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Toxicokinetics and tissue distribution of cadmium-based Quantum Dots in the marine mussel Mytilus galloprovincialis

Publication . Lopes Rocha, Thiago; Gomes, Tânia; P. Pinheiro, José; Serrão Sousa, Vânia; Nunes, Luís; Ribau Teixeira, Margarida; Bebianno, Maria João

Environmental health hazards of Quantum Dots (QDs) are of emergent concern, but limited data is available about their toxicokinetics (TK) and tissue distribution in marine bivalves. This study investigated the QDs behavior in seawater, their TK and tissue distribution in Mytilus galloprovincialis, in comparison with soluble Cd. Mussels were exposed to CdTe QDs and soluble Cd for 21 days at 10 μgCd L(-1) followed by a 50 days depuration. TK of QDs in mussels is related to the homo-aggregate uptake, surface charge, aggregation and precipitation as key factors. There were tissue- and time-dependent differences in the TK of both Cd forms, and soluble Cd is the most bioavailable form. Digestive gland is a preferential site for QDs storage and both Cd forms are not eliminated by mussels (t1/2>50 days). Results indicate that the TK model of CdTe QDs in marine mussels is distinct from their soluble counterparts.

2015-09Journal article

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Differential protein expression in mussels Mytilus galloprovincialis exposed to nano and ionic Ag

Publication . Gomes, Tânia; G. Pereira, Catarina; Cardoso, Cátia; Bebianno, Maria João

Ag NPs are one of the most commonly used NPs in nanotechnology whose environmental impacts are to date unknown and the information about bioavailability, mechanisms of biological uptake and toxic implications in organisms is scarce. So, the main objective of this study was to investigate differences in protein expression profiles in gills and digestive gland of mussels Mytilus galloprovincialis exposed to Ag NPs and Ag(+) (10 μg L(-1)) for a period of 15 days. Protein expression profiles of exposed gills and digestive glands were compared to those of control mussels using two-dimensional electrophoresis to discriminate differentially expressed proteins. Different patterns of protein expression were obtained for exposed mussels, dependent not only on the different redox requirements of each tissue but also to the Ag form used. Unique sets of differentially expressed proteins were affected by each silver form in addition to proteins that were affected by both Ag NPs and Ag(+). Fifteen of these proteins were subsequently identified by MALDI-TOF-TOF and database search. Ag NPs affected similar cellular pathways as Ag(+), with common response mechanisms in cytoskeleton and cell structure (catchin, myosin heavy chain), stress response (heat shock protein 70), oxidative stress (glutathione s-transferase), transcriptional regulation (nuclear receptor subfamily 1G), adhesion and mobility (precollagen-P) and energy metabolism (ATP synthase F0 subunit 6 and NADH dehydrogenase subunit 2). Exposure to Ag NPs altered the expression of two proteins associated with stress response (major vault protein and ras partial) and one protein involved in cytoskeleton and cell structure (paramyosin), while exposure to Ag(+) had a strong influence in one protein related to stress response (putative c1q domain containing protein) and two proteins involved in cytoskeleton and cell structure (actin and α-tubulin). Protein identification showed that Ag NPs toxicity is mediated by oxidative stress-induced cell signalling cascades (including mitochondria and nucleus) that can lead to cell death. This toxicity represents the cumulative effect of Ag(+) released from the particles and other properties as particle size and surface reactivity. This study helped to unravel the molecular mechanisms that can be associated with Ag NPs toxicity; nevertheless, some additional studies are required to investigate the exact interaction between these NPs and cellular components.

