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- Contaminant effects in shore crabs (Carcinus maenas) from Ria Formosa LagoonPublication . Maria, Vera L.; Santos, M. A.; Bebianno, Maria JoãoDefence and damage biomarkers signals were studied in female and male shore crabs Carcinus maenas transplanted between two sites at Ria Formosa Lagoon (South of Portugal). The cross transplantation occurred during 6 days at a hypothetical reference site (Ramalhete), and a contaminated site (Olhão). DNA unwinding technique was used for DNA integrity measurement. General enzymatic antioxidant responses in gills and hepatopancreas (catalase and gills glutathione peroxidase activities increase) showed that cross transplanted crabs (female and male) are suffering from pro-oxidant challenges at the Olhão site. Gills and hepatopancreas glutathione-S-transferase were reduced in both gender crabs transplanted from Ramalhete to Olhão. Metallothioneins induction occurred in crabs transplanted from Ramalhete to Olhão (contaminated by metals and polycyclic aromatic hydrocarbons (PAHs)). However metallothionein differences were also observed towards gender and organ specificities. High gills lipid peroxidation exist in male crabs transplanted from Ramalhete to Olhão, while in females it was the opposite. In both gender crabs from the Olhão site, gills DNA integrity decreased compared to the Ramalhete feral crabs. Moreover, hepatopancreas DNA integrity decreased in male crabs transplanted from Olhão to Ramalhete site which may be related to the environmental conditions (lower contamination levels) revealing the difficulty of selection of reference sites in field studies. Data demonstrated that female and male C. maenas antioxidant defences and damage biomarkers were sensitive to the mixture of contaminants present in these sites as well as good indicators of general stress.
- Contamination assessment of a coastal lagoon (Ria de Aveiro, Portugal) using defence and damage biochemical indicators in gill of Liza aurata – An integrated biomarker approachPublication . Oliveira, M.; Maria, Vera L.; Ahmad, I.; Serafim, Angela; Bebianno, Maria João; Pacheco, M.; Santos, M. A.Fish gill importance in toxicants uptake, bioconcentration and excretion allied to meagre knowledge on branchial damage/protection responses substantiate this study. Five critical sites in Ria de Aveiro (Portugal) were assessed in comparison with a reference site (Torreira), focusing on Liza aurata gill antioxidant defences versus damage (oxidative and genetic). Only in Barra fish displayed damage (lipid peroxidation) though no differences were found in antioxidants. In all other sites, except Rio, antioxidant alterations were found. Thus, fish from Gafanha, Laranjo and Vagos showed higher total glutathione, glutathione peroxidase and catalase. Higher glutathione reductase and glutathione S-transferase activity was also found in the first and the last sites, respectively. In Laranjo, metallothionein levels were higher though lower in Gafanha and Vagos. In general, damage was not accompanied by defences weakening confirming that predicting damage based on antioxidants depletion is not straightforward. The integrated biomarker response index ranked sites as: Gafanha>Barra>Laranjo>Vagos>Rio>Torreira.
- Evaluation of oxidative DNA lesions in plasma and nuclear abnormalities in erythrocytes of wild fish (Liza aurata) as an integrated approach to genotoxicity assessmentPublication . Oliveira, M.; Ahmad, I.; Maria, Vera L.; Ferreira, C. S. S.; Serafim, A.; Bebianno, Maria João; Pacheco, M.; Santos, M. A.Genetic lesions (8-hydroxy-2'-deoxyguanosine (8-OHdG) and erythrocytic nuclear abnormalities (ENA) were seasonally quantified in the blood of Liza aurata caught at Ria de Aveiro (Portugal), a multi-contaminated aquatic system. Thus, five critical sites were assessed and compared with a reference site (Torreira). Oxidative DNA damage was found in Gafanha (harbour-water area), Laranjo (metal-contaminated) and Vagos (contaminated with PAHs) in the spring; Rio Novo do Principe (near a former paper-mill effluent) in the autumn; Rio Novo do Principe and Vagos in the winter. ENA were higher than Torreira at VAG (spring and winter). Torreira did not display seasonal variation neither in terms of 8-OHdG or total ENA. A positive correlation between 8-OHdG and ENA was found, suggesting oxidative stress as a mechanism involved in the formation of ENA. This study clearly demonstrates the presence of DNA-damaging substances in Ria de Aveiro and recommends the use of 8-OHdG and ENA as biomarkers of environmental contamination.