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Woyessa D, Morou E, Wipf N, Dada N, Mavridis K, Vontas J, Yewhalaw D. Species composition, infection rate and detection of resistant alleles in Anopheles funestus (Diptera: Culicidae) from Lare, a malaria hotspot district of Ethiopia. Malar J 2023; 22:233. [PMID: 37573300 PMCID: PMC10422748 DOI: 10.1186/s12936-023-04667-3] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 08/07/2023] [Indexed: 08/14/2023] Open
Abstract
BACKGROUND Anopheles funestus, which is considered as secondary vector of malaria in Ethiopia, is known to have several morphologically indistinguishable (sibling) species. Accurate identification of sibling species is crucial to understand their biology, behaviour and vector competence. In this study, molecular identification was conducted on the Ethiopian An. funestus populations. Moreover, insecticide resistance mechanism markers were detected, including ace N485I, kdr L1014F, L1014S, and CYP6P9a TaqMan qPCR was used to detect the infective stage of the parasite from field collected adult female An. funestus populations. METHODS Adult female mosquito collection was conducted from Lare, Gambella Regional State of Ethiopia between June 2018 to July 2020 using CDC light traps and HLC. Sub-samples of the morphologically identified An. funestus mosquitoes were molecularly identified using species-specific PCR, and the possible presence of insecticide resistance alleles was investigated using TaqMan qPCR (N485I-Ace-1), PCR-Sanger sequencing (L1014F-kdr), and PCR-RFLP (CYP6P9a resistance allele). Following head/thorax dissection, the TaqMan qPCR assay was used to investigate the presence of the infective stage Plasmodium parasite species. RESULTS A total of 1086 adult female An. funestus mosquitoes were collected during the study period. All sub-samples (N = 20) that were morphologically identified as An. funestus sensu lato (s.l.) were identified as An. funestus sensu stricto (s.s.) using species- specific PCR assay. The PCR-RFLP assay that detects the CYP6P9a resistance allele that confers pyrethroid resistance in An. funestus was applied in N = 30 randomly selected An. funestus s.l. SPECIMENS None of the specimens showed a digestion pattern consistent with the presence of the CYP6P9a resistance allele in contrast to what was observed in the positive control. Consequently, all samples were characterized as wild type. The qPCR TaqMan assay that detects the N485I acetylcholinesterase-1 mutation conferring resistance to organophosphates/carbamates in An. funestus was used in (N = 144) samples. All samples were characterized as wild type. The kdr L1014F and L1014S mutations in the VGSC gene that confer resistance to pyrethroids and DDT were analysed with direct Sanger sequencing after PCR and clean-up of the PCR products were also characterized as wild type. None of the samples (N = 169) were found positive for Plasmodium (P. falciparum/ovale/malariae/vivax) detection. CONCLUSION All An. funestus s.l. samples from Lare were molecularly identified as An. funestus s.s. No CYP6P9, N485I acetylcholinesterase 1, kdr L1014F or L1014S mutations were detected in the An. funestus samples. None of the An. funestus samples were positive for Plasmodium. Although the current study did not detect any insecticide resistant mechanism, it provides a reference for future vector monitoring programmes. Regular monitoring of resistance mechanisms covering wider geographical areas of Ethiopia where this vector is distributed is important for improving the efficacy of vector control programs.
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Affiliation(s)
- Delelegn Woyessa
- Department of Biology, College of Natural Sciences, Jimma University, P. O. Box 378, Jimma, Ethiopia.
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.
- Tropical and Infectious Diseases Research Centre (TIDRC), P.O. Box 378, Jimma, Ethiopia.
| | - Evangelia Morou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Nadja Wipf
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Nsa Dada
- School of Life Sciences, College of Liberal Arts and Sciences, Arizona State University, Tempe, USA
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Centre (TIDRC), P.O. Box 378, Jimma, Ethiopia
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Alemayehu E, Asale A, Eba K, Getahun K, Tushune K, Bryon A, Morou E, Vontas J, Van Leeuwen T, Duchateau L, Yewhalaw D. Mapping insecticide resistance and characterization of resistance mechanisms in Anopheles arabiensis (Diptera: Culicidae) in Ethiopia. Parasit Vectors 2017; 10:407. [PMID: 28865490 PMCID: PMC5581456 DOI: 10.1186/s13071-017-2342-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [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: 08/04/2016] [Accepted: 08/22/2017] [Indexed: 12/05/2022] Open
Abstract
Background The emergence and spread of insecticide resistance in the major African malaria vectors Anopheles gambiae (s.s.) and An. arabiensis may compromise the current vector control interventions and threatens the global malaria control and elimination efforts. Methods Insecticide resistance was monitored in several study sites in Ethiopia from 2013 to 2015 using papers impregnated with discriminating concentrations of DDT, deltamethrin, bendiocarb, propoxur, malathion, fenitrothion and pirimiphos-methyl, following the WHO insecticide susceptibility test procedure. Mosquitoes sampled from different localities for WHO bioassay were morphologically identified as An. gambiae (s.l.) using standard taxonomic keys. Samples were identified to species using species-specific polymerase chain reaction (PCR) and screened for the presence of target site mutations L1014F, L1014S and N1575Y in the voltage gated sodium channel (VGSC) gene and G119S in the acethylcholinesterase (AChE) gene using allele-specific PCR. Biochemical assays were performed to assess elevated levels of acetylcholinesterases, carboxylcholinesterases, glutathione-S-transferases (GSTs) and cytochrome P450s monooxygenases in wild populations of An. arabiensis, compared to the fully susceptible Sekoru An. arabiensis laboratory strain. Results Populations of An. arabiensis were resistant to DDT and deltamethrin but were susceptible to fenitrothion in all the study sites. Reduced susceptibility to malathion, pirimiphos-methyl, propoxur and bendiocarb was observed in some of the study sites. Knockdown resistance (kdr L1014F) was detected in all mosquito populations with allele frequency ranging from 42 to 91%. Elevated levels of glutathione-S-transferases (GSTs) were detected in some of the mosquito populations. However, no elevated levels of monooxygenases and esterases were detected in any of the populations assessed. Conclusions Anopheles arabiensis populations from all surveyed sites in Ethiopia exhibited resistance against DDT and pyrethroids. Moreover, some mosquito populations exhibited resistance to propoxur and possible resistance to bendiocarb. Target site mutation kdr L1014F was detected in all mosquito populations while elevated levels of glutathione-S-transferases (GSTs) was detected in some mosquito populations. The reduced susceptibility of An. arabiensis to propoxur and bendiocarb, which are currently used for indoor residual spraying (IRS) in Ethiopia, calls for continuous resistance monitoring, in order to plan and implement evidence based insecticide resistance management. Electronic supplementary material The online version of this article (10.1186/s13071-017-2342-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Eba Alemayehu
