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Abagale SA, Woodcock CM, Hooper AM, Caulfield JC, Withall D, Chamberlain K, Acquaah SO, Van Emden H, Braimah H, Pickett JA, Birkett MA. (2R,5S)-Theaspirane Identified as the Kairomone for the Banana Weevil, Cosmopolites sordidus, from Attractive Senesced Leaves of the Host Banana, Musa spp. Chemistry 2018; 24:9217-9219. [PMID: 29644772 PMCID: PMC6055713 DOI: 10.1002/chem.201800315] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Indexed: 11/06/2022]
Abstract
The principal active component produced by highly attractive senesced host banana leaves, Musa spp., for the banana weevil, Cosmopolites sordidus, is shown by coupled gas chromatography-electroantennography (GC-EAG), coupled GC-mass spectrometry (GC-MS), chemical synthesis and coupled enantioselective (chiral) GC-EAG to be (2R,5S)-theaspirane. In laboratory behaviour tests, the synthetic compound is as attractive as natural host leaf material and presents a new opportunity for pest control.
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Affiliation(s)
- Samson A Abagale
- Crops Research Institute, Council for Scientific and Industrial Research, P.O. Box 3785, Fumesua-Kumasi, Ghana.,Department of Chemistry, Kwame Nkrumah University of, Science and Technology, PMB, Kumasi, Ghana
| | - Christine M Woodcock
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Antony M Hooper
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - John C Caulfield
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - David Withall
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Keith Chamberlain
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Samuel O Acquaah
- Department of Chemistry, Kwame Nkrumah University of, Science and Technology, PMB, Kumasi, Ghana
| | - Helmut Van Emden
- School of Agriculture, Policy and Development, The University of Reading, Earley Gate, P.O. Box 237, Reading, Berkshire, RG6 6AR, UK
| | - Haruna Braimah
- Crops Research Institute, Council for Scientific and Industrial Research, P.O. Box 3785, Fumesua-Kumasi, Ghana
| | - John A Pickett
- School of Chemistry, Cardiff University, Cardiff, Wales, CF10 3AT, UK
| | - Michael A Birkett
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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Subbarao GV, Arango J, Masahiro K, Hooper AM, Yoshihashi T, Ando Y, Nakahara K, Deshpande S, Ortiz-Monasterio I, Ishitani M, Peters M, Chirinda N, Wollenberg L, Lata JC, Gerard B, Tobita S, Rao IM, Braun HJ, Kommerell V, Tohme J, Iwanaga M. Genetic mitigation strategies to tackle agricultural GHG emissions: The case for biological nitrification inhibition technology. Plant Sci 2017; 262:165-168. [PMID: 28716411 DOI: 10.1016/j.plantsci.2017.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/01/2017] [Indexed: 05/16/2023]
Abstract
Accelerated soil-nitrifier activity and rapid nitrification are the cause of declining nitrogen-use efficiency (NUE) and enhanced nitrous oxide (N2O) emissions from farming. Biological nitrification inhibition (BNI) is the ability of certain plant roots to suppress soil-nitrifier activity, through production and release of nitrification inhibitors. The power of phytochemicals with BNI-function needs to be harnessed to control soil-nitrifier activity and improve nitrogen-cycling in agricultural systems. Transformative biological technologies designed for genetic mitigation are needed, so that BNI-enabled crop-livestock and cropping systems can rein in soil-nitrifier activity, to help reduce greenhouse gas (GHG) emissions and globally make farming nitrogen efficient and less harmful to environment. This will reinforce the adaptation or mitigation impact of other climate-smart agriculture technologies.
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Affiliation(s)
- G V Subbarao
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan.
| | - J Arango
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - K Masahiro
- International Maize and Wheat Improvement Center (CIMMYT), Mexico-Veracruz, Elbatan, Texcoco CP 56237, Edo.de Mexico, Mexico
| | - A M Hooper
- Rothamsted Research, Harpenden, AL5 2JO, UK
| | - T Yoshihashi
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - Y Ando
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - K Nakahara
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - S Deshpande
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, Telangana, India
| | - I Ortiz-Monasterio
- International Maize and Wheat Improvement Center (CIMMYT), Mexico-Veracruz, Elbatan, Texcoco CP 56237, Edo.de Mexico, Mexico
| | - M Ishitani
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - M Peters
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - N Chirinda
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - L Wollenberg
- CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), University of Vermont, Burlington, VT 05405, USA
| | - J C Lata
- Sorbonne Universites, UPMC Univ. Paris 06, IRD, CNRS, INRA, UPEC, Univ. Paris Diderot, Institute of Ecology and Environmental Sciences, iEES Paris, 4 place Jussieu, 75005 Paris, France
| | - B Gerard
- International Maize and Wheat Improvement Center (CIMMYT), Mexico-Veracruz, Elbatan, Texcoco CP 56237, Edo.de Mexico, Mexico
| | - S Tobita
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
| | - I M Rao
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - H J Braun
- International Maize and Wheat Improvement Center (CIMMYT), Mexico-Veracruz, Elbatan, Texcoco CP 56237, Edo.de Mexico, Mexico
| | - V Kommerell
- International Maize and Wheat Improvement Center (CIMMYT), Mexico-Veracruz, Elbatan, Texcoco CP 56237, Edo.de Mexico, Mexico
| | - J Tohme
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - M Iwanaga
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan
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Midega CA, Wasonga CJ, Hooper AM, Pickett JA, Khan ZR. Drought-tolerant Desmodium species effectively suppress parasitic striga weed and improve cereal grain yields in western Kenya. Crop Prot 2017; 98:94-101. [PMID: 28775391 PMCID: PMC5465939 DOI: 10.1016/j.cropro.2017.03.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 05/04/2023]
Abstract
The parasitic weed Striga hermonthica Benth. (Orobanchaceae), commonly known as striga, is an increasingly important constraint to cereal production in sub-Saharan Africa (SSA), often resulting in total yield losses in maize (Zea mays L.) and substantial losses in sorghum (Sorghum bicolor (L.) Moench). This is further aggravated by soil degradation and drought conditions that are gradually becoming widespread in SSA. Forage legumes in the genus Desmodium (Fabaceae), mainly D. uncinatum and D. intortum, effectively control striga and improve crop productivity in SSA. However, negative effects of climate change such as drought stress is affecting the functioning of these systems. There is thus a need to identify and characterize new plants possessing the required ecological chemistry to protect crops against the biotic stress of striga under such environmental conditions. 17 accessions comprising 10 species of Desmodium were screened for their drought stress tolerance and ability to suppress striga. Desmodium incanum and D. ramosissimum were selected as the most promising species as they retained their leaves and maintained leaf function for longer periods during their exposure to drought stress conditions. They also had desirable phenotypes with more above ground biomass. The two species suppressed striga infestation, both under controlled and field conditions, and resulted in significant grain yield increases, demonstrating the incremental capability of Desmodium species in striga suppression. These results demonstrate beneficial effects of Desmodium species in enhancing cereal productivity in dry areas.
