Efeitos de mixturas de contaminantes emergentes nos ecossistemas aquáticos: uma abordagem a vários níveis de organização biológica

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Effects of mixtures of anticancer drugs in the benthic polychaete Nereis diversicolor

Publication . Fonseca, Tainá; Abessa, Denis M. S.; Bebianno, Maria João

The increasing consumption of anticancer drugs through single and/or combinatory chemotherapy worldwide raised concern regarding their toxicity burden in coastal zones. The toxicity of a mixture of three compounds involving the drugs cisplatin (CisPt), cyclophosphamide (CP) and tamoxifen (TAM) was determined on the marine polychaete Nereis diversicolor exposed to an increasing range of their concentrations, respectively: Mix A: 0.1 + 10 + 0.1 ng L-1; Mix B: 10 + 100 + 10 ng L-1; Mix C: 100 + 500 + 25 ng L-1; Mix D: 100 + 1000 + 100 ng L-1. Different endpoints were assessed, including disturbance in the burrowing behaviour, neurotoxicity (acetylcholinesterase - AChE activity), antioxidant enzymes (superoxide dismutase - SOD; catalase - CAT; selenium-dependent glutathione peroxidase - Se-GPx and total glutathione peroxidases T-GPx activities), biotransformation metabolism (glutathione-S-transferases - GST), lipid peroxidation (LPO) and genotoxicity (DNA damage). Biological effects of the mixtures of anticancer compounds on N. diversicolor were compared with previous studies about effects on the same biological model under single-drug exposure conducted with the same molecules. Regarding SOD activity, TAM showed an antagonist effect over CisPt and CP in mixtures C and D. In Mix D, there was a synergistic effect of TAM and CisPt that inhibited CAT activity and an additive interaction of CisPt and CP on the Phase II biotransformation enzyme. Drugs in Mix A also suppressed polychaetes' GST activity, although different from the respective single-drug responses, besides able to induce T-GPx activity, that was not sufficient to avoid oxidative damage and mid-grade DNA damage. Due to the absence of burrowing impairment in Mix A, mechanisms involved in neurotoxicity were other than the one driven by AChE alterations. At the intermediary concentrations (Mix B and C), only LPO occurred. Data from drugs individually may not predict the risks provided by mixtures.

2019Journal article

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Effects of microplastics alone and with adsorbed benzo(a)pyrene on the gills proteome of Scrobicularia plana

Publication . Bebianno, Maria; Mendes, Vera M.; O'Donovan, Sarit; Carteny, Camila C.; Keiter, Stephen; Manadas, Bruno

Microplastics (MPs) are globally present in the marine environment, but the biological effects on marine organisms at the molecular and cellular levels remain scarce. Due to their lipophilic nature, MPs can adsorb other contaminants present in the marine environment, which may increase their detrimental effects once ingested by organisms. This study investigates the effects of low-density polyethylene (PE) MPs with and without adsorbed benzo[a]pyrene in the gills proteome of the peppery furrow shell clam, Scrobicularia. plana. Clams were exposed to PE MPs (11-13 µm; 1 mg L-1) for 14 days. BaP was analyzed in whole clams’ soft tissues, and a proteomic approach was changes, oxidative stress fatty acid, DNA binding and, neurotransmission highlighting the potential risk of this type of MPs for the clam health. Conversely, when clam gills were exposed to MPs adsorbed with BaP a higher differentiation of protein expression was observed that besides changes in cytoskeleton and cell structure, oxidative stress, energy metabolism and DNA binding also induce changes in glucose metabolism, RNA binding and apoptosis. These results indicate that the presence of both stressors (MPs and BaP) havea higher toxicological risk to the health of S. plana.

2022Journal article

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Ecotoxicity of emerging contaminants in the reproductive organ of marine mussels mytilus galloprovincialis

Publication . Gonçalves, Joanna M.; Bebianno, M.

Contaminants of emerging concern (CECs) present a new threat to the marine environment, and it is vital to under-stand the interactions and possible toxicity of CEC mixtures once they reach the ocean. CECs-such as metal nanopar-ticles, nanoplastics, and pharmaceuticals-are groups of contaminants some of which have been individually evaluated, though their interactions as mixtures are still not fully understood. To ensure a healthy and prosperous fu-ture generation, successful reproduction is key: however, if hindered, population dynamics may be at danger leading to a negative impact on biodiversity. This study aimed to understand the effects of silver (20 nm nAg, 10 mu g/L), polysty-rene nanoparticles (50 nm nPS, 10 mu g/L), and 5-fluorouracil (5FU, 10 ng/L) individually and as a mixture (10 mu g/L of nPS + 10 mu g/L of nAg +10 ng/L of 5FU) in the gonads of Mytilus galloprovincialis. A multibiomarker approach, namely the antioxidant defence system (ADS; superoxide dismutase, catalase, glutathione peroxidases, glutathione - S - trans-ferases activities), and oxidative damage (OD; lipid peroxidation) were analysed in the gonads of mussels. All exposure treatments after 3 days led to an increase of enzymatic activity, followed by an inhibition after 14 and 21 days. Thus, ADS was overwhelmed due to the generation of ROS, resulting in OD, except for nPS exposed mussels. The OD in Mix exposed mussels increased exponentially by 57-fold. When CEC mixtures interact, they are potentially more hazardous than their individual components, posing a major threat to marine species. To understand synergistic and antagonistic interactions, a model was applied, and antagonistic interactions were observed in evaluated biomarkers at all time-points, apart from a synergistic interaction at day 3 relative to LPO. Results indicate that the effects observed in Mix-exposed mussel gonads are mainly due to the interaction of nAg and 5FU but not nPS.

2023Journal article

Open access

Chronic toxicity of polystyrene nanoparticles in the marine mussel Mytilus galloprovincialis

Publication . Gonçalves, Joanna M.; Sousa, Vânia Serrão; Teixeira, Margarida Ribau; Bebianno, Maria

Nanoplastics (NP) (1–100 nm) are a growing global concern, and their adverse effects in marine organisms are still scarce. This study evaluated the effects of polystyrene nanoplastics (10 μg/L; 50 nm nPS) in the marine mussel Mytilus galloprovincialis after a 21 – day exposure. The hydrodynamic diameter and zeta potential of nPS were analysed, over time, in seawater and ultrapure water. A multibiomarker approach (genotoxicity (the comet assay) was assessed in mussel haemocytes, and the antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)), biotransformation enzyme (glutathione – S – transferase (GST)), and oxidative damage (LPO)) was assessed in gills and digestive glands to evaluate the toxicity of nPS towards mussels. In seawater, aggregation of nPS is favoured and consequently the hydrodynamic diameter increases. Genotoxicity was highly noticeable in mussels exposed to nPS, presenting a higher % tail DNA when compared to controls. Antioxidant enzymes are overwhelmed after nPS exposure, leading to oxidative damage in both tissues. Results showed that mussel tissues are incapable of dealing with the effects that this emerging stressor pursues towards the organism. The Integrated Biomarker Response index, used to summarise the biomarkers analysed into one index, shows that nPS toxicity towards mussels are both tissue and time dependent, being that gills are the tissue most compromised.

2021Journal article

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