Browsing by Author "Neves, Joana"
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- Dermocosmética: qualidade na produção e análise comparativaPublication . Neves, Joana; Oliveira, Ana Isabel; Nascimento, Ana Paula; Cunha, Sofia; Nogueira, Lúcia; Silva, Manuel; Prudêncio, Cristina; Vieira, MónicaOs cosméticos podem ser utilizados na higiene pessoal ajudando a melhorar a aparência. Para a sua produção, é necessário o cumprimento de normas específicas que garantam a qualidade do produto, pelo que o design da estrutura onde estes são produzidos é um fator determinante.
- Effects of interaction and bioaccessibility of the cyanotoxins microcystin and cylindrospermopsin in aquatic and terrestrial speciesPublication . Freitas, Marisa; Azevedo, Joana; Carvalho, António Paulo; Planchon, Sébastien; Renaut, Jenny; Mendes, Vera; Manadas, Bruno; Pinto, Edgar; Barreiro, Aldo; Neves, Joana; Campos, Alexandre; Vasconcelos, VitorThe occurrence and proliferation of toxic cyanobacteria blooms as a potential consequence of eutrophication and climate change are an emergent environmental concern worldwide. Microcystin-LR (MC-LR), mainly produced by Microcystisaeruginosa is the most documented and studied cyanotoxin. Cylindrospermopsin (CYN) has been recognized of increased concern due to the invasive nature of its main producer, Cylindrospermopsisraciborskii. Recent studies support the hypothesis that MC-LR and CYN exert harmful effects on crop plants. Lettuce, Lactuca sativa, is an important commercial leafy vegetable, which supplies important components for a healthy diet (e.g., fibers, minerals and antioxidants). Therefore, it is of particular interest the knowledge of lettuce sensitivity to ecologically relevant concentrations of cyanotoxins, inclusively mixtures. Proteomic technologies seem to be suitable to investigate the effects of MC-LR and CYN and may allow the identification of early stress responses, which are not perceptible by traditional endpoints. Proteomics may also provide new insights of protein biomarkers of exposure and the identification of allergenic proteins, which may be of interest for human health risk assessment. However, human health problems due to MC-LR and CYN are most likely associated to its chronic exposure by drinking water and contaminated food. Previous studies have shown that aquatic organisms, especially bivalves (filter-feeding organisms), can accumulate high levels of cyanotoxins without lethal effect. Based on the potential for human health risks, a provisional tolerable daily intake (TDI) of 0.04 and 0.03μg/kg-body weight, has been established for MC-LR and CYN, respectively. However, the risks associated to the consumption of contaminated food may increase if the consumers use storage and processing practices that enhance the concentration of cyanotoxins and their bioaccessibility. It has been reported that MCs are stable at high concentration of cyanotoxins and their bioaccessibility. It has been reported that MCs are stable at high temperatures (above 300 °C) and they can with stand several hours boiling. Likewise, CYN is highly watersoluble and stable to extreme temperatures and pHs, thus the knowledge of the influence of storage and cooking practices as well as human digestion on MC-LR and CYN concentration in food is required to a more accurate human risk assessment.