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Affiliation(s)
- Charles A.O. Midega
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi 00100, Kenya
| | - Charles J. Wasonga
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi 00100, Kenya
| | - Antony M. Hooper
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - John A. Pickett
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - Zeyaur R. Khan
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772, Nairobi 00100, Kenya
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Hao B, Caulfield JC, Hamilton ML, Pickett JA, Midega CAO, Khan ZR, Wang J, Hooper AM. Biosynthesis of natural and novel C-glycosylflavones utilising recombinant Oryza sativa C-glycosyltransferase (OsCGT) and Desmodium incanum root proteins. Phytochemistry 2016; 125:73-87. [PMID: 26923852 DOI: 10.1016/j.phytochem.2016.02.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/12/2016] [Accepted: 02/19/2016] [Indexed: 06/05/2023]
Abstract
The rice C-glycosyltransferase (OsCGT) is one of only a small number of characterised plant C-glycosyltransferases (CGT) known. The enzyme C-glucosylates a 2-hydroxyflavanone substrate with UDP-glucose as the sugar donor to produce C-glucosyl-2-hydroxyflavanones. We tested substrate specificity of the enzyme, using synthetic 2-hydroxyflavanones, and showed it has the potential to generate known natural CGFs that have been isolated from rice and also other plants. In addition, we synthesised novel, unnatural 2-hydroxyflavanone substrates to test the B-ring chemical space of substrate accepted by the OsCGT and demonstrated the OsCGT capacity as a synthetic reagent to generate significant quantities of known and novel CGFs. Many B-ring analogues are tolerated within a confined steric limit. Finally the OsCGT was used to generate novel mono-C-glucosyl-2-hydroxyflavanones as putative biosynthetic intermediates to examine the potential of Desmodium incanum biosynthetic CGTs to produce novel di-C-glycosylflavones, compounds implicated in the allelopathic biological activity of Desmodium against parasitic weeds from the Striga genus.
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Affiliation(s)
- B Hao
- College of Science, Northwest A&F University, Yangling, Shaanxi 712100, China; Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - J C Caulfield
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - M L Hamilton
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - J A Pickett
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - C A O Midega
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya.
| | - Z R Khan
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya.
| | - J Wang
- College of Science, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | - A M Hooper
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
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5
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Hao B, Caulfield JC, Hamilton ML, Pickett JA, Midega CAO, Khan ZR, Wang JR, Hooper AM. The biosynthesis of allelopathic di-C-glycosylflavones from the roots of Desmodium incanum (G. Mey.) DC. Org Biomol Chem 2015; 13:11663-73. [PMID: 26478440 DOI: 10.1039/c5ob01926e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The allelopathic root exudate of the drought-tolerant subsistence cereal intercrop D. incanum, protecting against the parasitic weed Striga hermonthica, comprises a number of di-C-glycosylflavones specifically containing C-glucosyl, C-galactosyl and C-arabinosyl moieties. Here we demonstrate that the biosynthesis of all compounds containing a C-glucose involves C-glucosylation of 2-hydroxynaringenin with subsequent C-galactosylation, C-glucosylation or C-arabinosylation. In addition, the crude soluble enzyme extract converts two fluorinated 2-hydroxyflavanone analogues to corresponding mono- and di-C-glycosylflavones demonstrating that some differences in C-ring substitution can be tolerated by the plant enzymes. Elucidating the biosynthesis of these C-glycosylflavones (CGFs) has the potential to open up opportunities for transferring the enzymic and genetic basis for the S. hermonthica inhibiting allelopathic trait to food crop plants.
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Affiliation(s)
- Bing Hao
- College of Science, Northwest A&F University, Yangling, Shaanxi 712100, China.
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6
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Hooper AM, Caulfield JC, Hao B, Pickett JA, Midega CAO, Khan ZR. Isolation and identification of Desmodium root exudates from drought tolerant species used as intercrops against Striga hermonthica. Phytochemistry 2015; 117:380-387. [PMID: 26164239 PMCID: PMC4560159 DOI: 10.1016/j.phytochem.2015.06.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/16/2015] [Accepted: 06/25/2015] [Indexed: 05/04/2023]
Abstract
Plants from the genus Desmodium, in particular D. uncinatum, are used on sub-Saharan small-holder farms as intercrops to inhibit parasitism of cereal crops by Striga hermonthica and Striga asiatica via an allelopathic mechanism. The search for Desmodium species which are adapted to more arid conditions, and which show resilience to increased drought stress, previously identified D. intortum, D. incanum and D. ramosissimum as potential drought tolerant intercrops. Their potential as intercrops was assessed for resource poor areas of rain-fed cereal production where drought conditions can persist through normal meteorological activity, or where drought may have increasing impact through climate change. The chemical composition of the root exudates were characterised and the whole exudate biological activity was shown to be active in pot experiments for inhibition of Striga parasitism on maize. Furthermore, rain fed plot experiments showed the drought tolerant Desmodium intercrops to be effective for Striga inhibition. This work demonstrates the allelopathic nature of the new drought tolerant intercrops through activity of root exudates and the major compounds seen in the exudates are characterised as being C-glycosylflavonoid. In young plants, the exudates show large qualitative differences but as the plants mature, there is a high degree of convergence of the C-glycosylflavonoid exudate chemical profile amongst active Desmodium intercrops that confers biological activity. This defines the material for examining the mechanism for Striga inhibition.
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Affiliation(s)
- A M Hooper
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - J C Caulfield
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - B Hao
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - J A Pickett
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
| | - C A O Midega
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya.
| | - Z R Khan
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya.
