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Chakroborty A, Pritchard DR, Bouillon ME, Cervi A, Kraehenbuehl R, Wild C, Fenn C, Holdsworth P, Capner C, Padalino G, Forde-Thomas JE, Payne J, Smith BG, Fisher M, Lahmann M, Baird MS, Hoffmann KF. Modified Hederagenin Derivatives Demonstrate Ex Vivo Anthelmintic Activity against Fasciola hepatica. Pharmaceutics 2023; 15:1869. [PMID: 37514055 PMCID: PMC10385850 DOI: 10.3390/pharmaceutics15071869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
Infection with Fasciola hepatica (liver fluke) causes fasciolosis (or fascioliasis) and poses a considerable economic as well as welfare burden to both the agricultural and animal health sectors. Here, we explore the ex vivo anthelmintic potential of synthetic derivatives of hederagenin, isolated in bulk from Hedera helix. Thirty-six compounds were initially screened against F. hepatica newly excysted juveniles (NEJs) of the Italian strain. Eleven of these compounds were active against NEJs and were selected for further study, using adult F. hepatica derived from a local abattoir (provenance unknown). From these eleven compounds, six demonstrated activity and were further assessed against immature liver flukes of the Italian strain. Subsequently, the most active compounds (n = 5) were further evaluated in ex vivo dose response experiments against adult Italian strain liver flukes. Overall, MC042 was identified as the most active molecule and the EC50 obtained from immature and adult liver fluke assays (at 24 h post co-culture) are estimated as 1.07 μM and 13.02 μM, respectively. When compared to the in vitro cytotoxicity of MDBK bovine cell line, MC042 demonstrated the highest anthelmintic selectivity (44.37 for immature and 3.64 for adult flukes). These data indicate that modified hederagenins display properties suitable for further investigations as candidate flukicides.
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Affiliation(s)
- Anand Chakroborty
- The Department of Life Sciences (DLS), Aberystwyth University, Aberystwyth SY23 3DA, UK
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430, USA
| | | | - Marc E Bouillon
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
| | - Anna Cervi
- Naturiol Bangor Ltd., MSParc, Gaerwen, Anglesey LL60 6AG, UK
| | | | - Charlotte Wild
- Ridgeway Research Limited, Park Farm Buildings, Park Lane, St. Briavels, Gloucestershire GL15 6QX, UK
| | - Caroline Fenn
- Ridgeway Research Limited, Park Farm Buildings, Park Lane, St. Briavels, Gloucestershire GL15 6QX, UK
| | - Peter Holdsworth
- Ridgeway Research Limited, Park Farm Buildings, Park Lane, St. Briavels, Gloucestershire GL15 6QX, UK
- PAH Consultancy Pty Ltd., 3/27 Gaunson Crescent, Wanniassa, Canberra 2903, Australia
| | - Colin Capner
- Ridgeway Research Limited, Park Farm Buildings, Park Lane, St. Briavels, Gloucestershire GL15 6QX, UK
| | - Gilda Padalino
- The Department of Life Sciences (DLS), Aberystwyth University, Aberystwyth SY23 3DA, UK
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB, UK
| | | | - Joseph Payne
- Ridgeway Research Limited, Park Farm Buildings, Park Lane, St. Briavels, Gloucestershire GL15 6QX, UK
| | - Brendan G Smith
- Bimeda UK, Bryn Cefni Industrial Estate, Unit 2A, Llangefni LL77 7XA, UK
| | - Maggie Fisher
- Ridgeway Research Limited, Park Farm Buildings, Park Lane, St. Briavels, Gloucestershire GL15 6QX, UK
| | - Martina Lahmann
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
- KTH Royal Institute of Technology, Biomedical Engineering and Health Systems, Hälsovägen 11, 141 52 Huddinge, Sweden
| | - Mark S Baird
- Naturiol Bangor Ltd., MSParc, Gaerwen, Anglesey LL60 6AG, UK
| | - Karl F Hoffmann
- The Department of Life Sciences (DLS), Aberystwyth University, Aberystwyth SY23 3DA, UK
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Chakroborty A, Pritchard D, Bouillon ME, Cervi A, Cookson A, Wild C, Fenn C, Payne J, Holdsworth P, Capner C, O’Neill J, Padalino G, Forde-Thomas J, Gupta S, Smith BG, Fisher M, Lahmann M, Baird MS, Hoffmann KF. Flukicidal effects of abietane diterpenoid derived analogues against the food borne pathogen Fasciola hepatica. Vet Parasitol 2022; 309:109766. [DOI: 10.1016/j.vetpar.2022.109766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/29/2022] [Accepted: 07/17/2022] [Indexed: 10/17/2022]
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Jones A, Davies CA, Fitch S, Al Dulayymi JR, Gwenin CD, Gibbons J, Williams AP, Baird MS. Elevated serum antibody responses to synthetic mycobacterial lipid antigens among UK farmers: an indication of exposure to environmental mycobacteria? RSC Med Chem 2021; 12:213-221. [PMID: 34046610 PMCID: PMC8128033 DOI: 10.1039/d0md00325e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 10/28/2020] [Indexed: 11/21/2022] Open
Abstract
Background: mycobacterial cells contain complex mixtures of mycolic acid esters. These can be used as antigens recognised by antibodies in the serum of individuals with active tuberculosis, caused by Mycobacterium tuberculosis. In high burden populations, a significant number of false positives are observed; possibly these antigens are also recognised by antibodies generated by other mycobacterial infections, particularly ubiquitous 'environmental mycobacteria'. This suggests similar responses may be observed in a low burden TB population, particularly in groups regularly exposed to mycobacteria. Methods: ELISA using single synthetic trehalose mycolates corresponding to major classes in many mycobacteria was used to detect antibodies in serum of individuals with no known mycobacterial infection, comprising farmers, abattoir workers, and rural and urban populations. Results: serum from four Welsh or Scottish cohorts showed lower (with some antigens significantly lower) median responses than those reported for TB negatives from high-burden TB populations, and significantly lower responses than those with active TB. A small fraction, particularly older farmers, showed strong responses. A second study examined BCG vaccinated and non-vaccinated farmers and non-farmers. Farmers gave significantly higher median responses than non-farmers with three of five antigens, while there was no significant difference between vaccinated or non-vaccinated for either farmer or non-farmer groups. Conclusions: this initial study shows that serodiagnosis with mycobacterial lipid antigens can detect antibodies in a population sub-group that is significantly exposed to mycobacteria, in an assay that is not interfered with by vaccination. Given the links between mycobacterial exposure and a range of immune system diseases, further understanding such responses may provide a new opportunity for monitoring public health and directing treatment.
