ESTM - Artigos em revistas internacionais
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- Acclimation capability inferred by metabolic performance in two sea cucumber species from different latitudesPublication . Kühnhold, Holger; Novais, Sara C.; Alves, Luís M. F.; Kamyab, Elham; Lemos, Marco F. L.; Slater, Matthew J.; Kunzmann, AndreasThe notion that thermal specialists from tropical regions live closer to their temperature limits than temperate eurytherms, seems too generalized. Species specific differences in physiological and biochemical stress reactions are linked to key components of organism fitness, like metabolic capacity, which indicates that acclimation potential across latitudes might be highly diverse rather than simplistic. In this study the exposure of a tropical (Holothuria scabra) and a temperate (Holothuria forskali) sea cucumber species to identical cold- and warmacclimation stress was compared using the key metabolic parameters, respiration rate, enzyme activity (ETS, LDH, IDH), and energy reserve fractions (lipid, carbohydrate and protein). Results show much broader respiratory adjustments, as response to temperature change, in H. scabra (2–30 μgO2*gww−1 *h−1) compared to H. forskali (1.5–6.6 μgO2*gww−1 *h−1). Moreover, the tropical species showed clearly pronounced up and down regulation of metabolic enzymes and shifts in energy reserves, due to thermal acclimation, while the same metabolic indicators remained consistent in the temperate species. In summary, these findings indicate enhanced metabolic plasticity in H. scabra at the cost of elevated energy expenditures, which seems to favor the tropical stenotherm in terms of thermal acclimation capacity. The comparison of such holistic metabolic analyses between conspecifics and congeners, may help to predict the heterogeneous effects of global temperature changes across latitudinal gradients.
- Accumulation of chemical elements and occurrence of microplastics in small pelagic fish from a neritic environmentPublication . Silva, Joana M. da; Alves, Luís M.F.; Laranjeiro, Maria I.; Bessa, Filipa; Silva, Andreia V.; Norte, Ana C.; Lemos, Marco F.L.; Ramos, Jaime A.; Novais, Sara C.; Ceia, Filipe R.The assessment of contaminant exposure in marine organisms often focuses on the most toxic chemical elements from upper trophic level species. Information on mid-trophic level species and particularly on potentially less harmful elements is lacking. Additionally, microplastics have been considered emergent contaminants in aquatic environments which have not been extensively studied in species from mid-trophic levels in food chains. This study aims to contribute to an overall assessment of environmental impacts of such chemicals in a community of small pelagic fish in the North Atlantic. The concentrations of 16 chemical elements, rarely simultaneously quantified (including minerals, trace elements and heavy metals), and the presence of microplastics were analysed in sardines (Sardina pilchardus) and mackerels (Scomber spp. and Trachurus trachurus) sampled along the Portuguese coast. Biochemical stress assessments and stable isotope analyses were also performed. The chemical element concentrations in S. pilchardus, T. trachurus, and Scomber spp. were relatively low and lower than the levels reported for the same species in the North Atlantic and adjacent areas. No clear relationships were found between chemical elements and oxidative damage in fish. However, the concentration of several chemical elements showed differences among species, being related with the species’ habitat use, trophic niches, and specific feeding strategies. The presence of plastic pieces in the stomachs of 29% of the sampled fishes is particularly concerning, as these small pelagic fish from mid-trophic levels compose a significant part of the diet of humans and other top predators. This study highlights the importance of multidisciplinary approaches focusing on the individual, including position data, stable isotopes, and oxidative stress biomarkers as complementary tools in contamination assessment of the marine mid-trophic levels in food chains.
