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Gough AM, Parker AC, O'Bryan PJ, Whitehead TR, Roy S, Garcia BL, Hoffman PS, Jeffrey Smith C, Rocha ER. New functions of pirin proteins and a 2-ketoglutarate: Ferredoxin oxidoreductase ortholog in Bacteroides fragilis metabolism and their impact on antimicrobial susceptibility to metronidazole and amixicile. Microbiologyopen 2024; 13:e1429. [PMID: 39109824 PMCID: PMC11304471 DOI: 10.1002/mbo3.1429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 07/05/2024] [Accepted: 07/12/2024] [Indexed: 08/10/2024] Open
Abstract
The understanding of how central metabolism and fermentation pathways regulate antimicrobial susceptibility in the anaerobic pathogen Bacteroides fragilis is still incomplete. Our study reveals that B. fragilis encodes two iron-dependent, redox-sensitive regulatory pirin protein genes, pir1 and pir2. The mRNA expression of these genes increases when exposed to oxygen and during growth in iron-limiting conditions. These proteins, Pir1 and Pir2, influence the production of short-chain fatty acids and modify the susceptibility to metronidazole and amixicile, a new inhibitor of pyruvate: ferredoxin oxidoreductase in anaerobes. We have demonstrated that Pir1 and Pir2 interact directly with this oxidoreductase, as confirmed by two-hybrid system assays. Furthermore, structural analysis using AlphaFold2 predicts that Pir1 and Pir2 interact stably with several central metabolism enzymes, including the 2-ketoglutarate:ferredoxin oxidoreductases Kor1AB and Kor2CDAEBG. We used a series of metabolic mutants and electron transport chain inhibitors to demonstrate the extensive impact of bacterial metabolism on metronidazole and amixicile susceptibility. We also show that amixicile is an effective antimicrobial against B. fragilis in an experimental model of intra-abdominal infection. Our investigation led to the discovery that the kor2AEBG genes are essential for growth and have dual functions, including the formation of 2-ketoglutarate via the reverse TCA cycle. However, the metabolic activity that bypasses the function of Kor2AEBG following the addition of phospholipids or fatty acids remains undefined. Overall, our study provides new insights into the central metabolism of B. fragilis and its regulation by pirin proteins, which could be exploited for the development of new narrow-spectrum antimicrobials in the future.
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Affiliation(s)
- Andrea M. Gough
- Department of Microbiology and ImmunologyBrody School of Medicine at East Carolina UniversityGreenvilleNorth CarolinaUSA
| | - Anita C. Parker
- Department of Microbiology and ImmunologyBrody School of Medicine at East Carolina UniversityGreenvilleNorth CarolinaUSA
| | | | | | - Sourav Roy
- Department of Microbiology and ImmunologyBrody School of Medicine at East Carolina UniversityGreenvilleNorth CarolinaUSA
| | - Brandon L. Garcia
- Department of Microbiology and ImmunologyBrody School of Medicine at East Carolina UniversityGreenvilleNorth CarolinaUSA
| | - Paul S. Hoffman
- Department of Medicine, Division of Infectious Diseases and International HealthUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - C. Jeffrey Smith
- Department of Microbiology and ImmunologyBrody School of Medicine at East Carolina UniversityGreenvilleNorth CarolinaUSA
| | - Edson R. Rocha
- Department of Microbiology and ImmunologyBrody School of Medicine at East Carolina UniversityGreenvilleNorth CarolinaUSA
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Luan J, Zhang F, Suo L, Zhang W, Li Y, Yu X, Liu B, Cao H. Analyzing lung cancer risks in patients with impaired pulmonary function through characterization of gut microbiome and metabolites. BMC Pulm Med 2024; 24:1. [PMID: 38166904 PMCID: PMC10759599 DOI: 10.1186/s12890-023-02825-6] [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: 10/21/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Lung cancer (LC) is one of the most devastating diseases worldwide, there is growing studies confirm the role of impaired lung function in LC susceptibility. Moreover, gut microbiota dysbiosis is associated with LC severity. Whether alterations in gut microbiota