Browsing by Author "Oliveira, Daniel"
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- Acute Loss of Cited2 Impairs Nanog Expression and Decreases Self-Renewal of Mouse Embryonic Stem CellsPublication . Kranc, Kamil R.; Oliveira, Daniel; Armesilla-Diaz, Alejandro; Pacheco-Leyva, Ivette; Matias, Ana Catarina; Escapa, Ana Luísa; Subramani, Chithra; Wheadon, Helen; Trindade, Marlene; Nichols, Jennifer; Kaji, Keisuke; Enver, Tariq; Bragança, JoséIdentifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2, and Nanog as well as delineating the interactions within the complex network is key to understanding self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC functions remains unclear. Here, we show that Cited2 is important for proliferation, survival, and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression. Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.
- Biological aspects of fish species from subsistence fisheries in “Bons Sinais” estuary, MozambiquePublication . Costa, E.F.S.; Mocuba, Jeremias; Oliveira, Daniel; Teodosio, Maria; Leitão, FranciscoKnowledge on biological aspects of commercially exploited fish is an important tool for assessing and managing of data-poor fisheries. In this study, we have collected information on biological aspects of commercial fish species, namely in the Bons Sinais estuary (BSE), Mozambique. Fish species were caught using a beach seine and a traditional fishing gear known as Chicocota, both used by local fishing communities for subsistence fisheries. The results revealed that most specimens caught were juveniles and below the size at first maturity. In general, mean body height (BH) estimated across all species (2.24 cm) was below the minimum mesh size established by Mozambique Fisheries Law (3.8 cm). Estimated W–L regression analysis were statistically significant with the coefficient of determination (r 2 ) explaining from 91 to 98% of the variance. The allometric coefficient b ranged from 2.728 (Stolephorus indicus) to 3.357 (Johnius dussumieri). All the species exhibited positive or isometric allometric growth, except S. indicus, which exhibited negative growth. This study provides new information that can be used to enhance sustainable fishery management in data-poor fisheries.
- Certificação sísmica das construções e perigosidade sísmica em PortugalPublication . Costa, Aníbal; Azevedo, João; Coelho, Ema; Fernandes, Francisco; Guerreiro, Luís M. C.; Carvalho, Alexandra; Matias, Luis; Oliveira, Daniel; Romão, Xavier; Estêvão, João Manuel CarvalhoA análise dos efeitos dos sismos nas construções permite evidenciar, novamente, que as estruturas construídas de acordo com as modernas regulamentações para o dimensionamento sísmico de estruturas se comportam bem, sendo naquelas que não obedecem a estas regulamentações que se verificam os maiores danos e que originam um grande número de mortes. A necessidade de garantir que todas as novas estruturas, ou aquelas que vierem a ser reabilitadas ou reconstruídas, cumpram as prescrições previstas na regulamentação para as dotar de bom comportamento sísmico deve, assim, constituir uma preocupação essencial das sociedades que habitam zonas em que exista um significativo risco sísmico, como é caso de Portugal. Neste contexto, a Sociedade Portuguesa de Engenharia Sísmica (SPES) tem ao longo dos últimos anos vindo a desenvolver campanhas para sensibilizar os poderes políticos para a necessidade de certificar as construções existentes. Nesse sentido a SPES está a desenvolver metodologias para brevemente apresentar uma proposta para a certificação do comportamento sísmico das construções onde serão identificados os procedimentos que devem ser adotados para a certificação dos edifícios existentes. Acrescente-se, ainda, uma outra preocupação da SPES, relacionada com os diferentes mapas de perigosidade sísmica para Portugal continental que têm resultado de vários projetos nacionais e internacionais, e que traduzem níveis de perigosidade sísmica muito diferentes para algumas regiões do território português, particularmente para o sul de Portugal. A SPES, espelhando a inquietude existente na comunidade científica, considerou urgente e promoveu a realização de um estudo criterioso acerca das opções tomadas, nos diferentes estudos, de forma a tentar perceber os fatores que mais contribuíram para as diferenças evidenciadas.
- Identification of proteins with potential osteogenic activity present in the water-soluble matrix proteins from crassostrea gigas nacre using a proteomic approachPublication . Oliveira, Daniel; Silva, Tome S.; Cordeiro, Odete D.; Cavaco, Sofia I.; Simes, DinaNacre, when implanted in vivo in bones of dogs, sheep, mice, and humans, induces a biological response that includes integration and osteogenic activity on the host tissue that seems to be activated by a set of proteins present in the nacre water-soluble matrix (WSM). We describe here an experimental approach that can accurately identify the proteins present in the WSM of shell mollusk nacre. Four proteins (three gigasin-2 isoforms and a cystatin A2) were for the first time identified in WSM of Crassostrea gigas nacre using 2DE and LC-MS/MS for protein identification. These proteins are thought to be involved in bone remodeling processes and could be responsible for the biocompatibility shown between bone and nacre grafts. These results represent a contribution to the study of shell biomineralization process and opens new perspectives for the development of new nacre biomaterials for orthopedic applications.