Comparative gonad protein and metabolite responses to a binary mixture of 2,4′-DDT and benzo(a)pyrene in the female green mussel Perna viridis

Abstract

Perna viridis is an ideal marine pollution bioindicator, benzo(a)pyrene (BaP) and 2,4′-dichlorodiphenyltrichloroethane (2,4′-DDT) are estrogenic and ubiquitous in marine environments. The toxic effects of a mixture of pollutants are more complicated. A global view of the protein and metabolite responses to single EEs compared to their mixture offers another dimension for revealing the toxic effects of EEs on marine animals. The objective of this study was to investigate the different proteomic and metabolomic responses in the female gonad of the green mussel P. viridis exposed to BaP, 2,4′-DDT and their mixture. Here we have applied NMR spectroscopy-based metabolomics and two-dimensional gel electrophoresis mass spectrometry-based proteomics to elucidate the protein and metabolite responses of female green mussel gonad exposed to BaP, 2,4′-DDT and their mixture. The statistical analysis methods including partial least squares discriminant analysis and orthogonal projection to the latent structure with discriminant analysis were used for data classification. Proteomic responses revealed that 2,4′-DDT and its mixture with BaP showed more severe disturbances in energy metabolism, cell structure and oxidative defense compared to BaP treatment alone. The results of the metabolic responses demonstrated that both 2,4′-DDT and its mixture with BaP mainly induced disturbances in energy metabolism and osmotic regulation. In contrast to what was found with the 2,4′-DDT treatment alone, the mixture of BaP and 2,4′-DDT mainly depressed taurine metabolism by lowering the expression of its metabolite, arginine. Furthermore, the differentially expressed proteins, pancreatic triacylglycerol lipase and the pyruvate dehydrogenase E1 component subunit beta, were confirmed by their related metabolic biomarkers, including ATP and acetoacetate. Our results provide an insight into the metabolic responses of mussel P. viridis exposed to either BaP, 2,4′-DDT or their mixture and characterize some potential biomarkers that were identified by a combined metabolomic and proteomic approach.