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- Gender-specific histopathological response in guppies Poecilia reticulata exposed to glyphosate or its metabolite aminomethylphosphonic acidPublication . Antunes, Adriana Maria; Lopes Rocha, Thiago; Pires, Fernando Santiago; de Freitas, Meire Alves; Milhomem Cruz Leite, Vanessa Rafaela; Arana, Sarah; Moreira, Paulo Cesar; Teixeira Saboia-Morais, Simone MariaEcotoxicity of glyphosate (GLY) and itsmetabolite aminomethylphosphonic acid (AMPA) was investigated in guppies, Poecilia reticulata. We tested the effects of these chemicals on the gills and liver of bothmale and female guppies using qualitative and quantitative histopathological analyses associated with histopathological condition indexes. Both genders showed similar median lethal concentration (LC50) at 96 h for GLY (68.78 and 70.87mg l(-1)) and AMPA (180 and 164.32mg l(-1)). However, the histopathological assessment of both fish organs exposed to sublethal concentrations of GLY (35mg l(-1)) and AMPA ( 82mg l(-1)) for 96h showed a tissue-and gender-specific histopathological response. In both exposure assays, fish presented mainly progressive changes, such as proliferation of the interlamellar epithelium, partial and total fusion of secondary lamellae. The liver showed mainly regressive changes, such as steatosis, pyknotic nuclei and high distribution of collagen fibers. Unusually large hepatocytes as degenerated cells were also detected. Histopathological changes in gills were similar for the males and females, but the liver response was different between the genders. The hepatic inflammatory changes were more common in males. The increase in the area of hepatocyte vacuoles is gender dependent with higher values in the male compared to the female guppies exposed to GLY and AMPA. Multiparametric analysis indicated that the male guppies are-more sensitive than females, particularly in the presence of AMPA. Our study shows that the histopathological assessment associated with gender-specific response can be successfully used in ecotoxicological assessment of GLY and the metabolite AMPA. Copyright (C) 2017 JohnWiley & Sons, Ltd.
- Changes in metallothionein transcription levels in the mussel Mytilus galloprovincialis exposed to CdTe quantum dotsPublication . Lopes Rocha, Thiago; Bilbao, Eider; Cardoso, Cátia; Soto, Manu; Bebianno, Maria JoãoQuantum dots (QDs) are a class of engineered nanoparticles (ENPs) with several biomedical, industrial and commercial applications. However, their metabolism and detoxification process in aquatic invertebrates and environmental health hazards remain unclear. This study investigate the transcriptional changes of metallothioneins (MTs) isoforms (mt10IIIa and mt20IV) induced by CdTe QDs, in comparison with its dissolved counterpart, in the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and to the same Cd concentration (10 µg Cd L-1) of dissolved Cd for 14 days and mt transcription levels were measured by real time quantitative PCR (qPCR). Tissue specific mt transcription patterns were observed in mussels exposed to both Cd forms, wherein the gills were a more sensitive organ compared to the digestive gland. No significant changes were observed in mt10IIIa transcription levels in mussels exposed to both Cd forms. In contrast, transcription of mt20IV was tissue and exposure time dependent, with higher mt20IV mRNA levels in mussels exposed to QDs and dissolved Cd when compared to unexposed mussels. Multivariate analysis indicates particle-specific effects after 14 days of exposure and a dual role of MTs in the QD metabolism and in the protection against oxidative stress in mussels exposed to Cd-based ENPs.
- Assessing cadmium-based quantum dots effect on the gonads of the marine mussel Mytilus galloprovincialisPublication . 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.
- Immunocytotoxicity, cytogenotoxicity and genotoxicity of cadmium-based quantum dots in the marine mussel Mytilus galloprovincialisPublication . Lopes Rocha, Thiago; Gomes, Tânia; Cardoso, Cátia; Letendre, Julie; Pinheiro, José Paulo; Serrão Sousa, Vânia; Ribau Teixeira, Margarida; Bebianno, MariaThere 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.
