Browsing by Author "Almeida, A."
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- Analysis of the use of microcystin-contaminated water in the growth and nutritional quality of the root-vegetable, Daucus carotaPublication . Machado, J.; Azevedo, J.; Freitas, Marisa; Pinto, Edgar; Almeida, A.; Vasconcelos, V.; Campos, A.Toxic cyanobacterial blooms are often observed in freshwaters and may reflect the increased eutrophication of these environments and alterations in climate. Cyanotoxins, such as microcystins (MCs), are an effective threat to many life forms, ranging from plants to humans. Despite the research conducted to date on cyanotoxins, the risks associated to the use of contaminated water in agriculture require further elucidation. To tackle this aim, a research was conducted with the root-vegetable Daucus carota. The specific aims of this work were the following: (i) to evaluate the effects of MC-LR on the plant growth and photosynthesis; (ii) to evaluate the nutritional quality of carrot roots; and (iii) to measure bioaccumulation. To this purpose, young carrots were grown in soil during 1 month in natural conditions and exposed to Mycrocystis aeruginosa aqueous extracts containing environmentally realistic concentrations of MC-LR (10 and 50 MC-LR μg/L). The results showed that MC-LR may decrease root growth after 28 days of exposure to 50 μg/L and increase photosynthetic efficiency. We also observed changes in mineral and vitamin content in carrots as a result of the exposure to contaminated water. Moreover, MC-LR was detected in carrot roots by ELISA at very low concentration 5.23 ± 0.47 ng MC eq./g FW. The soil retained 52.7 % of the toxin potentially available for plants. This result could be attributed to MC-LR adsorption by soil particles or due to microbial degradation of the toxin. We conclude that the prolonged use of MC-LR-contaminated water may affect crop growth, alter the nutritional value of vegetable products, and potentiate contamination.
- Anatomic region differences and age-related changes on Na+ and K+ levels in human brainPublication . Pinto, Edgar; Ramos, P.; Carvalhido, A.; Pinto, N.; Mendes, R.; Santos, A.; Almeida, A.Neurodegenerative diseases (ND) have been the subject of intensive research in last years in an attempt to understand the mechanisms underlying the neurodegeneration process. The etiology of these diseases is multifactorial, involving a complex interaction between the aging, genetic predisposition and environmental factors. In particular, the role of metals as risk factors for neurodegenerative disorders is currently being studied. As regards to this topic, the knowledge of metal distribution in the brain is of major importance. Evidence suggests that Alzheimer's disease (AD) is associated with impaired depressed Na+/K+ ATPase levels in AD brain that might lead to a cellular ion imbalance. Recent studies show that a pronounced levels in AD brain that might lead to a cellular ion imbalance. Recent studies show that a pronounced and the age of individuals.
- Biological effects and bioaccumulation of gold in gilthead seabream (Sparus aurata) – Nano versus ionic formPublication . Barreto, A.; Dias, A. A.; Duarte, B.; Pinto, Edgar; Almeida, A.; Trindade, T.; Soares, A. M. V. M.; Hylland, K.; Loureiro, S.; Oliveira, M.The question of whether gold (Au) is more toxic as nanoparticles or in its ionic form remains unclear and controversial. The present work aimed to clarify the effects of 96 h exposure to 4, 80 and 1600 μg·L−1 of 7 nm gold nanoparticles (AuNPs) – (citrate coated (cAuNPs) or polyvinylpyrrolidone coated (PVP-AuNPs)) – and ionic Au (iAu) on gilthead seabream (Sparus aurata). Effects at different levels of biological organization (behaviour, neurotransmission, biotransformation, oxidative stress/damage and genotoxicity) were assessed. cAuNPs induced oxidative stress and damage (lipid peroxidation increase), even at 4 μg·L−1, and reduced the ability of S. aurata to swim against a water flow at 1600 μg·L−1. Exposure to cAuNPs induced more adverse effects than exposure to PVP-AuNPs. All tested concentrations of Au (nano or ionic form) induced DNA breaks and cytogenetic damage in erythrocytes of S. aurata. Generally, iAu induced significantly more effects in fish than the nano form, probably associated with the significantly higher accumulation in the fish tissues. No fish mortality was observed following exposure to AuNPs, but mortality was observed in the group exposed to 1600 μg·L−1 of iAu.
