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- Asparagopsis armata exudate cocktail: the quest for the mechanisms of toxic action of an invasive seaweed on marine invertebratesPublication . Silva, Carla; Simões, Tiago; Félix, Rafael; A.M.V.M., Soares; Barata, Carlos; Novais, Sara C.; Lemos, Marco F.L.The seaweed Asparagopsis armata exhibits a strong invasive behavior, producing halogenated compounds with effective biological effects. This study addresses the biochemical responses to sublethal concentrations of A. armata exudate on the marine snail Gibbula umbilicalis whole body and the shrimp Palaemon elegans eyes and hepatopancreas. Antioxidant defenses superoxide dismutase (SOD) and glutathione-S-transferase (GST), oxidative damage endpoints lipid peroxidation (LPO) and DNA damage, the neuronal parameter acetylcholinesterase (AChE), and the fatty acid profile were evaluated. Results revealed different metabolic responses in both species. Despite previous studies indicating that the exudate affected G. umbilicalis’ survival and behavior, this does not seem to result from oxidative stress or neurotoxicity. For P. elegans, the inhibition of AChE and the decrease of antioxidant capacity is concomitant with the increase of LPO, suggesting neurotoxicity and oxidative stress as contributor mechanisms of toxicity for this species. Fatty acid profile changes were more pronounced for P. elegans with a general increase in polyunsaturated fatty acids (PUFAs) with the exudate exposure, which commonly means a defense mechanism protecting from membrane disruption. Nonetheless, the omega-3 PUFAs arachidonic acid (ARA) and docosapentaenoic acid (DPA) increased in both invertebrates, indicating a common regulation mechanism of inflammation and immunity responses
- Chironomus riparius proteome responses to spinosad exposurePublication . Monteiro, Hugo R.; Pestana, João L.T.; Soares, A.M.V.M.; Devreese, Bart; Lemos, Marco F.L.The potential of proteome responses as early-warning indicators of insecticide exposure was evaluated using the non-biting midge Chironomus riparius (Meigen) as the model organism. Chironomus riparius larvae were exposed to environmentally relevant concentrations of the neurotoxic pesticide spinosad to uncover molecular events that may provide insights on the long-term individual and population level consequences. The iTRAQ labeling method was performed to quantify protein abundance changes between exposed and non-exposed organisms. Data analysis revealed a general dose-dependent decrease in the abundance of globin proteins as a result of spinosad exposure. Additionally, the downregulation of actin and a larval cuticle protein was also observed after spinosad exposure, which may be related to previously determined C. riparius life-history traits impairment and biochemical responses. Present results suggest that protein profile changes can be used as early warning biomarkers of pesticide exposure and may provide a better mechanistic interpretation of the toxic response of organisms, aiding in the assessment of the ecological effects of environmental contamination. This work also contributes to the understanding of the sublethal effects of insecticides in invertebrates and their molecular targets.
- Biochemical performance of native and introduced clam species living in sympatry: The role of elements accumulation and partitioningPublication . Velez, Cátia; Leandro, Sérgio; Figueira, Etelvina; Soares, Amadeu M.V.M.; Freitas, RosaThe present study reports metal and arsenic contamination in sediments, as well as element accumulation and partitioning in native (Ruditapes decussatus and Venerupis corrugata) and introduced (Ruditapes philippinarum) clam species living in sympatry at the Obidos lagoon (Portugal). The biochemical performance and the human health risks derived from the consumption of these species are also discussed. The results obtained showed that R. decussatus was the most abundant species in all the sampling sites, revealing that the introduced clam has not yet supplanted the native species. The concentration of elements was higher in areas with higher Total Organic Matter (TOM) and fines content, being Chromium (Cr), Copper (Cu) and Lead (Pb) the most abundant metals. Clams from these areas showed the highest concentration of elements but the lowest bioaccumulation levels. Furthermore, except for As, higher concentration of elements was found in clams insoluble fraction, the less toxic fraction to the organisms. Due to the low contamination levels and because elements, except As, were mainly allocated to the insoluble fraction, clams presented similar biochemical parameters among distinct areas, with no significant oxidative stress induced. Furthermore, clams from the Obidos lagoon represent a low health risk to human consumption since, except for As, their contamination levels were below the maximum permissible limits defined by international organizations.