- Department of Biology, College of Natural Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia.,Department of Comparative Physiology and Biometrics, University of Ghent, Ghent, Belgium
| | - Abebe Asale
- Department of Biology, College of Natural Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Kasahun Eba
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Kefelegn Getahun
- Department of Geography and Environmental Studies, Jimma University, Jimma, Ethiopia
| | - Kora Tushune
- Department of Health Services Management, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Astrid Bryon
- Department of Crop Protection, Ghent University, Ghent, Belgium
| | - Evangelia Morou
- Department of Biology, University of Crete, Heraklion, Greece.,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.,Department of Crop Science, Pesticide Science Lab, Agricultural University of Athens, Athens, Greece
| | - Thomas Van Leeuwen
- Department of Crop Protection, Ghent University, Ghent, Belgium.,Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - Luc Duchateau
- Department of Comparative Physiology and Biometrics, University of Ghent, Ghent, Belgium
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia. .,Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia.
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Roditakis E, Mavridis K, Riga M, Vasakis E, Morou E, Rison JL, Vontas J. Identification and detection of indoxacarb resistance mutations in the para sodium channel of the tomato leafminer, Tuta absoluta. Pest Manag Sci 2017; 73:1679-1688. [PMID: 28019074 DOI: 10.1002/ps.4513] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 11/04/2016] [Revised: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Indoxacarb is an important active ingredient extensively used for the control of Tuta absoluta, a major tomato pest, playing a particular role in insecticide resistance management schemes. RESULTS Reduced susceptibility to indoxacarb was identified (1794-fold resistance) through toxicological bioassays in a field population from Greece and evolved rapidly to resistance after short laboratory selection. Combined bioassays with synergists and biochemical analysis suggested only a partial involvement of detoxification enzymes in the resistant phenotype. To investigate the role of target-site resistance, segment 6 of domain IV of the sodium channel in T. absoluta was cloned and the sequences compared between susceptible and indoxacarb-resistant T. absoluta insects. The presence of the F1845Y and the V1848I indoxacarb resistance mutations was detected and was strongly associated with the phenotype. These amino acid substitutions correspond to recently characterised indoxacarb resistance mutations in diamondback moth (Plutella xylostella). Robust and accurate PCR-RFLP assays were subsequently developed and successfully validated for detecting both indoxacarb resistance mutations in field T. absoluta populations. CONCLUSION The identification of indoxacarb resistance mutations and the development of diagnostic tools will allow early detection of indoxacarb resistance, facilitating implementation of appropriate resistance management strategies, thus delaying the spread of resistance. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Emmanouil Roditakis
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive, Subtropical Plants and Vine, Heraklion, Crete, Greece
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Crete, Greece
| | - Maria Riga
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Crete, Greece
- Department of Biology, University of Crete
| | - Emmanouil Vasakis
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive, Subtropical Plants and Vine, Heraklion, Crete, Greece
| | - Evangelia Morou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Crete, Greece
- Department of Biology, University of Crete
| | | | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Crete, Greece
- Department of Crop Science, Agricultural University of Athens, Athens, Greece
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Roditakis E, Steinbach D, Moritz G, Vasakis E, Stavrakaki M, Ilias A, García-Vidal L, Martínez-Aguirre MDR, Bielza P, Morou E, Silva JE, Silva WM, Siqueira ΗAA, Iqbal S, Troczka BJ, Williamson MS, Bass C, Tsagkarakou A, Vontas J, Nauen R. Ryanodine receptor point mutations confer diamide insecticide resistance in tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). Insect Biochem Mol Biol 2017; 80:11-20. [PMID: 27845250 DOI: 10.1016/j.ibmb.2016.11.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [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: 09/04/2016] [Revised: 10/14/2016] [Accepted: 11/11/2016] [Indexed: 06/06/2023]
Abstract
Insect ryanodine receptors (RyR) are the molecular target-site for the recently introduced diamide insecticides. Diamides are particularly active on Lepidoptera pests, including tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae). High levels of diamide resistance were recently described in some European populations of T. absoluta, however, the mechanisms of resistance remained unknown. In this study the molecular basis of diamide resistance was investigated in a diamide resistant strain from Italy (IT-GELA-SD4), and additional resistant field populations collected in Greece, Spain and Brazil. The genetics of resistance was investigated by reciprocally crossing strain IT-GELA-SD4 with a susceptible strain and revealed an autosomal incompletely recessive mode of inheritance. To investigate the possible role of target-site mutations as known from diamondback moth (Plutella xylostella), we sequenced respective domains of the RyR gene of T. absoluta. Genotyping of individuals of IT-GELA-SD4 and field-collected strains showing different levels of diamide resistance revealed the presence of G4903E and I4746M RyR target-site mutations. These amino acid substitutions correspond to those recently described for diamide resistant diamondback moth, i.e. G4946E and I4790M. We also detected two novel mutations, G4903V and I4746T, in some of the resistant T. absoluta strains. Radioligand binding studies with thoracic membrane preparations of the IT-GELA-SD4 strain provided functional evidence that these mutations alter the affinity of the RyR to diamides. In combination with previous work on P. xylostella our study highlights the importance of position G4903 (G4946 in P. xylostella) of the insect RyR in defining sensitivity to diamides. The discovery of diamide resistance mutations in T. absoluta populations of diverse geographic origin has serious implications for the efficacy of diamides under applied conditions. The implementation of appropriate resistance management strategies is strongly advised to delay the further spread of resistance.
