Browsing by Author "Pereira, R."
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- Antimicrobial activity and lipid profile of seaweed extracts from the North Portuguese coastPublication . Mendes, M.; Pereira, R.; Pinto, I. Sousa; Carvalho, A. P.; Gomes, A. M.Seaweeds or marine macroalgae are a potential renewable resource in the marine environment and can represent a source of new natural compounds for human nutrition. This experimental work focused on the selection of a suitable extraction method, using Gracilaria vermiculophylla as a model, followed by the characterization of the antimicrobial activity of different solvent extracts of Gracilaria vermiculophylla, Porphyra dioica and Chondrus crispus, both from wild and from an integrated multi-trophic aquaculture system (IMTA), collected in the north of Portugal. Additionally, the fatty acid profile of the seaweed extracts was also investigated. Extraction tests included the definition of the physical state of the seaweed, temperature and type of solvents to be used during the process. Results revealed that test organisms (Gram negative and Gram positive bacteria as well as one yeast species) were more sensitive to extracts obtained with dried algae, processed continuously at higher temperatures. Results from antimicrobial activity of wild and IMTA seaweed extracts showed stronger antimicrobial activity in extracts of ethyl acetate when compared with those from methanol and diethyl ether; furthermore, among the type of microorganisms tested, there was tendency for inhibition of the Gram positive ones. In general, there appears to be a higher antimicrobial activity for the microorganisms under study in extracts obtained from aquaculture species, when compared with the wild ones. The fatty acid profile of ethyl acetate extracts revealed a predominance of saturated fatty acids (SFA), especially palmitic acid (16:0), followed by polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA). A higher content of fatty acids in aquaculture extracts of Gracilaria vermiculophylla and Porphyra dioica was also observed.
- Biodegradation of polyethylene microplastics by the marine fungus zalerion maritimumPublication . Paço, Ana; Duarte, Kátia; Costa, João P. da; Santos, Patrícia S.M.; Pereira, R.; Pereira, M. E.; Freitas, Ana C.; Duarte, Armando C.; Rocha-Santos, Teresa A. P.Plastic yearly production has surpassed the 300milliontons mark and recycling has all but failed in constituting a viable solution for the disposal of plastic waste. As these materials continue to accumulate in the environment, namely, in rivers and oceans, in the form of macro-, meso-, micro- and nanoplastics, it becomes of the utmost urgency to find new ways to curtail this environmental threat. Multiple efforts have been made to identify and isolate microorganisms capable of utilizing synthetic polymers and recent results point towards the viability of a solution for this problem based on the biodegradation of plastics resorting to selected microbial strains. Herein, the response of the fungus Zalerion maritimum to different times of exposition to polyethylene (PE) pellets, in a minimum growth medium, was evaluated, based on the quantified mass differences in both the fungus and the microplastic pellets used. Additionally, molecular changes were assessed through attenuated total reflectance Fourier transform Infrared Spectroscopy (FTIR-ATR) and Nuclear Magnetic Resonance (NMR). Results showed that, under the tested conditions, Z. maritimum is capable of utilizing PE, resulting in the decrease, in both mass and size, of the pellets. These results indicate that this naturally occurring fungus may actively contribute to the biodegradation of microplastics, requiring minimum nutrients.
- Effects of dietary exposure to herbicide and of the nutritive quality of contaminated food on the reproductive output of Daphnia magnaPublication . Silva, M. Bessa da; Abrantes, N.; Rocha-Santos, T.A.P.; Duarte, A.C.; Freitas, A.C.; Gomes, Ana M. P.; Carvalho, A.P.; Marques, J.C.; Gonçalves, F.; Pereira, R.tRisk assessment of pesticides has been based on direct toxic effects on aquatic organisms. Indirect effectsdata are taken into account but with limitations, as it is frequently difficult to predict their real impactsin the ecosystems. In this context the main aim of this work was to assess how the exposure to theherbicide pendimethalin (Prowl®), under environmentally relevant concentrations, may compromise thenutritional composition of food for a relevant group of primary consumers of freshwater food webs—thedaphnids, thus affecting their reproduction performance and subsequently the long-term sustainabilityof active populations of this grazer. Therefore, Daphnia magna individuals were chronically exposed in aclean medium to a control diet (NCF – i.e., non-contaminated green algae Raphidocelis subcapitata) and to acontaminated diet (CF – i.e., the same monoalgal culture grown in a medium enriched with pendimethalinin a concentration equivalent to the EC20for growth inhibition of algae), during which reproductiveendpoints were assessed. The algae were analysed for protein, carbohydrate and fatty acid content. Thechemical composition of R. subcapitata in the CF revealed a slight decrease on total fatty acid levels, witha particular decrease of essential 9 monounsaturated fatty acids. In contrast, the protein content washigh in the CF. D. magna exposed to CF experienced a 16% reduction in reproduction, measured as thetotal number of offspring produced per female. Additionally, an internal pendimethalin body burden of4.226 g g−1was accumulated by daphnids fed with CF. Hence, although it is difficult to discriminate thecontribution of the pesticide (as a toxic agent transferred through the food web) from that of the food witha poor quality—compromised by the same pesticide, there are no doubts that, under environmentallyrelevant concentrations of pesticides, both pathways may compromise the populations of freshwatergrazers in the long term, with consequences in the control of the primary productivity of these systems.
