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- Chemical residues and biochemical responses in wild and cultured European sea bass (Dicentrarchus labrax L.)Publication . Fernandes, D; Porte, Cinta; Bebianno, Maria JoãoCultured and wild sea bass (Dicentrarchus labrax) from the Arade Estuary were sampled in summer and winter and the degree of exposure to metals and polycyclic aromatic hydrocarbons (PAHs) assessed, together with some biochemical responses against those and other pollutants. The highest levels of copper (up to 997 microg g-1 dry weight) and cadmium (up to 4.22 microg g-1 dry weight) were detected in the liver and kidney of cultured specimens, whereas the highest exposure to PAHs was observed in wild fish. Significant alterations in some biochemical markers were detected and associated to pollutant exposure. Thus, metallothionein concentrations were higher in the tissues of cultured fish and positively correlated with metal residues. The activity 7-ethoxyresorufin O-deethylase ranged from 28 pmol/min/mg protein in cultured fish to 83 pmol/min/mg protein in wild fish collected near a marina area. Cultured fish and wild fish from the marina area had depressed acetylcholinesterase in muscle tissue and a parasitic infection in the gonads. The obtained results support the usefulness of the combined use of chemical and biochemical markers to assess the impact of anthropogenic pollutants in both wild and cultured fish.
- Mitochondrial metabolism of 17α-hydroxyprogesterone in male sea bass (Dicentrarchus labrax): a potential target for endocrine disruptorsPublication . Fernandes, Denise; Bebianno, Maria João; Porte, CintaThe metabolism of 17alpha-hydroxyprogesterone (17P(4)) was investigated in different subcellular fractions isolated from male gonads of sea bass (Dicentrarchus labrax L). The existence of CYP17 (C17,20-lyase activity) and CYP11B (11beta-hydroxylase) catalyzed reactions was demonstrated in the mitochondrial fraction, where 17P(4) was converted to androstenedione (AD) and further metabolized to 11beta-hydroxyandrostenedione (betaAD). The synthesis of betaAD predominated in early spermatogenic testis, indicating a role of betaAD in testicular recrudescence. Additionally, the in vitro effect of model endocrine disrupting chemicals (i.e. nonylphenol (NP), p,p'-DDE, benzo[a]anthracene (BaA), tributyltin (TBT) and ketoconazole (KCZ)) on the mitochondrial metabolism of 17P(4) was investigated. Among the tested compounds, 100 microM NP inhibited the activity of CYP17 (C17,20-lyase) whereas 100 microM KCZ inhibited both CYP17 and CYP11B. Both chemicals showed the potential to disrupt the reproductive cycle of fish living in polluted environments due to impairment of testicular steroid biosynthesis. These results suggest that mitochondrial metabolism of 17P(4) may constitute a new sensitive probe for the assessment of endocrine disruption in fish.
- Assessing pollutant exposure in cultured and wild sea bass (Dicentrarchus labrax) from the Iberian PeninsulaPublication . Fernandes, Denise; Bebianno, Maria João; Porte, CintaThe aquaculture industry is an expanding activity, mainly due to the world population demand of fish. However, intensive production and the use of chemicals have raised environmental concerns and have questioned the quality of cultured fish in comparison to wild fish. Up to date, there is little information regarding pollutant residues in cultured stocks and the risks associated to consumption. Here we summarize recent data on pollutants exposure, together with biochemical responses in both cultured and wild sea bass (Dicentrarchus labrax) from the Iberian Peninsula. The obtained data highlights the use of chemicals in current aquaculture practices as a significant source of pollution in cultured fish that poses a risk to exposed individuals and may negatively impact aquatic ecosystems. Nonetheless, a controlled use of those chemicals and a careful selection of the aquaculture location can ensure relatively low and homogeneous levels of pollutants in cultured fish in comparison to wild specimens.