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Insecticide resistance characterization in the New World screwworm fly, Cochliomyia hominivorax: molecular and populational approaches

Abstract

Livestock is one of the most important economic activities in Brazil. Nevertheless, animal production has suffered significant losses due to the impact of endo-and ectoparasites on livestock. In this scenario there is the screwworm fly, Cochliomyia hominivorax, which is an important ectoparasite causing primary myiasis endemic in the Americas. In Brazil, this species control is accomplished primarily by insecticides, whose indiscriminate use has led to the selection of resistant individuals. The substitutions called Gly137Asp and Trp251Leu were observed in the active site of the enzyme carboxylesterase E3 and is mainly associated with resistance to diethyl and dimethyl organophosphates insecticides, respectively. With the emergence of resistant screwworm fly individuals, the effectiveness of these chemicals is reduced. Therefore, knowledge of the molecular basis and evolution of resistance as well as the distribution of mutations that are involved in this mechanism may contribute to an efficient management of resistance in natural populations of C. hominivorax. Systemic products such as macrocyclic lactones, activating chloride channel (GluCl±) have been extensively used as prevention and treatment of infestations by C. hominivorax in several parasites, and severe or prolonged use of macrolactones has led to the emergence of resistance to such products. The identification of molecular mechanisms of resistance to macrolactones in other species indicates the occurrence of possible changes in the chloride channel associated with resistance in C. hominivorax. Using sequences of the chloride channel from other species, previously deposited in the database, and sequences obtained in the characterization of the transcriptome of C. hominivorax Carvalho et al. 2010.Faced with these problems, these project aims to: (1) Evaluate the effects of natural selection on esterase E3 gene and the geographic distribution of genetic polymorphisms associated with insecticide resistance in C. hominivorax. Samples from different geographical regions of Brazil, Paraguay, Uruguay and Argentina will be analyzed from the characterization of genetic polymorphisms of the nucleotide sequence of part of the gene carboxylesterase E3. (2) The identification of molecular mechanisms of resistance to macrolactones and possible changes in the chloride channel associated with resistance in C. hominivorax. Using sequences of the chloride channel from other species, previously deposited in the database, and sequences obtained in the characterization of the transcriptome of C. hominivorax Carvalho et al. 2010, the objective of this project is to amplify and sequence the coding region of the chloride channel gene (GluCl±) in C. hominivorax. Furthermore, the sequences will be compared to individuals susceptible and resistant to macrolactones order to interpret(s) mutation(s) that gives resistance to such products and, consequently, the molecular diagnosis of resistance. (AU)

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Scientific publications (4)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FRESIA, PABLO; SILVER, MICHA; MASTRANGELO, THIAGO; DE AZEREDO-ESPIN, ANA MARIA L.; LYRA, MARIANA L.. Applying spatial analysis of genetic and environmental data to predict connection corridors to the New World screwworm populations in South America. Acta Tropica, v. 138, p. 8-pg., . (12/11654-9)
FRESIA, PABLO; SILVER, MICHA; MASTRANGELO, THIAGO; DE AZEREDO-ESPIN, ANA MARIA L.; LYRA, MARIANA L.. Applying spatial analysis of genetic and environmental data to predict connection corridors to the New World screwworm populations in South America. Acta Tropica, v. 138, n. S, SI, p. S34-S41, . (12/11654-9)
PAULO, D. F.; AZEREDO-ESPIN, A. M. L.; CANESIN, L. E. C.; VICENTINI, R.; JUNQUEIRA, A. C. M.. Identification and characterization of microRNAs in the screwworm flies Cochliomyia hominivorax and Cochliomyia macellaria (Diptera: Calliphoridae). Insect Molecular Biology, v. 26, n. 1, p. 46-57, . (12/11654-9, 12/06272-0)

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