JG, Schreier HJ. Unifying themes and distinct features of carbon and nitrogen assimilation by polysaccharide-degrading bacteria: a summary of four model systems. Appl Microbiol Biotechnol 2021; 105:8109-8127. [PMID: 34611726 DOI: 10.1007/s00253-021-11614-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/24/2022]
Abstract
Our current understanding of enzymatic polysaccharide degradation has come from a huge number of in vitro studies with purified enzymes. While this vast body of work has been invaluable in identifying and characterizing novel mechanisms of action and engineering desirable traits into these enzymes, a comprehensive picture of how these enzymes work as part of a native in vivo system is less clear. Recently, several model bacteria have emerged with genetic systems that allow for a more nuanced study of carbohydrate active enzymes (CAZymes) and how their activity affects bacterial carbon metabolism. With these bacterial model systems, it is now possible to not only study a single nutrient system in isolation (i.e., carbohydrate degradation and carbon metabolism), but also how multiple systems are integrated. Given that most environmental polysaccharides are carbon rich but nitrogen poor (e.g., lignocellulose), the interplay between carbon and nitrogen metabolism in polysaccharide-degrading bacteria can now be studied in a physiologically relevant manner. Therefore, in this review, we have summarized what has been experimentally determined for CAZyme regulation, production, and export in relation to nitrogen metabolism for two Gram-positive (Caldicellulosiruptor bescii and Clostridium thermocellum) and two Gram-negative (Bacteroides thetaiotaomicron and Cellvibrio japonicus) polysaccharide-degrading bacteria. By comparing and contrasting these four bacteria, we have highlighted the shared and unique features of each, with a focus on in vivo studies, in regard to carbon and nitrogen assimilation. We conclude with what we believe are two important questions that can act as guideposts for future work to better understand the integration of carbon and nitrogen metabolism in polysaccharide-degrading bacteria. KEY POINTS: • Regardless of CAZyme deployment system, the generation of a local pool of oligosaccharides is a common strategy among Gram-negative and Gram-positive polysaccharide degraders as a means to maximally recoup the energy expenditure of CAZyme production and export. • Due to the nitrogen deficiency of insoluble polysaccharide-containing substrates, Gram-negative and Gram-positive polysaccharide degraders have a diverse set of strategies for supplementation and assimilation. • Future work needs to precisely characterize the energetic expenditures of CAZyme deployment and bolster our understanding of how carbon and nitrogen metabolism are integrated in both Gram-negative and Gram-positive polysaccharide-degrading bacteria, as both of these will significantly influence a given bacterium's suitability for biotechnology applications.
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Affiliation(s)
- Jeffrey G Gardner
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.
| | - Harold J Schreier
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA.,Department of Marine Biotechnology, Institute of Marine and Environmental Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
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22
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Wang BX, Wu CM, Ribbeck K. Home, sweet home: how mucus accommodates our microbiota. FEBS J 2021; 288:1789-1799. [PMID: 32755014 PMCID: PMC8739745 DOI: 10.1111/febs.15504] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 07/17/2020] [Accepted: 07/30/2020] [Indexed: 12/16/2022]
Abstract
As a natural environment for human-microbiota interactions, healthy mucus houses a remarkably stable and diverse microbial community. Maintaining this microbiota is essential to human health, both to support the commensal bacteria that perform a wide array of beneficial functions and to prevent the outgrowth of pathogens. However, how the host selects and maintains a specialized microbiota remains largely unknown. In this viewpoint, we propose several strategies by which mucus may regulate the composition and function of the human microbiota and discuss how compromised mucus barriers in disease can give rise to microbial dysbiosis.
