FCT2-Artigos (em revistas ou actas indexadas)
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- Drying method matters: Differential preservation of lipids, pigments, and carbohydrates in edible macroalgae Fucus vesiculosus, Gracilaria sp., and Ulva sp.Publication . Neves, Mariana; Moreira, Ana S.P.; Conde, Tiago; Lopes, Diana; Metzner, Beatriz; Martins, Inês; Oliveira, Kayane; Ferreira, Andreia S.; Nunes, Cláudia; Coimbra, Manuel A.; Cardoso, Maria Helena; Ramos, Ana; Pereira, Hugo; Caria Mendes, Madalena; Oliveira, Inês; Martins, Margarida; Domingues, M. RosárioMarine macroalgae are increasingly recognized as sustainable sources for food, feed, and functional applications. Drying is widely used to stabilize biomass and preserve nutrients and bioactive compounds. Freeze-drying (FD) effectively preserves sensitive compounds, but high cost and energy demand limit scalability. Therefore, this study evaluated air-tunnel drying (ATD; 25 ◦C) and solar drying (SD; 40 ◦C) as alternative methods for preserving lipid, fatty acid (FA), pigment, and carbohydrate composition of edible Fucus vesiculosus, Gracilaria sp., and Ulva sp., using FD as a reference. In most cases, ATD preserved lipid and carbohydrate contents comparable to FD. In Ulva sp., ATD promoted hydrolytic FA release, increasing free FA, while ulvan polysaccharides remained stable across drying methods. F. vesiculosus exhibited high stability, maintaining lipid content, FA composition, and pigment levels under all conditions. SD induced species-dependent alterations, including reductions in lipid content, polyunsaturated FA, and pigment levels in Gracilaria sp. and Ulva sp. Although F. vesiculosus poly saccharides remained largely unchanged, a potential increase in fucoidans was observed under SD, suggesting a stress-induced response. SD also decreased galactose and sulphate esters contents in Gracilaria sp. These findings support the selection of drying strategies according to species, target compounds and applications to optimize biomass quality.
- Wave-driven storm impacts on Scotland's sedimentary barriers intensify with climate changePublication . Horsburgh, Nicola; Loureiro, Carlos; Rennie, Alistair; Hurst, Martin; Naylor, Larissa A.; Tyler, AndrewBeaches and dunes form vital natural barriers, protecting coastal communities from extreme sea levels. To support coastal management, a geomorphologically-informed understanding of how barriers may be impacted by storm-induced coastal hazards is essential. While storm wave runup can contribute significantly to local extreme sea levels and drive dramatic short- and near-term morphological change to sedimentary coasts, it remains only partly characterised in existing national and regional assessments. This study investigates wave-driven storm impacts at large spatial scales (100–1000 km), at a resolution sufficient to inform local decision making. Using higher resolution national and European datasets, established empirical parameterisations and a simplified barrier morphological evolution model, we predict extreme wave runup and storm impacts on Scotland's wavedominated sedimentary coasts, at 50 m alongshore resolution. We consider a synthetic storm comprised of 25- year return levels of tides and storm surge, and the 1% exceedance of wave height and period, and predict storm impacts for the present-day, mid- and end-century, under RCP4.5 and RCP8.5. Results show that wave runup contributes on average 38% to extreme sea levels, and over 50% in the most exposed locations under present conditions. Nationally, 416 km (65% of the assessed coast) experience barrier erosion during the synthetic storm event, while 72 km (11%) and 27 km (4%) undergo overwash and inundation, respectively. By 2100 the predicted length of inundated coast approximately doubles to 46 km (7%) under RCP4.5, and 59 km (9%) under RCP8.5. Results reveal strong sub-national variability in storm impacts, identifying clear hotspots with the potential for erosion-enhanced flooding.
