Browsing by Author "Teixeira Saboia-Morais, Simone Maria"
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- 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.
- 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.