BIOCONNECT - CONECTIVIDADE EM POPULAÇÕES DE PEIXES ESTUARINOS E COSTEIROS: MARCADORES NATURAIS COMO UM INSTRUMENTO PARA GESTÃO E CONSERVAÇÃO

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Organizational Unit

Publications

Comfortably numb: Ecotoxicity of the non-steroidal anti-inflammatory drug ibuprofen on Phaeodactylum tricornutum

Publication . Feijão, Eduardo; Carvalho, Ricardo da Cruz de; Duarte, Irina A.; Matos, Ana Rita; Cabrita, Maria Teresa; Barreiro, Aldo; Lemos, Marco F.L.; Novais, Sara C.; Marques, João Carlos; Caçador, Isabel; Reis-Santos, P.; Silva, Marisa; Fonseca, Vanessa; Duarte, Bernardo

Emerging pollutants such as pharmaceuticals are continuously released to aquatic environments posing a rising threat to marine ecosystems. Yet, monitoring routines and ecotoxicity data on biota worldwide for these substances are lacking. Non-steroidal anti-inflammatory drugs are among the most prescribed and found pharmaceuticals in aquatic environments. The toxicity effects of environmentally relevant concentrations of ibuprofen on primary productivity, oxidative stress and lipid metabolism of the diatom Phaeodactylum tricornutum were assessed. Diatom cultures were exposed to 0, 0.8, 3, 40, 100 and 300 μg L-1 ibuprofen concentrations, usually found in the vicinity of wastewater treatment plants and coastal environments. Higher concentrations (100 and 300 μg L-1) had a negative impact in P. triconutum growth, inhibiting the chloroplastic energy transduction in the electron transport chain resulting in lower energy reaching the PS I (r2 = - 0.55, p < 0.05). In contrast, the mitochondrial electron transport and available energy increased (r2 = 0.68 and r2 = 0.85, p < 0.05 respectively), mostly due to enhancements in lipid and protein contents as opposed to reduction of carbohydrates. A general up-regulation of the antioxidant enzymes could contributed to alleviate oxidative stress resulting in the decrease of lipid peroxidation products (r2 = 0.77, p < 0.05). Canonical analysis of principal components was performed and successfully discriminated exposure groups, with optical data excelling in classifying samples to different ibuprofen concentrations, being potentially used as environmental indicators. Finally, the identified mild to severe effects of ibuprofen on diatoms are likely to be exacerbated by the sustained use of this drug worldwide, underpinning the urgency of evaluating the impacts of this pharmaceutical on coastal and marine trophic webs.

2020Journal article

Restricted access

Glyphosate-based herbicide toxicophenomics in marine diatoms: impacts on primary production and physiological fitness

Publication . Carvalho, Ricardo Cruz de; Feijão, Eduardo; Matos, Ana Rita; Cabrita, Maria Teresa; Novais, Sara C.; Lemos, Marco F.L.; Caçador, Isabel; Marques, João Carlos; Reis-Santos, Patrick; Fonseca, Vanessa F.; Duarte, Bernardo

Glyphosate is the main active component of the commercial formulation Roundup®, the most widely used chemical herbicide worldwide. However, its potential high toxicity to the environment and throughout trophic webs has come under increasing scrutiny. The present study aims to investigate the application of bio-optical techniques and their correlation to physiological and biochemical processes, including primary productivity, oxidative stress, energy balance, and alterations in pigment and lipid composition in Phaeodactylum tricornutum, a representative species of marine diatoms, using the case study of its response to the herbicide glyphosate-based Roundup® formulation, at environmentally relevant concentrations. Cultures were exposed to the herbicide formulation representing effective glyphosate concentrations of 0, 10, 50, 100, 250, and 500 ug L-1. Results showed that high concentrations decreased cell density; furthermore, the inhibition of photosynthetic activity was not only caused by the impairment of electron transport in the thylakoids, but also by a decrease of antioxidant capacity and increased lipid peroxidation. Nevertheless, concentrations of one of the plastidial marker fatty acids had a positive correlation with the highest concentration as well as an increase in total protein. Cell energy allocation also increased with concentration, relative to control and the lowest concentration, although culture growth was inhibited. Pigment composition and fatty acid profiles proved to be efficient biomarkers for the highest glyphosate-based herbicide concentrations, while bio-optical data separated controls from intermediate concentrations and high concentrations.

