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allows the differentiation of a wide variety of cell types. This thesis describes the research work aimed at characterizing the role of a novel Notch ligand (Delta4) in the mammalian vascular development. In order to approach this, a mouse line with the inactivation of either one or both alleles of the Delta4 gene was analyzed. The phenotypic characterization of these mutants allowed us to discover that this gene is essential for the differentiation and development of the arteries, and that a decrease in the ligand induced Notch signalling increases endothelial cell sensibility to the angiogenic stimulus. Taken together, these results show that the Delta4 gene is essential for the normal blood vessel development and that it might also have an important role in the adult neoangiogenesis constituting a novel therapeutic target to be explored. 9 Estrutura e função de módulos não catalíticos envolvidos na degradação da parede celular vegetal: o efeito de enzimas exógenas na valorização nutritiva de dietas à base de Lupinus albus para leitões Virgínia Maria Rico Pires Doutoramento em: Ciência e Tecnologia Animal Orientador: Carlos Mendes Godinho de Andrade Fontes Provas concluídas em: 15 de Outubro de 2008 Resumo As glicósido hidrolases modulares, que atacam polissacáridos estruturais, possuem módulos não catalíticos de ligação a hidratos de carbono (CBMs) que desempenham uma função crucial na acção destas enzimas por possibilitarem um contacto prolongado da enzima com…