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Affiliation(s)
- Emmanouil Roditakis
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece.
| | - Denise Steinbach
- Bayer CropScience, R&D Pest Control, Monheim, Germany; Department of Biology, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Gerald Moritz
- Department of Biology, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Emmanouil Vasakis
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece
| | - Marianna Stavrakaki
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece
| | - Aris Ilias
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece
| | - Lidia García-Vidal
- Departamento de Producción Vegetal, Universidad Politécnica de Cartagena, Cartagena, Spain
| | | | - Pablo Bielza
- Departamento de Producción Vegetal, Universidad Politécnica de Cartagena, Cartagena, Spain
| | - Evangelia Morou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Crete, Greece
| | - Jefferson E Silva
- Departamento de Agronomia, Universidade Federal Rural de Pernambuco - UFRPE, Recife, Brazil
| | - Wellington M Silva
- Departamento de Agronomia, Universidade Federal Rural de Pernambuco - UFRPE, Recife, Brazil
| | - Ηerbert A A Siqueira
- Departamento de Agronomia, Universidade Federal Rural de Pernambuco - UFRPE, Recife, Brazil
| | | | | | | | - Chris Bass
- College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - Anastasia Tsagkarakou
- Hellenic Agricultural Organisation - 'Demeter', Institute of Olive Tree, Subtropical Crops and Viticulture, Heraklion, Crete, Greece
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, Crete, Greece; Department of Crop Science, Agricultural University of Athens, Athens, Greece
| | - Ralf Nauen
- Bayer CropScience, R&D Pest Control, Monheim, Germany.
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Riga M, Myridakis A, Tsakireli D, Morou E, Stephanou EG, Nauen R, Van Leeuwen T, Douris V, Vontas J. Functional characterization of the Tetranychus urticae CYP392A11, a cytochrome P450 that hydroxylates the METI acaricides cyenopyrafen and fenpyroximate. Insect Biochem Mol Biol 2015; 65:91-99. [PMID: 26363294 DOI: 10.1016/j.ibmb.2015.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [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: 07/01/2015] [Revised: 09/06/2015] [Accepted: 09/06/2015] [Indexed: 06/05/2023]
Abstract
Cyenopyrafen is a Mitochondrial Electron Transport Inhibitor (METI) acaricide with a novel mode of action at complex II, which has been recently developed for the control of the spider mite Tetranychus urticae, a pest of eminent importance globally. However, some populations of T. urticae are cross-resistant to this molecule, and cyenopyrafen resistance can be readily selected in the lab. The cytochrome P450s genes CYP392A11 and CYP392A12 have been strongly associated with the phenotype. We expressed the CYP392A11 and the CYP392A12 genes with T. urticae cytochrome P450 reductase (CPR) in Escherichia coli. CYP392A12 was expressed predominately as an inactive form, witnessed by a peak at P420, despite optimization efforts on expression conditions. However, expression of CYP392A11 produced a functional enzyme, with high activity and preference for the substrates Luciferin-ME EGE and ethoxycoumarin. CYP392A11 catalyses the conversion of cyenopyrafen to a hydroxylated analogue (kcat = 2.37 pmol/min/pmol P450), as well as the hydroxylation of fenpyroximate (kcat = 1.85 pmol/min/pmol P450). In addition, transgenic expression of CYP392A11 in Drosophila melanogaster, in conjunction with TuCPR, confers significant levels of fenpyroximate resistance. The overexpression of CYP392A11 in multi-resistant T. urticae strains, not previously exposed to cyenopyrafen, which had been indicated by microarray studies, was confirmed by qPCR, and it was correlated with significant levels of cyenopyrafen and fenpyroximate cross-resistance. The implications of our findings for insecticide resistance management strategies are discussed.
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Affiliation(s)
- M Riga
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - A Myridakis
- Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, 71003 Heraklion, Greece
| | - D Tsakireli
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - E Morou
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - E G Stephanou
- Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, 71003 Heraklion, Greece
| | - R Nauen
- Bayer CropScience AG, R&D Pest Control Biology, Alfred Nobel Str. 50, D-40789 Monheim, Germany
| | - T Van Leeuwen
- Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (UvA), Science Park 904, 1098 XH Amsterdam, The Netherlands; Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - V Douris
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - J Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13 Heraklion, Crete, Greece; Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, 75 Iera Odos Street, GR-11855 Athens, Greece.