- Acute Stress and an Electrolyte-Imbalanced Diet, but Not Chronic Hypoxia, Increase Oxidative Stress and Hamper Innate Immune Status in a Rainbow Trout (Oncorhynchus mykiss) Isogenic LinePublication . Magnoni, Leonardo J.; Novais, Sara C.; Eding, Ep; Leguen, Isabelle; Lemos, Marco F. L.; Ozório, Rodrigo O. A.; Geurden, Inge; Prunet, Patrick; Schrama, Johan W.In aquaculture, fish may be exposed to sub-optimal rearing conditions, which generate a stress response if full adaptation is not displayed. However, our current knowledge of several coexisting factors that may give rise to a stress response is limited, in particular when both chronic and acute stressors are involved. This study investigated changes in metabolic parameters, oxidative stress and innate immune markers in a rainbow trout (Oncorhynchus mykiss) isogenic line exposed to a combination of dietary (electrolyteimbalanced diet, DEB 700 mEq Kg−1 ) and environmental (hypoxia, 4.5 mg O2 L −1 ) challenges and their respective controls (electrolyte-balanced diet, DEB 200 mEq Kg−1 and normoxia, 7.9 or mg O2 L −1 ) for 49 days. At the end of this period, fish were sampled or subjected to an acute stressor (2 min of handling/confinement) and then sampled. Feeding trout an electrolyte-imbalanced diet produced a reduction in blood pH, as well as increases in cortisol levels, hepato-somatic index (HSI) and total energy content in the liver. The ratio between the lactate dehydrogenase (LDH) and isocitrate dehydrogenase (IDH) activities decreased in the liver of trout fed the DEB 700 diet, but increased in the heart, suggesting a different modulation of metabolic capacity by the dietary challenge. Several markers of oxidative stress in the liver of trout, mainly related to the glutathione antioxidant system, were altered when fed the electrolyteimbalanced diet. The dietary challenge was also associated with a decrease in the alternative complement pathway activity (ACH50) in plasma, suggesting an impaired innate immune status in that group. Trout subjected to the acute stressor displayed reduced blood pH values, higher plasma cortisol levels as well as increased levels of metabolic markers associated with oxidative stress in the liver. An interaction between diet and acute stressor was detected for oxidative stress markers in the liver of trout, showing that the chronic electrolyte-imbalance impairs the response of rainbow trout to handling/confinement. However, trout reared under chronic hypoxia only displayed changes in parameters related to energy use in both liver and heart. Taken together, these results suggest that trout displays an adaptative response to chronic hypoxia. Conversely, the dietary challenge profoundly affected fish homeostasis, resulting in an impaired physiological response leading to stress, which then placed constraints on a subsequent acute challenge.
- Adding value to stalked barnacles from Berlengas Nature Reserve (Portugal) by the development of a new foodPublication . Pinheiro, Joaquina; Fernandes, Wilson; Sá, Hugo; Bernardino, Raul; Leandro, Sérgio Miguel; Ganhão, RuiIn this work, a new and natural food product, stalked barnacle (Pollicipes Pollicipes) pâté enriched with blackberry, was developed to valorise the rejected stalked barnacle. To evaluate the addition of blackberry fruits (Rubus ulmifolius Schott.) as a natural preservative on pâté quality, four pâté sample groups were considered: a negative control without a synthetic additive (CTR), a positive control with butylated hydroxytoluene (BHT), a group with blackberry extract (blackberry), and a group with a mixture of BHT and blackberry (blackberry + BHT). In addition, the effect of pasteurization (80 °C for 30 min) versus sterilization (121 °C for 30 min) on the pâté quality were evaluated. The bioactive evaluation expressed by the total phenolic content (TPC) and antiradical activity by the DPPH radical scavenging associated with oxidative stability determined by thiobarbituric acid reacting substances (TBARS) were performed. The impact of packaging opening followed by refrigerated storage (4 ± 1 °C) simulating the consumer behavior at home, was assessed. All the heat-treated stalked barnacle pâté samples were found microbially safe with an interesting content of total phenolic, the highest ones being the CTR and Blackberry + BHT, ranging from 58.79 to 55.38 mg GAE/100 g. After the package opening of the barnacle pâté sample of Blackberry + BHT, it revealed a superior inhibition of TBARS (0.46 mg MDA/100 g) after 7 days at refrigerated storage compared to the other samples. These results state the efficacy of blackberry in minimizing the lipid oxidation of stalked barnacle pâte. This study showed the potential for rejected stalked barnacle to be valorised and improve the sustainability of resources.
