Browsing by Author "Mira, Sara"
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- A ciência-cidadã ao serviço da mudança: o exemplo do projeto A Minha PraiaPublication . Gouveia, Licínia; Lourenço, Carla R.; Afonso, João; Freitas, Ricardo; Veiga-Pires, C.; Reis, Emanuel; Rodrigues, Miguel; Gomes, Tiago; Rodrigues, Luís; Mira, Sara; Ferreira, Hélder; Pinto, Andreia; Vaz, Paula; Drago, Teresa; Soares, Isabel; Ramos, AnaVencedor da 1ª edição do Orçamento Participativo Portugal (2017), A Minha Praia é um projeto de monitorização ambiental que pretende sensibilizar para a conservação do meio marinho e estimular hábitos de consumo responsáveis, através de ações de ciência cidadã e civismo ambiental.
- A ciência-cidadã ao serviço da mudança: o exemplo do projeto A Minha PraiaPublication . Gouveia, Licínia; Lourenço, Carla; Afonso, João; Freitas, Ricardo; Veiga-Pires, C.; Reis, Emanuel; Rodrigues, Miguel; Gomes, Tiago; Rodrigues, Luís; Mira, Sara; Ferreira, Hélder; Pinto, Andreia; Vaz, Paula; Drago, Teresa; Soares, Isabel; Ramos, AnaVencedor da 1ª edição do Orçamento Participativo Portugal (2017), A Minha Praia é um projeto de monitorização ambiental que pretende sensibilizar para a conservação do meio marinho e estimular hábitos de consumo responsáveis, através de ações de ciência cidadã e civismo ambiental.
- Antioxidant, mineralogenic and osteogenic activities of Spartina alterniflora and Salicornia fragilis extracts rich in polyphenolsPublication . Roberto, Vania Palma; Surget, Gwladys; Le Lann, Klervi; Mira, Sara; Tarasco, Marco; Guérard, Fabienne; Poupart, Nathalie; Laizé, Vincent; Stiger-Pouvreau, Valérie; Cancela, M. LeonorOsteoporosis is an aging-related disease and a worldwide health issue. Current therapeutics have failed to reduce the prevalence of osteoporosis in the human population, thus the discovery of compounds with bone anabolic properties that could be the basis of next generation drugs is a priority. Marine plants contain a wide range of bioactive compounds and the presence of osteoactive phytochemicals was investigated in two halophytes collected in Brittany (France): the invasive Spartina alterniflora and the native Salicornia fragilis. Two semi-purified fractions, prepared through liquid-liquid extraction, were assessed for phenolic and flavonoid contents, and for the presence of antioxidant, mineralogenic and osteogenic bioactivities. Ethyl acetate fraction (EAF) wasrich in phenolic compounds and exhibited the highest antioxidant activity. While S. fragilis EAF only triggered a weak proliferative effect in vitro, S. alterniflora EAF potently induced extracellular matrix mineralization (7-fold at 250µg/mL). A strong osteogenic effect was also observed in vivo using zebrafish operculum assay (2.5-fold at 10µg/mL in 9-dpf larvae). Results indicate that polyphenol rich EAF of S. alterniflora has both antioxidant and bone anabolic activities. As an invasive species, this marine plant may represent a sustainable source of molecules for therapeutic applications in bone disorders.
- Avanços recentes em nutrição de larvas de peixesPublication . Conceicao, Luis; Aragão, C.; Richard, Nadège; Engrola, S.; Gavaia, Paulo; Mira, Sara; Dias, J.Os requisitos nutricionais de larvas de peixes são ainda mal compreendidos, o que leva a altas mortalidades e problemas de qualidade no seu cultivo. Este trabalho pretende fazer uma revisão de novas metodologias de investigação, tais como estudos com marcadores, genómica populacional, programação nutricional, génomica e proteómica funcionais, e fornecer ainda alguns exemplos das utilizações presentes e perspectivas futuras em estudos de nutrição de larvas de peixes.