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Affiliation(s)
- Benjamin X Wang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chloe M Wu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Katharina Ribbeck
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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23
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Briggs JA, Grondin JM, Brumer H. Communal living: glycan utilization by the human gut microbiota. Environ Microbiol 2020; 23:15-35. [PMID: 33185970 DOI: 10.1111/1462-2920.15317] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/15/2022]
Abstract
Our lower gastrointestinal tract plays host to a vast consortium of microbes, known as the human gut microbiota (HGM). The HGM thrives on a complex and diverse range of glycan structures from both dietary and host sources, the breakdown of which requires the concerted action of cohorts of carbohydrate-active enzymes (CAZymes), carbohydrate-binding proteins, and transporters. The glycan utilization profile of individual taxa, whether 'specialist' or 'generalist', is dictated by the number and functional diversity of these glycan utilization systems. Furthermore, taxa in the HGM may either compete or cooperate in glycan deconstruction, thereby creating a complex ecological web spanning diverse nutrient niches. As a result, our diet plays a central role in shaping the composition of the HGM. This review presents an overview of our current understanding of glycan utilization by the HGM on three levels: (i) molecular mechanisms of individual glycan deconstruction and uptake by key bacteria, (ii) glycan-mediated microbial interactions, and (iii) community-scale effects of dietary changes. Despite significant recent advancements, there remains much to be discovered regarding complex glycan metabolism in the HGM and its potential to affect positive health outcomes.
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Affiliation(s)
- Jonathon A Briggs
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Julie M Grondin
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Department of Chemistry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.,Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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24
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Glowacki RWP, Martens EC. If you eat it, or secrete it, they will grow: the expanding list of nutrients utilized by human gut bacteria. J Bacteriol 2020; 203:JB.00481-20. [PMID: 33168637 PMCID: PMC8092160 DOI: 10.1128/jb.00481-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In order to persist, successful bacterial inhabitants of the human gut need to adapt to changing nutrient conditions, which are influenced by host diet and a variety of other factors. For members of the Bacteroidetes and several other phyla, this has resulted in diversification of a variety of enzyme-based systems that equip them to sense and utilize carbohydrate-based nutrients from host, diet, and bacterial origin. In this review, we focus first on human gut Bacteroides and describe recent findings regarding polysaccharide utilization loci (PULs) and the mechanisms of the multi-protein systems they encode, including their regulation and the expanding diversity of substrates that they target. Next, we highlight previously understudied substrates such as monosaccharides, nucleosides, and Maillard reaction products that can also affect the gut microbiota by feeding symbionts that possess specific systems for their metabolism. Since some pathogens preferentially utilize these nutrients, they may represent nutrient niches competed for by commensals and pathogens. Finally, we address recent work to describe nutrient acquisition mechanisms in other important gut species such as those belonging to the Gram-positive anaerobic phyla Actinobacteria and Firmicutes, as well as the Proteobacteria Because gut bacteria contribute to many aspects of health and disease, we showcase advances in the field of synthetic biology, which seeks to engineer novel, diet-controlled nutrient utilization pathways within gut symbionts to create rationally designed live therapeutics.
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Affiliation(s)
- Robert W. P. Glowacki
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Eric C. Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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25
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Centanni M, Bell TJ, Sims IM, Tannock GW. Preferential use of plant glycans for growth by Bacteroides ovatus. Anaerobe 2020; 66:102276. [PMID: 32927049 DOI: 10.1016/j.anaerobe.2020.102276] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/31/2020] [Accepted: 09/11/2020] [Indexed: 10/23/2022]
Abstract
B. ovatus is a member of the human gut microbiota with a broad capability to degrade complex glycans. Here we show that B. ovatus degrades plant polysaccharides in a preferential order, and that glycan structural complexity plays a role in determining the prioritisation of polysaccharide usage.
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Affiliation(s)
- Manuela Centanni
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
| | - Tracey J Bell
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt, 5040, New Zealand
| | - Ian M Sims
- The Ferrier Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt, 5040, New Zealand
| | - Gerald W Tannock
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; Riddet Institute Centre of Research Excellence, Palmerston North, 4442, New Zealand
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26
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Ye M, Yu J, Shi X, Zhu J, Gao X, Liu W. Polysaccharides catabolism by the human gut bacterium - Bacteroides thetaiotaomicron: advances and perspectives. Crit Rev Food Sci Nutr 2020; 61:3569-3588. [PMID: 32779480 DOI: 10.1080/10408398.2020.1803198] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In recent years, the degradation processes of polysaccharides by human gut microbiota are receiving considerable attention due to the discoveries of the powerful function of gut microbiota. Gut microbiota has developed a sensitive, accurate, and complex system for sensing, capturing, and degrading different polysaccharides. Among the gut microbiota, Bacteroides thetaiotaomicron, a representative species of Bacteroides, is considered as the best degrader of polysaccharides and a potential probiotic in pharmaceutical and food industries. Here, we summarize the degradation system of B. thetaiotaomicron and the degradation pathways of different polysaccharides by B. thetaiotaomicron. We also describe a technical route for investigating a specific polysaccharide degradation pathway by human gut bacteria. In addition, we also provide the future perspectives in the development of novel polysaccharides or oligosaccharides drugs, precision microbiology medicine, and personalized nutrition.
