Metabolic profiling of Mytilus galloprovincialis and its potential applications for pollution assessment

Monitoring of the marine environment is crucial for determining the impact of environmental stressors and/or pollution on ecosystem health. Classical assays that traditionally focus on a limited number of selected endpoints have thus far proven to be of limited success in this regard. Here, we apply 1H-nuclear magnetic resonance (NMR)-based chemometric analysis to the marine mussel Mytilus galloprovincialis to investigate changes in the metabolic profile of digestive gland tissue as a response to exposure to nickel and chlorpyrifos, both as single chemicals and as a mixture. The multivariate data was analysed by principal component analysis and partial least-squares discriminant analysis. The major metabolite changes responsible for the spectral differences observed were related to amino acid, nucleotide and methylamine metabolism in all 3 cases. In addition, novel metabolic profiles were associated with exposure to each chemical and the mixture. Nickel produced changes in energy metabolism while chlorpyrifos resulted in an increase in acetylcholine levels. Mussels exposed to a single compound demonstrated a significantly different response to those given the mixture, where a small antagonistic effect was evident. The study demonstrates the potential of NMR-based metabolomics to provide a rapid and cost-effective screening tool for monitoring the aquatic environment.