- Dietary protein complexity modulates growth, protein utilisation and the expression of protein digestion-related genes in Senegalese sole larvaePublication . Canada, Paula; Conceicao, Luis E. C.; Mira, Sara; Teodósio, Rita; Fernandes, Jorge M. O.; Barrios, Carmen; Millan, Francisco; Pedroche, Justo; Valente, Luisa M. P.; Engrola, SofiaGiven its complex metamorphosis and digestive system ontogeny, Senegalese sole larvae capacity to digest and utilize dietary protein is likely to change throughout development. In the present study, we hypothesized that the manipulation of dietary protein complexity may affect Senegalese sole larvae capacity to digest, absorb and retain protein during metamorphosis, as well as the mRNA expression of genes encoding for the precursors of proteolytic enzymes of the digestive tract and the enterocyte peptide transporter PepT1, which may have further impact on somatic growth. Three diets were formulated using approximately the same practical ingredients, except for the main protein source. The Intact diet protein content was mostly based on intact plant protein where the target peptide molecular weight (MW) would be > 70 kDa. The PartH diet protein fraction was mostly based on a protein hydrolysate with a high content of 5-70 kDa peptides. The HighH diet protein fraction was mostly based on a protein hydrolysate with a high content of 5 kDa peptides. A growth trial was performed with larvae reared at 19 degrees C under a co-feeding regime from mouth opening. The transcription of pga, tryp1c, ialp, ampn and pepT1 (encoding respectively for PepsinogenA, Trypsinogen1C, Intestinal alkaline phosphatase, Aminopeptidase N and for the enterocyte peptide transporter 1) was quantified by qPCR, during the metamorphosis climax (16 DAH) and after the metamorphosis was completed (28 DAH). An in vivo method of controlled tube-feeding was used to assess the effect on the larvae capacity to utilize polypeptides with different MW (1.0 and 7.2 kDa) representing a typical peptide MW of each of the hydrolysates included in the diets. The PartH diet stimulated growth in metamorphosing larvae (16 DAH), whereas the Intact diet stimulated growth after 36 DAH. The Intact diet stimulated the larvae absorption capacity for 1.0 kDa peptides at 16 DAH, which may have contributed for enhanced growth in later stages. The PartH diet stimulated the transcription of tryp1c and pept1 at 28 DAH, which seemed to reflect on increased post-larvae capacity to retain dietary 7.2 kDa polypeptides. That may indicate a possible strategy to optimize the digestion and utilisation of the PartH dietary protein, though it did not reflect into increased growth. The Intact diet promoted the transcription of pepsinogenA, which may reflect a reduced gastrointestinal transit time, which could have enhanced the dietary nutrients assimilation, ultimately improving growth. The present results suggest that, whereas pre-metamorphic sole larvae utilize better dietary protein with a moderate degree of hydrolysis, post-metamorphic sole make a greater use of intact protein.
- Improvement of the cryopreservation protocols for the dusky grouper, Epinephelus marginatusPublication . F Riesco, Marta; Raposo de Magalhães, Cláudia; Engrola, Sofia; Martinez-Paramo, Sonia; Mira, Sara; Cunha, Maria Emilia; Cabrita, ElsaThe dusky grouper, Epinephelus marginatus, is a potential species for aquaculture production although the limited number of males kept in captivity has been the cause of some constraints in its production. Sperm cryopreservation emerged as a solution for this problem. However, spermatozoa can be severely affected by freezing/thawing processes and poor sperm quality is a limiting factor in reproduction success. The present study aimed at evaluating two main aspects in the design of a cryopreservation protocol-extender additives (taurine, glucose, cholesterol, BSA) and sperm containers (0.5 mL straws, 2 mL cryovials and 5 mL macrotubes). Sperm quality was assessed through the evaluation of the percentage of motile cells, viable cells, DNA fragmentation, lipid peroxidation and apoptosis. Some specific techniques, such as Caspase 3/7 detection, which provides information on membrane integrity and cell death, detecting early and late apoptotic and necrotic events, were required to establish an optimized cryopreservation protocol for this species. Taurine was the most suitable cryopreservation additive in terms of viable cells and cholesterol presented the highest percentage of necrotic cells in this study. Caspase 3/7 assay enabled us to detect necrotic damage induced by cryopreservation. Statement of relevance: The development of reproductive tools in dusky grouper, a potential species for aquaculture production, emerges as important tool to decrease the number of wild males maintained in captivity. A cryopreservation protocol was previously described for this species although several constraints in terms of sperm quality were detected. Our work provided new evidences that cryopreservation protocols can be improved through the addition of certain additives and use of appropriate sperm containers. Specific sperm analysis was crucial to identify and establish the most suitable conditions for breeders management and species conservation purposes. (C) 2016 Elsevier B.V. All rights reserved.