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Vuts J, Francke W, Mori K, Zarbin PHG, Hooper AM, Millar JG, Pickett JA, Tóth M, Chamberlain K, Caulfield JC, Woodcock CM, Tröger AG, Csonka ÉB, Birkett MA. Pheromone Bouquet of the Dried Bean Beetle, Acanthoscelides obtectus(Col.: Chrysomelidae), Now Complete (Eur. J. Org. Chem. 22/2015). European J Org Chem 2015. [DOI: 10.1002/ejoc.201590060] [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: 11/09/2022]
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Vuts J, Francke W, Mori K, Zarbin PHG, Hooper AM, Millar JG, Pickett JA, Tóth M, Chamberlain K, Caulfield JC, Woodcock CM, Tröger AG, Csonka ÉB, Birkett MA. Pheromone Bouquet of the Dried Bean Beetle,Acanthoscelides obtectus(Col.: Chrysomelidae), Now Complete. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500196] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pickett JA, Aradottír GI, Birkett MA, Bruce TJA, Hooper AM, Midega CAO, Jones HD, Matthes MC, Napier JA, Pittchar JO, Smart LE, Woodcock CM, Khan ZR. Delivering sustainable crop protection systems via the seed: exploiting natural constitutive and inducible defence pathways. Philos Trans R Soc Lond B Biol Sci 2014. [DOI: 10.1098/rstb.2014.0053] [Citation(s) in RCA: 2] [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: 11/12/2022] Open
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Pickett JA, Aradottír GI, Birkett MA, Bruce TJA, Hooper AM, Midega CAO, Jones HD, Matthes MC, Napier JA, Pittchar JO, Smart LE, Woodcock CM, Khan ZR. Delivering sustainable crop protection systems via the seed: exploiting natural constitutive and inducible defence pathways. Philos Trans R Soc Lond B Biol Sci 2014; 369:20120281. [PMID: 24535389 DOI: 10.1098/rstb.2012.0281] [Citation(s) in RCA: 16] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To reduce the need for seasonal inputs, crop protection will have to be delivered via the seed and other planting material. Plant secondary metabolism can be harnessed for this purpose by new breeding technologies, genetic modification and companion cropping, the latter already on-farm in sub-Saharan Africa. Secondary metabolites offer the prospect of pest management as robust as that provided by current pesticides, for which many lead compounds were, or are currently deployed as, natural products. Evidence of success and promise is given for pest management in industrial and developing agriculture. Additionally, opportunities for solving wider problems of sustainable crop protection, and also production, are discussed.
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Affiliation(s)
- John A Pickett
- Rothamsted Research, , Harpenden, Hertfordshire AL5 2JQ, UK
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Hamilton ML, Kuate SP, Brazier-Hicks M, Caulfield JC, Rose R, Edwards R, Torto B, Pickett JA, Hooper AM. Elucidation of the biosynthesis of the di-C-glycosylflavone isoschaftoside, an allelopathic component from Desmodium spp. that inhibits Striga spp. development. Phytochemistry 2012; 84:169-76. [PMID: 22959223 DOI: 10.1016/j.phytochem.2012.08.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/06/2012] [Accepted: 08/11/2012] [Indexed: 06/01/2023]
Abstract
Isoschaftoside, an allelopathic di-C-glycosylflavone from Desmodium spp. root exudates, is biosynthesised through sequential glucosylation and arabinosylation of 2-hydroxynaringenin with UDP-glucose and UDP-arabinose. Complete conversion to the flavone requires chemical dehydration implying a dehydratase enzyme has a role in vivo to complete the biosynthesis. The C-glucosyltransferase has been partially characterised and its activity demonstrated in highly purified fractions.
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Affiliation(s)
- Mary L Hamilton
- Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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12
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Abstract
The insect olfactory system, particularly the peripheral sensory system for sex pheromone reception in male moths, is highly selective, but specificity determinants at the receptor level are hitherto unknown. Using the Xenopus oocyte recording system, we conducted a thorough structure-activity relationship study with the sex pheromone receptor of the silkworm moth, Bombyx mori, BmorOR1. When co-expressed with the obligatory odorant receptor co-receptor (BmorOrco), BmorOR1 responded in a dose-dependent fashion to both bombykol and its related aldehyde, bombykal, but the threshold of the latter was about one order of magnitude higher. Solubilizing these ligands with a pheromone-binding protein (BmorPBP1) did not enhance selectivity. By contrast, both ligands were trapped by BmorPBP1 leading to dramatically reduced responses. The silkworm moth pheromone receptor was highly selective towards the stereochemistry of the conjugated diene, with robust response to the natural (10E,12Z)-isomer and very little or no response to the other three isomers. Shifting the conjugated diene towards the functional group or elongating the carbon chain rendered these molecules completely inactive. In contrast, an analogue shortened by two omega carbons elicited the same or slightly higher responses than bombykol. Flexibility of the saturated C1–C9 moiety is important for function as addition of a double or triple bond in position 4 led to reduced responses. The ligand is hypothesized to be accommodated by a large hydrophobic cavity within the helical bundle of transmembrane domains.
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Affiliation(s)
- Pingxi Xu
- Honorary Maeda-Duffey Laboratory, University of California Davis, Davis, California, United States of America
| | - Antony M. Hooper
- Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
| | - John A. Pickett
- Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
| | - Walter S. Leal
- Honorary Maeda-Duffey Laboratory, University of California Davis, Davis, California, United States of America
- * E-mail:
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Dufour S, Castets P, Pickett JA, Hooper AM. A diastereoselective synthesis of (1SR,3SR,7RS)-3-methyl-α-himachalene, the sex pheromone of the sandfly, Lutzomyia longipalpis (Diptera: Psychodidae). Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.04.037] [Citation(s) in RCA: 5] [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: 11/29/2022]
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14
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Pickett JA, Hooper AM. Delivering resistance to a major constraint for rain-fed rice production. New Phytol 2011; 192:792-794. [PMID: 22074336 DOI: 10.1111/j.1469-8137.2011.03961.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- John A Pickett
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
- (Author for correspondence: tel +44 (0)1582 763133; email )
| | - Antony M Hooper
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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15
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Spiegel CN, Batista-Pereira LG, Bretas JAC, Eiras AE, Hooper AM, Peixoto AA, Soares MJ. Pheromone gland development and pheromone production in lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae). J Med Entomol 2011; 48:489-495. [PMID: 21661306 DOI: 10.1603/me10133] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The sand fly Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae: Phlebotominae) is the main vector of American visceral leishmaniasis. Adult males produce a terpenoid sex pheromone that in some cases also acts as male aggregation pheromone. We have analyzed the correlation between male pheromone production levels and pheromone gland cell morphogenesis after adult emergence from pupae. The abdominal tergites of L. longipalpis males were dissected and fixed in glutaraldehyde for transmission electron microscopy, or the pheromone was extracted in analytical grade hexane. Pheromone chemical analysis was carried out at 3- to 6-h intervals during the first 24 h after emergence and continued daily until the seventh day. All extracts were analyzed by gas chromatography. For the morphological analysis, we used insects collected at 0-6, 9-12, 12-14, and 96 h after emergence. Ultrastructural data from 0- to 6-h-old adult males revealed smaller pheromone gland cells with small microvilli at the end apparatus. Lipid droplets and peroxisomes were absent or very rare, but a large number of mitochondria could be seen. Lipid droplets started to appear in the gland cells cytoplasm approximately 9 h after adult emergence, and their number and size increased with age, together with the presence of several peroxisomes, suggesting a role for these organelles in pheromone biosynthesis. At 12-15 h after emergence, the lipid droplets were mainly distributed near the microvilli but were smaller than those in mature older males (4 d old). Pheromone biosynthesis started around 12 h after emergence and increased continuously during the first 3 d, stabilizing thereafter, coinciding with the period when males are more able to attract females.
