Mechanisms of resistance to malathion in the medfly Ceratitis capitata.

Target site insensitivity and metabolic resistance mediated by esterases have been previously suggested to be involved in resistance to malathion in a field-derived strain (W) of Ceratitis capitata. In the present study, we have obtained the coding sequence for acetylcholinesterase (AChE) gene (Ccace) of C. capitata.

Point mutations associated with insecticide resistance in the Drosophila cytochrome P450 Cyp6a2 enable DDT metabolism.

Three point mutations R335S, L336V and V476L, distinguish the sequence of a cytochrome P450 CYP6A2 variant assumed to be responsible for 1,1,1-trichloro-2,2-bis-(4'-chlorophenyl)ethane (DDT) resistance in the RDDT(R) strain of Drosophila melanogaster. To determine the impact of each mutation on the function of CYP6A2, the wild-type enzyme (CYP6A2wt) of Cyp6a2 was expressed in Escherichia coli as well as three variants carrying a single mutation, the double mutant CYP6A2vSV and the triple mutant CYP6A2vSVL. All CYP6A2 variants were less stable than the CYP6A2wt protein.

Larvicidal properties of decomposed leaf litter in the subalpine mosquito breeding sites.

The larvicidal properties of the dietary leaf litter originating from the vegetation surrounding the subalpine mosquito breeding sites were investigated by using 10-month decomposed alder leaf litter against different field collections of culicine taxa of various ecological origin (Aedes cantans, Aedes caspius, Aedes cataphylla, Aedes detritus, Aedes punctor, Aedes pullatus, Aedes rusticus, Anopheles claviger, Culex hortensis, Culex pipiens, Culiseta morsitans). Larvae originating from sites with polyphenol-poor vegetation appeared more sensitive to ingested leaf litter than those originating from sites with polyphenol-rich vegetation. Within a given taxon (e.