Differential proteins revealed with proteomics in the brain tissue of Paralichthys olivaceus under the stress of methyl parathion

The proteins from the brain tissue of the fish Paralichthys olivaceus (PO) were separated by the optimized two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Approximately 650 protein spots were detected with 200 μg of protein load in each SDS-PAGE gel, and the pH varied from 3.0 to 10.0. The differential proteins were separated and identified by proteomic technologies, and further selected as potential protein markers to monitor the contamination levels of methyl parathion (MP). Compared with the control group, 17 differential proteins were obtained under the stress of MP at 3 mg/L. Among these spots, fourteen were up-regulated and three were down-regulated. Then these differential proteins were further identified by peptide mass fingerprint (PMF) and database search. The results showed that heat shock protein 70, glutathione S-transferase and cytochrome P450 were found significant in the differential proteins. These proteins might have great potential functions for monitoring the contamination levels of MP, searching for the toxicological mechanism, as well as for evaluating the degree of harm on human beings under the MP pollution because of their close connection with the stress of MP. The results also indicated that the application of multiple biomarkers has more advantages than that of a single biomarker for monitoring the levels of MP pollution in the flowing seawater.