- A glyphosate-based herbicide induces histomorphological and protein expression changes in the liver of the female guppy Poecilia reticulataPublication . Rezende dos Santos, Ana Paula; Lopes Rocha, Thiago; Borges, Clayton Luiz; Bailao, Alexandre Melo; de Almeida Soares, Celia Maria; Teixeira de Saboia-Morais, Simone MariaGlyphosate-based herbicides (GBH) are among the most common herbicides found in aquatic systems, but limited data are available about their mode of action and hepatotoxicity in fish. This study investigated the hepatotoxicity induced by GBH in the guppy Poecilia reticulae using a histopathological assessment associated with a proteomic approach. Guppies were exposed to GBH for 24 h at 1.8 mg of glyphosate L-1, corresponding to 50% of the LC50, 96 h. The results indicate that the GBH at 1.8 mg of glyphosate L-1 induce the development of hepatic damage in P. reticulate, which is exposure-time dependent. The histopathological indexes demonstrate that GBH cause inflammatory, regressive, vascular and progressive disorders in the liver of guppies. Using 2D gel electrophoresis associated with mass spectrometry, 18 proteins that changed by GBH were identified and were related to the cellular structure, motility and transport, energy metabolism and apoptosis. The results show that the acute exposure to GBH causes hepatic histopathological damage related to protein expression profile changes in P. reticulate, indicating that a histopathological assessment associated with a proteomic analysis provides a valuable approach to assess the toxic effects of GBH in sentinel fish species. (C) 2016 Elsevier Ltd. All rights reserved.
- Tissue specific responses to cadmium-based quantum dots in the marine mussel Mytilus galloprovincialisPublication . Lopes Rocha, Thiago; Gomes, Tânia; Mestre, Nélia; Cardoso, Cátia; Bebianno, Maria JoãoIn recent years, Cd-based quantum dots (QDs) have generated interest from the life sciences community due to their potential applications in nanomedicine, biology and electronics. However, these engineered nanomaterials can be released into the marine environment, where their environmental health hazards remain unclear. This study investigated the tissue-specific responses related to alterations in the antioxidant defense system induced by CdTe QDs, in comparison with its dissolved counterpart, using the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd for 14 days at 10 μgCd L(-1) and biomarkers of oxidative stress [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (total, Se-independent and Se-dependent GPx) and glutathione-S-transferase (GST) activities] were analyzed along with Cd accumulation in the gills and digestive gland of mussels. Results show that both Cd forms changed mussels' antioxidant responses with distinct modes of action (MoA). There were tissue- and time-dependent differences in the biochemical responses to each Cd form, wherein QDs are more pro-oxidant when compared to dissolved Cd. The gills are the main tissue affected by QDs, with effects related to the increase of SOD, GST and GPx activities, while those of dissolved Cd was associated to the increase of CAT activity, Cd accumulation and exposure time. Digestive gland is a main tissue for accumulation of both Cd forms, but changes in antioxidant enzyme activities are smaller than in gills. A multivariate analysis revealed that the antioxidant patterns are tissue dependent, indicating nano-specific effects possibly associated to oxidative stress and changes in redox homeostasis.
- Environmental behaviour and ecotoxicity of quantum dots at various trophic levels: A reviewPublication . Rocha, Thiago Lopes; Mestre, Nélia; Teixeira Saboia-Morais, Simone Maria; Bebianno, Maria JoãoDespite the wide application of quantum dots (QDs) in electronics, pharmacy and nanomedicine, limited data is available on their environmental health risk. To advance our current understanding of the environmental impact of these engineered nanomaterials, the aimof this review is to give a detailed insight on the existing information concerning the behaviour, transformation and fate of QDs in the aquatic environment, as well as on its mode of action (MoA), ecotoxicity, trophic transfer and biomagnification at various trophic levels (micro-organisms, aquatic invertebrates and vertebrates). Data show that several types of Cd-based QDs, even at low concentrations (bmg Cd L-1), induce different toxic effects compared to their dissolved counterpart, indicating nano-specific ecotoxicity. QD ecotoxicity at different trophic levels is highly dependent on its physico-chemical properties, environmental conditions, concentration and exposure time, as well as, species, while UV irradiation increases its toxicity. The state of the art regarding the MoA of QDs according to taxonomic groups is summarised and illustrated. Accumulation and trophic transfer of QDs was observed in freshwater and seawater species, while limited biomagnification and detoxification processes were detected. Finally, current knowledge gaps are discussed and recommendations for future research identified. Overall, the knowledge available indicates that in order to develop sustainable nanotechnologies there is an urgent need to develop Cd-free QDs and new "core-shell-conjugate" QD structures. (C) 2016 Elsevier Ltd. All rights reserved.