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Affiliation(s)
- Carolina N Spiegel
- Laboratório de Biologia Molecular de Insetos, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, Brazil.
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Khan ZR, Midega CAO, Bruce TJA, Hooper AM, Pickett JA. Exploiting phytochemicals for developing a 'push-pull' crop protection strategy for cereal farmers in Africa. J Exp Bot 2010; 61:4185-96. [PMID: 20670998 DOI: 10.1093/jxb/erq229] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Lepidopteran stemborers and parasitic weeds in the genus Striga are major constraints to efficient production of cereals, the most important staple food crops in Africa. Smallholder farmers are resource constrained and unable to afford expensive chemicals for crop protection. Development of a push-pull approach for integrated pest and weed management is reviewed here. Appropriate plants were discovered that naturally emit signalling chemicals (semiochemicals). Plants highly attractive for egg laying by stemborer pests were selected and employed as trap crops (pull), to draw pests away from the main crop. Of these, Napier grass, Pennisetum purpureum (Schumach), despite its attractiveness, supported minimal survival of the pests' immature stages. Plants that repelled stemborer pests, notably molasses grass, Melinis minutiflora P. Beauv., and forage legumes in the genus Desmodium, were selected as intercrops (push). Desmodium intercrops suppress Striga hermonthica (Del.) Benth. through an allelopathic mechanism. Their root exudates contain novel flavonoid compounds, which stimulate suicidal germination of S. hermonthica seeds and dramatically inhibit its attachment to host roots. The companion crops provide valuable forage for farm animals while the leguminous intercrops also improve soil fertility and moisture retention. The system is appropriate as it is based on locally available plants, not expensive external inputs, and fits well with traditional mixed cropping systems in Africa. To date it has been adopted by more than 30,000 smallholder farmers in East Africa where maize yields have increased from ∼1 t ha(-1) to 3.5 t ha(-1). Future directions for semiochemical delivery by plants including biotechnological opportunities are discussed.
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Affiliation(s)
- Zeyaur R Khan
- International Centre of Insect Physiology and Ecology, PO Box 30772, Nairobi, Kenya
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17
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Hooper AM, Tsanuo MK, Chamberlain K, Tittcomb K, Scholes J, Hassanali A, Khan ZR, Pickett JA. Isoschaftoside, a C-glycosylflavonoid from Desmodium uncinatum root exudate, is an allelochemical against the development of Striga. Phytochemistry 2010; 71:904-8. [PMID: 20211477 DOI: 10.1016/j.phytochem.2010.02.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 02/12/2010] [Accepted: 02/17/2010] [Indexed: 05/28/2023]
Abstract
In East African small-holder farming of maize, the cattle forage legume, Desmodium uncinatum is used as an intercrop due to its allelopathic inhibition of parasitism by Striga hermonthica, an obligate parasitic weed that can devastate the maize crop. Bioassay-guided fractionation of the root extract of D. uncinatum revealed isoschaftoside to be the main compound in the most potent fraction inhibiting growth of germinated S. hermonthica radicles. Bioassays repeated with isoschaftoside isolated from a different plant source, Passiflora incarnata, proved it to be a biologically active component. Analysis of the root exudates produced by hydroponically grown D. uncinatum showed isoschaftoside to be present in the hydroponic media at biologically active concentrations of 10-100 nM.
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Affiliation(s)
- Antony M Hooper
- Biological Chemistry Department, Centre for Sustainable Pest and Disease Management, Rothamsted Research, Harpenden, Herts, UK.
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18
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Abstract
Parasitic plants, through a range of infestation strategies, can attack crop plants and thereby require management. Because such problems often occur in resource-poor farming systems, companion cropping to manage parasitic plants is an appropriate approach. Many examples of companion cropping for this purpose have been reported, but the use of cattle forage legumes in the genus Desmodium as intercrops has been shown to be particularly successful in controlling the parasitic witchweeds (Striga spp.) that afflict approximately one quarter of sub-Saharan African cereal production. Through the use of this example, the development of effective companion crops is described, together with developments toward widespread adoption and understanding the underlying mechanisms, both for sustainability and ensuring food security, and also for exploitation beyond the cropping systems described here.
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Affiliation(s)
- John A Pickett
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom.
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Hamilton ML, Caulfield JC, Pickett JA, Hooper AM. C-Glucosylflavonoid biosynthesis from 2-hydroxynaringenin by Desmodium uncinatum (Jacq.) (Fabaceae). Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.07.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [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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20
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Zhou JJ, Robertson G, He X, Dufour S, Hooper AM, Pickett JA, Keep NH, Field LM. Characterisation of Bombyx mori Odorant-binding Proteins Reveals that a General Odorant-binding Protein Discriminates Between Sex Pheromone Components. J Mol Biol 2009; 389:529-45. [DOI: 10.1016/j.jmb.2009.04.015] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 04/01/2009] [Accepted: 04/04/2009] [Indexed: 10/20/2022]
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Hooper AM, Hassanali A, Chamberlain K, Khan Z, Pickett JA. New genetic opportunities from legume intercrops for controlling Striga spp. parasitic weeds. Pest Manag Sci 2009; 65:546-552. [PMID: 19266493 DOI: 10.1002/ps.1731] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In smallholder farming in East Africa, intercropping of maize with the cattle forage legume, Desmodium uncinatum Jacq., prevents parasitism by Striga hermonthica (Del.) Benth. (witchweed) through an allelopathic mechanism. Isoschaftoside, a di-C-glycosylflavone, isolated from the root extract and root exudate of Desmodium, interferes with in vitro radicle development of germinated Striga. The biosynthetic pathway of this class of compound is already mostly present in edible legumes and in cereals, so characterisation of the enzyme and genes that control C-glycosylflavone biosynthesis has the potential to create this protection mechanism in other agriculturally important plants.
