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Prediction of metal cation toxicity to the bioluminescent fungus Gerronema viridilucens

Authors

  • Luiz Fernando Mendes,

    1. Instituto de Química da Universidade de São Paulo, Caixa Postal 26077, 05599-970 São Paulo, SP, Brazil
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  • Erick Leite Bastos,

    1. Centro de Ciências Naturais e Humanas, Fundação Universidade Federal do ABC, 09210-170 Santo André, SP, Brazil
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  • Cassius Vinicius Stevani

    Corresponding author
    1. Instituto de Química da Universidade de São Paulo, Caixa Postal 26077, 05599-970 São Paulo, SP, Brazil
    • Instituto de Química da Universidade de São Paulo, Caixa Postal 26077, 05599-970 São Paulo, SP, Brazil.
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Abstract

A correlation between the physicochemical properties of mono- [Li(I), K(I), Na(I)] and divalent [Cd(II), Cu(II), Mn(II), Ni(II), Co(II), Zn(II), Mg(II), Ca(II)] metal cations and their toxicity (evaluated by the free ion median effective concentration, EC50F) to the naturally bioluminescent fungus Gerronema viridilucens has been studied using the quantitative ion character–activity relationship (QICAR) approach. Among the 11 ionic parameters used in the current study, a univariate model based on the covalent index (X2mr) proved to be the most adequate for prediction of fungal metal toxicity evaluated by the logarithm of free ion median effective concentration (log EC50F): log EC50F = 4.243 (±0.243) −1.268 (±0.125)·X2mr (adj-R2 = 0.9113, Alkaike information criterion [AIC] = −60.42). Additional two- and three-variable models were also tested and proved less suitable to fit the experimental data. These results indicate that covalent bonding is a good indicator of metal inherent toxicity to bioluminescent fungi. Furthermore, the toxicity of additional metal ions [Ag(I), Cs(I), Sr(II), Ba(II), Fe(II), Hg(II), and Pb(II)] to G. viridilucens was predicted, and Pb was found to be the most toxic metal to this bioluminescent fungus (EC50F): Pb(II) > Ag(I) > Hg(I) > Cd(II) > Cu(II) > Co(II) ≈ Ni(II) > Mn(II) > Fe(II) ≈ Zn(II) > Mg(II) ≈ Ba(II) ≈ Cs(I) > Li(I) > K(I) ≈ Na(I) ≈ Sr(II)> Ca(II). Environ. Toxicol. Chem. 2010;29:2177–2181. © 2010 SETAC

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