scholarly journals Insecticide resistance in Anopheles arabiensis populations from Dakar and its suburbs: role of target site and metabolic resistance mechanisms

2018 ◽  
Vol 17 (1) ◽  
Author(s):  
A. Kane Dia ◽  
O. Kalsom Guèye ◽  
E. Amadou Niang ◽  
S. Mocote Diédhiou ◽  
M. Demba Sy ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Arabiensis ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Metabolic Resistance

scholarly journals Genome-wide gene expression profiling reveals that cuticle alterations and P450 detoxification are associated with pyrethroid resistance in Anopheles arabiensis populations from Ethiopia

2018 ◽  
Author(s):  
Eba Alemayehu Simma ◽  
Wannes Dermauw ◽  
Vasileia Balabanidou ◽  
Simon Snoeck ◽  
Astrid Bryon ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Arabiensis ◽  
Pyrethroid Resistance ◽  
Resistance Mutation ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Malaria Vectors ◽  
Metabolic Resistance ◽  
Genome Wide ◽  
Target Site Resistance

AbstractBACKGROUNDVector control is the main intervention in malaria control and elimination strategies. However, the development of insecticide resistance is one of the major challenges for controlling malaria vectors. Anopheles arabiensis populations in Ethiopia showed resistance against both DDT and the pyrethroid deltamethrin. Although a L1014F target-site resistance mutation was present in the voltage gated sodium channel of investigated populations, the levels of resistance and biochemical studies indicated the presence of additional resistance mechanisms. In this study, we used genome-wide transcriptome profiling by RNAseq to assess differentially expressed genes between three deltamethrin and DDT resistant An. arabiensis field populations (Tolay, Asendabo, Chewaka) and two susceptible strains (Sekoru and Mozambique).RESULTSBoth RNAseq analysis and RT-qPCR showed that a glutathione-S-transferase, gstd3, and a cytochrome P450 monooxygenase, cyp6p4, were significantly overexpressed in the group of resistant populations compared to the susceptible strains, suggesting that the enzymes they encode play a key role in metabolic resistance against deltamethrin or DDT. Furthermore, a gene ontology enrichment analysis showed that expression changes of cuticle related genes were strongly associated with insecticide resistance, although this did not translate in increased thickness of the procuticle.CONCLUSIONOur transcriptome sequencing of deltamethrin/DDT resistant An. arabiensis populations from Ethiopia suggests non-target site resistance mechanisms and pave the way for further investigation of the role of cuticle composition in resistance.

scholarly journals Insecticide resistance selection and reversal in two strains of Aedes aegypti

2020 ◽  
Vol 5 ◽  
pp. 183
Author(s):  
Jonathan Thornton ◽  
Bruno Gomes ◽  
Constância Ayres ◽  
Lisa Reimer
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Competence ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Metabolic Resistance ◽  
Resistance Selection ◽  
Similar Phenotype ◽  
Target Site Resistance ◽  
Homozygous Resistant

Background: Laboratory reared mosquito colonies are essential tools to understand insecticide action. However, they differ considerably from wild populations and from each other depending on their origin and rearing conditions, which makes studying the effects of specific resistance mechanisms difficult. This paper describes our methods for establishing multiple resistant strains of Aedes aegypti from two colonies as a new resource for further research on metabolic and target site resistance. Methods: Two resistant colonies of Ae. aegypti, from Cayman and Recife, were selected through 10 generations of exposure to insecticides including permethrin, malathion and temephos, to yield eight strains with different profiles of resistance due to either target site or metabolic resistance. Resistance ratios for each insecticide were calculated for the selected and unselected strains. The frequency of kdr alleles in the Cayman strains was determined using TaqMan assays. A comparative gene expression analysis among Recife strains was conducted using qPCR in larvae (CCae3A, CYP6N12, CYP6F3, CYP9M9) and adults (CCae3A, CYP6N12, CYP6BB2, CYP9J28a). Results: In the selected strain of Cayman, mortality against permethrin reduced almost to 0% and kdr became fixated by 5 generations. A similar phenotype was seen in the unselected homozygous resistant colony, whilst mortality in the susceptible homozygous colony rose to 82.9%. The Recife strains showed different responses between exposure to adulticide and larvicide, with detoxification genes in the temephos selected strain staying similar to the baseline, but a reduction in detoxification genes displayed in the other strains. Conclusions: These selected strains, with a range of insecticide resistance phenotypes and genotypes, will support further research on the effects of target-site and/or metabolic resistance mechanisms on various life-history traits, behaviours and vector competence of this important arbovirus vector.

