title: Acute toxicity and cholinesterase inhibition of the nematicide ethoprophos in larvae of gar Atractosteus tropicus (Semionotiformes: Lepisosteidae).
abstract: Biomarkers are a widely applied approach in environmental studies. Analyses of cholinesterase (ChE), glutathione S-transferase (GST) and lipid peroxidation (LPO) are biomarkers that can provide information regarding early effects of pollutants at different biochemical levels on an organism. The aim of this study was to evaluate the biomarker approach on a Costa Rican native and relevant species. For this, larvae of gar (Atractosteus tropicus) were exposed to the organophosphorus nematicide, ethoprophos. Acute (96hr) exposure was conducted with pesticide concentrations ranging from 0.1 microg/L to 1 500 microg/L. The 96hr LC50 calculated was 859.7 microg/L. After exposure, three biomarkers (ChE, GST and LPO) were analyzed in fish that survived the acute test. The lowest observed effect concentration (LOEC) regarding ChE activity inhibition was 50 microg/L. This concentration produced a significant inhibition (p<0.05) of the enzyme by 20%. The highest concentration tested without showing any effect on ChE activity and therefore considered as no observed effect concentration (NOEC) was 10 microg/L. Ethoprophos concentration of 400 microg/L caused a ChE inhibition by 79%. In this study, no significant variations (p>0.05) in GST activity and LPO were observed in A. tropicus larvae after exposure to ethoprophos.
authors.affiliation: Laboratorio de Estudios Ecotoxicológicos del Instituto Regional de Estudios en Sustancias Tóxicas (IRET), Universidad Nacional de Costa Rica, Heredia, Costa Rica. fmena@una.ac.cr
authors.forename: Freylan
authors.initials: F
authors.lastname: Mena Torres
authors.forename: Sascha
authors.initials: S
authors.lastname: Pfennig
authors.forename: María de Jesús
authors.initials: Mde J
authors.lastname: Arias Andrés
authors.forename: Gabriel
authors.initials: G
authors.lastname: Márquez-Couturier
authors.forename: Adrían
authors.initials: A
authors.lastname: Sevilla
authors.forename: C Maurizio
authors.initials: CM
authors.lastname: Protti
mesh_terms: D000818:Animals; D000969:Antinematodal Agents / Q000633:toxicity*; D015415:Biomarkers / Q000097:blood; D002802:Cholinesterases / Q000097:blood* / Q000187:drug effects; D005399:Fishes / Q000097:blood; D005982:Glutathione Transferase / Q000097:blood* / Q000187:drug effects; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D015227:Lipid Peroxidation / Q000187:drug effects*; D063086:Organothiophosphates; D009946:Organothiophosphorus Compounds / Q000633:toxicity*; D023382:Toxicity Tests, Acute
chemical_list: D000969:Antinematodal Agents; D015415:Biomarkers; D063086:Organothiophosphates; D009946:Organothiophosphorus Compounds; C001182:ethoprop; D005982:Glutathione Transferase; D002802:Cholinesterases