Thèse de doctorat--Sciences naturelles--Faculté des sciences de l'Université de Paris, 1909. N°: 1347. / Notes bibliogr.

No description available.

Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 79-81.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1950. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The short-term interaction between nitrate and ammonium uptake was examined for a marine diatom, Thalassiosira pseudonana, grown in the continuous turbidostat cultures under different degrees of light limitation. Nitrate uptake in the absence and in the presence of ammonium and ammonium uptake in the absence and in the presence of nitrate were measured during a 6 min time course after a solution of both nitrate and ammonium was passed across the cells trapped on the filter. It was found that the interaction between nitrate and ammonium uptake occurred immediately and continued for the remainder of the time course. The effect of light on the interaction was apparent. In the less light-limited cultures, nitrate uptake was depressed by ammonium. In contrast, in the most light-limited culture, the depression of nitrate uptake by ammonium disappeared. Ammonium uptake was dependent on the degree of light limitation of the cultures. For all the cultures, ammonium uptake was initially enhanced and then declined with time. However, only the initial (1 min) enhanced uptake of ammonium was suppressed by the presence of nitrate, and the subsequent ammonium uptake rate was unaffected. Possible explanations and the ecological significance of the interaction are discussed. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Digitized by Kansas State University Libraries

Call number: LD2668 .T4 1932 H81 / Master of Science

Les reins jouent un rôle majeur dans la régulation de l'homéostasie acide-base. La production et l'excrétion rénale d'ammonium assurent environ deux tiers de l'excrétion nette d'acides dans les conditions normales et jusqu'à 90% en situation d'acidose métabolique. Bien que l'excrétion d'ammonium soit un processus finement régulé et capital au maintien de l'équilibre acido-basique, à ce jour aucun transporteur spécifique d'ammonium n'a été décrit chez les mammifères. Les protéines Rhésus Rhcg et Rhbg, membres distants de la famille des transporteurs d'ammonium Mep/Amt, semblaient de bons candidats à cette fonction. L'invalidation du gène Rhcg puis celle de Rhbg ont donc été entreprises chez la souris afin d'estimer leur rôle potentiel dans le transport de l'ammonium.

No description available.

No description available.