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Affiliation(s)
- Antony M Hooper
- Biological Chemistry Department, Centre for Sustainable Pest and Disease Management, Rothamsted Research, Harpenden, Herts, UK.
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22
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Hooper AM, Dufour S, He X, Muck A, Zhou JJ, Almeida R, Field LM, Svatoš A, Pickett JA. High-throughput ESI-MS analysis of binding between the Bombyx mori pheromone-binding protein BmorPBP1, its pheromone components and some analogues. Chem Commun (Camb) 2009:5725-7. [DOI: 10.1039/b914294k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Birkett MA, Abassi SA, Kröber T, Chamberlain K, Hooper AM, Guerin PM, Pettersson J, Pickett JA, Slade R, Wadhams LJ. Antiectoparasitic activity of the gum resin, gum haggar, from the East African plant, Commiphora holtziana. Phytochemistry 2008; 69:1710-5. [PMID: 18402993 DOI: 10.1016/j.phytochem.2008.02.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 02/18/2008] [Accepted: 02/22/2008] [Indexed: 05/08/2023]
Abstract
The mechanism of ixodid tick (Acari: Ixodidae) repellency by gum haggar, a resin produced by Commiphora holtziana (Burseraceae), was investigated by evaluating activity against the cattle tick, Boophilus microplus. In an arena bioassay, a hexane extract of the resin of C. holtziana exhibited a repellent effect lasting up to 5h. The hydrocarbon fraction of the resin extract was shown to account for the repellent activity, and was analysed by coupled gas chromatography-mass spectrometry (GC-MS). Major sesquiterpene hydrocarbons were tentatively identified as germacrene-D, delta-elemene and beta-bourbonene. The identity and stereochemistry of the former compound was confirmed as the (+)-isomer by peak enhancement using enantioselective GC, whereas the latter 2 compounds, which are most likely degradation products of germacrene-type precursors, were identified through isolation by preparative gas chromatography followed by microprobe-NMR spectroscopy. GC comparison of gum haggar with another resin, C. myrrha, which was inactive in the tick bioassay, showed that the latter contained much lower levels of these hydrocarbons. To assess the suitability of the gum haggar resin as a general acarine repellent, further tests were made on a major acarine pest of European and US animal husbandry systems, the red poultry mite, Dermanyssus gallinae (Acari: Dermanyssidae). Gum haggar extract, and the isolated hydrocarbon fraction, showed strong repellent effects in an olfactometer assay, and again gum myrrh showed no effect. These findings provide a scientific basis for the observed anti-tick properties of gum haggar, and demonstrate the potential for its development as a general acarine repellent for use in animal husbandry systems.
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Affiliation(s)
- Michael A Birkett
- Centre for Sustainable Pest and Disease Management, Biological Chemistry Department, Rothamsted Research, Harpenden, Herts., AL5 2JQ, United Kingdom.
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Stewart-Jones A, Dewhirst SY, Durrant L, Fitzgerald JD, Hardie J, Hooper AM, Pickett JA, Poppy GM. Structure, ratios and patterns of release in the sex pheromone of an aphid, Dysaphis plantaginea. J Exp Biol 2007; 210:4335-44. [DOI: 10.1242/jeb.009944] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Insect communication is primarily via chemicals. In Aphidinae aphids, the structure and ratio of iridoid (monoterpenoid) chemicals are known to be important components of the sex pheromone. However, for enhanced species specificity, it has been suggested that release of sex pheromone might be restricted to a narrow time period within the diel cycle. Here, we determine the structure, ratios and release patterns of iridoid chemicals produced by a serious global pest, the rosy apple aphid, Dysaphis plantaginea. Volatiles were collected from batches of oviparae (sexual females) and chemicals identified by gas chromatography, mass-spectrometry and microscale NMR spectroscopy.(1R,4aS,7S,7aR)-Nepetalactol and(4aS,7S,7aR)-nepetalactone were detected in a 3.7:1 ratio. To investigate timing of release, we constructed a sequential sampling device that allowed volatile chemicals to be captured hourly from 95 same-aged oviparae over 20 consecutive days. Release patterns of the two sex pheromone components show that D. plantaginea oviparae release high levels of the two components during photophase and low levels during scotophase. Release of the two components increased significantly during the first 3 h of photophase and thereafter remained at a high level until the onset of scotophase. The ratio of(1R,4aS,7S,7aR)-nepetalactol to(4aS,7S,7aR)-nepetalactone released did not change significantly between days two to 14 of the adult stadium, but from the 15th day onward there was a significant decrease in the relative amount of(1R,4aS,7S,7aR)-nepetalactol. Pheromone release was greatest on the eighth day of the adult stadium, with up to 8.4 ng of pheromone released per ovipara per hour. This is the first report on the full structural identification and ratios of volatile iridoid components collected from D. plantaginea oviparae and is also the most detailed temporal study on sex pheromone release from any aphid species. The lack of a temporally narrow and distinct period of very high sex pheromone release suggests that alternative mechanisms or factors for species recognition and isolation may be important. Findings are discussed broadly in relation to the biology of the aphid.
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Affiliation(s)
- Alex Stewart-Jones
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, Hampshire, SO16 7PX, UK
| | - Sarah Y. Dewhirst
- BCH Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ,UK
| | - Lisa Durrant
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, Hampshire, SO16 7PX, UK
| | | | - Jim Hardie
- Department of Biological Sciences, Imperial College at Silwood Park,Ascot, Berkshire, SL5 7PY, UK
| | - Antony M. Hooper
- BCH Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ,UK
| | - John A. Pickett
- BCH Division, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ,UK
| | - Guy M. Poppy
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, Hampshire, SO16 7PX, UK
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25
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Guchu SM, Yenesew A, Tsanuo MK, Gikonyo NK, Pickett JA, Hooper AM, Hassanali A. C-methylated and C-prenylated isoflavonoids from root extract of Desmodium uncinatum. Phytochemistry 2007; 68:646-51. [PMID: 17234222 DOI: 10.1016/j.phytochem.2006.11.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 11/18/2006] [Accepted: 11/29/2006] [Indexed: 05/13/2023]
Abstract
A pterocarpan, 1,9-dihydroxy-3-methoxy-2-methylpterocarpan (named uncinacarpan) and two isoflavanones, 5,7-dihydroxy-2',3',4'-trimethoxy-6-(3-methylbut-2-enyl)isoflavanone (named uncinanone D) and 5,4'-dihydroxy-7,2'-dimethoxy-6-methylisoflavanone (named uncinanone E), were isolated from the CH(2)Cl(2) root extract of Desmodium uncinatum (Jacq.) DC and characterised by spectroscopic methods. In addition, a rare pterocarpan edudiol and two known abietane diterpenes, 7-oxo-15-hydroxydehydroabietic acid and 7-hydroxycallitrisic acid were identified. The fraction of the root extract that was analysed induced germination of Striga hermonthica seeds, but none of the isolated compounds showed this activity.