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Affiliation(s)
- Meng Ye
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, PR China
| | - Juping Yu
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, PR China
| | - Xuexia Shi
- Department of Clinical Pharmacy, Qinghai University Affiliated Hospital, Xining, PR China
| | - Jingyi Zhu
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, PR China
| | - Xiangdong Gao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, PR China
| | - Wei Liu
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, State Key Laboratory of Natural Medicines, School of Life Science and Technology, China Pharmaceutical University, Nanjing, PR China.,Department of Clinical Pharmacy, Qinghai University Affiliated Hospital, Xining, PR China
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27
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Nutrient-dependent morphological variability of Bacteroides thetaiotaomicron. Microbiology (Reading) 2020; 166:624-628. [DOI: 10.1099/mic.0.000924] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Unique morphologies can enable bacteria to survive in their native environment. Furthermore, many bacteria change their cell shape to adapt to different environmental conditions. For instance, some bacteria increase their surface area under carbon or nitrogen starvation. Bacteriodes thetaiotaomicron is an abundant human gut species; it efficiently degrades a number of carbohydrates and also supports the growth of other bacteria by breaking down complex polysaccharides. The gut provides a variable environment as nutrient availability is subject to the diet and health of the host, yet how gut bacteria adapt and change their morphologies under different nutrient conditions has not been studied. Here, for the first time, we report an elongated
B. thetaiotaomicron
morphology under sugar-limited conditions using live-cell imaging; this elongated morphology is enhanced in the presence of sodium bicarbonate. Similarly, we also observed that sodium bicarbonate produces an elongated-length phenotype in another Gram-negative gut bacterium,
Escherichia coli
. The increase in cell length might provide an adaptive advantage for cells to survive under nutrient-limited conditions.
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28
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Engineering dual-glycan responsive expression systems for tunable production of heterologous proteins in Bacteroides thetaiotaomicron. Sci Rep 2019; 9:17400. [PMID: 31758019 PMCID: PMC6874557 DOI: 10.1038/s41598-019-53726-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 09/24/2019] [Indexed: 12/17/2022] Open
Abstract
Genetically engineering intestinal bacteria, such as Bacteroides thetaiotaomicron (B. theta), holds potential for creating new classes of biological devices, such as diagnostics or therapeutic delivery systems. Here, we have developed a series of B. theta strains that produce functional transgenic enzymes in response to dextran and arabinogalactan, two chemically distinct glycans. Expression systems for single glycan induction, and a novel “dual-glycan” expression system, requiring the presence of both dextran and arabinogalactan, have been developed. In addition, we have created two different chromosomal integration systems and one episomal vector system, compatible with engineered recipient strains, to improve the throughput and flexibility of gene cloning, integration, and expression in B. theta. To monitor activity, we have demonstrated the functionality of two different transgenic enzymes: NanoLuc, a luciferase, and BuGH16C, an agarase from the human intestinal bacterium, Bacteroides uniforms NP1. Together this expression platform provides a new collection of glycan-responsive tools to improve the strength and fidelity of transgene expression in B. theta and provides proof-of-concept for engineering more complex multi-glycan expression systems.
