dissertation com apr 2012 (2 résultats)

Taschenbuch. Etat : Neu. Neuware - Growth Associated Protein 43 (GAP-43), isolated from rat brain and considered a neuronal marker, is involved in neurite branching, cytoskeleton remodelling, neuronal development and protection. However, GAP-43 mRNA was found in embryonic chicken cells positive to meromyosin, as well as in human satellite cells, myoblasts and myotubes deriving from healthy or dystrophic muscles. Despite these findings, there is no clear evidence about its localization or relationship with other muscle proteins.The aim of this study was to investigate GAP-43 protein expression and localization in C2C12 cells and mice skeletal muscle fibers, using immunoblot and immunofluorescence protocols for confocal mycroscopy.Immunoblot analyses show the presence of GAP-43 in C2C12 cell homogenates as well as in mature muscle fibers. Immunofluorescent images reveal that the protein is localized nearby the external nuclear membranes in C2C12 myoblasts, while in C2C12 myotubes, it has been detected on muscular streaks, in a regular double strand pattern. This localization has been found also in Extensor Digitorum Longus fibers isolated from 1 week, 1 and 24 months old mice. In isolated adult mouse fibers, GAP-43 localization appears to be in relationship with crucial proteins such as triadin, alfa-actinin, RyR, DHPR, as well as mitochondria.In addition, cross-specimen analyses on skeletal muscle cells and mature fibers from Xenopus Laevis (amphibian), rat and human were performed, in order to interpret the results from an evolutionary point of view.In conclusion, these preliminary data confirm the presence of GAP-43 in all the analyzed skeletal muscles, and its localization supports the hypothesis of a possible new functional role in the muscle excitation-contraction coupling process.

Taschenbuch. Etat : Neu. Neuware - This book describes a doctoral research project which aims at investigating actual practices of dialogic oriented shared book reading targeting immigrant children in German kindergartens. In this particular research project, the potential contributions of these practices to children's German as second language learning were also assessed. The participants of the study were five native German speaking kindergarten teachers (Erzieherinnen) and five groups of four to six children ages 3- 6 years old. The data sources were videotaped shared book reading sessions which were afterwards transcribed and analysed by using content analysis method. The analysis phases of the study revealed the following findings: 1) there were three different forms of interactions found during the observed shared book reading situations; 2) there were various educators' strategies and children's behaviours observed during the videotaped shared book reading situations, which to some extent were congruent; 3) there were potential contributions of different forms of interactions to children's second language learning. Eventually, the findings of this study are expected to give theoretical and methodological contributions to the field of early childhood second language learning. Moreover, it is also expected to be a solid empirical basis to support the improvement of language promotion programs for immigrant children in German kindergartens.