and metabolites are associated with long-term lung dysfunction in LC patients remain unclear. Our study aimed to analyze the risk factors in LC patients with impaired pulmonary function based on the characteristics of the gut microbiome and metabolites. METHODS Fecal samples from 55 LC patients and 28 benign pulmonary nodules patients were collected. Pulmonary ventilation function was graded according to the American Thoracic Society/ European Respiratory Society (ATS/ERS) method. LC patients were divided into 3 groups, including 20 patients with normal lung ventilation, 23 patients with mild pulmonary ventilation dysfunction and 12 patients with moderate or above pulmonary ventilation dysfunction. The fecal samples were analyzed using 16 S rRNA gene amplicon sequencing and metabolomics. RESULTS The gut microbiome composition between LC patients and benign pulmonary nodules patients presented clearly differences based on Partial Least Squares Discriminant Analysis (PLS-DA). Pulmonary ventilation function was positively correlated with LC tumor stage, the richness and diversity of the gut microbiota in LC patients with moderate or above pulmonary ventilation dysfunction increased significantly, characterized by increased abundance of Subdoligranulum and Romboutsia. The metabolomics analysis revealed 69 differential metabolites, which were mainly enriched in beta-Alanine metabolism, styrene degradation and pyrimidine metabolism pathway. The area under the curve (AUC) combining the gut microbiome and metabolites was 90% (95% CI: 79-100%), indicating that the two species and four metabolites might regarded as biomarkers to assess the prediction of LC patients with impaired pulmonary function. CONCLUSIONS Our results showed that microbiome and metabolomics analyses provide important candidate to be used as clinically diagnostic biomarkers and therapeutic targets related to lung cancer with impaired pulmonary function.
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Affiliation(s)
- Jiahui Luan
- Department of Clinical Microbiology, Zibo City Key Laboratory of Respiratory Infection and Clinical Microbiology, Zibo City Engineering Technology Research Center of Etiology Molecular Diagnosis, Zibo Municipal Hospital, Zibo, 255400, China
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China
| | - Fuxin Zhang
- Department of Clinical Microbiology, Zibo City Key Laboratory of Respiratory Infection and Clinical Microbiology, Zibo City Engineering Technology Research Center of Etiology Molecular Diagnosis, Zibo Municipal Hospital, Zibo, 255400, China
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China
| | - Lijun Suo
- Department of Pulmonary and Critical Care Medicine, Zibo Municipal Hospital, Zibo, 255400, China
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China
| | - Wei Zhang
- Department of General Thoracic Surgery, Zibo Municipal Hospital, Zibo, 255400, China
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China
| | - Yige Li
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Xiaofeng Yu
- Department of Clinical Microbiology, Zibo City Key Laboratory of Respiratory Infection and Clinical Microbiology, Zibo City Engineering Technology Research Center of Etiology Molecular Diagnosis, Zibo Municipal Hospital, Zibo, 255400, China
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China
| | - Bo Liu
- Department of Clinical Microbiology, Zibo City Key Laboratory of Respiratory Infection and Clinical Microbiology, Zibo City Engineering Technology Research Center of Etiology Molecular Diagnosis, Zibo Municipal Hospital, Zibo, 255400, China.
- Department of Pulmonary and Critical Care Medicine, Zibo Municipal Hospital, Zibo, 255400, China.
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China.
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.
| | - Hongyun Cao
- Department of Clinical Microbiology, Zibo City Key Laboratory of Respiratory Infection and Clinical Microbiology, Zibo City Engineering Technology Research Center of Etiology Molecular Diagnosis, Zibo Municipal Hospital, Zibo, 255400, China.
- Shandong University-Zibo Municipal Hospital Research Center of Human Microbiome and Health, Zibo, 255400, China.