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29
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Déjean G, Tauzin AS, Bennett SW, Creagh AL, Brumer H. Adaptation of Syntenic Xyloglucan Utilization Loci of Human Gut Bacteroidetes to Polysaccharide Side Chain Diversity. Appl Environ Microbiol 2019; 85:e01491-19. [PMID: 31420336 PMCID: PMC6805095 DOI: 10.1128/aem.01491-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 08/08/2019] [Indexed: 12/16/2022] Open
Abstract
Genome sequencing has revealed substantial variation in the predicted abilities of individual species within animal gut microbiota to metabolize the complex carbohydrates comprising dietary fiber. At the same time, a currently limited body of functional studies precludes a richer understanding of how dietary glycan structures affect the gut microbiota composition and community dynamics. Here, using biochemical and biophysical techniques, we identified and characterized differences among recombinant proteins from syntenic xyloglucan utilization loci (XyGUL) of three Bacteroides and one Dysgonomonas species from the human gut, which drive substrate specificity and access to distinct polysaccharide side chains. Enzymology of four syntenic glycoside hydrolase family 5 subfamily 4 (GH5_4) endo-xyloglucanases revealed surprising differences in xyloglucan (XyG) backbone cleavage specificity, including the ability of some homologs to hydrolyze congested branched positions. Further, differences in the complement of GH43 alpha-l-arabinofuranosidases and GH95 alpha-l-fucosidases among syntenic XyGUL confer distinct abilities to fully saccharify plant species-specific arabinogalactoxyloglucan and/or fucogalactoxyloglucan. Finally, characterization of highly sequence-divergent cell surface glycan-binding proteins (SGBPs) across syntenic XyGUL revealed a novel group of XyG oligosaccharide-specific SGBPs encoded within select BacteroidesIMPORTANCE The catabolism of complex carbohydrates that otherwise escape the endogenous digestive enzymes of humans and other animals drives the composition and function of the gut microbiota. Thus, detailed molecular characterization of dietary glycan utilization systems is essential both to understand the ecology of these complex communities and to manipulate their compositions, e.g., to benefit human health. Our research reveals new insight into how ubiquitous members of the human gut microbiota have evolved a set of microheterogeneous gene clusters to efficiently respond to the structural variations of plant xyloglucans. The data here will enable refined functional prediction of xyloglucan utilization among diverse environmental taxa in animal guts and beyond.
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Affiliation(s)
- Guillaume Déjean
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alexandra S Tauzin
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stuart W Bennett
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Louise Creagh
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Harry Brumer
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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30
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Koch H, Dürwald A, Schweder T, Noriega-Ortega B, Vidal-Melgosa S, Hehemann JH, Dittmar T, Freese HM, Becher D, Simon M, Wietz M. Biphasic cellular adaptations and ecological implications of Alteromonas macleodii degrading a mixture of algal polysaccharides. THE ISME JOURNAL 2019; 13:92-103. [PMID: 30116038 PMCID: PMC6298977 DOI: 10.1038/s41396-018-0252-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/10/2018] [Accepted: 07/19/2018] [Indexed: 11/08/2022]
Abstract
Algal polysaccharides are an important bacterial nutrient source and central component of marine food webs. However, cellular and ecological aspects concerning the bacterial degradation of polysaccharide mixtures, as presumably abundant in natural habitats, are poorly understood. Here, we contextualize marine polysaccharide mixtures and their bacterial utilization in several ways using the model bacterium Alteromonas macleodii 83-1, which can degrade multiple algal polysaccharides and contributes to polysaccharide degradation in the oceans. Transcriptomic, proteomic and exometabolomic profiling revealed cellular adaptations of A. macleodii 83-1 when degrading a mix of laminarin, alginate and pectin. Strain 83-1 exhibited substrate prioritization driven by catabolite repression, with initial laminarin utilization followed by simultaneous alginate/pectin utilization. This biphasic phenotype coincided with pronounced shifts in gene expression, protein abundance and metabolite secretion, mainly involving CAZymes/polysaccharide utilization loci but also other functional traits. Distinct temporal changes in exometabolome composition, including the alginate/pectin-specific secretion of pyrroloquinoline quinone, suggest that substrate-dependent adaptations influence chemical interactions within the community. The ecological relevance of cellular adaptations was underlined by molecular evidence that common marine macroalgae, in particular Saccharina and Fucus, release mixtures of alginate and pectin-like rhamnogalacturonan. Moreover, CAZyme microdiversity and the genomic predisposition towards polysaccharide mixtures among Alteromonas spp. suggest polysaccharide-related traits as an ecophysiological factor, potentially relating to distinct 'carbohydrate utilization types' with different ecological strategies. Considering the substantial primary productivity of algae on global scales, these insights contribute to the understanding of bacteria-algae interactions and the remineralization of chemically diverse polysaccharide pools, a key step in marine carbon cycling.
