Toxicological evaluation of the herbicide Palace® in Drosophila melanogaster

ABSTRACT

Drosophila melanogaster is a suitable model for toxicological studies of environmental pollutants including pesticides, which are known to produce adverse effects on the ecosystem. The aim of the present study was to investigate the adverse influence of the pesticide Palace®, a mixture of 2,4-dichlorophenoxyacetic acid (2,4-D) and picloram, using D. melanogaster as a model organism. D. melanogaster larvae were exposed to 0.011%, 0.022%, 0.112%, 0.224%, and 1.12% of Palace® and development examined. Adult flies were treated with 0.224%, 1.12%, 2.24%, 11.2%, and 22.4% of Palace® and the following analyzed survival, locomotor behavior, acetylcholinesterase (AchE) activity, reactive oxygen species (ROS) production, total and non-protein thiol levels, and mitochondrial function. Data demonstrated that exposure of flies during larval stage to Palace® significantly affected development of larvae to the adult stage. In adults, treatment with Palace® resulted in dose-dependent progressive adverse effects on survival and behavior with males more sensitive than females. In both males and females, ROS production and AchE activity were not markedly affected by Palace®. However, total thiol levels increased in female heads treated with highest dilution of Palace®, while decreased levels of non-protein thiols were detected in heads of male flies following Palace® exposure. In females and males flies exposed to Palace® reduced mitochondrial oxygen consumption related to oxidative phosphorylation (OXPHOS) state, mitochondrial capacity of excess (E-P) and respiratory control ratio (RCR) was noted, indicating that the pesticide mixture altered mitochondrial complexes functionality with consequences on bioenergetics. In summary, Palace® exposure produced adverse effects on D. melanogaster affecting survival, development, behavior and mitochondrial function, which may exert ecotoxicological consequences which poses risks to different organisms in the ecosystem.

KEYWORDS:

• 24-D
• picloram
• behavioral toxicology
• developmental toxicity
• mitochondrial dysfunction

Acknowledgments

This work was supported by FAPERGS (Fundação de Amparo a Pesquisa do Estado do Rio Grande do Sul), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and CNPq/FAPERGS/PRONEM.

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico;Coordenação de Aperfeiçoamento de Pessoal de Nível Superior;Fundação de Amparo a Pesquisa do Estado do Rio Grande do Sul;CNPq/FAPERGS/PRONEM.