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Wang M, Feng X, Zhao Y, Lan Y, Xu H. Indole-3-acetamide from gut microbiota activated hepatic AhR and mediated the remission effect of Lactiplantibacillus plantarum P101 on alcoholic liver injury in mice. Food Funct 2023; 14:10535-10548. [PMID: 37947440 DOI: 10.1039/d3fo03585a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Alcoholic liver disease is a prevalent condition resulting from excessive alcohol consumption, characterized by hepatic lipid accumulation and inflammation. This study delved into the protective effects and mechanisms of L. plantarum P101 on alcoholic liver injury in mice. As a result, L. plantarum P101 intervention reduced ALT and AST release, indicative of hepatocyte injury alleviation, while enhancing the activity of the antioxidant enzymes SOD and CAT. A reduction in pro-inflammatory cytokine TNF-α and an increase in anti-inflammatory cytokine IL-10 levels were observed in the L. plantarum P101-intervened mouse liver, signifying reduced inflammation within the mice. Furthermore, L. plantarum P101 intervention altered the gut microbial composition, primarily marked by an increase in Bacteroidota abundance, along with significant enrichment of beneficial bacteria, including Coprostanoligenes, Blautia and Lactiplantibacillus. Correlation analysis unveiled connections between serum tryptophan metabolites and the altered gut microbiota genera, suggesting that gut microbiota-driven effects may extend to extraintestinal organs through their metabolites. Intriguingly, serum indole-3-acetamide (IAM) was elevated by L. plantarum P101-regulated gut microbiota. Subsequently, the role of IAM in ameliorating alcoholic injury was explored using HepG2 cells, where it bolstered cell viability and attenuated EtOH-induced oxidative damage. Concomitantly, IAM activated the gene and protein expression of AhR in cells. Likewise, hepatic AhR expression in mice subjected to L. plantarum P101 significantly up-regulated, possibly instigated by gut microbiota-mediated IAM. Collectively, L. plantarum P101 orchestrates a modulation of gut microbiota and its metabolites, particularly IAM, to activate AhR, thereby alleviating alcoholic liver injury.
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Affiliation(s)
- Mengqi Wang
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, P.R. China.
| | - Xiaoyan Feng
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, P.R. China.
| | - Yu Zhao
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, P.R. China.
| | - Yuzhi Lan
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, P.R. China.
| | - Hengyi Xu
- State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang 330047, P.R. China.
- International Institute of Food Innovation, Nanchang University, Nanchang 330299, P.R. China
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Li J, Chen X, Zhao S, Chen J. Arsenic-Containing Medicine Treatment Disturbed the Human Intestinal Microbial Flora. TOXICS 2023; 11:toxics11050458. [PMID: 37235272 DOI: 10.3390/toxics11050458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/07/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023]
Abstract
Human intestinal microbiome plays vital role in maintaining intestinal homeostasis and interacting with xenobiotics. Few investigations have been conducted to understand the effect of arsenic-containing medicine exposure on gut microbiome. Most animal experiments are onerous in terms of time and resources and not in line with the international effort to reduce animal experiments. We explored the overall microbial flora by 16S rRNA genes analysis in fecal samples from acute promyelocytic leukemia (APL) patients treated with arsenic trioxide (ATO) plus all-trans retinoic acid (ATRA). Gut microbiomes were found to be overwhelmingly dominated by Firmicutes and Bacteroidetes after taking medicines containing arsenic in APL patients. The fecal microbiota composition of APL patients after treatment showed lower diversity and uniformity shown by the alpha diversity indices of Chao, Shannon, and Simpson. Gut microbiome operational taxonomic unit (OTU) numbers were associated with arsenic in the feces. We evaluated Bifidobacterium adolescentis and Lactobacillus mucosae to be a keystone in APL patients after treatment. Bacteroides at phylum or genus taxonomic levels were consistently affected after treatment. In the most common gut bacteria Bacteroides fragilis, arsenic resistance genes were significantly induced by arsenic exposure in anaerobic pure culture experiments. Without an animal model, without taking arsenicals passively, the results evidence that arsenic exposure by drug treatment is not only associated with alterations in intestinal microbiome development at the abundance and diversity level, but also induced arsenic biotransformation genes (ABGs) at the function levels which may even extend to arsenic-related health outcomes in APL.