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Thawer NG, Ngondi JM, Mugalura FE, Emmanuel I, Mwalimu CD, Morou E, Vontas J, Protopopoff N, Rowland M, Mutagahywa J, Lalji S, Molteni F, Ramsan MM, Willilo R, Wright A, Kafuko JM, Ndong I, Reithinger R, Magesa SM. Use of insecticide quantification kits to investigate the quality of spraying and decay rate of bendiocarb on different wall surfaces in Kagera region, Tanzania. Parasit Vectors 2015; 8:242. [PMID: 25896604 PMCID: PMC4424830 DOI: 10.1186/s13071-015-0859-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/14/2015] [Indexed: 11/14/2022] Open
Abstract
Background Bendiocarb was introduced for the first time for Indoor Residual Spraying (IRS) in Tanzania in 2012 as part of the interim national insecticide resistance management plan. This move followed reports of increasingly alarming levels of pyrethroid resistance across the country. This study used the insecticide quantification kit (IQK) to investigate the intra-operational IRS coverage and quality of spraying, and decay rate of bendiocarb on different wall surfaces in Kagera region. Methods To assess intra-operational IRS coverage and quality of spraying, 104 houses were randomly selected out of 161,414 sprayed houses. A total of 509 samples (218 in Muleba and 291 in Karagwe) were obtained by scraping the insecticide samples from wall surfaces. To investigate decay rate, 66 houses (36 in Muleba and 30 in Karagwe) were selected and samples were collected monthly for a period of five months. Laboratory testing of insecticide concentration was done using IQKTM [Innovative Vector Control Consortium]. Results Of the 509 samples, 89.5% met the World Health Organization (WHO) recommended concentration (between 100–400 mg/m2) for IRS target dosage. The proportion of samples meeting WHO standards varied between Karagwe (84.3%) and Muleba (96.3%) (p < 0.001). Assessment of quality of spraying at house level revealed that Muleba (84.8%) had a significantly higher proportion of households that met the expected target dosage (100–400 mg/m2) compared to Karagwe (68.9%) (p < 0.001). The quality of spraying varied across different wall substrates in both districts. Evaluation of bendiocarb decay showed that the proportion of houses with recommended concentration declined from 96.9%, 93.5% and 76.2% at months one, two, and three post IRS, respectively (p-trend = 0.03). The rate of decay increased in the fourth and fifth month post spraying with only 55.9% and 26.3% houses meeting the WHO recommendations, respectively. Conclusion IQK is an important tool for assessing IRS coverage and quality of spraying. The study found adequate coverage of IRS; however, residual life of bendiocarb was observed to be three months. Results suggest that in order to maintain the recommended concentrations with bendiocarb, a second spray cycle should be carried out after three months. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-0859-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Evangelia Morou
- Liverpool School of Tropical Medicine, Liverpool, UK. .,Department of Biology, University of Crete, Heraklion, Greece.
| | - John Vontas
- Faculty of Crop Science, Pesticide Science Lab, Agricultural University of Athens, 11855, Athens, Greece. .,Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 73100, Heraklion, Greece.
| | | | - Mark Rowland
- London School of Hygiene and Tropical Medicine, London, UK.
| | | | | | - Fabrizio Molteni
- Swiss Tropical and Public Health Institute, Dar es Salaam, Tanzania.
| | | | | | | | - Jessica M Kafuko
- United States Agency for International Development, Abuja, Nigeria.
| | - Isaiah Ndong
- RTI international, Research Triangle Park, North Carolina, USA.
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Papadakis G, Tsortos A, Kordas A, Tiniakou I, Morou E, Vontas J, Kardassis D, Gizeli E. Acoustic detection of DNA conformation in genetic assays combined with PCR. Sci Rep 2014; 3:2033. [PMID: 23778520 PMCID: PMC3686166 DOI: 10.1038/srep02033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 06/03/2013] [Indexed: 11/09/2022] Open
Abstract
Application of PCR to multiplexing assays is not trivial; it requires multiple fluorescent labels for amplicon detection and sophisticated software for data interpretation. Alternative PCR-free methods exploiting new concepts in nanotechnology exhibit high sensitivities but require multiple labeling and/or amplification steps. Here, we propose to simplify the problem of simultaneous analysis of multiple targets in genetic assays by detecting directly the conformation, rather than mass, of target amplicons produced in the same PCR reaction. The new methodology exploits acoustic wave devices which are shown to be able to characterize in a fully quantitative manner multiple double stranded DNAs of various lengths. The generic nature of the combined acoustic/PCR platform is shown using real samples and, specifically, during the detection of SNP genotyping in Anopheles gambiae and gene expression quantification in treated mice. The method possesses significant advantages to TaqMan assay and real-time PCR regarding multiplexing capability, speed, simplicity and cost.
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Affiliation(s)
- G Papadakis
- Institute of Molecular Biology & Biotechnology, FORTH, Vassilika Vouton, 70013 Heraklion, Greece.