scholarly journals Insecticide Resistance Profiling of Anopheles coluzzii and Anopheles gambiae Populations in the Southern Senegal: Role of Target Sites and Metabolic Resistance Mechanisms

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1403
Author(s):  
Oumou. K. Gueye ◽  
Magellan Tchouakui ◽  
Abdoulaye K. Dia ◽  
Mouhamed B. Faye ◽  
Amblat A. Ahmed ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Anopheles Gambiae ◽  
Resistance Mechanisms ◽  
Target Site ◽  
World Health ◽  
Anopheles Coluzzii ◽  
Partial Recovery ◽  
Metabolic Resistance ◽  
Genes Expression ◽  
Main Target

The emergence and spread of insecticide resistance among the main malaria vectors is threatening the effectiveness of vector control interventions in Senegal. The main drivers of this resistance in the Anopheles gambiae complex (e.g., An. gambiae and Anopheles coluzzii) remains poorly characterized in Senegal. Here we characterized the main target site and metabolic resistances mechanisms among the An. gambiae and An. coluzzii populations from their sympatric and allopatric or predominance area in Senegal. Larvae and pupae of An. gambiae s.l. were collected, reared to adulthood, and then used for insecticides susceptibility and synergist assays using the WHO (World Health Organisation) test kits for adult mosquitoes. The TaqMan method was used for the molecular characterization of the main target site insecticide resistance mechanisms (Vgsc-1014F, Vgsc-1014S, N1575Y and G119S). A RT-qPCR (Reverse Transcriptase-quantitative Polymerase Chaine Reaction) was performed to estimate the level of genes expression belonging to the CYP450 (Cytochrome P450) family. Plasmodium infection rate was investigated using TaqMan method. High levels of resistance to pyrethroids and DDT and full susceptibility to organophosphates and carbamates where observed in all three sites, excepted a probable resistance to bendiocarb in Kedougou. The L1014F, L1014S, and N1575Y mutations were found in both species. Pre-exposure to the PBO (Piperonyl butoxide) synergist induced a partial recovery of susceptibility to permethrin and full recovery to deltamethrin. Subsequent analysis of the level of genes expression, revealed that the CYP6Z1 and CYP6Z2 genes were over-expressed in wild-resistant mosquitoes compared to the reference susceptible strain (Kisumu), suggesting that both the metabolic resistance and target site mutation involving kdr mutations are likely implicated in this pyrethroid resistance. The presence of both target-site and metabolic resistance mechanisms in highly pyrethroid-resistant populations of An. gambiae s.l. from Senegal threatens the effectiveness and the sustainability of the pyrethroid-based tools and interventions currently deployed in the country. The Kdr-west mutation is widely widespread in An. coluzzii sympatric population. PBO or Duo nets and IRS (Indoor Residual Spraying) with organophosphates could be used as an alternative measure to sustain malaria control in the study area.

scholarly journals Insecticide resistance selection and reversal in two strains of Aedes aegypti

2020 ◽  
Vol 5 ◽  
pp. 183
Author(s):  
Jonathan Thornton ◽  
Bruno Gomes ◽  
Constância Ayres ◽  
Lisa Reimer
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Vector Competence ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Metabolic Resistance ◽  
Resistance Selection ◽  
Similar Phenotype ◽  
Target Site Resistance ◽  
Homozygous Resistant

Background: Laboratory reared mosquito colonies are essential tools to understand insecticide action. However, they differ considerably from wild populations and from each other depending on their origin and rearing conditions, which makes studying the effects of specific resistance mechanisms difficult. This paper describes our methods for establishing multiple resistant strains of Aedes aegypti from two colonies as a new resource for further research on metabolic and target site resistance. Methods: Two resistant colonies of Ae. aegypti, from Cayman and Recife, were selected through 10 generations of exposure to insecticides including permethrin, malathion and temephos, to yield eight strains with different profiles of resistance due to either target site or metabolic resistance. Resistance ratios for each insecticide were calculated for the selected and unselected strains. The frequency of kdr alleles (F1534C and V1016I) in the Cayman strains was determined using TaqMan assays. A comparative gene expression analysis among Recife strains was conducted using qPCR in larvae (CCae3A, CYP6N12, CYP6F3, CYP9M9) and adults (CCae3A, CYP6N12, CYP6BB2, CYP9J28a). Results: In the selected strain of Cayman, mortality against permethrin reduced almost to 0% and kdr became fixated by 5 generations. A similar phenotype was seen in the unselected homozygous resistant colony, whilst mortality in the susceptible homozygous colony rose to 82.9%. The Recife strains showed different responses between exposure to adulticide and larvicide, with detoxification genes in the temephos selected strain staying similar to the baseline, but a reduction in detoxification genes displayed in the other strains. Conclusions: These selected strains, with a range of insecticide resistance phenotypes and genotypes, will support further research on the effects of target-site and/or metabolic resistance mechanisms on various life-history traits, behaviours and vector competence of this important arbovirus vector.

