Cytochrome P450 monooxygenases (P450s) are enzymes known to metabolize a wide variety of compounds including insecticides. Their overexpression leading to enhanced insecticide detoxification could result in insecticide resistance in insects. The increased mRNA expression of two P450 genes, CYP6P7 and CYP6AA3, has been previously observed in laboratory-selected deltamethrin-resistant Ano...

Worldwide, increasing numbers of insects have evolved resistance to a wide range of pesticides, which hampers their control in the field and, therefore, threatens agriculture. Members of the carboxylesterase and cytochrome P450 monooxygenase superfamilies are prominent candidates to confer metabolic resistance to pyrethroid insecticides. Both carboxylesterases and P450 enzymes have been shown t...

Background: Pyrethroid resistance in Anopheles funestus populations has led to an increase in malaria transmission in southern Africa. Resistance has been attributed to elevated activities of cytochrome P450s but the molecular basis underlying this metabolic resistance is unknown. Microsatellite and SNP markers were used to construct a linkage map and to detect a quantitative trait locus (QTL) ...

Pesticides are constantly being applied to agricultural catchments, but little is known about their impact on aquatic biota during natural exposure. In the present study, the impact of the pyrethroid lambda-cyhalothrin was studied in an in-stream mesocosm setup. Twice during the summer of 2002, the natural macroinvertebrate community was exposed in situ to a 30-min pulse of lambda-cyhalothrin. ...

This work was undertaken to determine the pre-harvest interval of bifenthrin and to minimize its residues in pulses and thereby ensure consumer safety and avoid non-compliance in terms of residues violations in export market. Furthermore the residue dynamics in the soil under pulses was explored to assess the environmental safety. The residues of bifenthrin dissipated following first order kine...

Pyrethroid insecticides alter the normal gating of voltage-gated sodium channels in the nervous system. Three sodium channel mutations (E434K, C764R, L993F) were recently identified in pyrethroid resistant German cockroach populations. In this report, we show that the L993F mutation decreased sodium channel sensitivity to the pyrethroid, deltamethrin, by five-fold in Xenopus oocytes. In contras...

A number of preventive measures for the protection of humans against tick-borne diseases were evaluated. Measures involving the avoidance of tick bites with the use of protective clothing and insect repellents are the simplest and most effective. Repellents are applied directly to the skin or clothing and other fabrics, such as bednets, tents and anti-mosquito screens. Currently, DEET (N,N-diet...

Pyrethroid insecticides widely used in forestry, agricultural, industrial, and residential applications have potential for human exposure. Short sample preparation time and sensitive, economical high-throughput assays are needed for biomonitoring studies that analyze a large number of samples. An enzyme-linked immunosorbent assay (ELISA) was used for determining 3-phenoxybenzoic acid (3-PBA), a...

Insecticides are widely used to control pests in agriculture and insect vectors that transmit human diseases. However, these chemicals can have a negative effect on nontarget, beneficial organisms including bees. Discovery and deployment of selective insecticides is a major mission of modern toxicology and pest management. Pyrethroids exert their toxic action by acting on insect voltage-gated s...

The horn fly, Haematobia irritans L., is an obligate blood-feeding fly and the primary insect pest parasitizing cattle in the United States. Pesticide resistance has become a substantial problem for cattle producers, and although several mechanisms of resistance are possible, target site resistance is the most important mechanism preventing control of this fly in the United States and possibly ...