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Affiliation(s)
- Salome M Guchu
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya
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26
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Bruce TJA, Hooper AM, Ireland L, Jones OT, Martin JL, Smart LE, Oakley J, Wadhams LJ. Development of a pheromone trap monitoring system for orange wheat blossom midge, Sitodiplosis mosellana, in the UK. Pest Manag Sci 2007; 63:49-56. [PMID: 17078014 DOI: 10.1002/ps.1307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Field-trapping experiments with synthetic 2,7-nonadiyl dibutyrate, the female-produced sex pheromone of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin), demonstrated that pheromone traps were highly attractive to males and caught very few non-target organisms. Different formulations of pheromone were tested to identify the optimum release rate and dispenser type for use in pheromone traps in the UK. Key findings were that racemic pheromone was as effective as enantiomerically pure (2S,7R)-2,7-nonadiyl dibutyrate, that release rates higher than 0.5 microg day(-1) were not necessary and that the optimal formulation was a 1 mg pheromone loading in a rubber septum. Pheromone traps gave a reliable indication of peak midge emergence, onset of flight and abundance of midges throughout the season. A strong correlation between maximum trap catch and crop infestation levels was obtained.
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Affiliation(s)
- Toby J A Bruce
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
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27
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Spiegel CN, Jeanbourquin P, Guerin PM, Hooper AM, Claude S, Tabacchi R, Sano S, Mori K. (1S,3S,7R)-3-methyl-alpha-himachalene from the male sandfly Lutzomyia longipalpis (Diptera: Psychodidae) induces neurophysiological responses and attracts both males and females. J Insect Physiol 2005; 51:1366-75. [PMID: 16226273 DOI: 10.1016/j.jinsphys.2005.08.007] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 05/10/2005] [Accepted: 05/10/2005] [Indexed: 05/04/2023]
Abstract
Lutzomyia longipalpis adult males form leks on or near hosts and release (1S,3S,7R)-3-methyl-alpha-himachalene from their tergal glands to lure females to the same site for mating and feeding. Here we have examined whether the male-produced attractant could also serve as a male aggregation stimulus. High resolution chiral capillary gas chromatography analysis of male tergal gland extracts, synthetic (1S,3S,7R)-3-methyl-alpha-himachalene, and a synthetic mixture of all isomers of 3-methyl-alpha-himachalene, was coupled to electrophysiological recordings from ascoid sensillum receptor cells in antennae of male and female sandflies. Receptor cells of both sexes responded only to the main component of the male tergal gland extract that eluted at the same retention time as (1S,3S,7R)-3-methyl-alpha-himachalene. Furthermore, of the eight 3-methyl-alpha-himachalene isomers in the synthetic mixture only the fraction containing (1S,3S,7R)-3-methyl-alpha-himachalene, co-eluting with an isomer of (1S*,3S*,7S*)-3-methyl-alpha-himachalene, elicited an electrophysiological response from male and female ascoid sensillum receptor cells. Both males and females flew upwind in a wind tunnel towards a filter paper disk treated with either 4-6 male equivalents of the tergal gland extract, pure (1S,3S,7R)-3-methyl-alpha-himachalene or the synthetic mixture of eight isomers. This indicates that (1S,3S,7R)-3-methyl-alpha-himachalene derived from L. longipalpis males may have a dual function in causing male aggregation as well as serving as a sex pheromone for females.
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Affiliation(s)
- C N Spiegel
- Institute of Zoology, University of Neuchâtel, Switzerland.
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28
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Bruce TJ, Birkett MA, Blande J, Hooper AM, Martin JL, Khambay B, Prosser I, Smart LE, Wadhams LJ. Response of economically important aphids to components of Hemizygia petiolata essential oil. Pest Manag Sci 2005; 61:1115-21. [PMID: 16059962 DOI: 10.1002/ps.1102] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The essential oil of Hemizygia petiolata Ashby (Lamiaceae) contains high levels (>70%) of the sesquiterpene (E)-beta-farnesene, the alarm pheromone for many economically important aphid species. In order to test the suitability of H. petiolata oil as a source of (E)-beta-farnesene for use in new integrated aphid control strategies, behavioural responses of pest aphid species were studied in laboratory and field experiments. In alarm pheromone assays the peach-potato aphid, Myzus persicae Sulzer, and the pea aphid, Acyrthosiphon pisum (Harr), showed a lower level of response to the oil than expected given the high levels of (E)-beta-farnesene. It was shown that minor components in the oil, (+)-bicyclogermacrene and (-)-germacrene D, caused inhibition of the alarm response for M. persicae and A. pisum respectively. Nevertheless, in olfactometer studies the oil was directly repellent to A. pisum and the grain aphid, Sitobion avenae F. Sitobion avenae was not only repelled by (E)-beta-farnesene but also by (-)-germacrene D. Furthermore, although it was not directly repellent to M. persicae, the oil interfered with its attraction to host plant stimuli. In field plot experiments, numbers of A. pisum were significantly reduced in plots treated with a slow release formulation of the oil, when compared with control plots.
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29
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Ndung'u MW, Kaoneka B, Hassanali A, Lwande W, Hooper AM, Tayman F, Zerbe O, Torto B. New mosquito larvicidal tetranortriterpenoids from Turraea wakefieldii and Turraea floribunda. J Agric Food Chem 2004; 52:5027-5031. [PMID: 15291470 DOI: 10.1021/jf049474y] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The crude methanol extracts of the root barks of Turraea wakefieldii and Turraea floribunda were found to show mosquito larvicidal activity against third-instar larvae of Anopheles gambiae sensu stricto. Four new limonoids comprising a vilasininoid 1 and three havanensinoids 2-4 were isolated from the chloroform fractions of the methanol extracts of T. wakefieldii and T. floribunda, respectively. The structures of the compounds were elucidated by NMR spectroscopy. Compounds 1, 2, and 4 had LD50 values of 7.1, 4.0, and 3.6 ppm, respectively, and were more potent than azadirachtin, which had an LD50 value of 57.1 ppm when tested against larvae of A. gambiae.
