title: Atrazine induction of a family 4 cytochrome P450 gene in Chironomus tentans (Diptera: Chironomidae).
abstract: Cytochrome P450-dependent microsomal monooxygenase (P450) activity was measured in control and atrazine-exposed third instar midge larvae, Chironomus tentans. Significantly elevated O-demethylase activity was observed in gut homogenates taken from midges exposed to atrazine concentrations from 1 to 10 ppm for 90 h. No significant induction was observed at atrazine concentrations below 1 ppm. A region of a cytochrome P450 family 4 gene was amplified and sequenced from C. tentans larvae. Alignments of inferred amino acid sequences with other insect CYP4 gene homologues indicate a high degree of similarity. Northern blot analysis employing the CYP4 gene fragment as a probe showed an over-expression in C. tentans exposed to atrazine. The results support the previously identified inducibility of cytochrome P450-dependent activity and provide insight into the potential consequences of atrazine exposure to aquatic organisms.
authors.affiliation: Department of Entomology, University of Nebraska-Lincoln, 202 Plant Industry Bldg., Lincoln, NE 68583-0816, USA.
authors.forename: Diana K
authors.initials: DK
authors.lastname: Londoño
authors.forename: Blair D
authors.initials: BD
authors.lastname: Siegfried
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lydy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001280:Atrazine / Q000633:toxicity*; D001483:Base Sequence; D015152:Blotting, Northern; D002683:Chironomidae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D010090:Oxidoreductases, O-Demethylating / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D003577:Cytochrome P-450 Enzyme System; D010090:Oxidoreductases, O-Demethylating; D001280:Atrazine