Liquid chromatography-mass spectrometry based metabolomics investigation of different tissues of Mytilus galloprovincialis.

The Mediterranean mussel (Mytilus galloprovincialis) is widely used in monitoring programs and in ecotoxicological studies to examine the biological effects of physicochemical parameter changes and the impact of chemical pollutants. Metabolomics has recently demonstrated high potential to gain further insight into the molecular effects of chemical exposure and the success of its application is dependent on the extent of prior metabolomics knowledge available on the target organism. Therefore, the purpose of this study was the investigation of the metabolites of five different functional tissues of male and female Mediterranean mussels (digestive gland, foot, gill and gonad tissues and in the remaining soft tissues) accessible to the analysis using the most common sample preparation recommended for tissue analysis (i.e. Bligh & Dyer). Metabolic fingerprints were acquired via liquid chromatography high-resolution mass spectrometry and the identification was based on an internal database developed in the laboratory. It led to the identification of 110 metabolites, among which amino acids, carboxylic acids, purine and pyrimidine metabolites were often the most abundant. The metabolic contents of the five tissues quantitatively and qualitatively differed, with a clear distinction between male and female contents observed in the gonads and digestive glands. These results underline the importance of selecting the most suitable tissue and sex to study the impact of contamination on metabolism and the need for further research to deeper characterize the metabolome of this organism.

Early Biological Modulations Resulting from 1-Week Venlafaxine Exposure of Marine Mussels Mytilus galloprovincialis Determined by a Metabolomic Approach.

There is growing evidence of the presence of pharmaceuticals in natural waters and their accumulation in aquatic organisms. While their mode of action on non-target organisms is still not clearly understood, their effects warrant assessment. The present study assessed the metabolome of the Mediterranean mussel (Mytilus galloprovincialis) exposed to a 10 µg/L nominal concentration of the antidepressant venlafaxine (VLF) at 3 time-points (1, 3, and 7 days). Over the exposure period, we observed up- or down-modulations of 113 metabolites, belonging to several metabolisms, e.g., amino acids (phenylalanine, tyrosine, tryptophan, etc.), purine and pyrimidine metabolisms (adenosine, cyclic AMP, thymidine, etc.), and several other metabolites involved in diverse functions. Serotonin showed the same time-course modulation pattern in both male and female mussels, which was consistent with its mode of action in humans, i.e., after a slight decrease on the first day of exposure, its levels increased at day 7 in exposed mussels. We found that the modulation pattern of impacted metabolites was not constant over time and it was gender-specific, as male and female mussels responded differently to VLF exposure.

Multi-omic approach to evaluate the response of gilt-head sea bream (Sparus aurata) exposed to the UV filter sulisobenzone.

Sulisobenzone (BP-4) is one of the benzophenone type UV filters most frequently detected in aquatic ecosystems. As a suspected endocrine disrupting compound, scarce information is available yet about other molecular effects and its mechanism of action. Here, we used an integrated transcriptomic and metabolomic approach to improve the current understanding on the toxicity of BP-4 towards aquatic species. Gilt-head sea bream individuals were exposed at environmentally relevant concentrations (10 µg L-1) for 22 days. Transcriptomic analysis revealed 371 differentially expressed genes in liver while metabolomic analysis identified 123 differentially modulated features in plasma and 118 in liver. Integration of transcriptomic and metabolomic data showed disruption of the energy metabolism (>10 pathways related to the metabolism of amino acids and carbohydrates were impacted) and lipid metabolism (5 glycerophospholipids and the expression of 3 enzymes were affected), suggesting oxidative stress. We also observed, for the first time in vivo and at environmental relevant concentrations, the disruption of several enzymes involved in the steroid and thyroid hormones biosynthesis. DNA and RNA synthesis was also impacted by changes in the purine and pyrimidine metabolisms. Overall, the multiomic workflow presented here increases the evidence on suspected effects of BP-4 exposure and identifies additional modes of action of the compounds that could have been overlooked by using single omic approaches.