- Effects of microcystin-LR, cylindrospermopsin and a microcystin-LR/cylindrospermopsin mixture on growth, oxidative stress and mineral content in lettuce plants (Lactuca sativa L.)Publication . Freitas, Marisa; Azevedo, Joana; Pinto, Edgar; Neves, Joana; Campos, Alexandre; Vasconcelos, VitorToxic cyanobacterial blooms are documented worldwide as an emerging environmental concern. Recent studies support the hypothesis that microcystin-LR (MC-LR) and cylindrospermopsin (CYN) produce toxic effects in crop plants. Lettuce (Lactuca sativa L.) is an important commercial leafy vegetable that supplies essential elements for human nutrition; thus, the study of its sensitivity to MC-LR, CYN and a MC-LR/CYN mixture is of major relevance. This study aimed to assess the effects of environmentally relevant concentrations (1, 10 and 100 µg/L) of MC-LR, CYN and a MC-LR/CYN mixture on growth, antioxidant defense system and mineral content in lettuce plants. In almost all treatments, an increase in root fresh weight was obtained; however, the fresh weight of leaves was significantly decreased in plants exposed to 100 µg/L concentrations of each toxin and the toxin mixture. Overall, GST activity was significantly increased in roots, contrary to GPx activity, which decreased in roots and leaves. The mineral content in lettuce leaves changed due to its exposure to cyanotoxins; in general, the mineral content decreased with MC-LR and increased with CYN, and apparently these effects are time and concentration-dependent. The effects of the MC-LR/CYN mixture were almost always similar to the single cyanotoxins, although MC-LR seems to be more toxic than CYN. Our results suggest that lettuce plants in non-early stages of development are able to cope with lower concentrations of MC-LR, CYN and the MC-LR/CYN mixture; however, higher concentrations (100 µg/L) can affect both lettuce yield and nutritional quality.
- Exposure of Lycopersicon Esculentum to Microcystin-LR: Effects in the Leaf Proteome and Toxin Translocation from Water to Leaves and FruitsPublication . Gutiérrez-Praena, Daniel; Campos, Alexandre; Azevedo, Joana; Neves, Joana; Freitas, Marisa; Guzmán-Guillén, Remédios; Cameán, Ana María; Renaut, Jenny; Vasconcelos, VítorNatural toxins such as those produced by freshwater cyanobacteria have been regarded as an emergent environmental threat. However, the impact of these water contaminants in agriculture is not yet fully understood. The aim of this work was to investigate microcystin-LR (MC-LR) toxicity in Lycopersicon esculentum and the toxin accumulation in this horticultural crop. Adult plants (2 month-old) grown in a greenhouse environment were exposed for 2 weeks to either pure MC-LR (100 μg/L) or Microcystis aeruginosa crude extracts containing 100 μg/L MC-LR. Chlorophyll fluorescence was measured, leaf proteome investigated with two-dimensional gel electrophoresis and Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF)/TOF, and toxin bioaccumulation assessed by liquid chromatography-mass spectrometry (LC-MS)/MS. Variations in several protein markers (ATP synthase subunits, Cytochrome b6-f complex iron-sulfur, oxygen-evolving enhancer proteins) highlight the decrease of the capacity of plants to synthesize ATP and to perform photosynthesis, whereas variations in other proteins (ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit and ribose-5-phosphate isomerase) suggest an increase of carbon fixation and decrease of carbohydrate metabolism reactions in plants exposed to pure MC-LR and cyanobacterial extracts, respectively. MC-LR was found in roots (1635.21 μg/kg fw), green tomatoes (5.15–5.41 μg/kg fw), mature tomatoes (10.52–10.83 μg/kg fw), and leaves (12,298.18 μg/kg fw). The results raise concerns relative to food safety and point to the necessity of monitoring the bioaccumulation of water toxins in agricultural systems affected by cyanotoxin contamination.
- The negative impact of cosmeticsPublication . Neves, Joana; Prudêncio, Cristina; Vieira, MónicaCosmetics are widely used by infants, children, adults and workers of salon beauty with different purposes. However, they can cause adverse effects due its composition. This review is focused in the potential adverse effects to the human and other organism’s health and to the environment of some of the ingredients used in the formulation of cosmetics. In order to prevent these harmful effects, there are also alternatives to the potential hazardous substances that should be taken in account by consumers and manufactures when choosing a product in order to enhance the quality of life, avoiding health risks.
- Tradução de contos russos retirados do livro "Читаем по-русски" de Natália VladimirovnaPublication . Ustimenko, Maria Helena Guimarães; Neves, JoanaTradução de contos russos retirados do livro "Читаем по-русски" de Natália Vladimirovna