Induction of cytochrome P450 activities in Drosophila melanogaster strains susceptible or resistant to insecticides

Regulation of an insect cytochrome P450 monooxygenase gene (CYP6B1) by aryl hydrocarbon and xanthotoxin response cascades

“…Caterpillars were reared on flat-leaf parsley (Petroselinum sativum) in a greenhouse (16:8 h L/D, 25 -C, 70% relative humidity). Actively feeding fifth instars were fed 0.7 g parsley topically treated with acetone (control diet), 48 mM xanthotoxin in acetone (for a final concentration of 0.25% xanthotoxin/g fresh weight parsley) or 0.2 nM benzo[a]pyrene in acetone (for a final concentration of 0.00125% benzo[a]pyrene/g fresh weight parsley) for 24 or 48 h. This concentration of xanthotoxin is within the range found in common hostplants of P. polyxenes (Cohen et al, 1989;Duke, 1992;Zangerl and Rutledge, 1996) and that of benzo[a]pyrene is within the range fed to D. melanogaster fruit flies in similar experiments (Amichot et al, 1998). Caterpillars were dissected as in Petersen et al (2001).…”

“…One point potentially explaining the inability of orally administered benzo[a]pyrene to induce CYP6B1 transcription in larvae is the fact that the CYP6B1 protein, which is constitutively expressed at a significant level in insect midguts, actually metabolizes discernible levels of aryl hydrocarbons such as a-naphthoflavone and flavone (Wen et al, 2005). In other insects, treatment with similar concentrations of benzo[a]pyrene induced ethoxyresorufin O-deethylation in D. melanogaster flies (Amichot et al, 1998) and treatment with 0.2% wt./vol. of the aryl hydrocarbons pentamethylbenzene and naphthalene induced benzo[a]pyrene hydroxylation in Spodoptera eridania (southern armyworm) larval midguts (Chang et al, 1983).…”

A comparison of Drosophila melanogaster detoxification gene induction responses for six insecticides, caffeine and phenobarbital

“…There is no reason to suspect that we are observing a strain or species-specific phenomenon, however this possibility remains. It has been observed that induction responses can be lower in insecticide resistant strains, for example PB induction of Cyp6a2 is lower in a DDT resistant strain in comparison to a wildtype strain (Brun et al, 1996;Amichot et al, 1998). This could reflect the nature of the mutation causing constitutive over-expression of Cyp6a2 in the DDTresistant strain.…”

Induction of microsomal cytochrome P450s by tire‐leachate compounds, habitat components of Aedes albopictus mosquito larvae

“…Their multiplicity enables them to metabolize a wide range of substrates. These enzymes can be induced by many kinds of compounds, including drugs, pesticides, and environmental pollutants (Amichot et al, 1998;Fuchs et al, 1994;Kao et al, 1995;Stevens et al, 2000). The induction causes over-production of the enzymes leading to increased catalytic activities and insecticide detoxification rates (Suwanchaichinda and Brattsten, 2001).…”