The proposed research activity will include both laboratorial work and Seminars and Lectures, as follows: The laboratorial work will be carried out on target organs, namely gills and liver, of the white seabream (Diplodus sargus) exposed to methylmercury (MeHg) in order to clarify the toxicity of MeHg in fish, and potential implications for human health. To this aim, a Nuclear Magnetic Resonance (NMR)-based metabolomic approach will be applied to simultaneously investigate the MeHg effects on various metabolic pathways. Furthermore, the proposed research activity is aimed to elucidate about the recovery of metabolomic shifts in gills and liver of the white seabream upon cessation of MeHg exposure. Two seminars will be held, one focused on the neurotoxicity of mercury in fish and another one concerning the previous findings of the collaboration between the research group at UniME and the candidate, namely on the assessment of mercury hepatotoxicity in fish under realistic environmental conditions – the case study of Aveiro lagoon (Portugal). Lectures will be held on the toxicokinetics and toxicodynamics of different mercury counterparts in fish within the course of Biotechnologies in Cytotoxicology held at UniME by Prof. Maria Maisano. Other lectures are planned for the course of Cellular Biology held at UniME by Prof. Angela Mauceri, concerning the following theme: “Oxidative stress as a critical event on metals toxicity in aquatic organisms”.
In order to evaluate the time-course of methylmercury (MeHg) toxicity in the gills and liver of the white seabream (Diplodus sargus), an experiment, comprising both an exposure period to MeHg that lasted 14 days and a post-exposure period of 28 days, was previously performed at the aquaculture research station of the Portuguese Institute for the Sea and Atmosphere. Realistic levels of MeHg in natural contaminated food of fish were considered (8.7 ± 0.5 µg g-1 ) to produce reliable data for environmental health assessment and fish population preservation. Within the proposed research activity at the University of Messina, fish tissues (gills and liver) from the previous experiment, will be surveyed for metabolomics shifts after 3, 7 and 14 days of MeHg exposure, as well as 14 and 28 days of post-exposure. Gills and liver were selected as target organs due to their specificities regarding MeHg tokicokinetics. A NMR-based metabolomics approach will be then applied, consisting in the extraction of polar metabolites from fish gills and liver, acquisition of NMR spectra, and identification and quantification of metabolites. Data will be then assayed by multi-variate (PCA) and uni-variate statistics.
The collaboration between the research group at the University of Messina and the applicant started in 2013, within the scope of a Portuguese research project named as NEUTOXMER (Neurotoxicity of mercury in fish and association with morphofunctional alterations and behavior shifts). Besides the evaluation of mercury (Hg) effects on brain, the NEUTOXMER project allowed to disclose the toxicity of Hg in target organs (e.g. gills and liver). This was successfully achieved within this collaboration between the research group at UniME and the applicant, as confirmed by the co-authored articles published in prestigious international peer-reviewed journals.