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8
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Kioulos I, Kampouraki A, Morou E, Skavdis G, Vontas J. Insecticide resistance status in the major West Nile virus vector Culex pipiens from Greece. Pest Manag Sci 2014; 70:623-627. [PMID: 23788440 DOI: 10.1002/ps.3595] [Citation(s) in RCA: 19] [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: 04/09/2013] [Revised: 05/29/2013] [Accepted: 06/20/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND One of the largest West Nile virus outbreaks in Europe occurred in Greece in 2010. Use of insecticides against Culex pipiens was substantially scaled up, as an emergency tool. Although mosquito control has been based on insecticides for several decades in Greece, insecticide resistance data are not available. RESULTS An examination was made of the resistance status of 13 Cx. pipiens populations from five regional units in Greece against four insecticides used for its control over a 3 year period. Bioassays demonstrated susceptibility of most populations to all insecticides, except for temephos in some regions, and deltamethrin and diflubenzuron on one occasion each. The authors also monitored the frequency of the pyrethroid target-site resistance mutations L1014F (kdr), as well as G119S and F290V in the Ace1 gene. Ace1 insensitivity mutations were found at low frequencies and always in heterozygocity. However, the frequency of kdr pyrethroid resistance mutations was higher (up to 63.0% in Thessaloniki). CONCLUSIONS The high frequency of kdr mutations indicates a risk that needs to be addressed, should the use of pyrethroids be further extended. There was no strong evidence of significant resistance levels against Bacillus thuringiensis var. israelensis and diflubenzuron. Continued monitoring of insecticide resistance is recommended for the application of appropriate management tactics.
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Affiliation(s)
- Ilias Kioulos
- Laboratory of Pesticide Science, Agricultural University of Athens, Athens, Greece
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Riga M, Tsakireli D, Ilias A, Morou E, Myridakis A, Stephanou EG, Nauen R, Dermauw W, Van Leeuwen T, Paine M, Vontas J. Abamectin is metabolized by CYP392A16, a cytochrome P450 associated with high levels of acaricide resistance in Tetranychus urticae. Insect Biochem Mol Biol 2014; 46:43-53. [PMID: 24463358 DOI: 10.1016/j.ibmb.2014.01.006] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [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: 11/22/2013] [Revised: 01/11/2014] [Accepted: 01/13/2014] [Indexed: 06/03/2023]
Abstract
Abamectin is one of the most important insecticides worldwide. It is used against major agricultural pests and insects of public health importance, as well as against endoparasites in animal health. Abamectin has been used successfully for the control of the spider mite Tetranychus urticae, a major agricultural pest with global distribution, an extremely diverse host range, and a remarkable ability to develop resistance against insecticides including abamectin. Target site resistance mutations may explain a large part of resistance, although genetic evidence and transcriptomic data indicated that additional mechanisms may also be implicated in the abamectin resistant phenotype. To investigate a functional link between cytochrome P450-mediated metabolism and abamectin resistance, we recombinantly expressed three cytochrome P450s (CYP392A16, CYP392D8 and CYP392D10) that have been associated with high levels of abamectin resistance in a resistant T. urticae strain isolated from Greece. CYP392A16 was expressed predominately in its P450 form however, both CYP392D8 and CYP392D10 were expressed predominately as P420, despite optimization efforts on expression conditions. CYP392A16 catalyses the hydroxylation of abamectin (Kcat=0.54 pmol/min/pmol P450; Km=45.9 μM), resulting in a substantially less toxic compound as confirmed by bioassays with the partially purified metabolite. However, CYP392A16 did not metabolize hexythiazox, clofentezine and bifenthrin, active ingredients that also showed reduced toxicity in the abamectin resistant strain. Among a number of fluorescent and luminescent substrates screened, Luciferin-ME EGE was preferentially metabolized by CYP392A16, and it may be a potential diagnostic probe for metabolic resistance detection and monitoring.
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Affiliation(s)
- M Riga
- Faculty of Applied Biotechnology and Biology, Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - D Tsakireli
- Faculty of Applied Biotechnology and Biology, Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - A Ilias
- Faculty of Applied Biotechnology and Biology, Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - E Morou
- Faculty of Applied Biotechnology and Biology, Department of Biology, University of Crete, 71409 Heraklion, Greece
| | - A Myridakis
- Faculty of Environmental & Analytical Chemistry, Department of Chemistry, University of Crete, 71409 Heraklion, Greece
| | - E G Stephanou
- Faculty of Environmental & Analytical Chemistry, Department of Chemistry, University of Crete, 71409 Heraklion, Greece
| | - R Nauen
- Bayer CropScience AG, RD-SMR Pest Control Biology, Alfred Nobel Str. 50, D-40789 Monheim, Germany
| | - W Dermauw
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Agricultural and Applied, Biological Sciences, Ghent University, B-9000 Ghent, Belgium
| | - T Van Leeuwen
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Agricultural and Applied, Biological Sciences, Ghent University, B-9000 Ghent, Belgium; Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam (UvA), Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - M Paine
- Department of Vector Biology, Liverpool School Tropical Medicine, UK
| | - J Vontas
- Faculty of Applied Biotechnology and Biology, Department of Biology, University of Crete, 71409 Heraklion, Greece.
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Mironidis GK, Kapantaidaki D, Bentila M, Morou E, Savopoulou-Soultani M, Vontas J. Resurgence of the cotton bollworm Helicoverpa armigera in northern Greece associated with insecticide resistance. Insect Sci 2013; 20:505-512. [PMID: 23955946 DOI: 10.1111/j.1744-7917.2012.01528.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/16/2012] [Indexed: 06/02/2023]
Abstract
Helicoverpa armigera has been controlled effectively with chemical insecticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, which significantly affected crop production. During a 4-year survey (2007-2010), we examined the insecticide resistance status of H. armigera populations from two major and representative cotton production areas in northern Greece against seven insecticides (chlorpyrifos, diazinon, methomyl, alpha-cypermethrin, cypermethrin, gamma-cyhalothrin and endosulfan). Full dose-response bioassays on third instar larvae were performed by topical application. Lethal doses at 50% were estimated by probit analysis and resistance factors (RF) were calculated, compared to a susceptible laboratory reference strain. Resistance levels were relatively moderate until 2009, with resistance ratios below 10-fold for organophosphates and carbamates and up to 16-fold for the pyrethroid alpha-cypermethrin. However, resistance rose to 46- and 81-fold for chlorpyrifos and alpha-cypermethrin, respectively in 2010, when the resurgence of the pest was observed. None of the known pyrethroid resistance mutations were found in the pyrethroid-resistant insects. The possible association between resistance and H. armigera resurgence in Greece is discussed.