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Affiliation(s)
- Alison Jones
- School of Natural Sciences, Bangor University Bangor Gwynedd LL57 2UW UK
| | - Carys A Davies
- School of Chemistry, Bangor University Bangor LL57 2UW UK
| | - Samuel Fitch
- School of Chemistry, Bangor University Bangor LL57 2UW UK
| | | | - Christopher D Gwenin
- School of Natural Sciences, Bangor University Bangor Gwynedd LL57 2UW UK
- Department of Chemistry, Xi'an Jiaotong-Liverpool University 111 Ren'ai Road, Suzhou Industrial Park Suzhou Jiangsu Province 215123 P. R. China
| | - James Gibbons
- School of Natural Sciences, Bangor University Bangor Gwynedd LL57 2UW UK
| | - A Prysor Williams
- School of Natural Sciences, Bangor University Bangor Gwynedd LL57 2UW UK
| | - Mark S Baird
- School of Chemistry, Bangor University Bangor LL57 2UW UK
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Alhuwaymil ZS, Al-Araj IQM, Al Dulayymi AR, Jones A, Gates PJ, Valero-Guillén PL, Baird MS, Al Dulayymi JR. Mycobacterium alvei (ω-1)-methoxy mycolic acids: Absolute stereochemistry and synthesis. Chem Phys Lipids 2020; 233:104977. [PMID: 32961166 DOI: 10.1016/j.chemphyslip.2020.104977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/24/2020] [Accepted: 09/14/2020] [Indexed: 11/28/2022]
Abstract
Cells of Mycobacterium alvei are known to contain a unique set of mycolic acids with a (ω-1)-methoxy group; although the various enzymes in the biosynthesis of other types of mycolic acid have been widely studied, the biosynthetic route to this substituent is unclear. We now define the stereochemistry of the (ω-1)-methoxy fragment as R, and describe the synthesis of a major R-(ω-1)-methoxy-mycolic acid and its sugar esters, and of two natural M. alvei diene mycolic acids.
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Affiliation(s)
- Zamzam S Alhuwaymil
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | | | - Ahmad R Al Dulayymi
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - Alison Jones
- School of Natural Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
| | - Paul J Gates
- School of Chemistry, Bristol University, Bristol, BS8 1TS, UK
| | - Pedro L Valero-Guillén
- Departamento de Genética y Microbiología, Facultad de Medicina, Universidad de Murcia, Spain, Instituto Murciano de Investigación Biosanitaria (IMIB), Spain
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd, LL57 2UW, UK
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Anderson O, Beckett J, Briggs CC, Natrass LA, Cranston CF, Wilkinson EJ, Owen JH, Mir Williams R, Loukaidis A, Bouillon ME, Pritchard D, Lahmann M, Baird MS, Denny PW. An investigation of the antileishmanial properties of semi-synthetic saponins. RSC Med Chem 2020; 11:833-842. [PMID: 33479679 PMCID: PMC7651632 DOI: 10.1039/d0md00123f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/21/2020] [Indexed: 12/25/2022] Open
Abstract
Leishmaniasis is a neglected tropical disease caused by insect-vector borne protozoan parasites of the, Leishmania species. Whilst infection threatens and affects millions of the global poor, vaccines are absent and drug therapy limited. Extensive efforts have recently been made to discover new leads from small molecule synthetic compound libraries held by industry; however, the number of new chemical entities identified and entering development as anti-leishmanials has been very low. This has led to increased interest in the possibility of discovering naturally derived compounds with potent antileishmanial activity which may be developed towards clinical applications. Plant-derived triterpenoid and steroidal saponins have long been considered as anti-microbials and here we describe an investigation of a library of 137 natural (9) and semi-synthetic saponins (128) for activity against Leishmania mexicana, a causative agent of cutaneous leishmaniasis. The triterpenoid sapogenin, hederagenin, readily obtained in large quantities from Hedera helix (common ivy), was converted into a range of 128 derivatives. These semi-synthetic compounds, as well as saponins isolated from ivy, were examined with a phenotypic screening approach to identify potent and selective anti-leishmanial hits. This led to the identification of 12 compounds, including the natural saponin gypsogenin, demonstrating high potency (ED50 < 10.5 μM) against axenic L. mexicana amastigotes, the mammalian pathogenic form. One of these, hederagenin disuccinate, was sufficiently non-toxic to the macrophage host cell to facilitate further analyses, selectivity index (SI) > 10. Whilst this was not active in an infected cell model, the anti-leishmanial properties of hederagenin-derivatives have been demonstrated, and the possibility of improving the selectivity of natural hederagenin through chemical modification has been established.
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Affiliation(s)
- Orlagh Anderson
- Department of Biosciences and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK . ; Tel: +44 (0)191 3343983
| | - Joseph Beckett
- Department of Biosciences and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK . ; Tel: +44 (0)191 3343983
| | - Carla C Briggs
- Department of Biosciences and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK . ; Tel: +44 (0)191 3343983
| | - Liam A Natrass
- Department of Biosciences and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK . ; Tel: +44 (0)191 3343983
- Department of Chemistry and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK
| | - Charles F Cranston
- Department of Biosciences and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK . ; Tel: +44 (0)191 3343983
| | - Elizabeth J Wilkinson
- Department of Chemistry , School of Natural Science , Bangor University , Gwynedd LL57 2UW , UK
| | - Jack H Owen
- Department of Chemistry , School of Natural Science , Bangor University , Gwynedd LL57 2UW , UK
| | - Rhodri Mir Williams
- Department of Chemistry , School of Natural Science , Bangor University , Gwynedd LL57 2UW , UK
| | - Angelos Loukaidis
- Department of Chemistry , School of Natural Science , Bangor University , Gwynedd LL57 2UW , UK
| | - Marc E Bouillon
- Department of Chemistry , School of Natural Science , Bangor University , Gwynedd LL57 2UW , UK
| | - Deiniol Pritchard
- Naturiol Bangor Ltd , Alun Roberts Building , Bangor University , Gwynedd LL57 2UW , UK
| | - Martina Lahmann
- Department of Chemistry , School of Natural Science , Bangor University , Gwynedd LL57 2UW , UK
| | - Mark S Baird
- Naturiol Bangor Ltd , Alun Roberts Building , Bangor University , Gwynedd LL57 2UW , UK
| | - Paul W Denny
- Department of Biosciences and Centre for Global Infectious Diseases , Durham University , Stockton Road , Durham , DH1 3LE , UK . ; Tel: +44 (0)191 3343983
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Chancellor A, Tocheva AS, Cave-Ayland C, Tezera L, White A, Al Dulayymi JR, Bridgeman JS, Tews I, Wilson S, Lissin NM, Tebruegge M, Marshall B, Sharpe S, Elliott T, Skylaris CK, Essex JW, Baird MS, Gadola S, Elkington P, Mansour S. CD1b-restricted GEM T cell responses are modulated by Mycobacterium tuberculosis mycolic acid meromycolate chains. Proc Natl Acad Sci U S A 2017; 114:E10956-E10964. [PMID: 29158404 PMCID: PMC5754766 DOI: 10.1073/pnas.1708252114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a major human pandemic. Germline-encoded mycolyl lipid-reactive (GEM) T cells are donor-unrestricted and recognize CD1b-presented mycobacterial mycolates. However, the molecular requirements governing mycolate antigenicity for the GEM T cell receptor (TCR) remain poorly understood. Here, we demonstrate CD1b expression in TB granulomas and reveal a central role for meromycolate chains in influencing GEM-TCR activity. Meromycolate fine structure influences T cell responses in TB-exposed individuals, and meromycolate alterations modulate functional responses by GEM-TCRs. Computational simulations suggest that meromycolate chain dynamics regulate mycolate head group movement, thereby modulating GEM-TCR activity. Our findings have significant implications for the design of future vaccines that target GEM T cells.