- Inclusion of carotenoids and Eicosapentaenoic Acid (EPA) in sea urchin (Paracentrotus lividus) broodstock diets improves gonad development and oocyte qualityPublication . Gomes da Silva, Ana Paula; Rodrigues, A. F.; Neves, M.; Roseiro, C.; Cardoso, H.; Violante, A. P.; Gavaia, Paulo; Suckling, C.; Lourenço, S.In aquaculture, broodstock conditioning diets are essential for enhancing reproductive performance, particularly as offspring survival remains a primary bottleneck in sea urchin production. This study investigated the effects of different broodstock diets on gonad development, fatty acid profiles, and oocyte size in the sea urchin Paracentrotus lividus. To determine if maternal investment could be enhanced through specific nutrients, three diets that differed in both ingredient matrix and pigment profile were tested over a two-month feeding period: 1) a formulated pumpkin/algal diet (PA) enriched with β-carotene via pumpkin and Nannochloropsis sp.; 2) a formulated pea/corn diet (PC) with a low-pigment profile, and 3) a natural kelp diet based on Saccorhiza polyschides, representing one of the natural foods for P. lividus in its local habitat. This Kelp diet provided a mixed-pigment reference with relatively high total carotenoids. Following the feeding trial, several key parameters were assessed, including gonadosomatic index (GSI), reproductive stage, fatty acid composition, oocyte size, and fertilization success. Results indicated that females fed the PA diet produced oocytes that were 18% larger and achieved a 7% higher fertilization rate than those on the PC diet. This enhancement is likely linked to the significantly higher deposition of carotenoids and omega-3 polyunsaturated fatty acids (n-3 PUFA) in the gonads. In contrast, while the PC diet promoted a high GSI, it resulted in smaller oocytes and lower fertilization rates, due to a deficiency in n-3 PUFA in their gonads. Females fed the Kelp diet presented the slowest gonadal development and failed to spawn, suggesting that seaweed is insufficient as a sole food source for short-term broodstock conditioning to support reproduction. This research provides valuable insights into developing broodstock conditioning diets by exploring alternative nutrient sources, such as pumpkin and microalgae, to enhance reproductive traits, particularly for emerging species like sea urchins.
- Waste literacy among portuguese first-year tertiary students after compulsory environmental educationPublication . Spínola, Hélder; Silva Fernandes, Maria Jacinta; Sousa, Cátia; Oliveira Campos, Clarice; Mourato, Sandra; Heleno, Lizete; Ventura, Maria Anunciação Mateus; Caeiro, Sandra; Bacelar-Nicolau, Paula; Mapar, Mahsa; Azeiteiro, Ulisses M.; Guimarães, Sandra C.; Rodrigues, Liliana; Carreira, Sílvia Mateus; Martins, Rute; Quadros, SílviaWaste management is essential for addressing local and global environmental challenges. Failure to manage waste effectively results in several consequences, including environmental degradation, public health risks, and economic costs. Besides the need for adequate and up-to-date waste management systems, citizens’ cooperation is crucial to achieving sustainable waste management in any community, which depends on their waste literacy levels, comprising the knowledge, attitudes, and behaviours required. This study assessed waste literacy among students completing compulsory education in Portugal to provide evidence regarding the outcomes of environmental education policies related to waste management. A representative sample of 1506 freshmen students was surveyed at the start of their undergraduate programmes. An online questionnaire was administered to the sample and the data were analyzed using statistical tests for assessing the influential factors associated with students’ waste knowledge, attitudes and behaviours. Results show that, on average, students demonstrated good levels of knowledge and practices on waste management, together with a predominantly ecocentric worldview. A higher performance in waste management knowledge and practices was observed among younger students, with higher grades and higher paternal educational attainment. Besides these variables, best practices were significantly more prevalent among those with a higher participation in environmental activities and holding membership in environmental organizations. The findings suggest that upon completing compulsory education in Portugal, students display generally high levels of waste literacy, while also revealing specific gaps in knowledge and practices that warrant further educational attention. The study identifies these areas for improvement, highlighting the potential value of more practical, participatory and community-based approaches to waste education.
- Ethnomedicinal uses, phytochemistry and bioactivities of halophytes and salt-tolerant plants with potential against metabolic syndrome: a comprehensive reviewPublication . Rodrigues, Maria João; García-Caparrós, Pedro; Guerreiro Pereira, Catarina Alexandra; Magné, Christian; Hamed, Karim Ben; Mesquita, Mariana Laundry de; Custódio, LuísaMetabolic syndrome (MetS) is a complex cluster of interconnected metabolic abnormalities, including central obesity, insulin resistance, dyslipidemia, hypertension, chronic inflammation, and impaired glucose metabolism, which collectively increase the risk of type 2 diabetes and cardiovascular diseases. Although current therapeutic strategies, including lifestyle interventions and pharmacological treatments, can be effective in managing specific MetS components, the multifactorial nature of this condition continues to encourage the search for complementary approaches and novel bioactive compounds. Salt-tolerant plants (STPs), particularly halophytes, survive under adverse saline and oxidative stress conditions through specialized physiological and biochemical adaptations, including the production of diverse secondary metabolites such as phenolic acids, flavonoids, sterols, terpenoids and polysaccharides. Several of these compounds have been associated with health-promoting properties, including antioxidant, anti-inflammatory, antidiabetic, antihypertensive, lipid-modulating and cardioprotective effects. This review provides an integrated and critical overview of the ethnomedicinal uses, phytochemistry and bioactivities of STPs with potential relevance to MetS and its associated conditions, namely chronic inflammation, diabetes, hypertension, cardiovascular disorders, dyslipidemia and obesity. The review first introduces the main features of MetS and the relevance of STPs as bioresources, followed by a synthesis of ethnomedicinal uses related to MetS-associated disorders. It then discusses in vitro and in vivo evidence for selected species, extracts and compounds, including reported bioactive metabolites and proposed mechanisms of action when available. Finally, the most promising species, extracts and metabolites are highlighted, together with current limitations and future research needs regarding efficacy, safety, bioavailability, standardization and clinical relevance.