- Marine green macroalgae: a source of natural compounds with mineralogenic and antioxidant activitiesPublication . Surget, Gwladys; Roberto, Vania Palma; Le Lann, Klervi; Mira, Sara; Guerard, Fabienne; Laizé, Vincent; Poupart, Nathalie; Leonor Cancela, M.; Stiger-Pouvreau, ValerieMarine macroalgae represent a valuable natural resource for bioactive phytochemicals with promising applications in therapeutics, although they remain largely under-exploited. In this work, the potential of two marine green macroalgae (Cladophora rupestris and Codium fragile) as a source of bioactive phenolic compounds was explored, and antioxidant, mineralogenic, and osteogenic activities were evaluated. For each species, a crude hydroalcoholic extract (CE) was prepared by solid/liquid extraction and fractionated by liquid/liquid purification into an ethyl acetate fraction (EAF) enriched in phenolic compounds and an aqueous fraction (AF). Antioxidant activity, assessed through radical scavenging activity and reducing power assay, was increased in EAF fraction of both species and closely related to the phenolic content in each fraction. Mineralogenic activity, assessed through extracellular matrix mineralization of a fish bone-derived cell line, was induced by EAF fractions (up to 600 % for C. rupestris EAF). Quantitative analysis of operculum formation in zebrafish larvae stained with alizarin red S further confirmed the osteogenic potential of EAF fractions in vivo, with an increase of more than 1.5-fold for both C. fragile and C. rupestris fractions, similar to vitamin D (control). Our results demonstrated a positive correlation between phenolic fractions and biological activity, suggesting that phenolic compounds extracted from marine green macroalgae may represent promising molecules toward therapeutic applications in the field of bone biology.
- Novel methodologies in marine fish larval nutritionPublication . Conceição, L. E. C.; Aragão, C.; Richard, Nadège; Engrola, S.; Gavaia, Paulo J.; Mira, Sara; Dias, J.Major gaps in knowledge on fish larval nutritional requirements still remain. Small larval size, and difficulties in acceptance of inert microdiets, makes progress slow and cumbersome. This lack of knowledge in fish larval nutritional requirements is one of the causes of high mortalities and quality problems commonly observed in marine larviculture. In recent years, several novel methodologies have contributed to significant progress in fish larval nutrition. Others are emerging and are likely to bring further insight into larval nutritional physiology and requirements. This paper reviews a range of new tools and some examples of their present use, as well as potential future applications in the study of fish larvae nutrition. Tube-feeding and incorporation into Artemia of 14C-amino acids and lipids allowed studying Artemia intake, digestion and absorption and utilisation of these nutrients. Diet selection by fish larvae has been studied with diets containing different natural stable isotope signatures or diets where different rare metal oxides were added. Mechanistic modelling has been used as a tool to integrate existing knowledge and reveal gaps, and also to better understand results obtained in tracer studies. Population genomics may assist in assessing genotype effects on nutritional requirements, by using progeny testing in fish reared in the same tanks, and also in identifying QTLs for larval stages. Functional genomics and proteomics enable the study of gene and protein expression under various dietary conditions, and thereby identify the metabolic pathways which are affected by a given nutrient. Promising results were obtained using the metabolic programming concept in early life to facilitate utilisation of certain nutrients at later stages. All together, these methodologies have made decisive contributions, and are expected to do even more in the near future, to build a knowledge basis for development of optimised diets and feeding regimes for different species of larval fish.