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Affiliation(s)
- Hanna Koch
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
- Department of Microbiology, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Alexandra Dürwald
- Institute of Marine Biotechnology, Greifswald, Germany
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Thomas Schweder
- Institute of Marine Biotechnology, Greifswald, Germany
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Beatriz Noriega-Ortega
- ICBM-MPI Bridging Group for Marine Geochemistry, University of Oldenburg, Oldenburg, Germany
| | - Silvia Vidal-Melgosa
- MARUM-MPI Bridge Group for Marine Glycobiology, University of Bremen, Bremen, Germany
| | - Jan-Hendrik Hehemann
- MARUM-MPI Bridge Group for Marine Glycobiology, University of Bremen, Bremen, Germany
| | - Thorsten Dittmar
- ICBM-MPI Bridging Group for Marine Geochemistry, University of Oldenburg, Oldenburg, Germany
| | - Heike M Freese
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Dörte Becher
- Institute of Marine Biotechnology, Greifswald, Germany
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Matthias Wietz
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany.
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31
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Li S, Li M, Yue H, Zhou L, Huang L, Du Z, Ding K. Structural elucidation of a pectic polysaccharide from Fructus Mori and its bioactivity on intestinal bacteria strains. Carbohydr Polym 2018; 186:168-175. [DOI: 10.1016/j.carbpol.2018.01.026] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/20/2017] [Accepted: 01/09/2018] [Indexed: 12/21/2022]
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32
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Navigating the Gut Buffet: Control of Polysaccharide Utilization in Bacteroides spp. Trends Microbiol 2017; 25:1005-1015. [DOI: 10.1016/j.tim.2017.06.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 06/09/2017] [Accepted: 06/20/2017] [Indexed: 12/26/2022]
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33
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Frank SA. Receptor uptake arrays for vitamin B 12, siderophores, and glycans shape bacterial communities. Ecol Evol 2017; 7:10175-10195. [PMID: 29238546 PMCID: PMC5723603 DOI: 10.1002/ece3.3544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/20/2017] [Accepted: 09/28/2017] [Indexed: 01/15/2023] Open
Abstract
Molecular variants of vitamin B12, siderophores, and glycans occur. To take up variant forms, bacteria may express an array of receptors. The gut microbe Bacteroides thetaiotaomicron has three different receptors to take up variants of vitamin B12 and 88 receptors to take up various glycans. The design of receptor arrays reflects key processes that shape cellular evolution. Competition may focus each species on a subset of the available nutrient diversity. Some gut bacteria can take up only a narrow range of carbohydrates, whereas species such as B. thetaiotaomicron can digest many different complex glycans. Comparison of different nutrients, habitats, and genomes provides opportunity to test hypotheses about the breadth of receptor arrays. Another important process concerns fluctuations in nutrient availability. Such fluctuations enhance the value of cellular sensors, which gain information about environmental availability and adjust receptor deployment. Bacteria often adjust receptor expression in response to fluctuations of particular carbohydrate food sources. Some species may adjust expression of uptake receptors for specific siderophores. How do cells use sensor information to control the response to fluctuations? This question about regulatory wiring relates to problems that arise in control theory and artificial intelligence. Control theory clarifies how to analyze environmental fluctuations in relation to the design of sensors and response systems. Recent advances in deep learning studies of artificial intelligence focus on the architecture of regulatory wiring and the ways in which complex control networks represent and classify environmental states. I emphasize the similar design problems that arise in cellular evolution, control theory, and artificial intelligence. I connect those broad conceptual aspects to many testable hypotheses for bacterial uptake of vitamin B12, siderophores, and glycans.
