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Synthesis of a Di-Mycoloyl Tri-Arabinofuranosyl Glycerol Fragment of the Mycobacterial Cell Wall, Based on Synthetic Mycolic Acids. Molecules 2019; 24:molecules24193596. [PMID: 31590468 PMCID: PMC6804083 DOI: 10.3390/molecules24193596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/24/2019] [Accepted: 10/01/2019] [Indexed: 11/24/2022] Open
Abstract
Fragments of mycobacterial cell walls such as arabinoglycerol mycolate and dimycoloyl diarabinoglycerol, comprising complex mixtures of mycolic acids, have immunostimulatory and antigenic properties. A related di-mycoloyl tri-arabinofuranosyl glycerol fragment has been isolated from cell wall hydrolysates. An effective stereoselective synthesis of tri-arabinofuranosyl glycerol, followed by coupling with stereochemically defined mycolic acids of different structural classes, to provide unique di-mycoloyl tri-arabinofuranosyl glycerols is now described.
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Ali OT, Mohammed MO, Gates PJ, Baird MS, Al Dulayymi JR. The synthesis of mycobacterial dimycoloyl diarabinoglycerol based on defined synthetic mycolic acids. Chem Phys Lipids 2019; 221:207-218. [PMID: 30639038 DOI: 10.1016/j.chemphyslip.2019.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/21/2018] [Accepted: 01/08/2019] [Indexed: 11/25/2022]
Abstract
Complex mixtures of natural dimycoloyl diarabinoglycerols isolated from mycobacteria have been shown to be both potent immune signalling agents and potentially valuable antigens in the serodiagnosis of mycobacterial infections. We now report the highly stereocontrolled synthesis of diacyl l-glycerol-(1'→1)-β-d-arabinofuranosyl-α-d-arabinofuranosides based on simple fatty acids and single defined synthetic mycolic acids. NMR analysis confirmed that the synthetic core was identical to that in natural mixtures.
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Affiliation(s)
- Omar T Ali
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - Mohsin O Mohammed
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - Paul J Gates
- School of Chemistry, Bristol University, Bristol, BS8 1TS, UK
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2UW, UK.
| | - Juma'a R Al Dulayymi
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2UW, UK; School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
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3
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Maes E, Sadovskaya I, Lévêque M, Elass-Rochard E, Payré B, Grard T, Théodorou V, Guérardel Y, Mercier-Bonin M. Structure and biological activities of a hexosamine-rich cell wall polysaccharide isolated from the probiotic Lactobacillus farciminis. Glycoconj J 2019; 36:39-55. [PMID: 30637506 DOI: 10.1007/s10719-018-09854-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/13/2018] [Accepted: 12/18/2018] [Indexed: 12/11/2022]
Abstract
Lactobacillus farciminis CIP 103136 is a bacterial strain with recognized probiotic properties. However, the mechanisms underlying such properties have only been partially elucidated. In this study, we isolated and purified a cell-wall associated polysaccharide (CWPS), and evaluated its biological role in vitro. The structure of CWPS and responses from stimulation of (i) human macrophage-like THP-1 cells, (ii) human embryonal kidney (HEK293) cells stably transfected with Toll-like receptors (TLR2 or TLR4) and (iii) human colonocyte-like T84 intestinal epithelial cells, upon exposure to CWPS were studied. The structure of the purified CWPS from L. farciminis CIP 103136 was analyzed by nuclear magnetic resonance (NMR), MALDI-TOF-TOF MS, and methylation analyses in its native form and following Smith degradation. It was shown to be a novel branched polysaccharide, composed of linear backbone of trisaccharide repeating units of: [→6αGlcpNAc1 → 4βManpNAc1 → 4βGlcpNAc1→] highly substituted with single residues of αGlcp, αGalp and αGlcpNAc. Subsequently, the lack of pro- or anti-inflammatory properties of CWPS was established on macrophage-like THP-1 cells. In addition, CWPS failed to modulate cell signaling pathways dependent of TLR2 and TLR4 in transfected HEK-cells. Finally, in T84 cells, CWPS neither influenced intestinal barrier integrity under basal conditions nor prevented TNF-α/IFN-γ cytokine-mediated epithelium impairment.