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Affiliation(s)
- Jiaojiao Li
- College of Ecology and Environmental Sciences & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650500, China
| | - Xinshuo Chen
- College of Ecology and Environmental Sciences & Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, Yunnan University, Kunming 650500, China
| | - Shixiang Zhao
- Hematology Department of First People's Hospital of Yunnan Province, Kunming 650032, China
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
- Institute of Environmental Remediation and Human Health, College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China
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Abstract
The functional diversity of the mammalian intestinal microbiome far exceeds that of the host organism, and microbial genes contribute substantially to the well-being of the host. However, beneficial gut organisms can also be pathogenic when present in the gut or other locations in the body. Among dominant beneficial bacteria are several species of Bacteroides, which metabolize polysaccharides and oligosaccharides, providing nutrition and vitamins to the host and other intestinal microbial residents. These topics and the specific organismal and molecular interactions that are known to be responsible for the beneficial and detrimental effects of Bacteroides species in humans comprise the focus of this review. The complexity of these interactions will be revealed.
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Affiliation(s)
- Hassan Zafar
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, USA
- Department of Microbiology and Molecular Genetics, Faculty of Life Sciences, University of Okara,Okara, PunjabPakistan
| | - Milton H. Saier
- Department of Molecular Biology, Division of Biological Sciences, University of California at San Diego, USA
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The uroS and yifB Genes Conserved among Tetrapyrrole Synthesizing-Deficient Bacteroidales Are Involved in Bacteroides fragilis Heme Assimilation and Survival in Experimental Intra-abdominal Infection and Intestinal Colonization. Infect Immun 2020; 88:IAI.00103-20. [PMID: 32457103 DOI: 10.1128/iai.00103-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/15/2020] [Indexed: 01/01/2023] Open
Abstract
The human intestinal anaerobic commensal and opportunistic pathogen Bacteroides fragilis does not synthesize the tetrapyrrole protoporphyrin IX in order to form heme that is required for growth stimulation and survival in vivo Consequently, B. fragilis acquires essential heme from host tissues during extraintestinal infection. The absence of several genes necessary for de novo heme biosynthesis is a common characteristic of many anaerobic bacteria; however, the uroS gene, encoding a uroporphyrinogen III synthase for an early step of heme biosynthesis, is conserved among the heme-requiring Bacteroidales that inhabit the mammalian gastrointestinal tract. In this study, we show that the ability of B. fragilis to utilize heme or protoporphyrin IX for growth was greatly reduced in a ΔuroS mutant. This growth defect appears to be linked to the suppression of reverse chelatase and ferrochelatase activities in the absence of uroS In addition, this ΔuroS suppressive effect was enhanced by the deletion of the yifB gene, which encodes an Mg2+-chelatase protein belonging to the ATPases associated with various cellular activities (AAA+) superfamily of proteins. Furthermore, the ΔuroS mutant and the ΔuroS ΔyifB double mutant had a severe survival defect compared to the parent strain in competitive infection assays using animal models of intra-abdominal infection and intestinal colonization. This shows that the presence of the uroS and yifB genes in B. fragilis seems to be linked to pathophysiological and nutritional competitive fitness for survival in host tissues. Genetic complementation studies and enzyme kinetics assays indicate that B. fragilis UroS is functionally different from canonical bacterial UroS proteins. Taken together, these findings show that heme assimilation and metabolism in the anaerobe B. fragilis have diverged from those of aerobic and facultative anaerobic pathogenic bacteria.