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Affiliation(s)
- Andrew Chancellor
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Public Health England, National Infections Service, Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Anna S Tocheva
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Chris Cave-Ayland
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Liku Tezera
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Andrew White
- Public Health England, National Infections Service, Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Juma'a R Al Dulayymi
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
| | | | - Ivo Tews
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Susan Wilson
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Histochemistry Unit, University of Southampton, Southampton SO16 6YD, United Kingdom
| | | | - Marc Tebruegge
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton SO17 1BJ, United Kingdom
- Global Health Research Institute, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Department of Paediatrics, Faculty of Medicine, University of Melbourne, 3052 Parkville, Australia
- Department of Paediatric Infectious Diseases & Immunology, Evelina London Children's Hospital, Guy's and St. Thomas' NHS Foundation Trust, London SE1 7EH, United Kingdom
| | - Ben Marshall
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton SO17 1BJ, United Kingdom
| | - Sally Sharpe
- Public Health England, National Infections Service, Porton Down, Salisbury SP4 0JQ, United Kingdom
| | - Tim Elliott
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Cancer Sciences Unit, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Chris-Kriton Skylaris
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Jonathan W Essex
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
| | - Stephan Gadola
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
| | - Paul Elkington
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton SO17 1BJ, United Kingdom
- Global Health Research Institute, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Salah Mansour
- Academic Unit of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom;
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
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Jones A, Pitts M, Al Dulayymi JR, Gibbons J, Ramsay A, Goletti D, Gwenin CD, Baird MS. New synthetic lipid antigens for rapid serological diagnosis of tuberculosis. PLoS One 2017; 12:e0181414. [PMID: 28806423 PMCID: PMC5555574 DOI: 10.1371/journal.pone.0181414] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 07/01/2017] [Indexed: 01/30/2023] Open
Abstract
Background During pulmonary tuberculosis (PTB) antibodies are generated to trehalose esters of mycolic acids which are cell wall lipids of Mycobacterium tuberculosis (Mtb). Attempts have been made to use these complex natural mixtures in serological tests for PTB diagnosis. Aim The aim of this work was to determine whether a serological test based on a panel of defined individual trehalose esters of characteristic synthetic mycolic acids has improved diagnostic accuracy in distinguishing patients with culture positive PTB from individuals who were Mtb culture negative. Method One hundred serum samples from well-characterized patients with presumptive tuberculosis, and diagnosed as having pulmonary smear and culture positive TB, or being culture and smear negative were evaluated by ELISA using different combinations of synthetic antigens and secondary antibodies. Using cut-off values determined from these samples, we validated this study blind in samples from a further 249 presumptive TB patients. Results With the first 100 samples, detailed responses depended both on the precise structure of the antigen and on the secondary antibody. Using a single antigen, a sensitivity/specificity combination for smear and culture positive PTB detection of 85 and 88% respectively was achieved; this increased to 96% and 95% respectively by a statistical combination of the results with seven antigens. In the blind study a sensitivity/specificity of 87% and 83% was reached with a single antigen. With some synthetic antigens, the responses from all 349 samples were significantly better than those with the natural mixture. Combining the results for seven antigens allowed a distinction between culture positive and negative with a ROC AUC of 0.95. Conclusion We have identified promising antigen candidates for serological assays that could be used to diagnose PTB and which could be the basis of a much-needed, simple, rapid diagnostic test that would bring care closer to communities.
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Affiliation(s)
- Alison Jones
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, United Kingdom
| | - Mark Pitts
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, United Kingdom
| | | | - James Gibbons
- School of Environment, Natural Resources and Geography, Bangor University, Bangor, Gwynedd, Wales, United Kingdom
| | - Andrew Ramsay
- Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organisation, Geneva, Switzerland
- University of St Andrews Medical School, St. Andrews, Scotland, United Kingdom
| | - Delia Goletti
- Translational Research Unit, Department of Epidemiology and Preclinical Research, ‘L. Spallanzani’ National Institute for Infectious Diseases, Rome, Italy
| | | | - Mark S. Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, United Kingdom
- * E-mail:
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Abstract
R- and S-Glycerol mycolates derived from single synthetic α-, keto- and methoxy-mycolic acids are described.
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Affiliation(s)
- Omar T Ali
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, LL57 2UW, UK
| | - Mohaned M Sahb
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, LL57 2UW, UK
| | | | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, LL57 2UW, UK.
