title: Tests with Daphnia magna: a new approach to prescreen toxicity of newly synthesized acetylcholinesterase reactivators.
abstract: Reactivators of phosphorylated acetylcholinesterase (oximes) are substances used as a human antidotal therapy for organophosphate poisoning. The objective of our study was to examine if juveniles of freshwater microcrustacean Daphnia magna could be employed as test animals in early screen toxicity tests of those substances as a first step for further experiments with daphnids intoxicated by organophosphates. For this purpose, seven different oximes were investigated. It was found that toxicity of all tested oximes increased with time. Mono-quaternary oximes were approximately ten fold (EC50, 14.9 mg.l(-1)) more toxic in 24 hour tests and five fold (EC50 was 79.46 mg.l(-1)) more toxic in 48 hour tests than bis-quaternary oximes. Tests with daphnids were shown to be easy to carry out at low cost and provided valuable results which could be used as a starting point for further research.
authors.affiliation: Research and Development Centre Hostivice, Jiraskova 165, Hostivice, Czech Republic. Sarkavesela@seznam.cz
authors.forename: Sarka
authors.initials: S
authors.lastname: Vesela
authors.forename: Vlastimil
authors.initials: V
authors.lastname: Ondruska
authors.forename: Kamil
authors.initials: K
authors.lastname: Kuca
authors.forename: Jiri
authors.initials: J
authors.lastname: Patocka
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002801:Cholinesterase Reactivators / Q000737:chemistry* / Q000494:pharmacology; D003445:Crustacea; D003621:Daphnia / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004789:Enzyme Activation; D005260:Female; D008956:Models, Chemical; D010755:Organophosphates / Q000737:chemistry; D010091:Oximes / Q000737:chemistry; D018675:Toxicity Tests / Q000379:methods*
chemical_list: D002801:Cholinesterase Reactivators; D010755:Organophosphates; D010091:Oximes; D000110:Acetylcholinesterase