2013Journal article

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Genotoxicity of copper oxide and silver nanoparticles in the mussel Mytilus galloprovincialis

Publication . Gomes, Tânia; Araújo, Olinda; Pereira, Rita; Catarina Almeida, Ana; Cravo, Alexandra; Bebianno, Maria João

Though there is some information on cytotoxicity of copper nanoparticles and silver nanoparticles on human cell lines, there is no information on their genotoxic and cytotoxic behaviour in bivalve molluscs. The aim of this study was to investigate the genotoxic impact of copper oxide and silver nanoparticles using mussels Mytilus galloprovincialis. Mussels were exposed to 10 μg L⁻¹ of CuO nanoparticles and Cu²⁺ and Ag nanoparticles and Ag⁺ for 15 days to assess genotoxic effects in hemocytes using the comet assay. The results obtained indicated that copper and silver forms (nanoparticles and ionic) induced DNA damage in hemolymph cells and a time-response effect was evident when compared to unexposed mussels. Ionic forms presented higher genotoxicity than nanoparticles, suggesting different mechanisms of action that may be mediated through oxidative stress. DNA strand breaks proved to be a useful biomarker of exposure to genotoxic effects of CuO and Ag nanoparticles in marine molluscs.

2013Journal article

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Immunocytotoxicity, cytogenotoxicity and genotoxicity of cadmium-based quantum dots in the marine mussel Mytilus galloprovincialis

Publication . Lopes Rocha, Thiago; Gomes, Tânia; Cardoso, Cátia; Letendre, Julie; Pinheiro, José Paulo; Serrão Sousa, Vânia; Ribau Teixeira, Margarida; Bebianno, Maria

There is an increased use of Quantum Dot (QDs) in biological and biomedical applications, but little is known about their marine ecotoxicology. So, the aim of this study was to investigate the possible immunocytotoxic, cytogenotoxic and genotoxic effects of cadmium telluride QDs (CdTe QDs) on the marine mussel Mytilus galloprovincialis. Mussels were exposed to 10 μg L(-1) of CdTe QDs or to soluble Cd [Cd(NO3)2] for 14 days and Cd accumulation, immunocytotoxicity [hemocyte density, cell viability, lysosomal membrane stability (LMS), differential cell counts (DCC)], cytogenotoxicity (micronucleus test and nuclear abnormalities assay) and genotoxicity (comet assay) were analyzed. Results show that in vivo exposure to QDs, Cd is accumulated in mussel soft tissues and hemolymph and induce immunotoxic effects mediated by a decrease in LMS, changes in DCC, as well as genotoxicity (DNA damage). However, QDs do not induce significant changes in hemocytes density, cell viability and cytogenetic parameters in opposition to Cd(2+). Soluble Cd is the most cytotoxic and cytogenotoxic form on Mytilus hemocytes due to a higher accumulation of Cd in tissues. Results indicate that immunotoxicity and genotoxicity of CdTe QDs and Cd(2+) are mediated by different modes of action and show that Mytilus hemocytes are important targets for in vivo QDs toxicity.

2014-10Journal article

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Assessing cadmium-based quantum dots effect on the gonads of the marine mussel Mytilus galloprovincialis

Publication . Gonçalves, Joanna M.; Rocha, Thiago Lopes; Nélia Mestre, N. C. Mestre, N. Mestre; Fonseca, T. G.; Bebianno, M.

This study assesses the sex-specific effects induced by CdTe QDs, on the marine mussel Mytilus galloprovincialis in comparison to its dissolved counterpart. A 14 days exposure to CdTe QDs and dissolved Cd was conducted (10 mu g Cd L-1), analysing Cd accumulation, oxidative stress, biotransformation, metallothionein and oxidative damage in the gonads. Both Cd forms caused significant antioxidant alterations, whereby QDs were more pro-oxidant, leading to oxidative damage, being females more affected. Overall, biochemical impairments on gonads of M. galloprovincialis demonstrate that the reproductive toxicity induced by CdTe QDs in mussels are sex-dependent and mediated by oxidative stress and lipid peroxidation. It is crucial to acknowledge how gametes are affected by metal-based nanoparticles, such as Cd-based QDs. As well as understanding the potential changes they may undergo at the cellular level during gametogenesis, embryogenesis and larval development potentially leading to serious impacts on population sustainability and ecosystem health.

2020-04Journal article

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