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Affiliation(s)
- George K Mironidis
- Laboratory of Applied Zoology and Parasitology, Faculty of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece
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11
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Morou E, Dowd AJ, Rajatileka S, Steven A, Hemingway J, Ranson H, Paine M, Vontas J. A simple colorimetric assay for specific detection of glutathione-S transferase activity associated with DDT resistance in mosquitoes. PLoS Negl Trop Dis 2010; 4. [PMID: 20824165 PMCID: PMC2930865 DOI: 10.1371/journal.pntd.0000808] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 08/03/2010] [Indexed: 11/28/2022] Open
Abstract
Background Insecticide-based methods represent the most effective means of blocking the transmission of vector borne diseases. However, insecticide resistance poses a serious threat and there is a need for tools, such as diagnostic tests for resistance detection, that will improve the sustainability of control interventions. The development of such tools for metabolism-based resistance in mosquito vectors lags behind those for target site resistance mutations. Methodology/Principal Findings We have developed and validated a simple colorimetric assay for the detection of Epsilon class Glutathione transferases (GST)-based DDT resistance in mosquito species, such as Aedes aegypti, the major vector of dengue and yellow fever worldwide. The colorimetric assay is based on the specific alkyl transferase activity of Epsilon GSTs for the haloalkene substrate iodoethane, which produces a dark blue colour highly correlated with AaGSTE2-2-overexpression in individual mosquitoes. The colour can be measured visually and spectrophotometrically. Conclusions/Significance The novel assay is substantially more sensitive compared to the gold standard CDNB assay and allows the discrimination of moderate resistance phenotypes. We anticipate that it will have direct application in routine vector monitoring as a resistance indicator and possibly an important impact on disease vector control. Aedes mosquitoes transmit many human viral pathogens including dengue, yellow fever and chikungunya. Most of these pathogens have no specific treatment or vaccine and hence their control is reliant on controlling the mosquito vectors, which usually involves the use of insecticides. In order to prevent the alarming prospect of mosquito control failure due to the rapid selection and spread of insecticide resistance in several mosquito populations worldwide, it is essential that effective resistance management strategies are implemented and adhered to. The development of simple diagnostic tests for the early identification and monitoring of resistance is an important prerequisite for this task. Here, we describe the development of a simple colorimetric test for the detection of GSTE2-2/DDTase-based resistance in individual mosquitoes. The novel assay combines the most desirable features of specificity and sensitivity with the low cost and ease of use required for a routine test in endemic countries. It can have direct application in routine vector monitoring as a resistance indicator and help improve the sustainability of insecticide based control strategies.
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Affiliation(s)
- Evangelia Morou
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Biology, University of Crete, Heraklio, Greece
| | - Andrew J. Dowd
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Shavanti Rajatileka
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Andrew Steven
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Janet Hemingway
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Hilary Ranson
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mark Paine
- Vector Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail: (MP); (JV)
| | - John Vontas
- Department of Biology, University of Crete, Heraklio, Greece
- * E-mail: (MP); (JV)
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Khajehali J, Van Leeuwen T, Grispou M, Morou E, Alout H, Weill M, Tirry L, Vontas J, Tsagkarakou A. Acetylcholinesterase point mutations in European strains of Tetranychus urticae (Acari: Tetranychidae) resistant to organophosphates. Pest Manag Sci 2010; 66:220-228. [PMID: 19894225 DOI: 10.1002/ps.1884] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
BACKGROUND In Tetranychus urticae Koch, acetylcholinesterase insensitivity is often involved in organophosphate (OP) and carbamate (CARB) resistance. By combining toxicological, biochemical and molecular data from three reference laboratory and three OP selected strains (OP strains), the AChE1 mutations associated with resistance in T. urticae were characterised. RESULTS The resistance ratios of the OP strains varied from 9 to 43 for pirimiphos-methyl, from 78 to 586 for chlorpyrifos, from 8 to 333 for methomyl and from 137 to 4164 for dimethoate. The insecticide concentration needed to inhibit 50% of the AChE1 activity was, in the OP strains, at least 2.7, 55, 58 and 31 times higher for the OP pirimiphos-methyl, chlorpyrifos oxon, paraoxon and omethoate respectively, and 87 times higher for the CARB carbaryl. By comparing the AChE1 sequence, four amino acid substitutions were detected in the OP strains: (1) F331W (Torpedo numbering) in all the three OP strains; (2) T280A found in the three OP strains but not in all clones; (3) G328A, found in two OP strains; (4) A201S found in only one OP strain. CONCLUSIONS Four AChE1 mutations were found in resistant strains of T. urticae, and three of them, F331W, G328A and A201S, are possibly involved in resistance to OP and CARB insecticides. Among them, F331W is probably the most important and the most common in T. urticae. It can be easily detected by the diagnostic PCR-RLFP assay developed in this study.