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Mohammed MO, Al Dulayymi JR, Baird MS. Preparation of the tri-arabino di-mycolate fragment of mycobacterial arabinogalactan from defined synthetic mycolic acids. Carbohydr Res 2017; 437:36-42. [DOI: 10.1016/j.carres.2016.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/07/2016] [Accepted: 11/07/2016] [Indexed: 11/30/2022]
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Ali HM, Koza G, Hameed RT, Rowles R, Davies C, Al Dulayymi JR, Gwenin CD, Baird MS. The synthesis of single enantiomers of trans-alkene containing mycolic acids and related sugar esters. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.08.089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Smet M, Pollard C, De Beuckelaer A, Van Hoecke L, Vander Beken S, De Koker S, Al Dulayymi JR, Huygen K, Verschoor J, Baird MS, Grooten J. Mycobacterium tuberculosis-associated synthetic mycolates differentially exert immune stimulatory adjuvant activity. Eur J Immunol 2016; 46:2149-54. [PMID: 27349218 DOI: 10.1002/eji.201646357] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 05/14/2016] [Accepted: 06/23/2016] [Indexed: 12/12/2022]
Abstract
Mycolic acids (MAs) are highly hydrophobic long-chain α-alkyl β-hydroxy fatty acids present in the cell wall of Mycobacterium tuberculosis (Mtb) as a complex mixture of molecules with a common general structure but with variable functional groups in the meromycolate chain. In this study, we addressed the relationship between the MA molecular structure and their contribution to the development of T-cell immune responses. Hereto, we used the model antigen ovalbumin and single synthetic MAs, differing in oxygenation class and cis versus trans proximal cyclopropane configuration, as immune stimulatory agents. Subcutaneous delivery of liposome-formulated MAs with a proximal cis cyclopropane elicited antigen-specific Th1 and cytotoxic T-cell immune responses, whereas intratracheal immunization elicited pulmonary Th17 responses. These immune stimulatory activities depended not only on the cis versus trans proximal cyclopropane configuration but also on the MA oxygenation class. Our study thus shows that both the presence and nature of the functional groups in the meromycolate chain affect the immune stimulatory adjuvant activity of Mtb mycolates and suggests that Mtb bacilli may impact on the host protective immune response by modulating the cis versus trans stereochemistry of its mycolates as well as by altering the oxygenation class of the meromycolate functional group.
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Affiliation(s)
- Muriel Smet
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Charlotte Pollard
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Ans De Beuckelaer
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Lien Van Hoecke
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.,Medical Biotechnology Center, Flanders Institute for Biotechnology, Ghent, Belgium
| | - Seppe Vander Beken
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Stefaan De Koker
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | | | - Kris Huygen
- Immunology Department, Scientific Institute of Public Health, Brussels, Belgium
| | - Jan Verschoor
- Department of Biochemistry, University of Pretoria, Pretoria, South Africa
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, United Kingdom
| | - Johan Grooten
- Laboratory of Molecular Immunology, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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13
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Taher SG, Al Dulayymi JR, Tima HG, Ali HM, Romano M, Baird MS. Synthesis of wax esters and related trehalose esters from Mycobacterium avium and other mycobacteria. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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15
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Ndlandla FL, Ejoh V, Stoltz AC, Naicker B, Cromarty AD, van Wyngaardt S, Khati M, Rotherham LS, Lemmer Y, Niebuhr J, Baumeister CR, Al Dulayymi JR, Swai H, Baird MS, Verschoor JA. Standardization of natural mycolic acid antigen composition and production for use in biomarker antibody detection to diagnose active tuberculosis. J Immunol Methods 2016; 435:50-9. [PMID: 27247168 DOI: 10.1016/j.jim.2016.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/21/2016] [Accepted: 05/24/2016] [Indexed: 10/21/2022]
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, is characterized by the abundance of species specific, antigenic cell wall lipids called mycolic acids. These wax-like molecules all share an identical, amphiphilic mycolic motif, but have different functional groups in a long hydrophobic hydrocarbon mero-chain that divide them into three main classes: alpha-, keto- and methoxy-mycolic acids. Whereas alpha-mycolic acids constitutively maintain an abundance of around 50%, the ratio of methoxy- to keto-mycolic acid types may vary depending on, among other things, the growth stage of M. tuberculosis. In human patients, antibodies to mycolic acids have shown potential as diagnostic serum biomarkers for active TB. Variations in mycolic acid composition affect the antigenic properties and can potentially compromise the precision of detection of anti-mycolic acids antibodies in patient sera to natural mixtures. We demonstrate this here with combinations of synthetic mycolic acid antigens, tested against TB patient and control sera. Combinations of methoxy- and α-mycolic acids are more antigenic than combinations of keto- and α-mycolic acids, showing the former to give a more sensitive test for TB biomarker antibodies. Natural mixtures of mycolic acids isolated from mature cultures of M. tuberculosis H37Rv give the same sensitivity as that with synthetic methoxy- and α-mycolic acids in combination, in a surface plasmon resonance inhibition biosensor test. To ensure that the antigenic activity of isolates of natural mycolic acids is reproducible, we cultured M. tuberculosis H37Rv on Middlebrook 7H10 solid agar plates to stationary growth phase in a standardized, optimal way. The proportions of mycolic acid classes in various batches of the isolates prepared from these cultures were compared to a commercially available natural mycolic acid isolate. LC-MS/MS and NMR data for quantitation of mycolic acids class compositions show that the variation in batches is small, suggesting that the quality of the results for anti-mycolic acid antibody detection in the TB patients should not be affected by different batches of natural mycolic acid antigens if prepared in a standard way.
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Affiliation(s)
- F L Ndlandla
- Polymers and Composites, Council for Scientific and Industrial Research, Pretoria, South Africa; Department of Biochemistry, University of Pretoria, South Africa
| | - V Ejoh
- Department of Biochemistry, University of Pretoria, South Africa
| | - A C Stoltz
- Division of Infectious Diseases, Faculty of Health Sciences, University of Pretoria, South Africa
| | - B Naicker
- Polymers and Composites, Council for Scientific and Industrial Research, Pretoria, South Africa; Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, South Africa
| | - A D Cromarty
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, South Africa
| | - S van Wyngaardt
- Department of Biochemistry, University of Pretoria, South Africa
| | - M Khati
- Biosciences, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - L S Rotherham
- Biosciences, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - Y Lemmer
- Polymers and Composites, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - J Niebuhr
- Department of Biochemistry, University of Pretoria, South Africa
| | - C R Baumeister
- Department of Biochemistry, University of Pretoria, South Africa
| | | | - H Swai
- Polymers and Composites, Council for Scientific and Industrial Research, Pretoria, South Africa
| | - M S Baird
- School of Chemistry, Bangor University, Wales, UK
| | - J A Verschoor
- Department of Biochemistry, University of Pretoria, South Africa
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16
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Hao P, Alaraj IQM, Dulayymi JRA, Baird MS, Liu J, Liu Q. Sterculic Acid and Its Analogues Are Potent Inhibitors of Toxoplasma gondii. Korean J Parasitol 2016; 54:139-45. [PMID: 27180571 PMCID: PMC4870972 DOI: 10.3347/kjp.2016.54.2.139] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/10/2016] [Accepted: 03/13/2016] [Indexed: 11/23/2022]
Abstract
Toxoplasmosis is a serious disease caused by Toxoplasma gondii, one of the most widespread parasites in the world. Lipid metabolism is important in the intracellular stage of T. gondii. Stearoyl-CoA desaturase (SCD), a key enzyme for the synthesis of unsaturated fatty acid is predicted to exist in T. gondii. Sterculic acid has been shown to specifically inhibit SCD activity. Here, we examined whether sterculic acid and its methyl ester analogues exhibit anti-T. gondii effects in vitro. T. gondii-infected Vero cells were disintegrated at 36 hr because of the propagation and egress of intracellular tachyzoites. All test compounds inhibited tachyzoite propagation and egress, reducing the number of ruptured Vero cells by the parasites. Sterculic acid and the methyl esters also inhibited replication of intracellular tachyzoites in HFF cells. Among the test compounds, sterculic acid showed the most potent activity against T. gondii, with an EC50 value of 36.2 μM, compared with EC50 values of 248-428 μM for the methyl esters. Our study demonstrated that sterculic acid and its analogues are effective in inhibition of T. gondii growth in vitro, suggesting that these compounds or analogues targeting SCD could be effective agents for the treatment of toxoplasmosis.
