Récemment, il a été proposé que le cervelet participe à l'acquisition de fonctions cognitives telle que la navigation. Un des mécanismes de plasticité synaptique du cervelet, la Dépression synaptique à Long Terme hétérosynaptique des fibres parallèles (DLT), est déjà connu pour être impliqué dans les apprentissages moteurs. L'objectif de ce travail de thèse était de déterminer si cette DLT participe également à l'acquisition d'une tâche de navigation. A l'aide de tests de navigation développés dans l'équipe, j'ai étudié les performances de souris transgéniques L7-PKCI dont ce mécanisme de DLT est altéré. Dans ces tests, les souris L7-PKCI étaient déficientes dans la capacité à élaborer une trajectoire efficace pour rejoindre leur but. Ces résultats suggèrent qu'un rôle essentiel du cervelet dans la navigation, et plus particulièrement de la DLT, est d'adapter en permanence la sortie motrice afin d'effectuer une trajectoire optimale.

Made available in DSpace on 2014-12-17T15:18:10Z (GMT). No. of bitstreams: 1 MariaAGD.pdf: 3831855 bytes, checksum: 0abe0a10e359f22bab7ed834fa8e296a (MD5) Previous issue date: 2009-02-26 / Sugarcane is one of the most important products of the world and Brazil is responsible for 25 % of the world production. One problem of this culture at northeast of Brazil is the early flowering. In our laboratory, it has been made before four subtractive libraries using early and late flowering genotypes in order to identify messages related to the flowering process. In this work, two cDNAs were chosen to make in silico analysis and overexpression constructs. Another approach to understand the flowering process in sugarcane was to use proteomic tools. First, the protocol for protein extraction using apical meristem was set up. After that, these proteins were separated on two bidimensional gels. It was possible to observe some difference for some regions of these gels as well as some proteins that can be found in all conditions. The next step, spots will be isolated and sequence on MS spectrometry in order to understand this physiological process in sugarcane / A cana-de-a??car ? uma das mais importantes culturas mundiais e atualmente o Brasil representa um dos maiores produtores de cana-de-a??car no ranque mundial. Sabendo-se da import?ncia da cana-de-a??car nos dias atuais, principalmente em rela??o ao biocombust?vel e do problema causado pela flora??o precoce a esta cultura na regi?o Nordeste, foi realizada uma an?lise in silico de dois cDNAs:, 14-3-3 like protein e Protein kinase C inhibitor-like (PKCI), envolvidos no processo de flora??o da cana-de-a??car, utilizando ferramentas gen?micas. Foi escolhido o cDNA PKCI para a constru??o de cassetes de super-express?o de modo a ser caracterizado o papel deste cDNA no processo de flora??o. Outra abordagem utilizada nesse trabalho foi de analisar prote?nas totais de ?pices meristem?ticos de variedades precoce e tardia em g?is uni e bidimensionais. Os resultados mostraram que existem algumas prote?nas que podem ser caracter?sticas de uma das variedades, e em outras foi observado uma express?o diferencial