- Circular economy using waste from different industries in leather retainningPublication . Alves, C.; Silva, V.F.; Crispim, Alfredo; Almeida, A.; Pinto, G.; Gaião, J.; Sousa, N.; Duarte, J.A circular economy is based on an economy that in principle, moves away from the accelerated model of consumption and disposal. Thus, the flow associated with the product, instead of being translated by a straight line, is now regarded as a circle or cycle. The leather manufacturing applies several physical and chemical treatments in different stages to transform the skin into leather. The pulp and paper industry generate several byproducts such as tannins and lignins. The sulfited lignins are a particular type of black liquor and could be used as dispersing, pre-tanning and retanning agents . During the chestnut freezing process, as consequence of the quality control, a significant quantity of chestnut fruit is rejected and not accepted by the consumer. Due to its high starch content, the chestnut fruit reject is used to produce chestnut flour which can be used as a filler retanning agent for leather. From the biodiesel process results a byproduct, which represents 10 % wt of the overall production, the crude glycerol. The hygroscopic effect of glycerol and its emulsifying and lubricant effect can be enhanced for the leather fatliquoring.
- Co-gasification of glycerol/fat mixtures in a downflow fixed bed reactor: Preliminary resultsPublication . Almeida, A.; Pilão, Rosa Maria; Ramalho, Elisa; Ribeiro, A.M.; Pinho, CarlosThe aim of this work was to assess the technical viability of glycerol/fat co-gasification. The gasification performance was studied in a downflow fixed bed reactor using steam as oxidizing agent. Tests were performed with a mixture of 10% of fat and 52% of water, and the effect of temperature was evaluated in the 800 ºC to 950 ºC range. Samples of dry gas from the gasifier were collected and analysed by gas chromatography in order to determine the CO, CO2, CH4 and H2 content. The results revealed that the co-gasification of glycerol/fat mixtures seems to be a feasible technical option. Best results of the gasification parameters were obtained at the highest tested temperature, 950 °C.
- Effects and bioaccumulation of gold nanoparticles in the gilthead seabream (Sparus aurata) – Single and combined exposures with gemfibrozilPublication . Barreto, A.; Luis, L.G.; Pinto, E.; Almeida, A.; Paíga, Paula; Santos, Lúcia H.M.L.M.; Delerue-Matos, Cristina; Trindade, T.; Soares, A.M.V.M.; Hylland, K.; Loureiro, S.; Oliveira, M.Gold nanoparticles (AuNPs) are found in a wide range of applications and therefore expected to present increasing levels in the environment. There is however limited knowledge concerning the potential toxicity of AuNPs as well as their combined effects with other pollutants. Hence, the present study aimed to investigate the effects of AuNPs alone and combined with the pharmaceutical gemfibrozil (GEM) on different biological responses (behaviour, neurotransmission, biotransformation and oxidative stress) in one of the most consumed fish in southern Europe, the seabream Sparus aurata. Fish were exposed for 96 h to waterborne 40 nm AuNPs with two coatings - citrate and polyvinylpyrrolidone (PVP), alone or combined with GEM. Antioxidant defences were induced in liver and gills upon both AuNPs exposure. Decreased swimming performance (1600 μg.L-1) and oxidative damage in gills (4 and 80 μg.L-1) were observed following exposure to polyvinylpyrrolidone coated gold nanoparticles (PVP-AuNPs). Generally, accumulation of gold in fish tissues and deleterious effects in S. aurata were higher for PVP-AuNPs than for cAuNPs exposures. Although AuNPs and GEM combined effects in gills were generally low, in liver, they were higher than the predicted. The accumulation and effects of AuNPs showed to be dependent on the size, coating, surface charge and aggregation/agglomeration state of nanoparticles. Additionally, it was tissue' specific and dependent on the presence of other contaminants. Although, gold intake by humans is expected to not exceed the estimated tolerable daily intake, it is highly recommended to keep it on track due to the increasing use of AuNPs.