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Affiliation(s)
- Pan Hao
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | | | | | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, UK
| | - Jing Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Qun Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
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17
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Mansour S, Tocheva AS, Cave-Ayland C, Machelett MM, Sander B, Lissin NM, Molloy PE, Baird MS, Stübs G, Schröder NWJ, Schumann RR, Rademann J, Postle AD, Jakobsen BK, Marshall BG, Gosain R, Elkington PT, Elliott T, Skylaris CK, Essex JW, Tews I, Gadola SD. Cholesteryl esters stabilize human CD1c conformations for recognition by self-reactive T cells. Proc Natl Acad Sci U S A 2016; 113:E1266-75. [PMID: 26884207 PMCID: PMC4780616 DOI: 10.1073/pnas.1519246113] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cluster of differentiation 1c (CD1c)-dependent self-reactive T cells are abundant in human blood, but self-antigens presented by CD1c to the T-cell receptors of these cells are poorly understood. Here we present a crystal structure of CD1c determined at 2.4 Å revealing an extended ligand binding potential of the antigen groove and a substantially different conformation compared with known CD1c structures. Computational simulations exploring different occupancy states of the groove reenacted these different CD1c conformations and suggested cholesteryl esters (CE) and acylated steryl glycosides (ASG) as new ligand classes for CD1c. Confirming this, we show that binding of CE and ASG to CD1c enables the binding of human CD1c self-reactive T-cell receptors. Hence, human CD1c adopts different conformations dependent on ligand occupancy of its groove, with CE and ASG stabilizing CD1c conformations that provide a footprint for binding of CD1c self-reactive T-cell receptors.
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Affiliation(s)
- Salah Mansour
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom;
| | - Anna S Tocheva
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Chris Cave-Ayland
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Moritz M Machelett
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom; Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Barbara Sander
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | | | - Peter E Molloy
- Immunocore Limited, Abingdon, Oxon OX14 4RY, United Kingdom
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2DG, United Kingdom
| | - Gunthard Stübs
- Institute for Community Medicine, University Medicine Greifswald, 17489 Greifswald, Germany
| | - Nicolas W J Schröder
- Institute for Pathology, Otto-von-Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Ralf R Schumann
- Institute for Microbiology and Hygiene, Charité University Medical Center, 10117 Berlin, Germany
| | - Jörg Rademann
- Division of Medicinal Chemistry, Institute of Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Anthony D Postle
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | | | - Ben G Marshall
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Rajendra Gosain
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Paul T Elkington
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Tim Elliott
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom; Cancer Sciences Unit, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Chris-Kriton Skylaris
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom; School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Jonathan W Essex
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom; School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Ivo Tews
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom; Centre for Biological Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Stephan D Gadola
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO17 1BJ, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom; Novartis Institutes of Biomedical Research, 4058 Basel, Switzerland
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18
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Taher SG, Muzael M, Al Dulayymi JR, Baird MS. Synthetic trehalose esters of cis-alkene and diene α′-mycolic acids of Mycobacteria. Chem Phys Lipids 2015; 189:28-38. [DOI: 10.1016/j.chemphyslip.2015.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/18/2015] [Indexed: 11/24/2022]
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19
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20
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Mustafa HH, Baird MS, Al Dulayymi JR, Tverezovskiy VV. A nine carbon homologating system for skip-conjugated polyenes. Chem Phys Lipids 2014; 183:34-42. [PMID: 24809236 DOI: 10.1016/j.chemphyslip.2014.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 10/25/2022]
Abstract
Ozonolysis of Z,Z,Z-cylonona-1,4,7-triene leads to a 1,9-difunctionalised Z,Z-3,6-nonadiene which is readily converted into a range of polyunsaturated pheromones and fatty acids.
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Affiliation(s)
- Hussein H Mustafa
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
| | - Mark S Baird
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom.
| | - Juma'a R Al Dulayymi
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
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21
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Groenewald W, Baird MS, Verschoor JA, Minnikin DE, Croft AK. Differential spontaneous folding of mycolic acids from Mycobacterium tuberculosis. Chem Phys Lipids 2014; 180:15-22. [DOI: 10.1016/j.chemphyslip.2013.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 10/25/2022]
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22
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Mustafa HH, Baird MS, Al Dulayymi JR, Tverezovskiy VV. Tandem rearrangements of a cyclic bis-allene. Tetrahedron 2014. [DOI: 10.1016/j.tet.2013.12.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Koza G, Muzael M, Schubert-Rowles RR, Theunissen C, Al Dulayymi JR, Baird MS. The synthesis of methoxy and keto mycolic acids containing methyl-trans-cyclopropanes. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.04.134] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Balogun MO, Huws EH, Sirhan MM, Saleh AD, Dulayymi JRA, Pilcher L, Verschoor JA, Baird MS. Thiol modified mycolic acids. Chem Phys Lipids 2013; 172-173:40-55. [DOI: 10.1016/j.chemphyslip.2013.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 03/21/2013] [Accepted: 03/23/2013] [Indexed: 11/30/2022]
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Abstract
Both diastereomers of the tris-allene, cyclododeca-1,2,5,6,9,10-hexaene have been obtained using a triple cyclopropylidene-allene rearrangement. On the NMR timescale, one has D3 symmetry, and is the smallest hydrocarbon synthesised to have this symmetry, and the second has C2 symmetry.
