title: Brain acetylcholinesterase as a marine pesticide biomarker using Brazilian fishes.
abstract: Brain acetylcholinesterase (AChE) of some fishes from the coast of Rio de Janeiro State was studied as a possible pesticide biomarker in marine environmental monitoring. AChE specific activity in brain varied from 145 to 530 U/g of proteins and the Michaelis-Menten constant (K(M)) for acetylthiocholine varied from 104 to 291 microM among the 20 species studied. The enzyme sensitivity to methyl paraoxon, evaluated by the inhibition kinetic constants, shows that some species (Paralonchurus brasiliensis and Genidens genidens) are more sensitive (IC50-30 min=455 and 468 nM, respectively). The less sensitive Merluccius hubbsi and Percophis brasiliensis (IC50-30 min=3339 and 3259 nM, respectively) belong to the super-order Paracanthopterygii, which includes the more ancient species. On the other hand, more susceptible species belong to the super-order Acanthopterygii, which includes more recent species. These results suggest a possible evolutionary linkage for AChE sensitivity to methyl paraoxon. The application of inhibition kinetic constants for fish brain AChE in phylogenetic studies is still being investigated. The results have shown that a fish sentinel species should have the highest brain AChE level among the more sensitive ones.
authors.affiliation: Departamento de Biologia, Faculdade da Região dos Lagos, FERLAGOS, Cabo Frio, RJ, Brazil.
authors.forename: Manildo M
authors.initials: MM
authors.lastname: Oliveira
authors.forename: Moacelio V
authors.initials: MV
authors.lastname: Silva Filho
authors.forename: Vera L F
authors.initials: VL
authors.lastname: Cunha Bastos
authors.forename: Flavio C
authors.initials: FC
authors.lastname: Fernandes
authors.forename: Jayme
authors.initials: J
authors.lastname: Cunha Bastos
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D001267:Atlantic Ocean; D015415:Biomarkers / Q000032:analysis*; D001921:Brain / Q000201:enzymology*; D001938:Brazil; D002800:Cholinesterase Inhibitors / Q000378:metabolism; D016000:Cluster Analysis; D004784:Environmental Monitoring / Q000379:methods*; D005399:Fishes / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D010261:Paraoxon / Q000031:analogs & derivatives / Q000378:metabolism; D010575:Pesticides / Q000032:analysis*; D010802:Phylogeny; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D015415:Biomarkers; D002800:Cholinesterase Inhibitors; D010575:Pesticides; D014874:Water Pollutants, Chemical; D000110:Acetylcholinesterase; D010261:Paraoxon; C008480:methylparaoxon