- The use of Cerastoderma glaucum as a sentinel and bioindicator species: Take-home messagePublication . Velez, Cátia; Pires, Adília; Sampaio, Leandro; Cardoso, Paulo; Moreira, Anthony; Leandro, Sérgio; Figueira, Etelvina; Soares, Amadeu M.V.M.tBivalves are frequently used to assess environmental contamination, and are often considered goodsentinel and/or bioindicator species. For that reason the bioaccumulation and toxicity induced by metalsand As in the cockle Cerastoderma glaucum, collected from areas with different contamination levelsalong the Óbidos lagoon (Portugal), were used to evaluate the use of this species as sentinel and/orbioindicator. The results showed that areas in the middle of the lagoon presented lower metals and Asconcentrations, lower total organic matter content and lower percentage of fine particles than areasin the Bom Sucesso arm. In all areas Cr, Pb and Cu were the most abundant elements, while Ni, As,Cd and Hg were less abundant. Results also showed a moderate correlation between total elementsconcentrations found in C. glaucum and in sediment, and thus caution should be taken when consideringthis species as a good sentinel species. The present study also revealed that, in general, C. glaucum fromareas in the middle of the lagoon accumulated higher concentrations of metals and As (Biota-SedimentAccumulation Factor >1) than cockles from the most polluted areas located in the Bom Sucesso arm.However, in all areas, the majority of metals (Cu, Cr, Pb) were found in cockles insoluble fraction whichmay explain low cellular damage and reduced oxidative stress responses observed. Therefore, our resultsmay further alert for caution when identifying C. glaucum as a good bioindicator species. Thus, our findingshighlight the fact that studies should be cautious when selecting species for environmental monitoring,since good sentinels or bioindicators in highly polluted systems may not act in the same way in lowor moderately contaminated areas. Furthermore, our study warns for the misclassification of cockles indifferent ecosystems.© 2015 Elsevier Ltd. All rights reserved.1. IntroductionCoastal systems have been constantly threatened by pollution,due to the increase of urbanization, agriculture and industrialactivities (Green-Ruiz and Páez-Osuna, 2001; Poulos et al., 2000).Considering this, it is well established that sediment act as a sink fora variety of contaminants, such as metals and metalloids (Buruaemet al., 2012; Hoffman et al., 2002), affecting benthic organisms(Dauvin, 2008). Environmental impact assessment studies haverelied on monitoring benthic community parameters (e.g. speciesrichness and abundance), measuring the concentrations of selected∗Corresponding author at: Departamento de Biologia & CESAM, Universi-dade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.Tel.: +351 234370782; fax: +351 234372587.E-mail
- Two-generational effects of contaminants in Daphnia magna : Effects of offspring qualityPublication . Campos, Bruno; Jordão, Rita; Rivetti, Claudia; Lemos, Marco; Soares, Amadeu; Tauler, Roma; Barata, CarlosThe authors set up a protocol to perform a 2-generational ring test using the existing guidelines for the Daphnia magna reproduction test. It is well known in ecology that size and quality of offspring vary across the first clutches in D. magna and that certain chemicals affect offspring quality. Therefore, the origin of the second generation is an important factor to consider. Two-generational effects across first, second, and third clutches were evaluated using 4-nonylphenol; those across first and third clutches were evaluated using tributyltin, and those across the third clutch were evaluated using piperonyl butoxide. The compound showing the greatest aggravation of toxic effects between the parental and second generations was piperonyl butoxide, followed by 4-nonylphenol, whereas intergenerational effects of tributyltin varied across experiments. The studied chemicals affected the quantity and quality of the offspring produced by exposed females of the parental generation, those effects being greater in third-clutch neonates. Therefore, when third-clutch offspring were further exposed, they turned out to be more sensitive than the parental generation. The results are in line with those obtained in multigenerational studies using mammalian tests, which showed that, in many cases, effects on the second generation can be predicted by evaluating the quality of the offspring produced.