- Adjunctive role of Calyptranthes tricona extract with probiotic Kluyveromyces marxianus on colorectal adenocarcinoma Caco-2 cellsPublication . Kich, Débora Mara; Bitencourt, Shanna; Faleiro, Dalana; Immich, Sheila Mariele; Marmitt, Diorge Jonatas; Baldasso, Tamara; Haute, Gabriela Viegas; Oliveira, Jarbas Rodrigues de; Laufer, Stefan; Pedrosa, Rui; Souza, Claucia Fernanda Volken de; Goettert, Márcia InêsThe composition of microbiota may influence the development of colorectal cancer (CRC). In addition, probiotics can decrease the chance of developing cancer or its progress. For that reason, it is encouraging to assess the influence of plant extracts as adjuvants of the health-promoting effects of probiotics. Thus, this study aimed to investigate the in vitro beneficial properties of Calyptranthes tricona leaf ethanol extract in association or not with the lactic yeast Kluyveromyces marxianus on colon adenocarcinoma Caco-2 cells. C. tricona extract inhibited the in vitro p38α MAPK activity and exhibited immunomodulation on isolated human lymphocytes. Further, the extract did not induce cytotoxicity towards K. marxianus or Caco-2 cells; leading to an increased yeast adhesion to cells in a dose-dependent manner. In conclusion, this preliminary study demonstrates that C. tricona extract has effects on enzyme inhibition and immune function. In addition, when associated with K. marxianus, C. tricona may possess beneficial properties for application as enhancer of probiotic’s protective role on CRC cells. However, further studies are necessary in order to elucidate the mechanisms involved.
- Age and growth of Brauer's lanternfish Gymnoscopelus braueri and rhombic lanternfish Krefftichthys anderssoni (Family Myctophidae) in the Scotia Sea, Southern OceanPublication . Saunders, Ryan A.; Lourenço, Sílvia; Vieira, Rui P.; Collins, Martin A.; Assis, Carlos A.; Xavier, Jose C.This study examines age and growth of Brauer's lanternfish Gymnoscopelus braueri and rhombic lanternfish Krefftichthys anderssoni from the Scotia Sea in the Southern Ocean, through the analysis of annual growth increments deposited on sagittal otoliths. Otolith pairs from 177 G. braueri and 118 K. anderssoni were collected in different seasons from the region between 2004 and 2009. Otolith‐edge analysis suggested a seasonal change in opaque and hyaline depositions, indicative of an annual growth pattern, although variation within the populations of both species was apparent. Age estimates varied from 1 to 6 years for G. braueri (40 to 139 mm standard length; L s) and from 0 to 2 years for K. anderssoni (26 to 70 mm L s). Length‐at‐age data were broadly consistent with population cohort parameters identified in concurrent length‐frequency data from the region for both species. The estimated values of von Bertalanffy growth curves for G. braueri were L∞ = 133.22 mm, k = 0.29 year−1 and t 0 = − 0.21 year and the values for K. anderssoni were L∞ = 68.60 mm, k = 0.71 year−1 and t 0 = − 0.49 year. There were no significant (P > 0.05) differences in growth between sexes for either species, suggesting that males and females have similar growth and development trajectories in the Scotia Sea. A positive allometric relationship between Ls and wet mass was found for each species, as well as a significant (P < 0.0001) linear relationship between otolith size and L s. Growth performance (Ф ′) was similar between the two species and congruent with other myctophid species across the Southern Ocean. This study provides important parameters for future Southern Ocean ecosystem studies in a resource management context.
- Algae from Portuguese Coast Presented High Cytotoxicity and Antiproliferative Effects on an In vitro Model of Human Colorectal CancerPublication . Alves, Celso; Pinteus, Susete; Rodrigues, Ana; Horta, André; Pedrosa, RuiBackground: The marine environment has shown to be an interesting source of new antitumor agents, representing an important tool in cancer research. Objective: The aim of this study was to evaluate the antitumor activities of 12 algae from Peniche coast (Portugal) on an in vitro model of human colorectal cancer (Caco‑2 cells). Materials and Methods: The antitumor potential was accessed by evaluating Caco‑2 cell’s viability and proliferation through the 3‑[4, 5‑dimethylthiazol‑2‑yl]‑2, 5‑diphenyl tetrazolium bromide and calcein‑AM methods. Results: The dichloromethane extracts of Asparagopsis armata and Sphaerococcus coronopifolius induced the highest decrease on cell’s viability (1 mg/mL; 24 h), 98.96% ± 0.39% and 98.08% ± 0.89%, respectively, followed by the methanolic extracts of S. coronopifolius (96.47% ± 1.26%) and A. armata (92.68% ± 1.17%). Regarding cell proliferation, the highest decrease of Caco‑2 cell’s proliferation (1 mg/mL; 24 h) was induced by the dichloromethane extract of A. armata (100% ± 0.48%), S. coronopifolius (99.04 ± 0.51%), and Plocamium cartilagineum (95.05% ± 1.19%). The highest potency was shown by the dichloromethane extract of S. coronopifolius in both, cytotoxicity and antiproliferative tests, with an IC50 of 21.3 and 36.5 µg/mL, respectively. Conclusion: The extracts of A. armata and S. coronopifolius are promising sources of new bioactive molecules with application in cancer therapeutics.