- Population genetics of an endangered species: the Bonelli's eagle (Hieraaetus fasciatus)Publication . Mira, Sara; Cancela, Maria Leonor; Dias, Pedro Beja; Dias, PaulaA águia de Bonelli é uma espécie ameaçada na Europa. No início dos anos 1980 elevadas taxas de mortalidade, devido a perseguição pela caça e electrocussão em linhas de alta tensão, provocaram um declínio acentuado nas populações. Actualmente existem cerca de 800 casais nidificantes, na Península Ibérica. As consequências genéticas de um decréscimo populacional são normalmente a perda de diversidade genética e o aumento dos níveis de consanguinidade, elevando assim o risco de extinção das populações. Com o objectivo de estudar a estrutura genética da ágia de Bonelli da Península Ibérica, foram desenvolvidos microsatélites para caracterizar quatro populações - Sudoeste de Portugal, Nordeste de Portugal, Cadiz e Estremadura. Os níveis de diversidade genética observados são moderados, excepto na população do Sudoeste de Portugal, onde foram observados baixos níveis de diversidade. Contrariamente ao esperado, nenhuma população revelou efeitos gargalo ou níveis de consanguinidade, o que sugere que a reprodução se faz de forma aleatória no interior de cada população. Contudo, as quatro populações estudadas apresentam uma forte estrutura espacial e genética significativa. Esta estrutura deve-se provavelmente ao comportamento filopátrico da espécie. Mais ainda a população do Sudoeste de Portugal apresenta indícios de um isolamento comportamental devido a apresentar uma estratégia de nidificação em árvores. Este trabalho termina sublinhando alguns aspectos importantes pra a preservação das populações estudadas de forma a manter a diversidade genética e comportamental existente.
- Projecto "A minha praia": cidadania ambiental para sensibilização, monitorização e limpeza do lixo marinho na região do AlgarvePublication . Ramos, Ana; Lourenço, Carla; Afonso, João; Freitas, Ricardo; Veiga-Pires, C.; Reis, Emanuel; Rodrigues, Miguel; Gomes, Tiago; Rodrigues, Luís; Mira, Sara; Leote, Catarina; Ferreira, Hélder; Pinto, Andreia; Vaz, Paula; Drago, Teresa; Borges, RitaO projecto “A minha praia”, um dos vencedores do Orçamento Participativo OPP – Ciência 2017 pretende contribuir para a conservação do meio marinho e desenvolvimento sustentável com a criação de uma rede alargada de monitorização de lixo marinho ao longo da costa Algarvia. Através da cooperação de diferentes intervenientes (Centros Ciência Viva, comunidade escolar, Investigadores, municípios e entidades regionais) serão promovidas acções de ciência cidadã de: 1) limpeza e monitorização do lixo marinho de seis praias referenciadas da região; 2) actividades educativas de reutilização e reciclagem de materiais de plástico recolhidos em estações de reciclagem implementadas nos Centros Ciência Viva. Para além da obtenção de informação relevante para avaliação do lixo marinho encontrado nas praias (e.g. origem, quantidade, variação anual) este projecto irá contribuir para a sensibilização da sociedade e em particular da comunidade escolar para a problemática e impacto da poluição do meio marinho, nomeadamente por plásticos, nos ecossistemas e nos serviços por eles fornecidos e para a necessidade de um consumo sustentável e preservação dos Oceanos. Adicionalmente, contribuirá para a aproximação entre os cidadãos e a comunidade científica.