Consequences of a short-term exposure to a sub lethal concentration of CdO nanoparticles on key life history traits in the fruit fly (Drosophila melanogaster)

Abstract

Nanoparticles of cadmium oxide (CdO NPs) are among the most common industrial metal oxide nanoparticles. Early adulthood (P1) fruit flies (D. melanogaster) were exposed for 7 days to a sub lethal concentration (0.03 mg CdO NPs/mL, which was 20% of the LC₅₀), spiked into food media to test whether short episodes of CdO NPs exposures early in adult life have long-lasting effects on life history traits such as fecundity well beyond exposure times. All studied life history traits, as well as climbing behavior were adversely affected by exposure to CdO NPs. A blistered wing phenotype was also observed in the non-exposed progeny (F1) of adult flies (P1) and their fecundity was significantly decreased (-50%) compared to the fecundity of non-exposed (control) F1 flies. Expressions of antioxidant enzymes encoding genes; catalase and superoxide dismutase (SOD2) were significantly up regulated in P1 flies compared to control. Expression of metallothionein encoding genes (MTn A-D) were significantly up-regulated in both parent flies (P1) and their progeny (F1) after exposure of P1 flies to CdO NPs compared to non-exposed control flies, suggesting long-term potential effects. Taken together, these findings indicate that short-term exposure to a sub-lethal CdO NP concentration is sufficient to have long-lasting, adverse effects on fruit flies.

Keywords: Bioaccumulation; Fruit fly; Metallothionein; Nano-sized cadmium oxide; Oxidative stress; Phenotype effects.