- Piecewise rational affine maps, multidimensional generalized shifts, and computation over the real numbersPublication . Graça, DanielIn this paper we study the computational power of certain classes of dynamical systems defined by the iteration of piecewise rational affine maps on the compact set [0,1]^n as a model of computation over the real numbers. To achieve this aim we use symbolic dynamics to study the dynamics of this class of piecewise rational affine maps and in the process introduce multidimensional generalized shifts, which are an extension of the generalized shift of Moore to higher dimensional spaces. We show that multidimensional generalized shifts are not equivalent (conjugate) to (one-dimensional) generalized shifts. We then establish that computable analysis, which allows to extend computability based on Turing machines to real numbers, is computationally equivalent to multidimensional generalized shifts, both at a computability and at a computational complexity (polynomial time) level. This implies that a certain class of dynamical systems defined by the iteration of rational piecewise affine maps on the unit ball can thus compute any function computable over the real numbers in the computable analysis sense. These results highlight that several distinct models of computation over the real numbers, such as computable analysis, Claude Shannon's General Purpose Analog Computer, certain classes of piecewise rational affine maps, and the generalized shift, are all computationally equivalent.
- Culturable yeasts associated to different life stages of the farmed red seaweed Porphyra dioicaPublication . Fernandes, Mónica A.; Matos, Madalena; Keller-Costa, Tina; Costa, Rodrigo; Caria Mendes, Madalena; Coutinho, Ana; Oliveira, Inês; Martins, Margarida; Sá-Correia, IsabelMacroalgal-associated microbiomes are increasingly recognized as key determinants of host fitness, biogeochemical cycling, and cultivation stability in industrial aquaculture. While bacterial assemblages of red macroalgae have received considerable attention, the associated mycobiome, and in particular the yeast fraction, remains poorly characterized, despite mounting evidence that fungal taxa contribute to phytohormone signaling, surface colonization dynamics, and host stress tolerance. In this study, we characterized the culturable yeast fraction associated with five life stages of the red macroalga Porphyra dioica cultivated in an Integrated Multi-Trophic Aquaculture (IMTA) system in Ílhavo, Portugal. Yeast isolates were recovered from conchocelis, conchosporangia, young blade, and adult blade stages by direct plating and enrichment on selective media and taxonomically assigned by rRNA gene sequencing. Isolates were further screened for functional traits of ecological and biotechnological relevance, including auxin biosynthesis, biosurfactant and bioemulsifier production, and intracellular lipid accumulation. A total of 21 isolates were recovered and assigned to Rhodotorula mucilaginosa, Naganishia diffluens, Williopsis vartiovaarae, Taphrina sp., and Sporobolomyces roseus, spanning both Ascomycota and Basidiomycota. Yeast recovery was constrained by chloramphenicol-resistant bacterial overgrowth in algae samples cultivated with filtered, non-sterilized seawater, and therefore the dataset represents the recoverable culturable fraction. Assemblages were structured by host developmental stage: N. diffluens was recovered from conchocelis, R. mucilaginosa from conchosporangia, and a shift from ascomycetous taxa (W. vartiovaarae, Taphrina sp.) to pigmented basidiomycetous yeasts (N. diffluens, S. roseus) was observed in adult blades approaching harvest. Several isolates produced auxin, biosurfactants, and bioemulsifiers, and accumulated intracellular lipids, supporting potential roles as probiotics in industrial macroalgal cultivation and as candidate strains for value-added bioproducts. This study provides a first insight into the culturable yeast community associated with industrially cultivated P. dioica and establishes a basis for future studies addressing the role of yeasts in macroalgal performance cultivated under IMTA systems.
