title: Age-related pyrethroid resistance is not a function of  P450 gene expression in the major African malaria vector, Anopheles funestus (Diptera: Culicidae).
abstract: Anopheles funestus is a major vector of malaria in most of the African  region. Resistance to pyrethroid and carbamate insecticides has been recorded  in populations of this species in South Africa and Mozambique. The P450 gene, CYP6P9,  has been shown to be highly transcribed in a permethrin (pyrethroid)-resistant  laboratory strain, FUMOZ-R, originating from southern Mozambique. We  examined the relationship between pyrethroid resistance and gene transcription  levels of two closely related genes, CYP6P9 and CYP6P13, in  FUMOZ-R. Levels of resistance to 0.75% permethrin were determined based on  standard WHO insecticide susceptibility assays using females and males of  different ages, ranging from 3 to 30 days old. The transcription levels of the  two genes were quantified using qPCR for each age cohort. In the WHO  insecticide susceptibility assays, survival of both males and females  significantly decreased as age increased. Quantitative analysis of the two  genes CYP6P9 and CYP6P13 showed the highest levels of expression  at 10 days of age. There was no correlation between expression of these two  genes and pyrethroid survival by age. We conclude that the resistance of this  mosquito strain to permethrin is not directly related to age-mediated  differences in CYP6P9 and CYP6P13 expression.
authors.affiliation: Malaria Entomology Research Unit, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: R N
authors.initials: RN
authors.lastname: Christian
authors.forename: T S
authors.initials: TS
authors.lastname: Matambo
authors.forename: B L
authors.initials: BL
authors.lastname: Spillings
authors.forename: B D
authors.initials: BD
authors.lastname: Brooke
authors.forename: M
authors.initials: M
authors.lastname: Coetzee
authors.forename: L L
authors.initials: LL
authors.lastname: Koekemoer
mesh_terms: D000367:Age Factors; D000818:Animals; D000852:Anopheles / Q000201:enzymology / Q000235:genetics*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000032:analysis / Q000096:biosynthesis; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D007303:Insect Vectors / Q000201:enzymology / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides; D008288:Malaria / Q000517:prevention & control / Q000635:transmission; D008297:Male; D009073:Mozambique; D026023:Permethrin; D012313:RNA / Q000096:biosynthesis; D060888:Real-Time Polymerase Chain Reaction; D013019:South Africa
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D007306:Insecticides; D026023:Permethrin; D012313:RNA; D003577:Cytochrome P-450 Enzyme System