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  • Lethal and sublethal effects of three insecticides on two developmental stages of Xenopus laevis and comparison with other amphibians.

Lethal and sublethal effects of three insecticides on two developmental stages of Xenopus laevis and comparison with other amphibians.

Environmental toxicology and chemistry (2013-05-21)
Shuangying Yu, Mike R Wages, Qingsong Cai, Jonathan D Maul, George P Cobb
ABSTRACT

It has been suggested that Xenopus laevis is less sensitive than other amphibians to some chemicals, and therefore, that the Frog Embryo Teratogenesis Assay-Xenopus (FETAX) may have limited use in risk assessments for other amphibians. However, comparisons are based mostly on results of FETAX, which emphasizes embryos. Larval X. laevis may be more sensitive to chemicals than embryos and may serve as a better life stage in risk assessments. The present study was conducted to determine the lethal and sublethal effects of 3 insecticides (malathion, endosulfan, and α-cypermethrin) on X. laevis embryos and larvae and to compare toxicity of X. laevis with that of other amphibians. All 3 insecticides have different modes of action, and they caused mortality, malformations, and growth inhibition in both developmental stages. Compared with embryos, larvae were more sensitive to endosulfan and α-cypermethrin but not to malathion. Xenopus laevis larvae had low sensitivity to endosulfan, median sensitivity to malathion, and high sensitivity to α-cypermethrin/cypermethrin relative to other larval amphibians. Our results suggest that X. laevis larvae may generate more protective toxicity estimates in risk assessments than embryos. Xenopus laevis may have limited use in evaluating risk of organochlorine insecticides to other amphibians but may provide useful toxicity thresholds for pyrethroid and perhaps organophosphorus insecticides.

MATERIALS
Product Number
Brand
Product Description

Supelco
Cypermethrin, certified reference material, TraceCERT®
Supelco
Endosulfan, PESTANAL®, analytical standard
Supelco
Cypermethrin, PESTANAL®, analytical standard
Supelco
Malathion, certified reference material, TraceCERT®
Supelco
Malathion solution, 100 μg/mL in cyclohexane, PESTANAL®, analytical standard
Supelco
Malathion, PESTANAL®, analytical standard
Supelco
Cypermethrin solution, 100 μg/mL in acetonitrile, PESTANAL®, analytical standard
Supelco
α-Cypermethrin, PESTANAL®, analytical standard