2020Journal article

Open access

Depressed, hypertense and sore: Long-term effects of fluoxetine, propranolol and diclofenac exposure in a top predator fish

Publication . Duarte, Irina A.; Ries-Santos, Patrick; Novais, Sara C.; Rato, Lénia D.; Lemos, Marco F.L.; Freitas, Andreia; Pouca, Ana Sofia Vila; Barbosa, Jorge; Cabral, Henrique N.; Fonseca, Vanessa F.

Pharmaceutical compounds are continuously released into the aquatic environment, resulting in their ubiquitous presence in many estuarine and coastal systems. As pharmaceuticals are designed to produce effects at very low concentrations and target specific evolutionary conserved pathways, there are growing concerns over their potential deleterious effects to the environment and specifically to aquatic organisms, namely in early life-stages. In this context, the long-term effects of exposure of juvenile meagre Argyrosomus regius to three different pharmaceuticals were investigated. Fish were exposed to environmental concentrations of one of three major used pharmaceuticals: the antidepressant fluoxetine (0.3 and 3 μg/L for 15 days), the anti-hypertensive propranolol and the non-steroidal anti-inflammatory agent diclofenac (0.3 and 15 μg/L for 30 days). Pharmaceuticals bioconcentration in fish muscle was examined, along with biomarkers in different tissues related with antioxidant and biotransformation responses (catalase, superoxide dismutase, ethoxyresorufin-O-deethylase and glutathione S-transferase), energetic metabolism (lactate dehydrogenase, isocitrate dehydrogenase and electron transport systemactivities), neurotransmission (acetylcholinesterase activity) and oxidative damage (DNA damage and lipid peroxidation levels). Overall, each pharmaceutical had different potential for bioconcentration in the muscle (FLX N PROP N DCF) and induced different biological responses: fluoxetine was the most toxic compound to juvenile meagre, affecting fish growth, triggering antioxidant defense responses, inhibiting detoxification mechanisms and increasing lipid peroxidation and DNA damage in the liver; propranolol exposure increased DNA damage and decreased aerobic metabolism in fish muscle; and diclofenac showed no potential to bioconcentrate, yet it affected fish metabolism by increasing cellular energy consumption in the muscle and consequently reducing fish net energy budget. The diverse response patterns evidence the need for future research focused on pharmaceuticals with different modes of action and their exposure effects on organismal physiological mechanisms and homeostatic status. Ultimately, the combination of sub-individual and individual responses is key for ecologically relevant assessments of pharmaceutical toxicity.

2020Journal article

Restricted access

Fluoxetine arrests growth of the model diatom Phaeodactylum tricornutum by increasing oxidative stress and altering energetic and lipid metabolism

Publication . Feijão, Eduardo; Carvalho, Ricardo Cruz de; Duarte, Irina A.; Matos, Ana Rita; Cabrita, Maria Teresa; Novais, Sara C.; Lemos, Marco F.L.; Caçador, Isabel; Marques, João Carlos; Reis-Santos, Patrick; Fonseca, Vanessa F.; Duarte, Bernardo

