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ABSTRACT:
PROVIDER: PRJNA702915 | ENA |
REPOSITORIES: ENA
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Project description:Mosquitoes host and pass on to humans a variety of disease-causing pathogens such as infectious viruses and other parasitic microorganisms. The emergence and spread of insecticide resistance is threatening the effectiveness of current control measures for common mosquito vector borne diseases, such as malaria, dengue and Zika. Therefore, the emerging resistance to the widely used pyrethroid insecticides is an alarming problem for public health. Among the new approaches implemented for pest control, one of the most promising is RNA interference (RNAi). The aim of this study was to provide a feasible RNAi solution that can be applied on wild pyrethroid resistant mosquito populations in the near future. To achieve this, high dsRNA efficacy at economic quantities is required. It is recognized that the sodium channel transcript variability governs its functional diversity including the emergence of insecticide resistance. Therefore, to maximize the RNAi effect, we tiled a number of overlapping dsRNA constructs that together target about half of the voltage-gated sodium channel (VGSC) transcript variants annotated in this work. This strategy provided a refined dsRNA trigger that increased mortality with a three-fold decrease in dsRNA amounts compared to the primary VGSC dsRNA construct. Thus, we demonstrated the use of RNA interference (RNAi) to increase susceptibility of adult mosquitoes to a widely used pyrethroid insecticide.
2016-07-06 | GSE84030 | GEO
Project description:Mosquitoes host and pass on to humans a variety of disease-causing pathogens such as infectious viruses and other parasitic microorganisms. The emergence and spread of insecticide resistance is threatening the effectiveness of current control measures for common mosquito vector borne diseases, such as malaria, dengue and Zika. Therefore, the emerging resistance to the widely used pyrethroid insecticides is an alarming problem for public health. Among the new approaches implemented for pest control, one of the most promising is RNA interference (RNAi). The aim of this study was to provide a feasible RNAi solution that can be applied on wild pyrethroid resistant mosquito populations in the near future. To achieve this, high dsRNA efficacy at economic quantities is required. It is recognized that the sodium channel transcript variability governs its functional diversity including the emergence of insecticide resistance. Therefore, to maximize the RNAi effect, we tiled a number of overlapping dsRNA constructs that together target about half of the voltage-gated sodium channel (VGSC) transcript variants annotated in this work. This strategy provided a refined dsRNA trigger that increased mortality with a three-fold decrease in dsRNA amounts compared to the primary VGSC dsRNA construct. Thus, we demonstrated the use of RNA interference (RNAi) to increase susceptibility of adult mosquitoes to a widely used pyrethroid insecticide. Small RNA sequences from 5 mosquitoes treated with Random or VGSC dsRNAs were generated using Illumina HiSeq 2500.
2016-07-06 | E-GEOD-84030 | biostudies-arrayexpress
Project description:Custom microarrays were used to examine differential gene expression between pyrethroid resistant vs pyrethroid susceptible phenotypes of the dengue vector mosquito Aedes aegypti. Pyrethroid resistant population were from Cayenne (French Guiana, GUY), Baie Mahault (Guadeloupe, GUA) and Noumea (New Caledonia, CAL) whilst New Orleans lab colony represented the lab susceptible strain Pools of total RNA was extracted from the whole bodies of 3 day old female mosquitoes that had survived exposure to 0.06% deltamethrin (for GUY, GUA, CAL) . Single colour hybridization experiments were performed using labelled cDNA on the Agilent 'Aedes aegypti detox chip plus': A-MTAB-574. Four unique biological replicates per population were used in the study
2015-11-08 | E-MTAB-4022 | biostudies-arrayexpress
Project description:Resistance to chemical insecticides including pyrethroids, the main insecticide class used against mosquitoes, led to a regain of interest for neonicotinoids. In this context, the present study aims at characterizing the molecular basis of neonicotinoid resistance in the mosquito Aedes aegypti. Resistance mechanisms were studied by combining transcriptomic and genomic data obtained from a laboratory strain selected at the larval stage for 30 generations with imidacloprid (Imida-R line). After thirty generations of selection, larvae of Imida-R line showed a 8-fold increased resistance to imidacloprid and a significant cross-tolerance to the pyrethroids permethrin and deltamethrin. Cross-resistance to pyrethroids was only observed in adults when larvae were previously exposed to imidacloprid suggesting a low but inducible expression of resistance alleles at the adult stage. Resistance of the Imida-R line was associated with a slower larval development time in females. Multiple detoxification enzymes were over-transcribed in larvae in association with resistance including the P450s CYP6BB2, CYP9M9 and CYP6M11 previously associated with pyrethroid resistance. Some of them together with their redox partner NADPH P450 reductase were also affected by non-synonymous mutations associated with resistance. Combining genomic and transcriptomic data allowed identifying promoter variations associated with the up-regulation of CYP6BB2 in the resistant line. Overall, these data confirm the key role of P450s in neonicotinoid resistance in Ae. aegypti and their potential to confer cross-resistance to pyrethroids, raising concerns about the use of neonicotinoids for resistance management in this mosquito species.