scholarly journals Transcriptomic analysis of insecticide resistance in the lymphatic filariasis vectorCulex quinquefasciatus

2019 ◽  
Author(s):  
Walter Fabricio Silva Martins ◽  
Craig Stephen Wilding ◽  
Alison Taylor Isaacs ◽  
Emily Joy Rippon ◽  
Karine Megy ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Lymphatic Filariasis ◽  
Fold Increase ◽  
Target Site ◽  
Detoxification Enzymes ◽  
Site Mutation ◽  
Public Health Importance ◽  
Metabolic Resistance ◽  
Vector Borne Diseases ◽  
Bendiocarb Resistance

ABSTRACTCulex quinquefasciatusplays an important role in transmission of vector-borne diseases of public health importance, including lymphatic filariasis (LF), as well as many arboviral diseases. Currently, efforts to tackleC. quinquefasciatusvectored diseases are based on either mass drug administration (MDA) for LF, or insecticide-based interventions. Widespread and intensive insecticide usage has resulted in increased resistance in mosquito vectors, includingC. quinquefasciatus. Herein, the transcriptome profile of Ugandan bendiocarb-resistantC. quinquefasciatuswas explored to identify candidate genes associated with insecticide resistance. Resistance to bendiocarb in exposed mosquitoes was marked, with 2.04% mortality following 1h exposure and 58.02% after 4h. Genotyping of the G119SAce-1target site mutation detected a highly significant association (p<0.0001; OR=25) between resistance andAce1-119S. However, synergist assays using the P450 inhibitor PBO or the esterase inhibitor TPP resulted in markedly increased mortality (to ≈80%), suggesting a role of metabolic resistance in the resistance phenotype. Using a novel, custom 60K whole-transcriptome microarray 16 genes significantly overexpressed in resistant mosquitoes were detected, with the P450Cyp6z18showing the highest differential gene expression (>8-fold increase vs unexposed controls). These results provide evidence that bendiocarb-resistance in UgandanC. quinquefasciatusis mediated by both target-site mechanisms and over-expression of detoxification enzymes.

Genetic linkage between malathion and dieldrin resistance in Anopheles arabiensis

1984 ◽  
Vol 26 (6) ◽  
pp. 646-650 ◽  
Author(s):  
J. D. Lines ◽  
C. F. Curtis
Keyword(s):  
Linkage Disequilibrium ◽  
Insecticide Resistance ◽  
Resistance Genes ◽  
Recombination Rate ◽  
Genetic Linkage ◽  
Anopheles Arabiensis ◽  
Backcross Progeny ◽  
Resistance Mechanisms ◽  
Susceptible Strain ◽  
Insecticide Exposure

A strain of Anopheles arabiensis resistant to both malathion and dieldrin was crossed and backcrossed to a susceptible strain. The progeny were tested on each insecticide in turn. Less than 50% mortality in the second insecticide exposure among the backcross progeny indicated linkage between the resistance genes. In a backcross of A. gambiae × A. arabiensis hybrids a recombination rate of 7.5% was observed. A Y-translocation strain of A. arabiensis showed less than 2.8% recombination between the resistance genes. It is impossible to confirm the genotype of apparent recombinants using existing stocks, but the two resistance mechanisms are biochemically distinguishable. If the two genes are very closely linked, linkage disequilibrium could influence the consequences of switching to malathion spraying after dieldrin resistance has evolved.Key words: Anopheles, linkage, insecticide resistance, translocation.

