Transgenerational effects of illicit drugs on Daphnia magna

Abstract

Cocaine is one of the most illicit drugs found in aquatic environments. Studies have shown that cocaine's main metabolite (benzoylecgonine) can cause adverse effects in invertebrates and vertebrates. Daphnia magna is considered a suitable biological model for ecotoxicological studies, primarily for its features of sensibility and easy handling. Many authors have performed assays to assess drug-induced immobility or mortality and reproduction as endpoints. However, studies exploring effects of drugs on more than one generation are scarce. Transgenerational studies intend to understand the transfer of adverse effects that contaminants may cause in the parental generation to the offspring. This study aims at investigating the transgenerational effects caused by benzoylecgonine (BE) on the freshwater microcrustacean Daphnia magna. Transgenerational toxicity will be evaluated from F0 to F3 generations of D. magna. One third brood of neonates will be selected and considered as parental generation (F0). F0 will be exposed to environmentally relevant concentrations of BE for 21 days. Individuals from F1 to F3 will be established using the third brood of the previous generation and exposed again to evaluate the transgenerational effects of BE. Effects on survival, somatic growth, swimming behavior and reproduction of D. magna will be evaluated. Moreover, at the end of the exposures, the effects at sub-individual level in terms of changes in oxidative status [i.e., levels of pro-oxidant molecules (TOS) and enzymatic antioxidant defenses (SOD, CAT, GPx, GST] and oxidative damage (LPO and protein carbonylation) will be explored, while modulation of behavioral changes will be considered as individual endpoints. (AU)