Percorrer por autor "Gravato, Carlos"
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- An in situ assessment of key biomarkers in limpets exposed to sewage pollutionPublication . Silva, Cátia SE; Novais, Sara; Gravato, Carlos; Simões, Tiago; Caramalho, Márcia; Neves, Janete; Tecelão, Carla; Rodrigues, Maria J.; Maranhão, Paulo; Lemos, Marco F. L.
- Oxidative stress responses of Daphnia magna exposed to effluents spiked with emerging contaminants under ozonation and advanced oxidation processesPublication . Oropesa, Ana Lourdes; Novais, Sara C.; Lemos, Marco F. L.; Espejo, Azahara; Gravato, Carlos; Beltrán, FernandoIntegration of conventional wastewater treatments with advanced oxidation processes (AOPs) has become of great interest to remove pharmaceuticals and their metabolites from wastewater. However, application of these technologies generates reactive oxygen species (ROS) that may reach superficial waters through effluents from sewage treatment plants. The main objective of the present study was to elucidate if ROS present in real effluents after biological and then chemical (single ozonation, solar photolytic ozonation, solar photocatalytic ozonation (TiO2, Fe3O4) and solar photocatalytic oxidation (TiO2)) treatments induce oxidative stress in Daphnia magna. For this, the activity of two antioxidant enzymes (superoxide dismutase and catalase) and the level of lipid peroxidation were determined in Daphnia. The results of oxidative stress biomarkers studied suggest that D. magna is able to cope with the superoxide ion radical (O2·-) present in the treated effluent due to single ozonation by mainly inducing the antioxidant activity superoxide dismutase, thus preventing lipid peroxidation. Lethal effects (measured in terms of immobility) were not observed in these organisms after exposure to any solution. Therefore, in order to probe the ecological efficiency of urban wastewater treatments, studies on lethal and sublethal effects in D. magna would be advisable.
- Using biomarkers to address the impacts of pollution on limpets ( Patella depressa ) and their mechanisms to cope with stressPublication . Silva, Cátia S. E.; Novais, Sara C.; Simões, Tiago; Caramalho, Márcia; Gravato, Carlos; Rodrigues, Maria J.; Maranhão, Paulo; Lemos, Marco F. L.Contaminant discharges, derived from human activities, are major concerns as they exert a continuous ecological pressure on aquatic systems, causing in fact cascading community effects. Although with associated ecological and fitness costs, physiological and biochemical defense mechanisms may restore the organism’s internal balance. Several studies have pointed biomarkers as tools to assess contamination levels, and also to understand potential mechanisms to cope with stress. In the present study, the fitness costs of limpets Patella depressa located in two different contaminated sites and when transplanted into a different common environment – with no known historical contamination – were assessed through the measurement of oxidative stress, energy metabolism responses, and fatty acid profile changes. Integrated biomarker response index (IBR) revealed differences in responses between organisms of the different origin sites, with greater antioxidant and detoxification activities in the site with the higher contamination life-history (higher IBR index). Moreover, different abilities of this species to deal with the new environmental condition were also observed. After the transplant, and despite the differences in the initial profiles, response patterns became similar between both populations (similar IBR index), with organisms from the less contaminated site suffering a higher impact with a demarked increase in their detoxification and antioxidant defenses, as well as higher changes on fatty acid abundance/composition. Through an integrated biomarker profile analysis in a transplant context, this work provides a distinct insight on the mechanisms of response and tolerance to environmental stress, and fitness costs of this potential sentinel marine species in the context of environmental contamination changes.