title: A survey of mutations in the Cochliomyia hominivorax (Diptera: Calliphoridae) esterase E3 gene associated with organophosphate resistance and the molecular identification of mutant alleles.
abstract: Cochliomyia hominivorax (Calliphoridae) is one of the most important myiasis-causing flies and is responsible for severe economic losses to the livestock industry throughout the Neotropical region. In Brazil, C. hominivorax has been controlled mainly with organophosphate (OP) insecticides, although the inappropriate use of these chemicals can result in the selection of resistant flies. Changes in carboxylesterase activity have been associated with OP insecticides in some arthopodan species. In this work, we isolated and characterized part of the E3 gene in C. hominivorax (ChalphaE7), which contained the same substitutions responsible for the acquisition of OP hydrolase activity in Lucilia cuprina (Calliphoridae). Digestion of the polymerase chain reaction products with a restriction enzyme that specifically recognized the mutation site unambiguously differentiated wild and mutated esterase alleles. The PCR-RFLP assay therefore provided a fast, reliable DNA-based method for identifying C. hominivorax individuals with a mutation in the esterase gene. Further bioassays to determine the association of this mutation with OP resistance in C. hominivorax should allow the development of more effective strategies for managing this species.
authors.affiliation: Laboratório de Genética Animal, Centro de Biologia Molecular e Engenharia Genética (CBMEG), Universidade Estadual de Campinas (UNICAMP), 13083-875 Campinas, SP, Brazil. rassis@unicamp.br
authors.forename: Renato Assis
authors.initials: RA
authors.lastname: de Carvalho
authors.forename: Tatiana Teixeira
authors.initials: TT
authors.lastname: Torres
authors.forename: Ana Maria Lima
authors.initials: AM
authors.lastname: de Azeredo-Espin
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001938:Brazil; D004175:Diptera / Q000201:enzymology*; D004351:Drug Resistance / Q000235:genetics*; D004950:Esterases / Q000737:chemistry / Q000235:genetics*; D005784:Gene Amplification; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping / Q000662:veterinary; D016415:Sequence Alignment
chemical_list: D004950:Esterases