To tackle the problem of insecticide resistance, all resistance mechanisms need to be studied. This study investigated the involvement of the cuticle in pyrethroid resistance in a strain of Anopheles gambiae, MRS, free of kdr mutations. Bioassays revealed MRS to be resistant to pyrethroids and DDT, indicated by increasing knockdown times and resistance ratios. Moreover, biochemical analysis indicated that metabolic resistance based on enhanced CYP450 activity may also play a role. Insecticide penetration assays showed that there were significantly lower amounts of insecticide in the MRS strain than in the susceptible control. Analysis of the levels of the selected transcripts by qPCR showed that CYP6M2, a major pyrethroid metaboliser, CYP4G16, a gene implicated in resistance via its contribution to the biosynthesis of elevated epicuticular hydrocarbons that delay insecticide uptake, and the cuticle genes CPAP3-E and CPLCX1 were upregulated after insecticide exposure. Other metabolic (CYP6P3, GSTe2) and cuticle (CPLCG3, CPRs) genes were also constitutively upregulated. Microscopic analysis showed that the cuticle layers of the MRS strain were significantly thicker than those of the susceptible strain. This study allowed us to assess the contribution made by the cuticle and metabolic mechanisms to pyrethroid resistance in Anopheles gambiae without target-site mutations.
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http://dx.doi.org/10.1038/s41598-017-11357-z | DOI Listing |
Sci Rep
January 2025
Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
The ectoparasitic mite Varroa destructor remains a great threat for the beekeeping industry, for example contributing to excessive winter colony loss in Canada. For decades, beekeepers have sequentially used the registered synthetic varroacides tau-fluvalinate, coumaphos, amitraz, and flumethrin, leading to the risk of resistance evolution in the mites. In addition to the widespread resistance to coumaphos and pyrethroids, a decline in amitraz efficacy has recently been reported in numerous beekeeping regions in Canada.
View Article and Find Full Text PDFPest Manag Sci
January 2025
Unidad Mixta Gestión Biotecnológica de Plagas UV-IVIA, Department of Genetics, Institut de Biotecnologia i Biomedicina, Universitat de València, Valencia, Spain.
Background: The rising demand for environmentally friendly pest control highlights the importance of understanding the interaction between natural enemies and pesticides. Amblyseius swirskii, a predatory mite extensively used in biocontrol, plays a crucial role in managing pest populations in agricultural systems. Integrating this mite with selective pesticide use within integrated pest management (IPM) would significantly advance pest control and may reduce pesticide residues in the environment and agricultural produce.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya 572024, China; School of Tropical Agriculture and Forestry (School of Agricultural and Rural Affairs, School of Rural Revitalization), Hainan University, Danzhou 571700, China. Electronic address:
A voltage-gated sodium channel (VGSC) plays a crucial role in insect electrical signals, and it is a target for various naturally occurring and synthesized neurotoxins, including pyrethroids and dichlorodiphenyltrichloroethane. The type of agent is typically widely used to prevent and control sanitary and agricultural pests. The perennial use of insecticides has caused mutations in VGSCs that have given rise to resistance in most insects.
View Article and Find Full Text PDFPathogens
December 2024
Department of Medical Microbiology, Acibadem University School of Medicine, Istanbul 34752, Türkiye.
Head lice infestation (HLI), caused by De Geer, 1767, has long been a common global problem of school children. Permethrin is an old pyrethroid derivative that has been used commonly for its treatment, and it exerts its activity over the voltage-sensitive calcium channels (VSCC) of the lice. There has been a growing list of persistent HLI cases lately in the world among patients using permethrin, and knockdown resistance (kdr)-related point mutations on VSCC have been identified and reported from those resistant lice samples.
View Article and Find Full Text PDFInsects
November 2024
Department of Entomology, Michigan State University, East Lansing, MI 48824, USA.
This study examines resistance inheritance to the pyrethroid insecticides esfenvalerate and deltamethrin in a Puerto Rican strain of fall armyworm (FAW), , a major global pest of corn. The resistant strain (PPR) showed significantly higher resistance compared to a susceptible strain (SUS), with a 62-fold X-linked and 15-fold autosomal-linked resistance ratio (RR) for esfenvalerate and deltamethrin, respectively. Resistance was incompletely dominant for both insecticides.
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