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Affiliation(s)
- Jahangir Khajehali
- Laboratory of Agrozoology, Department of Crop Protection, Ghent University, Coupure links 653, 9000 Ghent, Belgium
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Karunker I, Morou E, Nikou D, Nauen R, Sertchook R, Stevenson BJ, Paine MJI, Morin S, Vontas J. Structural model and functional characterization of the Bemisia tabaci CYP6CM1vQ, a cytochrome P450 associated with high levels of imidacloprid resistance. Insect Biochem Mol Biol 2009; 39:697-706. [PMID: 19716416 DOI: 10.1016/j.ibmb.2009.08.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 08/12/2009] [Accepted: 08/13/2009] [Indexed: 05/28/2023]
Abstract
The neonicotinoid imidacloprid is one of the most important insecticides worldwide. It is used extensively against the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), an insect pest of eminent importance globally, which was also the first pest to develop high levels of resistance against imidacloprid and other neonicotinoids in the field. Recent reports indicated that in both the B and Q biotypes of B. tabaci, the resistant phenotype is associated with over-expression of the cytochrome P450 gene CYP6CM1. In this study, molecular docking and dynamic simulations were used to analyze interactions of imidacloprid with the biotype Q variant of the CYP6CM1 enzyme (CYP6CM1vQ). The binding mode with the lowest energy in the enzyme active site, the key amino acids involved (i.e. Phe-130 and Phe-226), and the putative hydroxylation site (lowest distance to carbon 5 of the imidazolidine ring system of imidacloprid) were predicted. Heterologous expression of the CYP6CM1vQ confirmed the accuracy of our predictions and demonstrated that the enzyme catalyses the hydroxylation of imidacloprid to its less toxic 5-hydroxy form (K(cat) = 3.2 pmol/min/pmol P450, K(m) = 36 microM). The data identify CYP6CM1vQ as a principle target for inhibitor design, aimed at inactivating insecticide-metabolizing P450s in natural insect pest populations.
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Affiliation(s)
- Iris Karunker
- Department of Entomology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
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Dowd AJ, Steven A, Morou E, Hemingway J, Vontas J, Paine MJ. A simple glutathione transferase-based colorimetric endpoint assay for insecticide detection. Enzyme Microb Technol 2009. [DOI: 10.1016/j.enzmictec.2009.05.008] [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] [Indexed: 11/29/2022]
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Roditakis E, Grispou M, Morou E, Kristoffersen JB, Roditakis N, Nauen R, Vontas J, Tsagkarakou A. Current status of insecticide resistance in Q biotype Bemisia tabaci populations from Crete. Pest Manag Sci 2009; 65:313-22. [PMID: 19115232 DOI: 10.1002/ps.1690] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND A major problem of crop protection in Crete, Greece, is the control of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) with chemical insecticides owing to the rapid development of resistance. The aim of this study was to investigate the establishment of resistance and the underlying mechanisms to major insecticide classes with classical bioassays and known biochemical resistance markers. RESULTS During a 2005-2007 survey, 53 Q biotype populations were collected. Application history records showed extensive use of neonicotinoids, organophosphates, carbamates and pyrethroids. High resistance levels were identified in the majority of populations (>80%) for imidacloprid (RF: 38-1958x) and alpha-cypermethrin (RF: 30-600x). Low resistance levels (RF < 12) were observed for pirimiphos-methyl. A strong correlation between resistance to imidacloprid and the number of applications with neonicotinoids was observed. Significant correlations were observed between COE and P450-dependent monoxygenase activity with resistance to alpha-cypermethrin and imidacloprid respectively. A propoxur-based AChE diagnostic test indicated that iAChE was widespread in most populations. Resistance levels for alpha-cypermethrin were increased when compared with a previous survey (2002-2003). Differentiation of LC(50) values between localities was observed for imidacloprid only. CONCLUSION Bemisia tabaci resistance evolved differently in each of the three insecticides studied. Imidacloprid resistance seems less established and less persistent than alpha-cypermethrin resistance. The low resistance levels for pirimiphos-methyl suggest absence of cross-resistance with other organophosphates or carbamates used.
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Affiliation(s)
- Emmanouil Roditakis
- National Agricultural Research Foundation, Plant Protection Institute of Heraklion, PO Box 2228, 71003 Heraklion, Greece.
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Margaritopoulos JT, Skavdis G, Kalogiannis N, Nikou D, Morou E, Skouras PJ, Tsitsipis JA, Vontas J. Efficacy of the pyrethroid alpha-cypermethrin against Bactrocera oleae populations from Greece, and improved diagnostic for an iAChE mutation. Pest Manag Sci 2008; 64:900-908. [PMID: 18381673 DOI: 10.1002/ps.1580] [Citation(s) in RCA: 21] [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] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
BACKGROUND The most important pest of olive orchards worldwide is the olive fruit fly Bactrocera oleae (Gmelin). Its control in Greece has been based on organophosphates (OPs), but their intense use has led to the development of resistance. A test previously developed to monitor the trait may not be as robust as originally thought. The pyrethroid alpha-cypermethrin has recently been registered for bait sprays, as an alternative to OPs. RESULTS The susceptibility of 20 B. oleae populations to alpha-cypermethrin was examined. Variation was observed in their response, with LD(50) ranging from 0.14 to 3.28 ng insect(-1) and resistance factors from 2.3 to 54.7. Resistance mechanisms were investigated. Cytochrome P450 monoxygenase activities showed an association with resistance. Sequences in the domain IIS4-IIS6 of the B. oleae para-type sodium channel were also analysed, but no resistance-associated mutations were identified. Finally, a novel diagnostic assay able to reliably monitor the frequency of the iAChE G488S resistance mutation was developed. CONCLUSION This is the first attempt to evaluate the efficacy of alpha-cypermethrin against B. oleae from Greece. Data showed that it can be used effectively, but also highlighted the importance of continuous monitoring. The IIS4-IIS6 sodium channel region is the default area in which to look for resistance mutations if target-site resistance to pyrethroids arises. The application of the novel iAChE molecular diagnostic may facilitate the introduction of pyrethroids alongside OPs currently in use.