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Affiliation(s)
- Mary W Ndung'u
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi, Kenya
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30
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Goldansaz SH, Dewhirst S, Birkett MA, Hooper AM, Smiley DWM, Pickett JA, Wadhams L, McNeil JN. Identification of Two Sex Pheromone Components of the Potato Aphid, Macrosiphum euphorbiae (Thomas). J Chem Ecol 2004; 30:819-34. [PMID: 15260226 DOI: 10.1023/b:joec.0000028434.19319.b4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Females of the potato aphid Macrosiphum euphorbiae exhibit typical calling behavior, with virgin female oviparae raising their back legs off the substrate to release sex pheromone from glands on the tibia. Airborne collections from calling oviparae were analyzed by GC and GC-MS to determine if, like the majority of aphids examined to date, they produced (1R,4aS,7S,7aR)-nepetalactol (1) and (4aS,7S,7aR)-nepetalactone (2). Both components were present and produced in ratios that varied with age from 4:1 to 2:1. The relative stereochemical configurations of these components were determined by GC-coinjection of the aphid-derived sample with synthetic standards on both HP-1 and DB-Wax GC columns. The absolute stereochemical configuration of the nepetalactol (determined from approximately 15 microg of material in an air entrainment sample) was determined as (1R,4aS,7S,7aR)-1 by derivatization of the aphid sample with (S)-(+)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride (Mosher's acid chloride) to generate a diastereoisomer that was compared to synthetic samples by NMR spectroscopy and GC. In bioassays in the wind tunnel, M. euphorbiae males responded to potato plants with oviparae but not to unattacked plants or those infested with parthenogenetically reproducing apterae. In no-choice laboratory bioassays, the same level of male response was observed to virgins and to the 3:1-5:1 synthetic blends of nepetalactol (1):nepetalactone (2). However, the time taken to reach the source was significantly less to virgin females than to the synthetic pheromone blends. In all cases, males walked rather than flew to the source. Males showed lower responses to a 1:1 synthetic mixture and did not respond to either of the components when presented alone. Under field conditions, few M. euphorbiae males were captured in traps baited with different ratios of the synthetic pheromone. Possible reasons for the different responses under laboratory and field conditions are discussed.
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Affiliation(s)
- Seyed H Goldansaz
- Département de biologie, Université Laval, Ste-Foy, Quebec Canada G1K 7P4
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31
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Ndung'u M, Hassanali A, Hooper AM, Chhabra S, Miller TA, Paul RL, Torto B. Ring A-seco mosquito larvicidal limonoids from Turraea wakefieldii. Phytochemistry 2003; 64:817-823. [PMID: 14559274 DOI: 10.1016/j.phytochem.2003.08.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Five novel limonoids, 1-5, were isolated from the root bark of Turraea wakefieldii and were characterized as tecleaninoid derivatives. This is the first report of the natural occurrence of tecleanin-type limonoids with a five-membered-ring A-seco structure for which we propose the name neotecleanins. The relative stereochemical structures of compounds 1-5 were established on the basis of NMR spectroscopy. The absolute stereochemical structure of 5 was confirmed by X-ray diffraction methods. In mosquito larvicidal assays, compounds 1, 2 and 4 showed dose-dependent larvicidal activity against larvae of Anopheles gambiae s.s.
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Affiliation(s)
- Mary Ndung'u
- International Centre of Insect Physiology and Ecology (ICIPE), PO Box 30772, Nairobi, Kenya
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32
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Tsanuo MK, Hassanali A, Hooper AM, Khan Z, Kaberia F, Pickett JA, Wadhams LJ. Isoflavanones from the allelopathic aqueous root exudate of Desmodium uncinatum. Phytochemistry 2003; 64:265-273. [PMID: 12946425 DOI: 10.1016/s0031-9422(03)00324-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Three isoflavanones, 5,7,2',4'-tetrahydroxy-6-(3-methylbut-2-enyl)isoflavanone (1), 4",5"-dihydro-5,2',4'-trihydroxy-5"-isopropenylfurano-(2",3";7,6)-isoflavanone (2) and 4",5"-dihydro-2'-methoxy-5,4'-dihydroxy-5"-isopropenylfurano-(2",3";7,6)-isoflavanone (3) and a previously known isoflavone 5,7,4'-trihydroxyisoflavone [genistein (4)] were isolated and characterised spectroscopically from the root exudate of the legume Desmodium uncinatum (Jacq.) DC. We propose the names uncinanone A, B, and C for compounds 1, 2 and 3, respectively. Isolated fractions containing uncinanone B (2) induced germination of seeds from the parasitic weed Striga hermonthica (Del.) Benth. and fractions containing uncinanone C (3) moderately inhibited radical growth, the first example of a newly identified potential allelopathic mechanism to prevent S. hermonthica parasitism.
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Affiliation(s)
- Muniru K Tsanuo
- Chemistry Department, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000, Nairobi, Kenya
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Khambay BP, Beddie DG, Hooper AM, Simmonds MS. Isolation, characterisation and synthesis of an insecticidal tetramethyltetrahydrochromenedione-spiro-bicyclo[3.1.1]cycloheptane from two species of Myrtaceae. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)01095-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Khan ZR, Hassanali A, Overholt W, Khamis TM, Hooper AM, Pickett JA, Wadhams LJ, Woodcock CM. Control of witchweed Striga hermonthica by intercropping with Desmodium spp., and the mechanism defined as allelopathic. J Chem Ecol 2002; 28:1871-85. [PMID: 12449513 DOI: 10.1023/a:1020525521180] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
During investigations into the control of insect damage to maize crops in subsistence farming in Kenya, which involved intercropping with repellent plants, the fodder legumes silverleaf (Desmodium uncinatum) and greenleaf (D. intortum) were also found to reduce dramatically the infestation of maize by parasitic witchweeds such as Striga hermonthica. This effect was confirmed by further field testing and shown to be significantly greater than that observed with other legumes, e.g., cowpea, as were the concomitant yield increases. The mechanism was investigated, and although soil shading and addition of nitrogen fertilizer showed some benefits against S. hermonthica infestation, a putative allelopathic mechanism for D. uncinatum was observed. In screenhouse studies, a highly significant reduction in S. hermonthica infestation was obtained when an aqueous solution, eluting from pots in which D. uncinatum plants were growing, was used to irrigate pots of maize planted in soil seeded with high levels of S. hermonthica. Growth of the parasitic weed was almost completely suppressed. whereas extensive infestation occurred with the control eluate. Laboratory investigations into the allelopathic effect of D. uncinatum, using samples of water-soluble chemical components exuded from cleaned roots, demonstrated that this involved a germination stimulant for S. hermonthica and also an inhibitor for haustorial development.
