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Amplification of a serine esterase gene is involved in insecticide resistance in Sri Lankan Culex tritaeniorhynchus
Author(s) -
Karunaratne S. H. P. P.,
Vaughan A.,
Paton M. G.,
Hemingway J.
Publication year - 1998
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1046/j.1365-2583.1998.740307.x
Subject(s) - culex tritaeniorhynchus , biology , esterase , culex quinquefasciatus , gene , genetics , population , japanese encephalitis , botany , biochemistry , virus , enzyme , aedes aegypti , encephalitis , demography , sociology , larva
Culex tritaeniorhynchus , the major vector of Japanese encephalitis in Sri Lanka, is resistant to organophosphorus insecticides, with a 10‐fold resistance ratio at the LC 50 for chlorpyrifos, and a high heterogeneity factor in the insect field population. The major mechanism of resistance in this species, as in the mosquito C. quinquefasciatus , is elevation of esterase activity. Basic biochemical, immunological and molecular analysis suggests that the C. tritaeniorhynchus CtrEstβ1 gene is orthologous to the C. quinquefasciatus amplified Est7beta;s . The Estβ2 1 antiserum cross‐reacts strongly with CtrEstβ1 1 . Its corresponding cDNA, over the 545 base pairs sequenced, has ∼84% identity with the various C. quinquefasciatus Estβs . The gene is amplified in C. tritaeniorhynchus . Amplification of the same esterase in two independent species, along with multiple amplification events involving this esterase gene in C. quinquefasciatus suggests that the location of this gene within the genome predisposes it to amplification.