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Affiliation(s)
- Hussein H Mustafa
- School of Chemistry, Bangor University, Bangor, Gwynedd, Wales, UK LL57 2UW
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26
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Verschoor JA, Baird MS, Grooten J. Towards understanding the functional diversity of cell wall mycolic acids of Mycobacterium tuberculosis. Prog Lipid Res 2012; 51:325-39. [PMID: 22659327 DOI: 10.1016/j.plipres.2012.05.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 03/05/2012] [Accepted: 05/23/2012] [Indexed: 01/08/2023]
Abstract
Mycolic acids constitute the waxy layer of the outer cell wall of Mycobacterium spp. and a few other genera. They are diverse in structure, providing a unique chromatographic foot-print for almost each of the more than 70 Mycobacterium species. Although mainly esterified to cell wall arabinogalactan, trehalose or glucose, some free mycolic acid is secreted during in vitro growth of Mycobacterium tuberculosis. In M. tuberculosis, α-, keto- and methoxy-mycolic acids are the main classes, each differing in their ability to attract neutrophils, induce foamy macrophages or adopt an antigenic structure for antibody recognition. Of interest is their particular relationship to cholesterol, discovered by their ability to attract cholesterol, to bind Amphotericin B or to be recognised by monoclonal antibodies that cross-react with cholesterol. The structural elements that determine this diverse functionality include the carboxylic acid in the mycolic motif, as well as the nature and stereochemistry of the two functional groups in the merochain. The functional diversity of mycolic acid classes implies that much information may be contained in the selective expression and secretion of mycolic acids to establish tuberculosis after infection of the host. Their cholesteroid nature may relate to how they utilize host cholesterol for their persistent survival.
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Affiliation(s)
- Jan A Verschoor
- Department Biochemistry, University of Pretoria, Pretoria 0002, South Africa.
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27
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Vander Beken S, Al Dulayymi JR, Naessens T, Koza G, Maza-Iglesias M, Rowles R, Theunissen C, De Medts J, Lanckacker E, Baird MS, Grooten J. Molecular structure of the Mycobacterium tuberculosis virulence factor, mycolic acid, determines the elicited inflammatory pattern. Eur J Immunol 2010; 41:450-60. [PMID: 21268014 DOI: 10.1002/eji.201040719] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 10/20/2010] [Accepted: 11/17/2010] [Indexed: 11/12/2022]
Abstract
Mycolic acids (MAs) occur in the cell wall of Mycobacterium tuberculosis as variable mixtures of different classes and chain lengths. Here, we address the relationship between the structure and its inflammatory function of this virulence factor using single synthetic MA isomers, differing in oxygenation class and cis- versus α-methyl-trans proximal cyclopropane orientation. Analysis of bronchoalveolar inflammation, lung histopathology and alveolar macrophage transcription revealed a strong dependence on these meromycolic chemistries of mouse pulmonary inflammation in response to intratracheal treatments with MAs. Whereas α-MA was inert, oxygenated methoxy- and keto-MA with cis-cyclopropane stereochemistry elicited solid to mild inflammatory responses respectively. In trans-cyclopropane orientation, methoxy-MA partially lost its inflammatory activity and keto-MA exerted anti-inflammatory alternative activation of alveolar macrophages and counteracted cis-methoxy-MA induced airway inflammation. The differential innate immune activities of MAs demonstrated here, dependent on oxygenation class and cis versus α-methyl-trans cyclopropane chemistry, identify a novel means for M. tuberculosis to steer host immune responses during infection.
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Affiliation(s)
- Seppe Vander Beken
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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28
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Beukes M, Lemmer Y, Deysel M, Al Dulayymi JR, Baird MS, Koza G, Iglesias MM, Rowles RR, Theunissen C, Grooten J, Toschi G, Roberts VV, Pilcher L, Van Wyngaardt S, Mathebula N, Balogun M, Stoltz AC, Verschoor JA. Structure-function relationships of the antigenicity of mycolic acids in tuberculosis patients. Chem Phys Lipids 2010; 163:800-8. [PMID: 20875402 PMCID: PMC3025329 DOI: 10.1016/j.chemphyslip.2010.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 09/14/2010] [Accepted: 09/17/2010] [Indexed: 11/17/2022]
Abstract
Cell wall mycolic acids (MA) from Mycobacterium tuberculosis (M.tb) are CD1b presented antigens that can be used to detect antibodies as surrogate markers of active TB, even in HIV coinfected patients. The use of the complex mixtures of natural MA is complicated by an apparent antibody cross-reactivity with cholesterol. Here firstly we report three recombinant monoclonal scFv antibody fragments in the chicken germ-line antibody repertoire, which demonstrate the possibilities for cross-reactivity: the first recognized both cholesterol and mycolic acids, the second mycolic acids but not cholesterol, and the third cholesterol but not mycolic acids. Secondly, MA structure is experimentally interrogated to try to understand the cross-reactivity. Unique synthetic mycolic acids representative of the three main functional classes show varying antigenicity against human TB patient sera, depending on the functional groups present and on their stereochemistry. Oxygenated (methoxy- and keto-) mycolic acid was found to be more antigenic than alpha-mycolic acids. Synthetic methoxy-mycolic acids were the most antigenic, one containing a trans-cyclopropane apparently being somewhat more antigenic than the natural mixture. Trans-cyclopropane-containing keto- and hydroxy-mycolic acids were also found to be the most antigenic among each of these classes. However, none of the individual synthetic mycolic acids significantly and reproducibly distinguished the pooled serum of TB positive patients from that of TB negative patients better than the natural mixture of MA. This argues against the potential to improve the specificity of serodiagnosis of TB with a defined single synthetic mycolic acid antigen from this set, although sensitivity may be facilitated by using a synthetic methoxy-mycolic acid.
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Affiliation(s)
- Mervyn Beukes
- Department of Biochemistry, University of Pretoria, South Africa
| | - Yolandy Lemmer
- Department of Biochemistry, University of Pretoria, South Africa
| | - Madrey Deysel
- Department of Biochemistry, University of Pretoria, South Africa
| | | | - Mark S. Baird
- School of Chemistry, University of Wales, Bangor, United Kingdom
| | - Gani Koza
- School of Chemistry, University of Wales, Bangor, United Kingdom
| | | | | | | | - Johan Grooten
- Department of Molecular Biomedical Research, Molecular Immunology Unit, Gent University, Belgium
| | - Gianna Toschi
- Department of Biochemistry, University of Pretoria, South Africa
| | | | - Lynne Pilcher
- Department of Chemistry, University of Pretoria, South Africa
| | | | - Nsovo Mathebula
- Department of Chemistry, University of Pretoria, South Africa
| | | | - Anton C. Stoltz
- Department of Infectious Diseases, University of Pretoria, South Africa
| | - Jan A. Verschoor
- Department of Biochemistry, University of Pretoria, South Africa
- Corresponding author. Tel.: +27 124202477; fax: +27 123625302.