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Affiliation(s)
- Zeyaur R Khan
- The International Centre of Insect Physiology and Ecology, Mbita Point Field Station, S. Nyanza, Kenya
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Prosser I, Phillips AL, Gittings S, Lewis MJ, Hooper AM, Pickett JA, Beale MH. (+)-(10R)-Germacrene A synthase from goldenrod, Solidago canadensis; cDNA isolation, bacterial expression and functional analysis. Phytochemistry 2002; 60:691-702. [PMID: 12127586 DOI: 10.1016/s0031-9422(02)00165-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Profiling of sesquiterpene hydrocarbons in extracts of goldenrod, Solidago canadensis, by GC-MS revealed the presence of both enantiomers of germacrene D and lesser amounts of germacrene A, alpha-humulene, and beta-caryophyllene. A similarity-based cloning strategy using degenerate oligonucleotide primers, based on conserved amino acid sequences in known plant sesquiterpene synthases and RT-PCR, resulted in the isolation of a full length sesquiterpene synthase cDNA. Functional expression of the cDNA in E. coli, as an N-terminal thioredoxin fusion protein using the pET32b vector yielded an enzyme that was readily purified by nickel-chelate affinity chromatography. Chiral GC-MS analysis of products from of (3)H- and (2)H-labelled farnesyl diphosphate identified the enzyme as (+)-(10R)-germacrene A synthase. Sequence analysis and molecular modelling was used to compare this enzyme with the mechanistically related epi-aristolochene synthase from tobacco.
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Affiliation(s)
- Ian Prosser
- Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, Bristol, BS41 9AF, Long Ashton, UK
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Hooper AM, Donato B, Woodcock CM, Park JH, Paul RL, Boo KS, Hardie J, Pickett JA. Characterization of (1'R,4S,4aR,7S,7aR)-dihydronepetalactol as a semiochemical for lacewings, including Chrysopa spp. and Peyerimhoffina gracilis. J Chem Ecol 2002; 28:849-64. [PMID: 12035931 DOI: 10.1023/a:1015201129331] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The enantiomerically pure diastereoisomers (1R,4S,4aR,7S,7aR)- (1) and (1R,4R,4aR,7S,7aR)-dihydronepetalactol (2) were synthesized diastereoselectively from a renewable resource, (4aS,7S,7aR)-nepetalactone (3), isolated as the main constituent of the essential oil of the catmint plant Nepeta cataria. The stereochemistry of the compounds was determined by NMR spectroscopy and X-ray crystallography, and the compounds were identified, respectively, as neomatatabiol and isoneomatatabiol, natural products from Actinidia polygama, for which the lactol stereochemistry was previously incompletely defined. Compound 1 was found to catch significant numbers of three species of lacewing in the field: in Korea. Chrysopa cognata, and in the United Kingdom, Nineta vittata and most notably Peverimhoffina gracilis. All species caught in significant numbers were found more frequently in traps releasing 1 than 2, while more C. cognata, C. formosa, and C. phyllochroma were found in traps releasing (1R,4aS,7S,7aR)-nepetalactol (4). The catch of P. gracilis with 1 is of particular interest as this lacewing has only recently been recorded in the United Kingdom. Where sexed, the lacewings of all species trapped were found to be male, implying a possible pheromonal role for these or structurally related compounds.
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Affiliation(s)
- A M Hooper
- Biological Chemistry Division, IACR-Rothamsted Harpenden, Herts, United Kingdom
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Hamilton JGC, Hooper AM, Pickett JA, Mori K, Sano S. 3-Methyl-α-himachalene is confirmed, and the relative stereochemistry defined, by synthesis as the sex pheromone of the sandfly Lutzomyia longipalpis from Jacobina, Brazil. Chem Commun (Camb) 1999. [DOI: 10.1039/a900242a] [Citation(s) in RCA: 31] [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] [Indexed: 11/21/2022]
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Hamilton JGC, Ibbotson HC, Hooper AM, Pickett JA. 9-Methylgermacrene-B is confirmed as the sex pheromone of the sandfly Lutzomyia longipalpis from Lapinha, Brazil, and the absolute stereochemistry defined as S. Chem Commun (Camb) 1999. [DOI: 10.1039/a907910f] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hooper AM, Rickards RW. 3-Amino-5-hydroxybenzoic acid in antibiotic biosynthesis. XII. Origin of the oxygen functionality of the ansamycin antibiotic actamycin. J Antibiot (Tokyo) 1998; 51:958-62. [PMID: 9917011 DOI: 10.7164/antibiotics.51.958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- A M Hooper
- Research School of Chemistry, Australian National University, Canberra, ACT
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Hooper AM, Rickards RW. 3-amino-5-hydroxybenzoic acid in antibiotic biosynthesis. XI. Biological origins and semisynthesis of thionaphthomycins, and the structures of naphthomycins I and J. J Antibiot (Tokyo) 1998; 51:845-51. [PMID: 9820235 DOI: 10.7164/antibiotics.51.845] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fermentations of Streptomyces sp. E/784 produce low levels of the novel C-30 alkylthio-substituted ansamycin antibiotics naphthomycins J (9) and I (10), in addition to the more abundant C-30 hydroxylated analogues actamycin (1) and naphthomycin D (2) and C-30 chlorinated analogues naphthomycins H (3) and A (4). The addition of N-acetyl-L-cysteine to the fermentation medium substantially increases the production of the thionaphthomycins J and I at the expense of their chloro analogues H and A. Other thiols and thiol progenitors are similarly utilised, including N-acetyl-L-cysteine methyl ester which affords the known naphthomycin F (8) and its novel 2-demethyl homologue (7). The formation of thioansamycins from chloroansamycins and thiols in vivo is probably non-enzymic since similar conversions can be effected in vitro.
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Affiliation(s)
- A M Hooper
- Research School of Chemistry, Australian National University, Canberra, A.C.T
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Dutton CJ, Hooper AM, Leadlay PF, Staunton J. Avermectin biosynthesis. Intact incorporation of a diketide chain-assembly intermediate into the polyketide macrocyclic ring. Tetrahedron Lett 1994. [DOI: 10.1016/s0040-4039(00)76544-0] [Citation(s) in RCA: 10] [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: 10/18/2022]
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