Larvicidal activity of mosquito sterol carrier protein-2 inhibitors to the insecticide-resistant mosquito Culex quinquefasciatus (Diptera: Culicidae).
AeSCP-2 inhibitors (SCPIs) compete with cholesterol for binding to a mosquito sterol carrier protein-2 (AeSCP-2) known to aid in the uptake of cholesterol in mosquito cells. The larvicidal activities of AeSCP-2 inhibitor-1 (SCPI-1) and inhibitor-2 (SCPI-2) against Culex quinquefasciatus Say (Diptera: Culicidae) were therefore examined in insecticide-resistant Culex mosquitoes HAmCq(G9), MAmCq(G2), and BAmCq(G0). All of the resistant Culex mosquito strains exhibited similar sensitivity to SCPI-1 and SCPI-2 inhibitors compared with a susceptible S-Lab strain. When an AeSCP-2 inhibitor was applied simultaneously with permethrin, the toxicity of permethrin to the second-instar larvae of all four strains of Culex mosquitoes increased, suggesting a synergistic effect of AeSCP-2 inhibitors on the toxicity of permethrin against Culex mosquitoes. Both SCPI-1 and SCPI-2 inhibitors caused a 2.4- to 3-fold reduction in the level of permethrin resistance in the highly resistant strain HAmCq(G9). This result suggests that the mode of action of the AeSCP-2 inhibitors, which reduces the uptake of cholesterol by inhibiting the function of AeSCP-2 in mosquito cells, may interfere with the mechanisms or ability that govern permethrin resistance in the HAmCq(G9) mosquito strain.
Li
Ting
T
Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
Lan
Que
Q
Liu
Nannan
N
D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D003465:Culex / Q000254:growth & development* / Q000378:metabolism; D004357:Drug Synergism; D019476:Insect Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007305:Insecticide Resistance; D007306:Insecticides; D007814:Larva / Q000378:metabolism; D026023:Permethrin
D002352:Carrier Proteins; D019476:Insect Proteins; D007306:Insecticides; C072087:sterol carrier proteins; D026023:Permethrin; D002784:Cholesterol