Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.

A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies.

Estabelecimento do teste do cometa em hemócitos de Biomphalaria glabrata (Say, 1818) expostos à radiação gama (60 Co) / Establishment of comet assay in haemocytes of Biomphalaria glabrata (Say, 1818) exposed to gamma radiation (60 Co)

A eletroforese em gel de células únicas ou o ensaio cometa foi estabelecido nos caramujos de água doce Biomphalaria glabrata. Para a detecção de danos nos DNA de hemócitos circulantes, caramujos adultos foram irradiados com doses únicas de 2,5, 5, 10 e 20Gy de radiação gama (60Co). Os efeitos genotóxicos da radiação ionizante foram detectados em todas as doses como um aumento da dose dependente na migração do DNA. O ensaio cometa em B. glabrata demonstrou ser uma ferramenta simples, rápida e confiável na avaliação de efeitos genotóxicos de mutagênicos ambientais.

Estabelecimento do teste do cometa em hemócitos de Biomphalaria glabrata (Say, 1818) expostos à radiação gama (60 Co)

A eletroforese em gel de células únicas ou o ensaio cometa foi estabelecido nos caramujos de água doce Biomphalaria glabrata. Para a detecção de danos nos DNA de hemócitos circulantes, caramujos adultos foram irradiados com doses únicas de 2,5, 5, 10 e 20Gy de radiação gama (60Co). Os efeitos genotóxicos da radiação ionizante foram detectados em todas as doses como um aumento da dose dependente na migração do DNA. O ensaio cometa em B. glabrata demonstrou ser uma ferramenta simples, rápida e confiável na avaliação de efeitos genotóxicos de mutagênicos ambientais.

Establishment of the comet assay in the freshwater snail Biomphalaria glabrata (Say, 1818).

The single cell gel electrophoresis or the comet assay was established in the freshwater snail Biomphalaria glabrata. For detecting DNA damage in circulating hemocytes, adult snails were irradiated with single doses of 2.5, 5, 10 and 20 Gy of (60)Co gamma radiation. Genotoxic effect of ionizing radiation was detected at all doses as a dose-related increase in DNA migration. Comet assay in B. glabrata demonstrated to be a simple, fast and reliable tool in the evaluation of genotoxic effects of environmental mutagens.