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Valguarnera E, Wardenburg JB. Good Gone Bad: One Toxin Away From Disease for Bacteroides fragilis. J Mol Biol 2019; 432:765-785. [PMID: 31857085 DOI: 10.1016/j.jmb.2019.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 11/27/2019] [Accepted: 12/05/2019] [Indexed: 02/06/2023]
Abstract
The human gut is colonized by hundreds of trillions of microorganisms whose acquisition begins during early infancy. Species from the Bacteroides genus are ubiquitous commensals, comprising about thirty percent of the human gut microbiota. Bacteroides fragilis is one of the least abundant Bacteroides species, yet is the most common anaerobe isolated from extraintestinal infections in humans. A subset of B. fragilis strains carry a genetic element that encodes a metalloprotease enterotoxin named Bacteroides fragilis toxin, or BFT. Toxin-bearing strains, or Enterotoxigenic B. fragilis (ETBF) cause acute and chronic intestinal disease in children and adults. Despite this association with disease, around twenty percent of the human population appear to be asymptomatic carriers of ETBF. BFT damages the colonic epithelial barrier by inducing cleavage of the zonula adherens protein E-cadherin and initiating a cell signaling response characterized by inflammation and c-Myc-dependent pro-oncogenic hyperproliferation. As a consequence, mice harboring genetic mutations that predispose to colonic inflammation or tumor formation are uniquely susceptible to toxin-mediated injury. The recent observation of ETBF-bearing biofilms in colon biopsies from humans with colon cancer susceptibility loci strongly suggests that ETBF is a driver of colorectal cancer. This article will address ETBF biology from a host-pathobiont perspective, including clinical data, analysis of molecular mechanisms of disease, and the complex ecological context of the human gut.
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Affiliation(s)
- Ezequiel Valguarnera
- Department of Pediatrics, Washington University School of Medicine, 660 S. Euclid Ave. Box 8208, St. Louis, MO 63110
| | - Juliane Bubeck Wardenburg
- Department of Pediatrics, Washington University School of Medicine, 660 S. Euclid Ave. Box 8208, St. Louis, MO 63110.
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Cabral DJ, Penumutchu S, Reinhart EM, Zhang C, Korry BJ, Wurster JI, Nilson R, Guang A, Sano WH, Rowan-Nash AD, Li H, Belenky P. Microbial Metabolism Modulates Antibiotic Susceptibility within the Murine Gut Microbiome. Cell Metab 2019; 30:800-823.e7. [PMID: 31523007 PMCID: PMC6948150 DOI: 10.1016/j.cmet.2019.08.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/24/2019] [Accepted: 08/20/2019] [Indexed: 12/22/2022]
Abstract
Although antibiotics disturb the structure of the gut microbiota, factors that modulate these perturbations are poorly understood. Bacterial metabolism is an important regulator of susceptibility in vitro and likely plays a large role within the host. We applied a metagenomic and metatranscriptomic approach to link antibiotic-induced taxonomic and transcriptional responses within the murine microbiome. We found that antibiotics significantly alter the expression of key metabolic pathways at the whole-community and single-species levels. Notably, Bacteroides thetaiotaomicron, which blooms in response to amoxicillin, upregulated polysaccharide utilization. In vitro, we found that the sensitivity of this bacterium to amoxicillin was elevated by glucose and reduced by polysaccharides. Accordingly, we observed that dietary composition affected the abundance and expansion of B. thetaiotaomicron, as well as the extent of microbiome disruption with amoxicillin. Our work indicates that the metabolic environment of the microbiome plays a role in the response of this community to antibiotics.
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Affiliation(s)
- Damien J Cabral
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Swathi Penumutchu
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Elizabeth M Reinhart
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Cheng Zhang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55904, USA
| | - Benjamin J Korry
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Jenna I Wurster
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Rachael Nilson
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - August Guang
- Center for Computation & Visualization, Brown University, Brown University, Providence, RI 02906, USA; Center for Computational Biology of Human Disease, Brown University, Providence, RI 02906, USA
| | - William H Sano
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Aislinn D Rowan-Nash
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA
| | - Hu Li
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55904, USA
| | - Peter Belenky
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02906, USA.