Pharmaceutical residues impose a new and emerging threat to aquatic environments and its biota. One of the most commonly prescribed pharmaceuticals is the antidepressant fluoxetine, a selective serotonin re-uptake inhibitor that has been frequently detected, in concentrations up to 40 ug L-1, in aquatic ecosystems. The present study aims to investigate the ecotoxicity of fluoxetine at environmentally relevant concentrations (0.3, 0.6, 20, 40, and 80 ug L-1) on cell energy and lipid metabolism, as well as oxidative stress biomarkers in the model diatom Phaeodactylum tricornutum. Exposure to higher concentrations of fluoxetine negatively affected cell density and photosynthesis through a decrease in the active PSII reaction centers. Stress response mechanisms, like b-carotene (b-car) production and antioxidant enzymes [superoxide dismutase (SOD) and ascorbate peroxidase (APX)] up-regulation were triggered, likely as a positive feedback mechanism toward formation of fluoxetine-induced reactive oxygen species. Lipid peroxidation products increased greatly at the highest fluoxetine concentration whereas no variation in the relative amounts of long chain polyunsaturated fatty acids (LC-PUFAs) was observed. However, monogalactosyldiacylglycerol-characteristic fatty acids such as C16:2 and C16:3 increased, suggesting an interaction between light harvesting pigments, lipid environment, and photosynthesis stabilization. Using a canonical multivariate analysis, it was possible to evaluate the efficiency of the application of bio-optical and biochemical techniques as potential fluoxetine exposure biomarkers in P. tricornutum. An overall classification efficiency to the different levels of fluoxetine exposure of 61.1 and 88.9% were obtained for bio-optical and fatty acids profiles, respectively, with different resolution degrees highlighting these parameters as potential efficient biomarkers. Additionally, the negative impact of this pharmaceutical molecule on the primary productivity is also evident alongside with an increase in respiratory oxygen consumption. From the ecological point of view, reduction in diatom biomass due to continued exposure to fluoxetine may severely impact estuarine and coastal trophic webs, by both a reduction in oxygen primary productivity and reduced availability of key fatty acids to the dependent heterotrophic upper levels.

2020Journal article

Open access

Effects of propranolol on growth, lipids and energy metabolism and oxidative stress response of Phaeodactylum tricornutum

Publication . Duarte, Bernardo; Feijão, Eduardo; Carvalho, Ricardo Cruz de; Duarte, Irina A.; Silva, Marisa; Matos, Ana Rita; Cabrita, Maria Teresa; Novais, Sara C.; Lemos, Marco F.L.; Marques, João Carlos; Caçador, Isabel; Reis-Santos, Pactick; Fonseca, Vanessa F.

Present demographic trends suggest a rise in the contributions of human pharmaceuticals into coastal ecosystems, underpinning an increasing demand to evaluate the ecotoxicological effects and implications of drug residues in marine risk assessments. Propranolol, a non-selective B-adrenoceptor blocker, is used worldwide to treat high blood pressure conditions and other related cardiovascular conditions. Although diatoms lack B-adrenoceptors, this microalgal group presents receptor-like kinases and proteins with a functional analogy to the animal receptors and that can be targeted by propranolol. In the present work, the authors evaluated the effect of this non-selective B-adrenoceptor blocker in diatom cells using P. tricornutum as a model organism, to evaluate the potential effect of this compound in cell physiology (growth, lipids and energy metabolism and oxidative stress) and its potential relevance for marine ecosystems. Propranolol exposure leads to a significant reduction in diatom cell growth, more evident in the highest concentrations tested. This is likely due to the observed impairment of the main primary photochemistry processes and the enhancement of the mitochondrial respiratory activity. More specifically, propranolol decreased the energy transduction from photosystem II (PSII) to the electron transport chain, leading to an increase in oxidative stress levels. Cells exposed to propranolol also exhibited high-dissipated energy flux, indicating that this excessive energy is effciently diverted, to some extent, from the photosystems, acting to prevent irreversible photoinhibition. As energy production is impaired at the PSII donor side, preventing energy production through the electron transport chain, diatoms appear to be consuming storage lipids as an energy backup system, to maintain essential cellular functions. This consumption will be attained by an increase in respiratory activity. Considering the primary oxygen production and consumption pathways, propranolol showed a significant reduction of the autotrophic O2 production and an increase in the heterotrophic mitochondrial respiration. Both mechanisms can have negative effects on marine trophic webs, due to a decrease in the energetic input from marine primary producers and a simultaneous oxygen production decrease for heterotrophic species. In ecotoxicological terms, bio-optical and fatty acid data appear as highly effcient tools for ecotoxicity assessment, with an overall high degree of classification when these traits are used to build a toxicological profile, instead of individually assessed.

2020Journal article

Open access