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Affiliation(s)
- Emmanuel Maes
- CNRS UMR 8576, UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Univ Lille, 59 000, Lille, France
| | - Irina Sadovskaya
- Equipe Biochimie des Produits Aquatiques BPA, Institut Régional Charles Violette EA 7394, USC Anses-ULCO, Université du Littoral-Côte d'Opale, Bassin Napoléon, 62327, Boulogne-sur-mer cedex, France
| | - Mathilde Lévêque
- Toxalim (Research Centre in Food Toxicology), INRA, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Elisabeth Elass-Rochard
- CNRS UMR 8576, UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Univ Lille, 59 000, Lille, France
| | - Bruno Payré
- Faculté de Médecine Rangueil, Centre de Microscopie Electronique Appliquée à la Biologie (CMEAB), Toulouse Cedex, France
| | - Thierry Grard
- Equipe Biochimie des Produits Aquatiques BPA, Institut Régional Charles Violette EA 7394, USC Anses-ULCO, Université du Littoral-Côte d'Opale, Bassin Napoléon, 62327, Boulogne-sur-mer cedex, France
| | - Vassilia Théodorou
- Toxalim (Research Centre in Food Toxicology), INRA, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Yann Guérardel
- CNRS UMR 8576, UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, Univ Lille, 59 000, Lille, France
| | - Muriel Mercier-Bonin
- Toxalim (Research Centre in Food Toxicology), INRA, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France.
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Szulc-Kielbik I, Pawelczyk J, Kielbik M, Kremer L, Dziadek J, Klink M. Severe inhibition of lipooligosaccharide synthesis induces TLR2-dependent elimination of Mycobacterium marinum from THP1-derived macrophages. Microb Cell Fact 2017; 16:217. [PMID: 29183333 PMCID: PMC5706390 DOI: 10.1186/s12934-017-0829-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/17/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Although mycobacterial glycolipids are among the first-line molecules involved in host-pathogen interactions, their contribution in virulence remains incomplete. Mycobacterium marinum is a waterborne pathogen of fish and other ectotherms, closely related to Mycobacterium tuberculosis. Since it causes tuberculosis-like systemic infection it is widely used as a model organism for studying the pathogenesis of tuberculosis. It is also an occasional opportunistic human pathogen. The M. marinum surface-exposed lipooligosaccharides (LOS) are immunogenic molecules that participate in the early interactions with macrophages and modulate the host immune system. Four major LOS species, designated LOS-I to LOS-IV, have been identified and characterized in M. marinum. Herein, we investigated the interactions between a panel of defined M. marinum LOS mutants that exhibited various degrees of truncation in the LOS structure, and human-derived THP-1 macrophages to address the potential of LOSs to act as pro- or avirulence factors. RESULTS A moderately truncated LOS structure did not interfere with M. marinum invasion. However, a deeper shortening of the LOS structure was associated with increased entry of M. marinum into host cells and increased elimination of the bacilli by the macrophages. These effects were dependent on Toll-like receptor 2. CONCLUSION We provide the first evidence that LOSs inhibit the interaction between mycobacterial cell wall ligands and appropriate macrophage pattern recognition receptors, affecting uptake and elimination of the bacteria by host phagocytes.
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Affiliation(s)
- Izabela Szulc-Kielbik
- Institute of Medical Biology, Polish Academy of Sciences, 106 Lodowa Str., 93-232 Lodz, Poland
| | - Jakub Pawelczyk
- Institute of Medical Biology, Polish Academy of Sciences, 106 Lodowa Str., 93-232 Lodz, Poland
| | - Michal Kielbik
- Institute of Medical Biology, Polish Academy of Sciences, 106 Lodowa Str., 93-232 Lodz, Poland
| | - Laurent Kremer
- IRIM (ex-CPBS)-UMR 9004, Research Institute of Infectiology of Montpellier, Université de Montpellier, CNRS, 34293 Montpellier, France
- INSERM, IRIM, 34293 Montpellier, France
| | - Jaroslaw Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, 106 Lodowa Str., 93-232 Lodz, Poland
| | - Magdalena Klink
- Institute of Medical Biology, Polish Academy of Sciences, 106 Lodowa Str., 93-232 Lodz, Poland
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Harvey DJ. Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2011-2012. MASS SPECTROMETRY REVIEWS 2017; 36:255-422. [PMID: 26270629 DOI: 10.1002/mas.21471] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Abstract
This review is the seventh update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2012. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, and fragmentation are covered in the first part of the review and applications to various structural types constitute the remainder. The main groups of compound are oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:255-422, 2017.
