Etude moleculaire de souches de dipteres resistantes aux pyrethrinoides par modification du canal sodium dependant du voltage

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78955 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Les mécanismes responsables de la résistance aux insecticides chez les insectes et les acariens

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The Foraging Gene, a New Environmental Adaptation Player Involved in Xenobiotic Detoxification

International audienceForaging is vital for animals, especially for food. In Drosophila melanogaster, this behavior is controlled by the foraging gene (for) which encodes a cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). In wild populations of Drosophila, rover individuals that exhibit long foraging trails and sitter individuals that exhibit short ones coexist and are characterized by high and low levels of PKG activity, respectively. We, therefore, postulated that rover flies are more exposed to environmental stresses, including xenobiotics contamination, than sitter flies. We then tested whether these flies differed in their ability to cope with xenobiotics by exposing them to insecticides from different chemical families. We performed toxicological tests and measured the activity and expression levels of different classes of detoxification enzymes. We have shown that a link exists between the for gene and certain cytochrome P450-dependent activities and that the expression of the insecticide-metabolizing cytochrome P450 Cyp6a2 is controlled by the for gene. An unsuspected regulatory pathway of P450s expression involving the for gene in Drosophila is revealed and we demonstrate its involvement in adaptation to chemicals in the environment. This work can serve as a basis for reconsidering adaptation to xenobiotics in light of the behavior of species, including humans

Voltage-dependent sodium channels in susceptible and pyrethroid-resistant Drosophila strains

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Cytochrome P450 monooxygenases and insecticide resistance in insects

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Genetic improvment of Trichogramma to pesticide resistance

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Purification and characterization of a carboxylesterase involved in malathion-specific resistance from Tribolium castaneum (Coleoptera: Tenebrionidae)

Specific resistance to malathion in a strain of Tribolium castaneum is due to a 44-fold increase in malathion carboxylesterase (MCE) activity relative to a susceptible strain, whereas non-specific esterase levels are slightly lower. Unlike the overproduced esterase of some mosquito and aphid species, MCE in Tribolium castaneum accounts for only a small fraction (0.033-0.045%) of the total extractable protein respectively in resistant and susceptible strains. The enzyme was purified to apparent homogeneity from these two strains and has a similar molecular weight of 62,000. However, preparative isoelectricfocusing indicated that resistant insects possess one MCE with pI of 7.3, while susceptible insects possess a MCE with a pI of 6.6. Purified MCE from both populations had different Km and Vm values for hydrolysis of malathion as well as for α-naphthyl acetate. The kinetic analysis suggests that MCE of resistant insects hydrolyses malathion faster than the purified carboxylesterase from susceptible beetles and that this enzyme has greater affinity for malathion than for naphthyl esters. Malathion-specific resistance is due to the presence of a qualitatively different esterase in the resistant strain

Identification and in-situ localization of subunit of voltage-sensitive sodium channels from Drosophila using polyclonal antibodies

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Cloning and expression of cytochrome P450 genes belonging to the CYP4 family and to a novel family, CYP48, in two Hymenopteran insects, Trichogramma cacoeciae and Apis melifera

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Effects of sorption and biodegradation on toxicity of parathion and paraoxon to nematodes : experiments and modeling

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