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Lynch A, Tammireddy SR, Doherty MK, Whitfield PD, Clarke DJ. The Glycine Lipids of Bacteroides thetaiotaomicron Are Important for Fitness during Growth In Vivo and In Vitro. Appl Environ Microbiol 2019; 85:e02157-18. [PMID: 30367006 PMCID: PMC6498176 DOI: 10.1128/aem.02157-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/22/2018] [Indexed: 01/02/2023] Open
Abstract
Acylated amino acids function as important components of the cellular membrane in some bacteria. Biosynthesis is initiated by the N-acylation of the amino acid, and this is followed by subsequent O-acylation of the acylated molecule, resulting in the production of the mature diacylated amino acid lipid. In this study, we use both genetics and liquid chromatography-mass spectrometry (LC-MS) to characterize the biosynthesis and function of a diacylated glycine lipid (GL) species produced in Bacteroides thetaiotaomicron We, and others, have previously reported the identification of a gene, named glsB in this study, that encodes an N-acyltransferase activity responsible for the production of a monoacylated glycine called N-acyl-3-hydroxy-palmitoyl glycine (or commendamide). In all of the Bacteroidales genomes sequenced so far, the glsB gene is located immediately downstream from a gene, named glsA, that is also predicted to encode a protein with acyltransferase activity. We use LC-MS to show that the coexpression of glsB and glsA results in the production of GL in Escherichia coli We constructed a deletion mutant of the glsB gene in B. thetaiotaomicron, and we confirm that glsB is required for the production of GL in B. thetaiotaomicron Moreover, we show that glsB is important for the ability of B. thetaiotaomicron to adapt to stress and colonize the mammalian gut. Therefore, this report describes the genetic requirements for the biosynthesis of GL, a diacylated amino acid species that contributes to fitness in the human gut bacterium B. thetaiotaomicronIMPORTANCE The gut microbiome has an important role in both health and disease of the host. The mammalian gut microbiome is often dominated by bacteria from the Bacteroidales, an order that includes Bacteroides and Prevotella In this study, we have identified an acylated amino acid, called glycine lipid, produced by Bacteroides thetaiotaomicron, a beneficial bacterium originally isolated from the human gut. In addition to identifying the genes required for the production of glycine lipids, we show that glycine lipids have an important role during the adaptation of B. thetaiotaomicron to a number of environmental stresses, including exposure to either bile or air. We also show that glycine lipids are important for the normal colonization of the murine gut by B. thetaiotaomicron This work identifies glycine lipids as an important fitness determinant in B. thetaiotaomicron and therefore increases our understanding of the molecular mechanisms underpinning colonization of the mammalian gut by beneficial bacteria.
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Affiliation(s)
- Alli Lynch
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
| | - Seshu R Tammireddy
- Lipidomics Research Facility, Department of Diabetes and Cardiovascular Disease, University of the Highlands and Islands, Inverness, United Kingdom
| | - Mary K Doherty
- Lipidomics Research Facility, Department of Diabetes and Cardiovascular Disease, University of the Highlands and Islands, Inverness, United Kingdom
| | - Phillip D Whitfield
- Lipidomics Research Facility, Department of Diabetes and Cardiovascular Disease, University of the Highlands and Islands, Inverness, United Kingdom
| | - David J Clarke
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- School of Microbiology, University College Cork, Cork, Ireland
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10
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The Bacteroidales produce an N-acylated derivative of glycine with both cholesterol-solubilising and hemolytic activity. Sci Rep 2017; 7:13270. [PMID: 29038461 PMCID: PMC5643525 DOI: 10.1038/s41598-017-13774-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 10/02/2017] [Indexed: 02/08/2023] Open
Abstract
The contribution of the gut microbiota to the metabolism of cholesterol is not well understood. In this study, we identify 21 fosmid clones from a human gut microbiome metagenomic library that, when expressed in Escherichia coli, produce halos on LB agar supplemented with 0.01% (w/v) cholesterol (LBC agar). Analysis of 14 of these clones revealed that they all share a fragment of DNA with homology to the genome of Bacteroides vulgatus. The gene responsible for halo production on LBC agar, named choA, was identified as an N-acyltransferase known to produce an acylated glycine molecule called commendamide. In this study we show that commendamide is capable of producing a halo on LBC agar suggesting that this molecule is solubilizing the cholesterol micelles in LBC agar. We also show that commendamide is responsible for the previously described hemolytic activity associated with the choA orthologue in Bacteroides fragilis. A functional analysis of ChoA identified 2 amino acids that are important for commendamide biosynthesis and we present phylogenetic and functional data showing that orthologues of choA are found only in the order Bacteroidales. Therefore, the production of commendamide may be an adaptation to the environments colonized by the Bacteroidales, including the mammalian gut.