- Ecotoxicity of rare earths in the marine mussel Mytilus galloprovincialis and a preliminary approach to assess environmental riskPublication . Mestre, Nélia; Serrão Sousa, Vânia; Lopes Rocha, Thiago; Bebianno, Maria JoãoThe increasing use of rare earth elements (REEs) in diverse technological applications has augmented the demand and exploitation of these worldwide, leading to a higher input of REEs + Yttrium (Y) in the marine environment. The present study investigated the ecotoxicity of Lanthanum (La) and Y to Mytilus galloprovincialis developing embryos and juveniles. This was achieved by quantifying the embryogenesis success after 48 h, and survival of juveniles after 96 h of exposure to different concentrations of La and Y. Results show that both La and Y are more toxic to developing embryos and larvae than to juveniles of M. galloprovincialis. Predicted no-effect concentration (PNEC) values were also derived for the embryo development as a preliminary approach to assess the environmental risk for these compounds to marine organisms. Results revealed that La is more toxic than Y. The high sensitivity of the early developmental stages to these compounds highlight the relevance of including these stages when evaluating the toxicity of chemicals where little information is available. Although older life stages may be more tolerant to toxicants, the population survival will be compromised if new recruits are not viable, with implications to the whole ecosystem health and functioning of the impacted area. Information on the ecotoxicity of chemicals with expanded technological use and that may be released during deep-sea mining activities is urgent in order to help estimate environmental impacts.
- Toxicokinetics and tissue distribution of cadmium-based Quantum Dots in the marine mussel Mytilus galloprovincialisPublication . Lopes Rocha, Thiago; Gomes, Tânia; P. Pinheiro, José; Serrão Sousa, Vânia; Nunes, Luís; Ribau Teixeira, Margarida; Bebianno, Maria JoãoEnvironmental 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.
- Ecotoxicological impact of engineered nanomaterials in bivalve molluscs: an overviewPublication . Lopes Rocha, Thiago; Gomes, Tânia; Serrão Sousa, Vânia; Mestre, Nélia; Bebianno, Maria JoãoThe increasing production and application of engineered nanomaterials (ENMs) in consumer products over the past decade will inevitably lead to their release into aquatic systems and thereby cause the exposure to aquatic organisms, resulting in growing environmental and human health concern. Since bivalves are widely used in the monitoring of aquatic pollution, the aim of this review was to compile and analyse data concerning the ecotoxicity of ENMs using bivalve molluscs. The state of the art regarding the experimental approach, characterization, behaviour, fate, bioaccumulation, tissue and subcellular distribution and mechanisms of toxicity of ENMs in marine and freshwater bivalve molluscs is summarized to achieve a new insight into the mode of action of these nanoparticles in invertebrate organisms. This review shows that the studies about the toxic effects of ENMs in bivalves were conducted mainly with seawater species compared to freshwater ones and that the genus Mytilus is the main taxa used as a model system. There is no standardization of experimental approaches for toxicity testing and reviewed data indicate the need to develop standard protocols for ENMs ecotoxicological testing. In general, the main organ for ENM accumulation is the digestive gland and their cellular fate differs according to nano-specific properties, experimental conditions and bivalve species. Endosomal-lysosomal system and mitochondria are the major cellular targets of ENMs. Metal based ENMs mode of action is related mainly to the dissolution and/or release of the chemical component of the particle inducing immunotoxicity, oxidative stress and cellular injury to proteins, membrane and DNA damage. This review indicates that the aquatic environment is the potential ultimate fate for ENMs and confirms that bivalve molluscs are key model species for monitoring aquatic pollution by ENMs.