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29
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Muzael M, Koza G, Dulayymi JJA, Baird MS. The synthesis of a major α′-mycolic acid of Mycobacterium smegmatis. Chem Phys Lipids 2010; 163:678-84. [DOI: 10.1016/j.chemphyslip.2010.05.203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 05/19/2010] [Accepted: 05/26/2010] [Indexed: 10/19/2022]
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31
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Driver CH, Balogun MO, Toschi G, Verschoor JA, Baird MS, Pilcher LA. A biomimetic approach to the synthesis of a mycolic acid motif. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2009.12.105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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32
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Sheshenev AE, Baird MS, Bolesov IG, Shashkov AS. Stereo- and regiocontrol in ene-dimerisation and trimerisation of 1-trimethylsilyl-3-phenylcyclopropene. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.10.077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Koza G, Rowles R, Theunissen C, Al-Dulayymi JR, Baird MS. The synthesis of single enantiomers of trans-alkene-containing mycolic acids. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Gratraud P, Huws E, Falkard B, Adjalley S, Fidock DA, Berry L, Jacobs WR, Baird MS, Vial H, Kremer L. Oleic acid biosynthesis in Plasmodium falciparum: characterization of the stearoyl-CoA desaturase and investigation as a potential therapeutic target. PLoS One 2009; 4:e6889. [PMID: 19707292 PMCID: PMC2731242 DOI: 10.1371/journal.pone.0006889] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 08/05/2009] [Indexed: 01/16/2023] Open
Abstract
Background Plasmodium falciparum parasitization of erythrocytes causes a substantial increase in the levels of intracellular fatty acids, notably oleic acid. How parasites acquire this monounsaturated fatty acid has remained enigmatic. Here, we report on the biochemical and enzymatic characterization of stearoyl-CoA desaturase (SCD) in P. falciparum. Methodology/Principal Findings Metabolic labeling experiments allowed us to demonstrate the production of oleic acid from stearic acid both in lysates of parasites incubated with [14C]-stearoyl-CoA and in parasite-infected erythrocytes labeled with [14C]-stearic acid. Optimal SCD activity was detected in schizonts, the stage of maximal membrane synthesis. This activity correlated with a late trophozoite stage-specific induction of PFE0555w transcripts. PFE0555w harbors a typical SCD signature. Similar to mammalian SCDs, this protein was found to be associated with the endoplasmic reticulum, as determined with PFE0555w-GFP tagged transgenic P. falciparum. Importantly, these parasites exhibited increased rates of stearic to oleic acid conversion, providing additional evidence that PFE0555w encodes the plasmodial SCD (PfSCD). These findings prompted us to assess the activity of sterculic acid analogues, known to be specific Δ9-desaturase inhibitors. Methyl sterculate inhibited the synthesis of oleic acid both with parasite lysates and infected erythrocytes, most likely by targeting PfSCD. This compound exhibited significant, rapid and irreversible antimalarial activity against asexual blood stages. This parasiticidal effect was antagonized by oleic acid. Conclusion/Significance Our study provides evidence that parasite-mediated fatty acid modification is important for blood-stage survival and provides a new strategy to develop a novel antimalarial therapeutic based on the inhibition of PfSCD.
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Affiliation(s)
- Paul Gratraud
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS, UMR 5235, case 107, Montpellier, France
| | - Enlli Huws
- School of Chemistry, Bangor University, Bangor, Wales
| | - Brie Falkard
- Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Sophie Adjalley
- Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - David A. Fidock
- Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Laurence Berry
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS, UMR 5235, case 107, Montpellier, France
| | - William R. Jacobs
- Howard Hughes Medical Institute, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Mark S. Baird
- School of Chemistry, Bangor University, Bangor, Wales
| | - Henri Vial
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS, UMR 5235, case 107, Montpellier, France
- INSERM, DIMNP, Montpellier, France
| | - Laurent Kremer
- Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS, UMR 5235, case 107, Montpellier, France
- INSERM, DIMNP, Montpellier, France
- * E-mail:
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Benadie Y, Deysel M, Siko DGR, Roberts VV, Van Wyngaardt S, Thanyani ST, Sekanka G, Ten Bokum AM, Collett LA, Grooten J, Baird MS, Verschoor JA. Cholesteroid nature of free mycolic acids from M. tuberculosis. Chem Phys Lipids 2008; 152:95-103. [DOI: 10.1016/j.chemphyslip.2008.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Revised: 12/23/2007] [Accepted: 01/28/2008] [Indexed: 10/22/2022]
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Baird MS. Functionalised cyclopropenes as synthetic intermediates. Top Curr Chem (Cham) 2007. [DOI: 10.1007/bfb0111230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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Baird MS, Boitsov VM, Stepakov AV, Molchanov AP, Kopf J, Rajaratnam M, Kostikov RR. Preparation and reactions of some 2,2-difunctional 1,1-dibromocyclopropanes. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.04.104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Al Dulayymi JR, Baird MS, Roberts E, Deysel M, Verschoor J. The first syntheses of single enantiomers of the major methoxymycolic acid of Mycobacterium tuberculosis. Tetrahedron 2007. [DOI: 10.1016/j.tet.2007.01.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Al Dulayymi JR, Baird MS, Roberts E, Minnikin DE. The synthesis of single enantiomers of meromycolic acids from mycobacterial wax esters. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.09.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Liu CF, Xu F, Sun JX, Ren JL, Curling S, Sun RC, Fowler P, Baird MS. Physicochemical characterization of cellulose from perennial ryegrass leaves (Lolium perenne). Carbohydr Res 2006; 341:2677-87. [PMID: 16934239 DOI: 10.1016/j.carres.2006.07.008] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 07/03/2006] [Accepted: 07/13/2006] [Indexed: 11/24/2022]
Abstract
In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 degrees C with 18% NaOH and 18% KOH for 2h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of 'cellulose' residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS (13)C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4-38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0-38.6%) than that from wood-based fibres (60-70%) and had much shorter fibres (0.35-0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.