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Shah NB, Tande AJ, Patel R, Berbari EF. Anaerobic prosthetic joint infection. Anaerobe 2015; 36:1-8. [DOI: 10.1016/j.anaerobe.2015.08.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/23/2015] [Accepted: 08/24/2015] [Indexed: 12/01/2022]
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Dps and DpsL Mediate Survival In Vitro and In Vivo during the Prolonged Oxidative Stress Response in Bacteroides fragilis. J Bacteriol 2015; 197:3329-38. [PMID: 26260459 DOI: 10.1128/jb.00342-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/05/2015] [Indexed: 12/27/2022] Open
Abstract
UNLABELLED Bacteroides fragilis is a Gram-negative anaerobe and member of the human intestinal tract microbiome, where it plays many beneficial roles. However, translocation of the organism to the peritoneal cavity can lead to peritonitis, intra-abdominal abscess formation, bacteremia, and sepsis. During translocation, B. fragilis is exposed to increased oxidative stress from the oxygenated tissues of the peritoneal cavity and the immune response. In order to survive, B. fragilis mounts a robust oxidative stress response consisting of an acute and a prolonged oxidative stress (POST) response. This report demonstrates that the ability to induce high levels of resistance to tert-butyl hydroperoxide (tBOOH) after extended exposure to air can be linked to the POST response. Disk diffusion assays comparing the wild type to a Δdps mutant and a Δdps Δbfr mutant showed greater sensitivity of the mutants to tBOOH after exposure to air, suggesting that Dps and DpsL play a role in the resistance phenotype. Complementation studies with dps or bfr (encoding DpsL) restored tBOOH resistance, suggesting a role for both of these ferritin-family proteins in the response. Additionally, cultures treated with the iron chelator dipyridyl were not killed by tBOOH, indicating Dps and DpsL function by sequestering iron to prevent cellular damage. An in vivo animal model showed that the Δdps Δbfr mutant was attenuated, indicating that management of iron is important for survival within the abscess. Together, these data demonstrate a role for Dps and DpsL in the POST response which mediates survival in vitro and in vivo. IMPORTANCE B. fragilis is the anaerobe most frequently isolated from extraintestinal opportunistic infections, but there is a paucity of information about the factors that allow this organism to survive outside its normal intestinal environment. This report demonstrates that the iron storage proteins Dps and DpsL protect against oxidative stress and that they contribute to survival both in vitro and in vivo. Additionally, this work demonstrates an important role for the POST response in B. fragilis survival and provides insight into the complex regulation of this response.
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Efficient utilization of complex N-linked glycans is a selective advantage for Bacteroides fragilis in extraintestinal infections. Proc Natl Acad Sci U S A 2014; 111:12901-6. [PMID: 25139987 DOI: 10.1073/pnas.1407344111] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Bacteroides fragilis is the most common anaerobe isolated from clinical infections, and in this report we demonstrate a characteristic of the species that is critical to their success as an opportunistic pathogen. Among the Bacteroides spp. in the gut, B. fragilis has the unique ability of efficiently harvesting complex N-linked glycans from the glycoproteins common to serum and serous fluid. This activity is mediated by an outer membrane protein complex designated as Don. Using the abundant serum glycoprotein transferrin as a model, it has been shown that B. fragilis alone can rapidly and efficiently deglycosylate this protein in vitro and that transferrin glycans can provide the sole source of carbon and energy for growth in defined media. We then showed that transferrin deglycosylation occurs in vivo when B. fragilis is propagated in the rat tissue cage model of extraintestinal growth, and that this ability provides a competitive advantage in vivo over strains lacking the don locus.
