title: Dissecting the insect metabolic machinery using twin ion mass spectrometry: a single P450 enzyme metabolizing the insecticide imidacloprid in vivo.
abstract: Insecticide resistance is one of the most prevalent examples of anthropogenic genetic change, yet our understanding of metabolic-based resistance remains limited by the analytical challenges associated with rapidly tracking the in vivo metabolites of insecticides at nonlethal doses. Here, using twin ion mass spectrometry analysis of the extracts of whole Drosophila larvae and excreta, we show that (i) eight metabolites of the neonicotinoid insecticide, imidacloprid, can be detected when formed by susceptible larval genotypes and (ii) the specific overtranscription of a single gene product, Cyp6g1, associated with the metabolic resistance to neonicotinoids, results in a significant increase in the formation of three imidacloprid metabolites that are formed in C-H bond activation reactions; that is, Cyp6g1 is directly linked to the enhanced metabolism of imidacloprid in vivo. These results establish a rapid and sensitive method for dissecting the metabolic machinery of insects by directly linking single gene products to insecticide metabolism.
authors.affiliation: School of Chemistry, ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , Melbourne, Victoria 3010, Australia.
authors.forename: Kin Kuan
authors.initials: KK
authors.lastname: Hoi
authors.forename: Phillip J
authors.initials: PJ
authors.lastname: Daborn
authors.forename: Paul
authors.initials: P
authors.lastname: Battlay
authors.forename: Charles
authors.initials: C
authors.lastname: Robin
authors.forename: Philip
authors.initials: P
authors.lastname: Batterham
authors.forename: Richard A J
authors.initials: RA
authors.lastname: O'Hair
authors.forename: William A
authors.initials: WA
authors.lastname: Donald
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004331:Drosophila melanogaster; D007093:Imidazoles / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000378:metabolism*
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid; D003577:Cytochrome P-450 Enzyme System