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Affiliation(s)
- C F Liu
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China
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Xu F, Geng ZC, Sun JX, Liu CF, Ren JL, Sun RC, Fowler P, Baird MS. Fractional and structural characterization of hemicelluloses from perennial ryegrass (Lolium perenne) and cocksfoot grass (Dactylis glomerata). Carbohydr Res 2006; 341:2073-82. [PMID: 16750181 DOI: 10.1016/j.carres.2006.04.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2006] [Revised: 04/06/2006] [Accepted: 04/19/2006] [Indexed: 11/16/2022]
Abstract
Sequential three-stage treatments with 80% EtOH containing 0.2% NaOH, 2.5% H2O2-0.2% EDTA containing 1.5% NaOH and 2.5% H2O2-0.2% TAED containing 1.0% NaOH at 75 degrees C for 3h released 8.0% and 10.4%, 79.1% and 77.0% and 12.9% and 12.5% of the original hemicelluloses from perennial grass and cocksfoot grass, respectively. It was found that the four alkaline peroxide-soluble hemicellulosic fractions contained higher amounts of xylose (33.4-38.2%), uronic acids (9.3-15.3%) and rhamnose (3.0-3.9%), but were lower in glucose (25.1-28.3%), galactose (13.3-15.3%) and mannose (0.4-1.5%) than those of the two alkaline EtOH-soluble hemicellulosic fractions in which glucose (32.9-36.0%), xylose (20.1-22.6%), arabinose (14.1-21.4%), galactose (16.6-19.9%), mannose (4.1-9.9%) and uronic acids (3.4-7.4%) were the major sugar components. 13C NMR spectroscopy confirmed that all the six hemicellulosic fractions were composed of galactoarabinoxylans, 4-O-methylglucuronoarabinoxylans and beta-glucan. In addition, the studies showed that the four alkaline peroxide-soluble hemicellulosic fractions were more linear and acidic and had larger molecular weights (Mw, 28,400-38,650 g mol(-1)) than those of the two alkaline EtOH-soluble hemicellulosic fractions (Mw, 16,460-17,420 g mol(-1)).
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Affiliation(s)
- F Xu
- College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China
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Al-Dulayymi JR, Baird MS, Mohammed H, Roberts E, Clegg W. The synthesis of one enantiomer of the α-methyl-trans-cyclopropane unit of mycolic acids. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sheshenev AE, Baird MS, Croft AK, Starikova ZA, Shashkov AS, Zhuze AL, Bolesov IG. Stereocontrol in ene-dimerisation and trimerisation of 1-trimethylsilyl-3-phenylcyclopropene. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2005.12.111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Roberts IO, Baird MS. A new short synthesis of 10R-tuberculostearic acid and its enantiomer. Chem Phys Lipids 2006; 142:111-7. [PMID: 16690044 DOI: 10.1016/j.chemphyslip.2006.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2005] [Revised: 03/11/2006] [Accepted: 03/16/2006] [Indexed: 11/21/2022]
Abstract
Tuberculostearic acid (10R-methyloctadecanoic acid) and its 10S-enantiomer were synthesised by a chiral pool strategy, in four steps from citronellyl bromide.
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Affiliation(s)
- Ieuan O Roberts
- Department of Chemistry, University of Wales, Bangor, Gwynedd, Wales LL57 2UW, UK
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Sun XF, Xu F, Zhao H, Sun RC, Fowler P, Baird MS. Physicochemical characterisation of residual hemicelluloses isolated with cyanamide-activated hydrogen peroxide from organosolv pre-treated wheat straw. Bioresour Technol 2005; 96:1342-1349. [PMID: 15792581 DOI: 10.1016/j.biortech.2004.11.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 10/18/2004] [Accepted: 11/16/2004] [Indexed: 05/24/2023]
Abstract
Seven residual hemicellulosic preparations (19.6-45.0% of the original hemicelluloses) were extracted from wheat straw pre-treated with various organic solvents using 1.8% H2O2-0.18% cyanamide at 50 degrees C and pH 10.0 for 4 h. Their chemical compositions and physicochemical properties were determined using GC, HPLC, GPC, FT-IR and 13NMR spectroscopy. The results indicated that all the residual hemicellulosic preparations were heteropolysaccharides containing xylose, glucose, arabinose, galactose, mannose, rhamnose and 4-O-methyl-alpha-D-glucopyranosyluronic acid. The predominant monosaccharide was xylose, ranging between 67.7% and 81.9% of the total neutral sugars, composed mainly of L-arabino-(4-O-methyl-D-glucurono)-D-xylan. The content of contaminant lignin in the isolated residual hemicelluloses was 2.89-5.31%. The Mw values of the two residual hemicellulosic preparations H6 and H7 (42,710 and 44,080 g mol-1, respectively) obtained from the aqueous-alcohol pre-treated straw were much higher than those of H1-H5 (12,980-15,950 g mol-1) extracted from the organic acid pre-treated straw.
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Affiliation(s)
- Xiao Feng Sun
- College of Forestry, The North-Western University of Agricultural and Forest Sciences and Technology, Yangling 712100, China
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Sun XF, Sun R, Fowler P, Baird MS. Extraction and characterization of original lignin and hemicelluloses from wheat straw. J Agric Food Chem 2005; 53:860-70. [PMID: 15712990 DOI: 10.1021/jf040456q] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Original lignin and hemicelluloses were sequentially extracted with high yield/purity, using acidic dioxane/water solution and dimethyl sulfoxide, from ball-milled wheat straw. The acidic dioxane lignin fraction is distinguished by high beta-O-4' structures and by low amounts of condensed units (beta-5', 5-5', and beta-1'). Hemicelluloses contain arabinoxylans as the major polysaccharides, which are substituted by alpha-l-arabinofuranose, 4-O-methylglucuronic acid, acetyl group (DS = 0.1), and xylose at O-3 and/or O-2 of xylans. It was found that arabinoxylans form cross-links with lignins through ferulates via ether bonds, glucuronic acid via ester bonds, and arbinose/xylose via both ether and glycosidic bonds, respectively, in the cell walls of wheat straw. Diferulates are also incorporated into cross-links between lignin and hemicelluloses as well as lignification of wheat straw cell walls. The guaiacyl unit is considered to be a significant condensed structural constructor in extracted lignin and a connector between lignin and carbohydrates.
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Affiliation(s)
- Xiao-Feng Sun
- College of Forestry, North-Western Science and Technology University of Agriculture and Forestry, Yangling 712100, China
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