- Effects of cylindrospermopsin and glyphosate at environmentally relevant concentrations on growth and mineral content of beetroot plants (Beta vulgaris)Publication . Priya, V.; Freitas, Marisa; Pinto, Edgar; Almeida, A.; Oliveira, F.; Azevedo, J.; Campos, A.; Sudhakaran, R.; Vasconcelos, V.Natural toxins produced by freshwater cyanobacteria, such as cylindrospermopsin (CYN), have been regarded as an emergent environmental threat. Cyanotoxins can be applied directly to soil by using contaminated water for agricultural irrigation. Despite the risks for food safety, the impact of cyanotoxins in agriculture is not yet fully understood. Furthermore, in soil-plant system the simultaneous occurrence of cyanotoxins and pesticides can be highly expectable. Pesticides, especially residues of glyphosate (GLY), have been frequently detected in soils and have been recognized to contribute to soil toxicity. Beetroot (Beta vulgaris) are root vegetables, extensively consumed worldwide with great importance for human nourishment and economy. It is, therefore, important to evaluate the effects of using water contaminated with CYN and GLY on beetroot cultivation. This study aimed to assess the effects of environmentally relevant concentrations of CYN, GLY and a mixture of both on growth and mineral content of beetroot (roots and leaves) cultivated in soil system. Plants were exposed in controlled conditions to CYN-crude extracts (50μg/kg) (Chrysosporum ovalisporum culture - LEGE X-001), isolated and in mixture with GLY (750 μg/kg) for 4 months. Beetroot growth was assessed by determining its fresh (Fw) and dry weight (Dw). The determination of mineral content was made by inductively coupled plasma-mass spectrometry (ICP-MS), after sample mineralization by microwaveassisted acid digestion. The results denote that Fw and Dw of beetroot (leaves and roots, respectively) were significantly changed (P
- Effects of gold nanoparticles in gilthead seabream—A proteomic approachPublication . Barreto, A.; Carvalho, A.; Campos, A.; Osório, H.; Pinto, Edgar; Almeida, A.; Trindade, T.; Soares, A. M. V. M.; Hylland, H.; Loureiro, S.; Oliveira, M.Despite the widespread use of nanoparticles (NPs), there are still major gaps of knowledge regarding the impact of nanomaterials in the environment and aquatic animals. The present work aimed to study the effects of 7 and 40 nm gold nanoparticles (AuNPs) – citrate and polyvinylpyrrolidone (PVP) coated – on the liver proteome of the estuarine/marine fish gilthead seabream (Sparus aurata). After 96 h, exposure to AuNP elicited alterations on the abundance of 26 proteins, when compared to the control group.
- Effects of single and combined exposures of gold (nano versus ionic form) and gemfibrozil in a liver organ culture of Sparus aurataPublication . Barreto, A.; Carvalho, A.; Silva, D.; Pinto, E.; Almeida, A.; Paíga, P.; Correia-Sá, L.; Delerue-Matos, C.; Trindade, T.; Soares, A.M.V.M.; Hylland, K.; Loureiro, S.; Oliveira, M.In vitro methods have gained rising importance in ecotoxicology due to ethical concerns. The aim of this study was to assess the single and combined in vitro effects of gold, as nanoparticle (AuNPs) and ionic (Au+) form, and the pharmaceutical gemfibrozil (GEM). Sparus aurata liver organ culture was exposed to gold (4 to 7200 μg·L−1), GEM (1.5 to 15,000 μg·L−1) and combination 80 μg·L−1 gold +150 μg·L−1 GEM for 24 h. Endpoints related with antioxidant status, peroxidative/genetic damage were assessed. AuNPs caused more effects than Au+, increasing catalase and glutathione reductase activities and damaging DNA and cellular membranes.
- Genotoxicity of gold nanoparticles in the gilthead seabream (Sparus aurata) after single exposure and combined with the pharmaceutical gemfibrozilPublication . Barreto, A.; Luis, L.G.; Pinto, E.; Almeida, A.; Paíga, Paula; H.M.L.M. Santos, Lúcia; Delerue-Matos, Cristina; Trindade, T.; Soares, A.M.V.M.; Hylland, K.; Loureiro, S.; Oliveira, M.Due to their diverse applications, gold nanoparticles (AuNPs) are expected to increase of in the environment, although few studies are available on their mode of action in aquatic organisms. The genotoxicity of AuNPs, alone or combined with the human pharmaceutical gemfibrozil (GEM), an environmental contaminant frequently detected in aquatic systems, including in marine ecosystems, was examined using gilthead seabream erythrocytes as a model system. Fish were exposed for 96 h to 4, 80 and 1600 μg L-1 of 40 nm AuNPs with two coatings - citrate or polyvinylpyrrolidone; GEM (150 μg L-1); and a combination of AuNPs and GEM (80 μg L-1 AuNPs + 150 μg L-1 GEM). AuNPs induced DNA damage and increased nuclear abnormalities levels, with coating showing an important role in the toxicity of AuNPs to fish. The combined exposures of AuNPs and GEM produced an antagonistic response, with observed toxic effects in the mixtures being lower than the predicted. The results raise concern about the safety of AuNPs and demonstrate interactions between them and other contaminants.