Effects of environmentally relevant concentrations of glyphosate and aminomethylphosphonic acid on biotransformation and stress response proteins in the liver of zebrafish (Danio rerio)

Abstract

Herbicides pose a threat to various non-target organisms, including fish. A widely used herbicide, glyphosate, and its main breakdown product, aminomethylphosphonic acid (AMPA), are quite ubiquitous in freshwater systems. The aim of this work was to analyze changes in the relative abundance of hepatic proteins participating in the biotransformation and response to chemical stress in adult zebrafish Danio rerio exposed to environmentally relevant concentrations of glyphosate (100 μg/L), AMPA (100 μg/L), and their mixture (50 μg/L + 50 μg/L) for two weeks. Proteomic analysis showed that the tested concentrations caused dysregulation of various biotransformation proteins, the most upregulated of which in all treatment groups was the Phase I enzyme cyp27a7. While glyphosate had a more pronounced impact on the biotransformation pathways, AMPA showed stronger interference with redox homeostasis. When acting together, the parent compound and its metabolite were more potent to disturb fish metabolic processes, including nucleotide metabolism and proteasome pathway, and to downregulate proteins known for their roles in protection from oxidative modifications of cellular constituents and disruption of redox signaling.