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Secreted Gaussia princeps luciferase as a reporter of Escherichia coli replication in a mouse tissue cage model of infection. PLoS One 2014; 9:e90382. [PMID: 24595353 PMCID: PMC3942414 DOI: 10.1371/journal.pone.0090382] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/28/2014] [Indexed: 11/26/2022] Open
Abstract
Measurement of bacterial burden in animal infection models is a key component for both bacterial pathogenesis studies and therapeutic agent research. The traditional quantification means for in vivo bacterial burden requires frequent animal sacrifice and enumerating colony forming units (CFU) recovered from infection loci. To address these issues, researchers have developed a variety of luciferase-expressing bacterial reporter strains to enable bacterial detection in living animals. To date, all such luciferase-based bacterial reporters are in cell-associated form. Production of luciferase-secreting recombinant bacteria could provide the advantage of reporting CFU from both infection loci themselves and remote sampling (eg. body fluid and plasma). Toward this end, we have genetically manipulated a pathogenic Escherichia coli (E. coli) strain, ATCC25922, to secrete the marine copepod Gaussia princeps luciferase (Gluc), and assessed the use of Gluc as both an in situ and ex situ reporter for bacterial burden in mouse tissue cage infections. The E. coli expressing Gluc demonstrates in vivo imaging of bacteria in a tissue cage model of infection. Furthermore, secreted Gluc activity and bacterial CFUs recovered from tissue cage fluid (TCF) are correlated along 18 days of infection. Importantly, secreted Gluc can also be detected in plasma samples and serve as an ex situ indicator for the established tissue cage infection, once high bacterial burdens are achieved. We have demonstrated that Gluc from marine eukaryotes can be stably expressed and secreted by pathogenic E. coli in vivo to enable a facile tool for longitudinal evaluation of persistent bacterial infection.
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Amir I, Bouvet P, Legeay C, Gophna U, Weinberger A. Eisenbergiella tayi gen. nov., sp. nov., isolated from human blood. Int J Syst Evol Microbiol 2014; 64:907-914. [DOI: 10.1099/ijs.0.057331-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A catalase-positive, rod-shaped, non-proteolytic, non-motile, anaerobic bacterial strain, designated B086562T, was isolated from a blood culture of an 84-year-old male patient in Israel. According to 16S rRNA gene sequence phylogeny, this strain has no known close relatives among recognized bacteria but should be placed within the family
Lachnospiraceae
. The most closely related recognized bacteria were from the ‘
Clostridium clostridioforme
group’:
C. clostridioforme
(92.4 %) and
Clostridium bolteae
(92.3 %). The isolate produced butyrate, lactate, acetate and succinate as major metabolic end products. The major fatty acids were C16 : 0 and C18 : 1
cis 9 DMA and the DNA G+C content was 46.0 mol%. On the basis of the phenotypic properties and phylogenetic distinctiveness, the blood isolate represents a novel species of a new genus in the family
Lachnospiraceae
, for which the name Eisenbergiella tayi gen. nov., sp. nov. is proposed. The type strain of Eisenbergiella tayi is B086562T ( = LMG 27400T = DSM 26961T = ATCC BAA-2558T).
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Affiliation(s)
- Itay Amir
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel
- The Microbiology Laboratory, Ma'ayanei Hayeshua Medical Center, Bnei-Brak 51544, Israel
| | - Philippe Bouvet
- Institut Pasteur, Centre National de Référence des Bactéries Anaérobies et du Botulisme, 25-28 rue du Docteur Roux, F-75724 Paris cedex 15, France
| | - Christine Legeay
- Institut Pasteur, Centre National de Référence des Bactéries Anaérobies et du Botulisme, 25-28 rue du Docteur Roux, F-75724 Paris cedex 15, France
| | - Uri Gophna
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel
| | - Abraham Weinberger
- The Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 69978, Israel
- Department of Internal Medicine, Ma'ayanei Hayeshua Medical Center, Bnei-Brak 51544, Israel
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