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Affiliation(s)
- Steven A. Frank
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaIrvineCAUSA
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34
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Tuncil YE, Xiao Y, Porter NT, Reuhs BL, Martens EC, Hamaker BR. Reciprocal Prioritization to Dietary Glycans by Gut Bacteria in a Competitive Environment Promotes Stable Coexistence. mBio 2017; 8:e01068-17. [PMID: 29018117 PMCID: PMC5635687 DOI: 10.1128/mbio.01068-17] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/28/2017] [Indexed: 12/22/2022] Open
Abstract
When presented with nutrient mixtures, several human gut Bacteroides species exhibit hierarchical utilization of glycans through a phenomenon that resembles catabolite repression. However, it is unclear how closely these observed physiological changes, often measured by altered transcription of glycan utilization genes, mirror actual glycan depletion. To understand the glycan prioritization strategies of two closely related human gut symbionts, Bacteroides ovatus and Bacteroides thetaiotaomicron, we performed a series of time course assays in which both species were individually grown in a medium with six different glycans that both species can degrade. Disappearance of the substrates and transcription of the corresponding polysaccharide utilization loci (PULs) were measured. Each species utilized some glycans before others, but with different priorities per species, providing insight into species-specific hierarchical preferences. In general, the presence of highly prioritized glycans repressed transcription of genes involved in utilizing lower-priority nutrients. However, transcriptional sensitivity to some glycans varied relative to the residual concentration in the medium, with some PULs that target high-priority substrates remaining highly expressed even after their target glycan had been mostly depleted. Coculturing of these organisms in the same mixture showed that the hierarchical orders generally remained the same, promoting stable coexistence. Polymer length was found to be a contributing factor for glycan utilization, thereby affecting its place in the hierarchy. Our findings not only elucidate how B. ovatus and B. thetaiotaomicron strategically access glycans to maintain coexistence but also support the prioritization of carbohydrate utilization based on carbohydrate structure, advancing our understanding of the relationships between diet and the gut microbiome.IMPORTANCE The microorganisms that reside in the human colon fulfill their energy requirements mainly from diet- and host-derived complex carbohydrates. Members of this ecosystem possess poorly understood strategies to prioritize and compete for these nutrients. Based on direct carbohydrate measurements and corresponding transcriptional analyses, our findings showed that individual bacterial species exhibit different preferences for the same set of glycans and that this prioritization is maintained in a competitive environment, which may promote stable coexistence. Such understanding of gut bacterial glycan utilization will be essential to eliciting predictable changes in the gut microbiota to improve health through the diet.
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Affiliation(s)
- Yunus E Tuncil
- Whistler Center for Carbohydrate Research, Food Science Department, Purdue University, West Lafayette, Indiana, USA
| | - Yao Xiao
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Nathan T Porter
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Bradley L Reuhs
- Whistler Center for Carbohydrate Research, Food Science Department, Purdue University, West Lafayette, Indiana, USA
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Bruce R Hamaker
- Whistler Center for Carbohydrate Research, Food Science Department, Purdue University, West Lafayette, Indiana, USA
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35
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Abstract
The human intestine harbors a dense microbial ecosystem (microbiota) that is different between individuals, dynamic over time, and critical for aspects of health and disease. Dietary polysaccharides directly shape the microbiota because of a gap in human digestive physiology, which is equipped to assimilate only proteins, lipids, simple sugars, and starch, leaving nonstarch polysaccharides as major nutrients reaching the microbiota. A mutualistic role of gut microbes is to digest dietary complex carbohydrates, liberating host-absorbable energy via fermentation products. Emerging data indicate that polysaccharides play extensive roles in host-gut microbiota symbiosis beyond dietary polysaccharide digestion, including microbial interactions with endogenous host glycans and the importance of microbial polysaccharides. In this review, we consider multiple mechanisms through which polysaccharides mediate aspects of host-microbe symbiosis in the gut, including some affecting health. As host and microbial metabolic pathways are intimately connected with diet, we highlight the potential to manipulate this system for health.
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Affiliation(s)
- Nathan T Porter
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109;
| | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109;
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36
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Abstract
The complex carbohydrates of terrestrial and marine biomass represent a rich nutrient source for free-living and mutualistic microbes alike. The enzymatic saccharification of these diverse substrates is of critical importance for fueling a variety of complex microbial communities, including marine, soil, ruminant, and monogastric microbiota. Consequently, highly specific carbohydrate-active enzymes, recognition proteins, and transporters are enriched in the genomes of certain species and are of critical importance in competitive environments. In Bacteroidetes bacteria, these systems are organized as polysaccharide utilization loci (PULs), which are strictly regulated, colocalized gene clusters that encode enzyme and protein ensembles required for the saccharification of complex carbohydrates. This review provides historical perspectives and summarizes key findings in the study of these systems, highlighting a critical shift from sequence-based PUL discovery to systems-based analyses combining reverse genetics, biochemistry, enzymology, and structural biology to precisely illuminate the molecular mechanisms underpinning PUL function. The ecological implications of dynamic PUL deployment by key species in the human gastrointestinal tract are explored, as well as the wider distribution of these systems in other gut, terrestrial, and marine environments.
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