Loading...
5 results
Search Results
Now showing 1 - 5 of 5
- 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.
- Drospirenone intake alters plasmatic steroid levels and cyp17a1 expression in gonads of juvenile sea bassPublication . Blanco, Maria; Fernandes, Denise; Medina, Paula; Blazquez, Mercedes; Porte, CintaDrospirenone (DRO) is one of the most widely used progestins in contraceptive treatments and hormone replacement therapies. The pharmacokinetics and potential toxicological effects of DRO were investigated in juvenile sea bass (Dicentrarchus labrax) exposed through the diet (0.01-10 mu g DRO/g) for up to 31 days. DRO was detected in the blood (4-27 ng/mL) of fish exposed to the highest concentration, with no significant bioaccumulation over time and no alteration of hepatic metabolizing enzymes, namely, CYP1A and CYP3A-catalysed activities and UDP-glucuronyltransferase (UGT). Pregnenolone (P5), progesterone (P4), 17 alpha-hydroxyprogesterone (17P4), 17 alpha-hydroxypregnenolone (17P5), androstenedione (AD) and testosterone (T) were determined in plasma and gene expression of cyp17a1, cyp19a1a and cyp11 beta analysed by qRT-PCR in gonads. The significant increase in plasmatic levels of 17P5, 17P4 and AD detected after 31 days exposure to 10 ng DRO/g together with the increased expression of cyp17a1 in females evidence the ability of DRO to alter steroid synthesis at low intake concentrations (7 ng DRO/day). However, the potential consequences of this steroid shift for female reproduction remain to be investigated. (C) 2016 Elsevier Ltd. All rights reserved.
- 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.
- Assessment of pollution along the Northern Iberian shelf by the combined use of chemical and biochemical markers in two representative fish speciesPublication . Fernandes, D; Andreu-Sánchez, Oscar; Bebianno, Maria João; Porte, CintaMuscle concentrations of organochlorinated compounds as well as biliary levels of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) were determined in two different fish species, the four-spotted megrim (Lepidorhombus boscii) and the pouting (Trisopterus luscus) collected along the Northern Iberian coast. Additionally, a set of biochemical markers namely, 7-ethoxyresorufin O-deethylase (EROD), UDP-glucuronosyltransferase (UGT) and catalase (CAT) were measured in liver subcellular fractions. Chemical analysis indicated geographical differences in pollutant loads that were further reinforced by biomarker responses. Thus, EROD activity showed a good correlation with the amount of PCBs bioaccumulated in muscle tissue of both fish species. Elevated UGT activity was observed in those individuals highly exposed to APEs and 1-naphthol. The study reinforces the need to select representative sentinel species from different habitats for biomonitoring purposes and provides further support for the use of biomarkers in assessing the health of coastal areas.