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Affiliation(s)
- John T Margaritopoulos
- Laboratory of Entomology and Agricultural Zoology, Department of Agriculture Crop Production and Rural Environment, University of Thessaly, Fytokou Str. 384 46, Nea Ionia, Magnesia, Greece.
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Morou E, Ismail HM, Dowd AJ, Hemingway J, Labrou N, Paine M, Vontas J. A dehydrochlorinase-based pH change assay for determination of DDT in sprayed surfaces. Anal Biochem 2008; 378:60-4. [DOI: 10.1016/j.ab.2008.03.046] [Citation(s) in RCA: 18] [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] [Received: 02/12/2008] [Revised: 03/20/2008] [Accepted: 03/22/2008] [Indexed: 11/28/2022]
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Morou E, Georgoussi Z. Expression of the third intracellular loop of the delta-opioid receptor inhibits signaling by opioid receptors and other G protein-coupled receptors. J Pharmacol Exp Ther 2005; 315:1368-79. [PMID: 16160084 DOI: 10.1124/jpet.105.089946] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [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: 11/22/2022] Open
Abstract
To explore the feasibility of developing inhibitors of signaling by opioid receptors and other G protein-coupled receptors (GPCRs) that use the same G protein pool, we investigated the capacity of a minigene encoding the third intracellular loop of the delta-opioid receptor (delta-i3L) to act as competitive antagonist of the receptor-G protein interface interaction. In delta-i3L-expressing cells, the peptide blocked high-affinity agonist binding to both the delta- and the mu-opioid (delta-OR and mu-OR) and attenuated opioid and alpha2-adrenergic receptor (alpha2AR)-dependent [35S]guanosine-5'-O-(3-thio)triphosphate binding. Furthermore, delta-i3L expression resulted in inhibition of delta-, mu-OR-, and alpha2AR-receptor-mediated cAMP accumulation, whereas the cAMP response produced by activation of the beta2-adrenergic receptor was unaffected, suggesting that the inhibitory effects of delta-i3L expression were selective for Gi/Go proteins. Moreover, although delta-i3L expression also attenuated drastically phospholipase C accumulation and Ca2+ release following mu- and delta-OR stimulation, it failed to inhibit carbachol-mediated stimulation of inositol phosphate accumulation in M1-muscarinic receptor-expressing human embryonic kidney 293 cells. Finally, we also examined the effects of delta-i3L expression on the regulation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase pathway. Our results demonstrate that, although ERK activation by mu- and delta-ORs is attenuated by the presence of delta-i3L, ERK activation mediated by alpha2AR remained unaffected. Collectively, our data demonstrate that the delta-i3L can be used as potent inhibitor of G protein signaling for various GPCRs that use a common pool of G proteins.
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MESH Headings
- Calcium/analysis
- Calcium/metabolism
- Cell Line
- Cyclic AMP/antagonists & inhibitors
- Cyclic AMP/biosynthesis
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Proteins/antagonists & inhibitors
- Humans
- Models, Chemical
- Narcotic Antagonists
- Oligopeptides/metabolism
- Oligopeptides/pharmacology
- Phosphatidylinositols/analysis
- Phosphatidylinositols/metabolism
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/chemistry
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, delta/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Evangelia Morou
- Laboratory of Cellular Signaling and Molecular Pharmacology, Institute of Biology, National Center for Scientific Research "Demokritos", 15310 Ag. Paraskevi, Athens, Greece
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Swevers L, Morou E, Balatsos N, Iatrou K, Georgoussi Z. Functional expression of mammalian opioid receptors in insect cells and high-throughput screening platforms for receptor ligand mimetics. Cell Mol Life Sci 2005; 62:919-30. [PMID: 15868413 DOI: 10.1007/s00018-005-4537-1] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lepidopteran cell lines have been engineered to constitutively express high levels of mouse delta opioid receptors either alone or in combination with human Galpha16 protein. Biochemical and pharmacological studies demonstrate that these lines contain all the mediator G proteins and downstream effectors required for opioid receptor function, including phospholipase C, and that expression of exogenous Galpha16 does not contribute significantly to increased receptor responses upon activation. The activation of the phospholipase C pathway in the transformed cells upon stimulation with known receptor ligands results in easily and quantitatively measurable increases in free intracellular calcium, which can be monitored by automated fluorescent methods, while the addition of specific antagonists blocks the agonist-induced responses. Therefore, the transformed lepidopteran cell lines can be used as sensitive high-throughput screening platforms for fast detection of delta opioid receptor ligand mimetics (agonists and antagonists) in collections of natural products and synthetic compounds.
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Affiliation(s)
- L Swevers
- Insect Molecular Genetics and Biotechnology Group, Institute of Biology, National Centre for Scientific Research Demokritos, 153 10 Aghia Paraskevi Attikis, Athens, Greece
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Swevers L, Farrell PJ, Kravariti L, Xenou-Kokoletsi M, Sdralia N, Lioupis A, Morou E, Balatsos NAA, Douris V, Georgoussi Z, Mazomenos B, Iatrou K. Transformed insect cells as high throughput screening tools for the discovery of new bioactive compounds. Commun Agric Appl Biol Sci 2003; 68:333-341. [PMID: 24757768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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