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Title: Gene structure and expression of a pyrethroid-metabolizing esterase, CzEst9, from a pyrethroid resistant Mexican population of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

Author
item Guerrero, Felicito
item NENE, V - TIGR, ROCKVILLE, MD

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2008
Publication Date: 7/1/2008
Citation: Guerrero, F., Nene, V.M. 2008. Gene structure and expression of a pyrethroid-metabolizing esterase, CzEst9, from a pyrethroid resistant Mexican population of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). Journal of Medical Entomology. 45(4):677-685.

Interpretive Summary: A population of Boophilus microplus, the southern cattle tick, sampled from a ranch near Vera Cruz, Mexico was found to possess a high level of resistance to pyrethroid-based acaricides. Bioassay, biochemical and molecular analysis had previously shown the resistance in this population could primarily be attributed to expression of a highly active protein designated CzEst9. This protein is a member of a family of proteins called metabolic esterases and are important in a number of physiological processes in the tick. One of the roles of esterases involves detoxification or binding of toxic substances, including pesticides. We cloned and sequenced the entire CzEst9 gene coding region, including regions which are thought to be critical to expression of the gene. We compared the DNA sequences from individual resistant and susceptible ticks of several tick populations with different pyrethroid resistance characteristics. The CzEst9 protein was produced in recombinant E. coli and Pichia pastoris yeast systems and esterase activity was obtained in recombinant CzEst9 from the P. pastoris system

Technical Abstract: A population of Rhipicephalus (Boophilus) microplus, designated Coatzacoalcos, sampled from a ranch near Vera Cruz, Mexico was found to possess a high level of resistance to pyrethroid based acaricides. Bioassay, biochemical and molecular analysis had previously shown the resistance in this population could primarily be attributed to expression of a highly active metabolic esterase designated CzEst9. We cloned and sequenced the entire CzEst9 coding region, including introns and over 1.0 kb upstream from the transcription start site, and compared the upstream region sequence between individual resistant and susceptible ticks from several populations with different pyrethroid resistance characteristics.CzEst9 was expressed in recombinant E. coli and Pichia pastoris systems and esterase activity was obtained in recombinant CzEst9 from the P. pastoris system.