Aerobic Metabolism Alterations as an Evidence of Underlying Deltamethrin Resistance Mechanisms in Triatoma infestans (Hemiptera: Reduviidae)

2020 ◽  
Vol 57 (6) ◽  
pp. 1988-1991
Author(s):  
Carmen Rolandi ◽  
Gonzalo Roca-Acevedo ◽  
Pablo E Schilman ◽  
Mónica D Germano
Keyword(s):  
Resistance Mechanism ◽  
Resistance Management ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Triatoma Infestans ◽  
Co2 Production ◽  
Mechanisms Of Resistance ◽  
Metabolic Resistance ◽  
Open Flow ◽  
Deltamethrin Resistance

Abstract Triatoma infestans (Klug, 1834), the main vector of Chagas disease in Latin America, is regularly controlled by spraying the pyrethroid deltamethrin, to which some populations have developed resistance. The three main mechanisms of resistance are 1) metabolic resistance by overexpression or increased activity of detoxifying enzymes, 2) target site mutations, and 3) cuticle thickening/modification. We use open-flow respirometry to measure real-time H2O loss rate (V˙H2O) and CO2 production rate (V˙CO2), on nymphs from susceptible and resistant populations before and after exposure to the insecticide to understand the underlying mechanisms of resistance in live insects. Lack of differences in V˙H2O between populations suggested that cuticular thickness/composition is not acting as a relevant resistance mechanism. Similarly, there was no difference in resting V˙CO2, suggesting a trade-off between resistance mechanisms and other physiological processes. The increment in V˙CO2 after application of deltamethrin was similar in both populations, which suggested that while enhanced enzymatic detoxification may play a role in resistance expression in this population, the main mechanism involved should be a passive one such as target site mutations. Open-flow respirometry provided useful evidence for evaluating the mechanisms involved in deltamethrin resistance. Using this technique could improve efficiency of scientific research in the area of insecticide resistance management, leading to a faster decision making and hence improved control results.

scholarly journals A Scaffold-Level Genome Assembly of the Pirate Bug, Orius Laevigatus, and a Comparative Analysis of Insecticide Resistance-Related Gene Families with Hemipteran Crop Pests

2021 ◽  
Author(s):  
Emma Bailey ◽  
Linda Field ◽  
Christopher Rawlings ◽  
Rob King ◽  
Fady Mohareb ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Genome Assembly ◽  
Hybrid Approach ◽  
Gene Families ◽  
Resistance Mechanisms ◽  
Target Site ◽  
Genomic Information ◽  
Orius Laevigatus ◽  
Crop Pests ◽  
Comparative Analyses

Abstract Background: The pirate bug, Orius laevigatus, is a highly effective beneficial predator of crop pests including aphids, spider mites and thrips in integrated pest management (IPM) programmes. No genomic information is currently available for O. laevigatus, as is the case for the majority of beneficial predators which feed on crop pests. In contrast, genomic information for crop pests is far more readily available. The lack of publicly available genomes for beneficial predators to date has limited our ability to perform comparative analyses of genes encoding potential insecticide resistance mechanisms between crop pests and their predators. These mechanisms include several gene/protein families including cytochrome P450s (P450s), ATP binding cassette transporters (ABCs), glutathione S-transferases (GSTs), UDP-glucosyltransferases (UGTs) and carboxyl/cholinesterases (CCEs).Methods and findings: In this study, a high-quality scaffold level de novo genome assembly for O. laevigatus has been generated using a hybrid approach with PacBio long-read and Illumina short-read data. The final assembly achieved a scaffold N50 of 125,649bp and a total genome size of 150.98Mb. The genome assembly achieved a level of completeness of 93.6% using a set of 1,658 core insect genes present as full-length genes. The assembly was annotated with 15,102 protein-coding genes - 87% of which were assigned a putative function - and the resultant gene set achieved a completeness of 84.5%. Comparative analyses revealed gene expansions of sigma class GSTs and CYP3 P450s. Conversely the UGT gene family showed limited expansion. Differences were seen in the distributions of resistance-associated gene families at the subfamily level between O. laevigatus and some of its targeted crop pests. A target site mutation in ryanodine receptors (I4790M, PxRyR) which has strong links to diamide resistance in crop pests and had previously only been identified in lepidopteran species was found to also be present in hemipteran species, including O. laevigatus. Conclusion and significance: This assembly is the first published genome for the Anthocoridae family and will serve as a useful resource for further research into target-site selectivity issues and potential resistance mechanisms in beneficial predators. Furthermore, the expansion of gene families often linked to insecticide resistance may be an indicator of the capacity of this predator to detoxify selective insecticides. These findings could be exploited by targeted pesticide screens and functional studies to increase effectiveness of IPM strategies, which aim to increase crop yields by effectively controlling pests in a sustainable and environmentally-friendly manner, without impacting beneficial predator populations.

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