Impact of glyphosate and benzo[a]pyrene on the tolerance of mosquito larvae to chemical insecticides. Role of detoxification genes in response to xenobiotics.
The effect of exposure of Aedes aegypti larvae for 72h to sub-lethal concentrations of the herbicide glyphosate and the polycyclic aromatic hydrocarbon benzo[a]pyrene on their subsequent tolerance to the chemical insecticides imidacloprid, permethrin and propoxur, detoxification enzyme activities and transcription of detoxification genes was investigated. Bioassays revealed a significant increase in larval tolerance to imidacloprid and permethrin following exposure to benzo[a]pyrene and glyphosate. Larval tolerance to propoxur increased moderately after exposure to benzo[a]pyrene while a minor increased tolerance was observed after exposure to glyphosate. Cytochrome P450 monooxygenases activities were strongly induced in larvae exposed to benzo[a]pyrene and moderately induced in larvae exposed to imidacloprid and glyphosate. Larval glutathione S-transferases activities were strongly induced after exposure to propoxur and moderately induced after exposure to benzo[a]pyrene and glyphosate. Larval esterase activities were considerably induced after exposure to propoxur but only slightly induced by other xenobiotics. Microarray screening of 290 detoxification genes following exposure to each xenobiotic with the DNA microarray Aedes Detox Chip identified multiple detoxification and red/ox genes induced by xenobiotics and insecticides. Further transcription studies using real-time quantitative RT-PCR confirmed the induction of multiple P450 genes, 1 carboxy/cholinelesterase gene and 2 red/ox genes by insecticides and xenobiotics. Overall, this study reveals the potential of benzo[a]pyrene and glyphosate to affect the tolerance of mosquito larvae to chemical insecticides, possibly through the cross-induction of particular genes encoding detoxification enzymes.
Laboratoire d'Ecologie Alpine (LECA, UMR CNRS 5553), Equipe Perturbation Environnementales et Xenobiotiques, France.
Muhammad Asam
MA
Riaz
Rodolphe
R
Poupardin
Stéphane
S
Reynaud
Clare
C
Strode
Hilary
H
Ranson
Jean-Philippe
JP
David
D000330:Aedes / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001564:Benzo(a)pyrene / Q000493:pharmacokinetics / Q000633:toxicity*; D001681:Biological Assay; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D004347:Drug Interactions; D004950:Esterases / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000633:toxicity; D007093:Imidazoles / Q000493:pharmacokinetics / Q000633:toxicity; D008658:Inactivation, Metabolic / Q000235:genetics; D007306:Insecticides / Q000493:pharmacokinetics* / Q000633:toxicity; D007814:Larva / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000493:pharmacokinetics / Q000633:toxicity; D020411:Oligonucleotide Array Sequence Analysis; D026023:Permethrin / Q000493:pharmacokinetics / Q000633:toxicity; D001074:Propoxur / Q000493:pharmacokinetics / Q000633:toxicity; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097797:Glyphosate
D001564:Benzo(a)pyrene; D003577:Cytochrome P-450 Enzyme System; D004950:Esterases; D005982:Glutathione Transferase; D005998:Glycine; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D026023:Permethrin; D001074:Propoxur; D012333:RNA, Messenger; D000097797:Glyphosate; C082359:imidacloprid