Thesis (Ph. D.)--University of Wyoming, 2005. / Title from PDF title page (viewed on March 10, 2008). Includes bibliographical references (p. 130-139).

La maturation in vitro (MIV) est une étape clé de la production d’embryons bovins in vitro. Les cellules du cumulus (CC) jouent un rôle essentiel dans l’acquisition par l’ovocyte de sa compétence à soutenir le développement embryonnaire. Dans les conditions actuelles, les ovocytes issus de MIV sont moins compétents que ceux qui ont été maturés in vivo. Les mécanismes moléculaires impliqués dans la contribution du cumulus au potentiel de développement des ovocytes sont encore mal élucidés. Afin de de comprendre ces mécanismes et de rechercher dans le cumulus des marqueurs potentiels de la compétence au développement des ovocytes, nous avons analysé le transcriptome du cumulus dans différentes conditions de maturation (MIV vs in vivo ; différents temps de MIV). Nous avons ensuite étudié par RT-PCR en temps réel et par western blot dans des cellules de cumulus bovines la cinétique d'expression de plusieurs gènes candidats impliqués dans la formation de la matrice extracellulaire, la réponse au stress oxydatif, l'apoptose, le métabolisme des stéroïdes et de la transmission du signal. Nos données suggèrent l'implication d'un certain nombre de gènes exprimés dans les cellules du cumulus, parmi lesquels des membres des voies de signalisation AKT, MAP kinases et TGF-beta, des gènes impliquées dans la régulation de la méiose ovocytaire, en particulier dans la transition de métaphase I à métaphase-II. L’analyse de l'expression génique dans le cumulus de COC contenant des ovocytes dont la compétence au développement est analysée individuellement, a permis de suggérer plusieurs gènes, marqueurs potentiels de la compétence ovocytaire au développement in vitro. / In vitro maturation (IVM) of oocytes is a crucial step of assisted reproductive technologies in cattle; however, the molecular mechanisms of cumulus cells (CC) contribution to oocyte developmental potential, which is still higher after in vivo maturation, require more investigation. In order to find potential markers of oocyte developmental competence in CC, we performed a transcriptomic analysis of CC from cumulus-oocyte complexes (COC) matured either in vitro or in vivo. Based on these data, we followed by real-time RT-PCR and western blot in bovine cumulus cells the kinetics of expression of several candidate genes involved in extracellular matrix formation, oxidative stress response, apoptosis, steroid metabolism and signal transmission throughout IVM. Our data suggested the involvement of a number of genes including members of AKT, MAP kinases and TGF-beta signaling pathways, expressed in cumulus cells, in the regulation of oocyte meiosis and particularly Metaphase-I to Metaphase-II transition. Analysis of gene expression in CC from COC containing oocytes with different competence to support the fertilisation and early development, revealed several factors in bovine cumulus cells that varied in relation with the developmental potential of corresponding oocytes. Some of these genes might be potential markers of oocyte developmental potential in vitro.

Thesis (Ph. D.)--University of Oklahoma, 1997. / Includes bibliographical references (leaves 125-131).

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The effects of cumulus cloud ensembles on the dynamics of mid-latitude explosive cyclones are studied both from a diagnostic and from a theoretical point of view. / A diagnostic study of an explosive winter storm shows that significant residuals attributable to cumulus convection are present in the horizontal momentum, thermodynamic and vorticity budgets, but not in the divergence budget, and that the finite-amplitude wave is well described by linear dynamics. / A scale analysis appropriate for mid-latitude synoptic-scale waves with intense convection indicates the importance of three mechanisms by which cumulus clouds can influence these storms. These mechanisms are the thermodynamic and dynamical effects of clouds, and certain cloud-induced non-geostrophic effects. / A series of experiments with linear models of moist baroclinic instability using an idealized basic state shows the significant role of the ageostrophic terms and the important damping due to the dynamical effects of clouds. With a realistic wintertime basic state, we conclude that the different cloud forcings are necessary to account for the observed features of explosive storms.

Thesis (Ph.D.). / Written for the Dept. of Atmospheric and Oceanic Sciences. Title from title page of PDF (viewed 2008/02/12). Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1994. / Vita. Includes bibliographical references (leaves [117]-121).

Thesis (Ph. D.)--University of Oklahoma, 1994. / Includes bibliographical references (247-256 leaves).

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Meteorology. / Microfiche copy available in Archives and Science. / Bibliography: leaves 133-137. / M.S.

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