- Oral health literacy strategies focused on community-based learningPublication . Veiga, N.; Moura, A. C.; Correia, P.; Couto, P.; Pereira, R.; Lopes, P.; Correia, M. J.
- Oral health literacy strategies focused on community-based learningPublication . Veiga, N.; Mello-Moura, A. C.; Correia, P.; Couto, P.; Pereira, R.; Lopes, P.; Correia, M. J.
- Oral health literacy strategies focused on community-based learningPublication . Veiga, N.; Mello-Moura, A. C.; Correia, P.; Couto, P.; Pereira, R.; Lopes, P.; Correia, M. J.
- Preface to the special issue: urban food production: challenges and opportunities towards sustainable citiesPublication . Calheiros, C. S. C.; Pereira, R.; Skar, S. L. G.; Pereira, S. I. A.
- Salinity induced effects on the growth rates and mycelia composition of basidiomycete and zygomycete fungiPublication . Venâncio, C.; Pereira, R.; Freitas, A. C.; Rocha-Santos, T. A. P.; Costa, J. P. da; Duarte, A. C.; Lopes, I.Soil salinization, as the combination of primary and secondary events, can adversely affect organisms inhabiting this compartment. In the present study, the effects of increased salinity were assessed in four species of terrestrial fungi: Lentinus sajor caju, Phanerochaete chrysosporium, Rhizopus oryzae and Trametes versicolor. The mycelial growth and biochemical composition of the four fungi were determined under three exposure scenarios: 1) exposure to serial dilutions of natural seawater (SW), 2) exposure to serial concentrations of NaCl (potential surrogate of SW); and 3) exposure to serial concentrations of NaCl after a period of pre-exposure to low levels of NaCl. The toxicity of NaCl was slightly higher than that of SW, for all fungi species: the conductivities causing 50% of growth inhibition (EC50) were within 14.9 and 22.0 mScm−1 for NaCl and within 20.2 and 34.1 mScm−1 for SW. Phanerochaete chrysosporium showed to be the less sensitive species, both for NaCl and SW. Exposure to NaCl caused changes in the biochemical composition of fungi, mainly increasing the production of polysaccharides. When fungi were exposed to SW this pattern of biochemical response was not observed. Fungi pre-exposed to low levels of salinity presented higher EC50 than fungi non-pre-exposed, though 95% confidence limits overlapped, with the exception of P. chrysosporium. Pre-exposure to low levels of NaCl also induced changes in the biochemical composition of the mycelia of L. sajor caju and R. oryzae, relatively to the respective control. These results suggest that some terrestrial fungi may acquire an increased tolerance to NaCl after being pre-exposed to low levels of this salt, thus, suggesting their capacity to persist in environments that will undergo salinization. Furthermore, NaCl could be used as a protective surrogate of SW to derive safe salinity levels for soils, since it induced toxicity similar or higher than that of SW.
- The use of emergent technologies to extract added value compounds from grape by-productsPublication . Coelho, M. C.; Pereira, R.; Rodrigues, A. S.; Teixeira, J. A.; Pintado, M.EBackground: The current circular economy system-based sustainability and the social lifestyle trends, have led to a developed structure that is restorative or regenerative by purpose and innovation. It substitutes the end-of-life idea of a by-product adding value to it, shifts towards the usage of environmentally friendly solutions, elimi-nating the harmful chemicals, which impair reuse. Scope and approach: Considering the wine production, which is one of the most critical agro-industrial sectors worldwide, generating large amounts of by-products with environmental impact, but also with high economic and nutritional potential. This review aims to evaluate the effects of alternative green technologies on the functionality and recovery of bioactive compounds (BCs) from wine by-products. Key findings and conclusions: These agro-industrial by-products, e.g., skins and pulp remnants, are rich in BCs with health benefits such as supporting the immune system, anti-tumoral, and preventing cardiovascular diseases. Besides, the consumer has increased interest in diet and health, demanding suppliers to consider the reuse of agro-food by-products. Thus, the application of green recovery technologies eliminates the harmful effects comparing to conventional technologies, can be recycled into the food chain as functional additives for different products and applications, guaranteeing the sustainability and reducing the winemaking by-products.