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Affiliation(s)
- David J Harvey
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford, OX1 3QU, UK
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Hsieh LTH, Nastase MV, Roedig H, Zeng-Brouwers J, Poluzzi C, Schwalm S, Fork C, Tredup C, Brandes RP, Wygrecka M, Huwiler A, Pfeilschifter J, Schaefer L. Biglycan- and Sphingosine Kinase-1 Signaling Crosstalk Regulates the Synthesis of Macrophage Chemoattractants. Int J Mol Sci 2017; 18:ijms18030595. [PMID: 28282921 PMCID: PMC5372611 DOI: 10.3390/ijms18030595] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 02/27/2017] [Accepted: 03/06/2017] [Indexed: 12/14/2022] Open
Abstract
In its soluble form, the extracellular matrix proteoglycan biglycan triggers the synthesis of the macrophage chemoattractants, chemokine (C-C motif) ligand CCL2 and CCL5 through selective utilization of Toll-like receptors (TLRs) and their adaptor molecules. However, the respective downstream signaling events resulting in biglycan-induced CCL2 and CCL5 production have not yet been defined. Here, we show that biglycan stimulates the production and activation of sphingosine kinase 1 (SphK1) in a TLR4- and Toll/interleukin (IL)-1R domain-containing adaptor inducing interferon (IFN)-β (TRIF)-dependent manner in murine primary macrophages. We provide genetic and pharmacological proof that SphK1 is a crucial downstream mediator of biglycan-triggered CCL2 and CCL5 mRNA and protein expression. This is selectively driven by biglycan/SphK1-dependent phosphorylation of the nuclear factor NF-κB p65 subunit, extracellular signal-regulated kinase (Erk)1/2 and p38 mitogen-activated protein kinases. Importantly, in vivo overexpression of soluble biglycan causes Sphk1-dependent enhancement of renal CCL2 and CCL5 and macrophage recruitment into the kidney. Our findings describe the crosstalk between biglycan- and SphK1-driven extracellular matrix- and lipid-signaling. Thus, SphK1 may represent a new target for therapeutic intervention in biglycan-evoked inflammatory conditions.
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Affiliation(s)
- Louise Tzung-Harn Hsieh
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Madalina-Viviana Nastase
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
- National Institute for Chemical-Pharmaceutical Research and Development, 112 Vitan Avenue, Bucharest 031299, Romania.
| | - Heiko Roedig
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Jinyang Zeng-Brouwers
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Chiara Poluzzi
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Stephanie Schwalm
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Christian Fork
- Institut für Kardiovaskulare Physiologie, Klinikum der Goethe-Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Claudia Tredup
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Ralf P Brandes
- Institut für Kardiovaskulare Physiologie, Klinikum der Goethe-Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Malgorzata Wygrecka
- Department of Biochemistry, Faculty of Medicine, Universities of Giessen and Marburg Lung Center, Friedrichstrasse 24, Giessen 35392, Germany.
| | - Andrea Huwiler
- Institute of Pharmacology, University of Bern, Inselspital INO-F, Bern CH-3010, Switzerland.
| | - Josef Pfeilschifter
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
| | - Liliana Schaefer
- Pharmazentrum Frankfurt, Institut für Allgemeine Pharmakologie und Toxikologie, Klinikum der Goethe Universität, Theodor-Stern-Kai 7, Frankfurt am Main 60590, Germany.