- Piecewise rational affine maps, multidimensional generalized shifts, and computation over the real numbersPublication . Graça, DanielIn this paper we study the computational power of certain classes of dynamical systems defined by the iteration of piecewise rational affine maps on the compact set [0, 1] n as a model of computation over the real numbers. To achieve this aim we use symbolic dynamics to study the dynamics of this class of piecewise rational affine maps and in the process introduce multidimensional generalized shifts, which are an extension of the generalized shift of Moore to higher dimensional spaces. We show that multidimensional generalized shifts are not equivalent (conjugate) to (one-dimensional) generalized shifts. We then establish that computable analysis, which allows to extend computability based on Turing machines to real numbers, is computationally equivalent to multidimensional generalized shifts, both at a computability and at a computational complexity (polynomial time) level. This implies that a certain class of dynamical systems defined by the iteration of rational piecewise affine maps on the unit ball can thus compute any function computable over the real numbers in the computable analysis sense. These results highlight that several distinct models of computation over the real numbers, such as computable analysis, Claude Shannon’s General Purpose Analog Computer, certain classes of piecewise rational affine maps, and the generalized shift, are all computationally equivalent.
- Chemical characterization of volatile and non-volatile constituents of aqueous extracts from euphorbia officinarum and E. resinifera: influence of extraction conditions on antioxidant and α-glucosidase inhibitory activitiesPublication . BOUTOUB, OUMAIMA; El Ghadraoui, Lahsen; El-Guendouz, Soukaina; Aazza, Smail; Figueiredo, Ana Cristina; Silva, José Paulo da; Miguel, Maria da GraçaThis study performed a chemical characterization of Euphorbia officinarum and Euphorbia resinifera volatile and non-volatile aqueous extracts. It was also evaluated how extraction variables (extraction time and plant-tosolvent ratio, PSR) influenced the chemical composition and biological responses of the aqueous extracts of four populations of E. officinarum and one population of E. resinifera. The experimental results were fitted using second-order polynomial equations for all response variables. The volatiles (essential oils) were isolated by hydrodistillation and analyzed for quantification and component identification, by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS), respectively. The volatile fraction of E. officinarum contained higher percentages of oxygenated monoterpenes and phenylpropanoids, whereas palmitic acid predominated in E. resinifera. Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the aqueous extract of both species and the tentatively annotated compounds included particularly flavonoids, coumarins, oxylipins, and aliphatic dicarboxylic acids. Two-way ANOVA and response surface methodology highlighted that PSR was generally the main factor affecting the measured responses, whereas the influence of extraction time was response- and population-dependent. In addition, Pearson correlation and principal component analyses showed that the in vitro biological activities were more dependent on phytochemical composition than on total phenolic content.
- Salinity-induced modulation of phenolic compounds and antioxidant activity in lavandula viridis and thymus lotocephalusPublication . Paixão Mansinhos, Inês Filipa; Gonçalves, Sandra; Rodríguez Solana, Raquel; Pereira-Caro, Gema; Romano, AnabelaMediterranean Lamiaceae species are important sources of bioactive compounds with potential applications in food, pharmaceutical, and cosmetic industries. In the present study, controlled salinity was evaluated as a biotechnological elicitation strategy to enhance the accumulation of bioactive metabolites in two species, Lavandula viridis and Thymus lotocephalus, cultured in vitro. Morphological, biochemical and metabolic responses of shoots grown for seven weeks in culture medium containing four NaCl concentrations (0, 25, 50, or 75 mM) were assessed. Mild salinity (25 mM NaCl) stimulated shoot growth in both species, whereas higher salt concentrations progressively reduced growth. Salinity induced oxidative stress, as indicated by elevated malondialdehyde (MDA) levels at 25 mM NaCl in both species, while hydrogen peroxide (H2O2) exhibited contrasting patterns, decreasing with increasing salinity in L. viridis but peaking at 50 mM NaCl in T. lotocephalus. Salt stress caused reductions in photosynthetic pigments, phenolic compounds, antioxidant capacity (DPPH, FRAP, ABTS, and ORAC), and overall metabolic performance in L. viridis, indicating limited tolerance to salinity. Conversely, T. lotocephalus displayed greater metabolic plasticity, characterized by increased levels of phenolic compounds, particularly rosmarinic acid and its derivatives, and higher antioxidant activity of the extracts, as well as the accumulation of proline and soluble sugars. These findings demonstrate marked species-specific differences in salinity responses and identify controlled salinity as an effective elicitation strategy to sustainably produce high-value bioactive compounds in T. lotocephalus.