- Amitraz toxicity to the midge Chironomus riparius: Life-history and biochemical responsesPublication . Monteiro, Hugo R.; Lemos, Marco F. L.; Novais, Sara C.; Soares, Amadeu M. V. M.; Pestana, João L. T.Acute and chronic toxicity of the formamidine pesticide amitraz to the midge Chironomus riparius was assessed using conventional ecotoxicological tests and biochemical approaches (biomarkers). Amitraz is mainly used as an ectoparasiticide in veterinary medicine, but also in agriculture and apiculture. However, information of amitraz toxicity to non-target invertebrates is limited. Besides the impairment of developmental and emergence rates (reduced larval growth, emergence, and delayed development time) caused by chronic exposure to amitraz, acute exposures induced alterations in the antioxidant enzymes glutathione peroxidase (GPx) and catalase (CAT), and in energetic metabolism biomarkers, lactate dehydrogenase (LDH) and electron transport system (ETS) activities. Moreover, lipid peroxidation (LPO) increased by amitraz exposure. Our results reveal potential secondary effects of amitraz to invertebrates and biomarkers that may aid in the interpretation of sub-lethal toxic responses to amitraz. These results add information concerning the potential outcomes of amitraz exposure to freshwater invertebrates underlining the importance of risk assessment studies of formamidine pesticides.
- Amplified ribosomal DNA restriction analysis as a routine tool to assess toxicant driven changes in hindgut bacterial populations of Porcellio dilatatus (Crustacea: Isopoda)Publication . Santos, Miguel J. G.; Sousa, José Paulo; Tiago, Igor; Veríssimo, António; Lemos, MarcoChanges in saprophytic organism's gut microbial communities may present a threat to organic matter breakdown which can ultimately lead to soil function impairment. In this study, Amplified Ribosomal DNA Restriction Analysis (ARDRA) was evaluated as a potential simple molecular tool to assess shifts in bacterial community structure in hindgut populations of Porcellio dilatatus exposed to contaminated food. This prospective tool can also be used for a variety of purposes and samples prior to the use of more specific and sophisticated methods.
- An emergent treat: Marine heatwaves: Implications for marine decapod crustacean species: An overviewPublication . Monteiro, Marta; Castro, Samuel L.P. de; Marques, Sónia Cotrim; Freitas, Rosa; Azeiteiro, Ulisses M.Anthropogenic-mediated climate change severely affects the oceans. The most common definition of a Marine heatwave (MHW) considers that water temperatures rise above the 90th percentile threshold values, based on the last 30 years' average of temperature records for a particular location, and remains this high for five or more days. The current review addresses the evolution of definitions used, as well as the current understanding of the driving mechanisms of MHWs. The collected information shows that the study of MHW is recent and there is a growing interest among the scientific community on this topic, motivated largely by the impacts that pose to marine ecosystems. Further, a more in-depth analysis was carried out, addressing the impacts of MHW events on marine decapod crustacean species. The investigation of such impacts has been carried out using three main methodological approaches: the analysis of in situ records, observed in 33 studies; simulating MHW events through mesocosm experiments, found in 6 studies; and using computational predictive models, detected in 1 study. From the literature available it has been demonstrated that consequences are serious for these species, from altered expansion ranges to alterations of assemblages’ abundances. Still, studies addressing the impacts of these extreme events on the decapod communities are scarce, often only limited to adult life forms of commercially relevant species, neglecting non-commercial ones and meroplanktonic life stages. Despite the severe impacts on the health of ecosystems, repercussions on socioeconomic human activities, like fisheries and aquaculture, are also a reality. Overall, this review aims to raise scientific and public awareness of these marine events, which are projected to increase in intensity and frequency in the coming decades. Therefore, there is a growing need to better understand and predict the mechanisms responsible for these extreme events and the impacts on key species, like decapod crustaceans.