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Ait-Ali T, Díaz I, Soldevila F, Cano E, Li Y, Wilson AD, Giotti B, Archibald AL, Mateu E, Darwich L. Distinct functional enrichment of transcriptional signatures in pigs with high and low IFN-gamma responses after vaccination with a porcine reproductive and respiratory syndrome virus (PRRSV). Vet Res 2016; 47:104. [PMID: 27765052 PMCID: PMC5073823 DOI: 10.1186/s13567-016-0392-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 10/05/2016] [Indexed: 01/05/2023] Open
Abstract
Little is known about the host factor in the response to PRRSV vaccination. For this purpose, piglets were immunized with a commercial PRRSV-live vaccine and classified as high responders (HR) or low responders (LR) as regards to the frequencies of virus-specific IFN-γ-secreting cells. Six weeks post vaccination, PBMCs isolated from three individuals with the most extreme responses in each HR and LR groups and 3 unvaccinated controls, were either stimulated with phytohaemagglutinin, challenged with the vaccine or mock treated for 24 h, prior conducting transcriptional studies, gene ontology and pathway analyses. The LR group had very low neutralizing antibody levels and showed a higher number of down-regulated transcripts compared with the HR group (FDR < 0.2, P < 0.001). Down-regulated genes encoded chemoattractants, proinflammatory cytokines and the interferon-inducible GBP family, and showed enrichment in wounding (FDR < 3.6E-13), inflammation (FDR < 8E-12), defence (FDR < 8.7E-09) and immunity (FDR < 7.6E-08), suggesting immune response impairment. In the HR group, down-regulated genes were involved in protein transport (FDR < 4.77E-03), locomotory behavior (FDR < 5.47E-3), regulation of protein localization (FDR < 1.02E-02), and regulation of TNF superfamily member 15 and miR181. In contrast, the HR group presented up-regulated transcripts associated with wounding (FDR < 4.95). Moreover, IFN-γ was predicted to be an inhibited upstream regulator since IFN-γ pathways were associated with higher number of down-regulated genes in the LR (n = 40) than the HR (n = 10). Divergent responses to PRRSV-vaccination may be the result of the genetic background of the host.
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Affiliation(s)
- Tahar Ait-Ali
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Ivan Díaz
- Centre de Recerca en Sanitat Animal (CReSA)- IRTA, Campus de la Universitat Autònoma de Barcelona (UAB), 08193, Cerdanyola del Valles, Spain
| | - Ferran Soldevila
- Virology Department, Animal and Plant Health and Agency, Addlestone, KT15 3NB, UK.,Department of Pathology and Pathogen Biology, Royal Veterinary College, Hatfield, AL9 7TA, UK
| | - Esmeralda Cano
- Centre de Recerca en Sanitat Animal (CReSA)- IRTA, Campus de la Universitat Autònoma de Barcelona (UAB), 08193, Cerdanyola del Valles, Spain
| | - Yanli Li
- Department Sanitat i Anatomia Animals, Faculty of Veterinary, UAB, 08193, Cerdanyola del Valles, Spain
| | - Alison D Wilson
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Bruno Giotti
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Alan L Archibald
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Enric Mateu
- Centre de Recerca en Sanitat Animal (CReSA)- IRTA, Campus de la Universitat Autònoma de Barcelona (UAB), 08193, Cerdanyola del Valles, Spain.,Department Sanitat i Anatomia Animals, Faculty of Veterinary, UAB, 08193, Cerdanyola del Valles, Spain
| | - Laila Darwich
- Centre de Recerca en Sanitat Animal (CReSA)- IRTA, Campus de la Universitat Autònoma de Barcelona (UAB), 08193, Cerdanyola del Valles, Spain. .,Department Sanitat i Anatomia Animals, Faculty of Veterinary, UAB, 08193, Cerdanyola del Valles, Spain.