2021-05-07 | GSE174009 | GEO
Project description:In the current study we examined the speed of resistance development in the silverleaf whitefly, Bemisia tabaci, after selection with either a neonicotinoid (thiacloprid) or pyrethroid (alpha-cypermethrin) insecticide alone or in combination with PBO. We used one control sample with no selection, 2 samples for neonicotinoid (thiacloprid) and Pyrethroid treatment and 2 samples for neonicotinoid (thiacloprid) + PBO and Pyrethroid + PBO treatments. The findings of this study demonstrate that PBO used in combination with certain insecticides can suppress the development of resistance in a laboratory setting.
2016-05-02 | E-MTAB-4601 | biostudies-arrayexpress
Project description:Aedes aegypti SP strain vs. SMK strain. Aedes aegypti is the major vector of yellow fever and dengue/dengue hemorrhagic fever. Starting with a population collected from Singapore, we established a pyrethroid-resistant A. aegypti strain (SP) and investigated three major possible mechanisms of insecticide resistance. After 10 generations of adult selection, an A. aegypti strain developed 1650-fold resistance to permethrin, which is one of the most widely used pyrethroid insecticides for mosquito control. SP larvae also developed 8790-fold resistance following selection of the adults. Prior to the selections, the frequencies of V1016G and F1534C mutations in domains II and III, respectively, of voltage-sensitive sodium channel genes (Vssc) were 0.44 and 0.56, respectively. In contrast, only G1016 alleles were present after two permethrin selections, indicating that G1016 can contribute more to the insensitivity of Vssc than C1534. In vivo metabolism studies showed that the SP strain excreted permethrin metabolites more rapidly than the susceptible SMK strain. Pretreatment with piperonyl butoxide caused strong inhibition of excretion of permethrin metabolites, suggesting that cytochrome P450 monooxygenases (P450s) play an important role in resistance development. In vitro metabolism studies also indicated an association of P450s with resistance. Microarray analysis showed that multiple P450 genes were over-expressed during the larval and adult stages in the SP strain. Following quantitative real time PCR, we focused on two P450 isoforms, CYP9M6 and CYP6BB2, and confirmed that they were capable of detoxifying permethrin to 4'-HO-permethrin. Over-expression of CYP9M6 was partially due to gene amplification. Association analysis demonstrated that CYP9M6 and CYP6BB2 complementarily conferred permethrin resistance. Two other P450s (CYP9J26 and CYP9J28), which are capable of metabolizing permethrin, were also over-expressed in the SP strain, indicating that at least four P450 isoforms are likely involved in resistance development. Our data show that it is unlikely that reduced cuticle penetration of permethrin contributes to resistance. One-color experiment with two strains (SP, SMK) and 3 developmental stages/genders (larvae, adult males, and adult females), 4 biological replicates each.
2014-01-01 | E-GEOD-50069 | biostudies-arrayexpress
Project description:Α reduction of pyrethroid efficacy has been recently recorded in the olive fruit fly Bactrocera oleae, the most destructive insect pest of olives worldwide. We analyzed the transcriptomic differences between two highly pyrethroid resistant populations versus a relatively susceptible field population and two laboratory strains to gain more insight into the molecular mechanism of resistance. A large number of genes was found to be significantly differentially transcribed across the pairwise comparisons between resistant and susceptible insect populations. Interestingly, gene set analysis revealed that genes of the ‘electron carrier activity’ GO group were enriched in one specific pairwise transcriptomic comparison. As P450 monooxygenase enzymes are typically associated with this Molecular Function GO-group, this might reflect a P450-mediated resistance mechanism. These results suggest that transcriptional induction of the CYP6 P450s might be an important mechanism of pyrethroid resistance in B. oleae and pave the way for the development of synergists and molecular diagnostics for insecticide resistance management.
2018-05-12 | GSE112178 | GEO