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Mohammed MO, Baird MS, Al Dulayymi JR. Mycolyl arabino glycerols from synthetic mycolic acids. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.01.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Abstract
ABSTRACT
Mycolic acids are major and specific long-chain fatty acids that represent essential components of the
Mycobacterium tuberculosis
cell envelope. They play a crucial role in the cell wall architecture and impermeability, hence the natural resistance of mycobacteria to most antibiotics, and represent key factors in mycobacterial virulence. Biosynthesis of mycolic acid precursors requires two types of fatty acid synthases (FASs), the eukaryotic-like multifunctional enzyme FAS I and the acyl carrier protein (ACP)–dependent FAS II systems, which consists of a series of discrete mono-functional proteins, each catalyzing one reaction in the pathway. Unlike FAS II synthases of other bacteria, the mycobacterial FAS II is incapable of
de novo
fatty acid synthesis from acetyl-coenzyme A, but instead elongates medium-chain-length fatty acids previously synthesized by FAS I, leading to meromycolic acids. In addition, mycolic acid subspecies with defined biological properties can be distinguished according to the chemical modifications decorating the meromycolate. Nearly all the genetic components involved in both elongation and functionalization of the meromycolic acid have been identified and are generally clustered in distinct transcriptional units. A large body of information has been generated on the enzymology of the mycolic acid biosynthetic pathway and on their genetic and biochemical/structural characterization as targets of several antitubercular drugs. This chapter is a comprehensive overview of mycolic acid structure, function, and biosynthesis. Special emphasis is given to recent work addressing the regulation of mycolic acid biosynthesis, adding new insights to our understanding of how pathogenic mycobacteria adapt their cell wall composition in response to environmental changes.
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Mycobacterium ulcerans fails to infect through skin abrasions in a guinea pig infection model: implications for transmission. PLoS Negl Trop Dis 2014; 8:e2770. [PMID: 24722416 PMCID: PMC3983084 DOI: 10.1371/journal.pntd.0002770] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 02/18/2014] [Indexed: 11/19/2022] Open
Abstract
Transmission of M. ulcerans, the etiological agent of Buruli ulcer, from the environment to humans remains an enigma despite decades of research. Major transmission hypotheses propose 1) that M. ulcerans is acquired through an insect bite or 2) that bacteria enter an existing wound through exposure to a contaminated environment. In studies reported here, a guinea pig infection model was developed to determine whether Buruli ulcer could be produced through passive inoculation of M. ulcerans onto a superficial abrasion. The choice of an abrasion model was based on the fact that most bacterial pathogens infecting the skin are able to infect an open lesion, and that abrasions are extremely common in children. Our studies show that after a 90d infection period, an ulcer was present at intra-dermal injection sites of all seven animals infected, whereas topical application of M. ulcerans failed to establish an infection. Mycobacterium ulcerans was cultured from all injection sites whereas infected abrasion sites healed and were culture negative. A 14d experiment was conducted to determine how long organisms persisted after inoculation. Mycobacterium ulcerans was isolated from abrasions at one hour and 24 hours post infection, but cultures from later time points were negative. Abrasion sites were qPCR positive up to seven days post infection, but negative at later timepoints. In contrast, M. ulcerans DNA was detected at intra-dermal injection sites throughout the study. M. ulcerans was cultured from injection sites at each time point. These results suggest that injection of M. ulcerans into the skin greatly facilitates infection and lends support for the role of an invertebrate vector or other route of entry such as a puncture wound or deep laceration where bacteria would be contained within the lesion. Infection through passive inoculation into an existing abrasion appears a less likely route of entry.
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Discovery of a glycerol 3-phosphate phosphatase reveals glycerophospholipid polar head recycling in Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2013; 110:11320-5. [PMID: 23801751 DOI: 10.1073/pnas.1221597110] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Functional assignment of enzymes encoded by the Mycobacterium tuberculosis genome is largely incomplete despite recent advances in genomics and bioinformatics. Here, we applied an activity-based metabolomic profiling method to assign function to a unique phosphatase, Rv1692. In contrast to its annotation as a nucleotide phosphatase, metabolomic profiling and kinetic characterization indicate that Rv1692 is a D,L-glycerol 3-phosphate phosphatase. Crystal structures of Rv1692 reveal a unique architecture, a fusion of a predicted haloacid dehalogenase fold with a previously unidentified GCN5-related N-acetyltransferase region. Although not directly involved in acetyl transfer, or regulation of enzymatic activity in vitro, this GCN5-related N-acetyltransferase region is critical for the solubility of the phosphatase. Structural and biochemical analysis shows that the active site features are adapted for recognition of small polyol phosphates, and not nucleotide substrates. Functional assignment and metabolomic studies of M. tuberculosis lacking rv1692 demonstrate that Rv1692 is the final enzyme involved in glycerophospholipid recycling/catabolism, a pathway not previously described in M. tuberculosis.
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