|
|
|
| Registros recuperados: 15 | |
|
|
| Thebault, A; Robert, M.; Chollet, Bruno; Dumais, Muriel; Joly, Jean-pierre; Garcia, C.; Comtet, Thierry; Le Coguic, Matthieu; Martin, Anne-genevieve; Pichot, Yves. |
| Tipo: Text |
|
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00080/19111/16706.pdf |
| |
|
|
| Laudelout, H.; Robert, M.. |
| This study of the biogeochemical cycle of Ca has been carried out in an oak-hornbeam forest ecosystem on a soil derived from the alteration of Famennian (upper Devonian) shales. The physical nature of the geologic substrate made it possible to use the watershed-ecosystem approach by monitoring the loss of Ca by streamflow. Input of hydrogen ions and Ca from rain were average as well as that of mineral nitrogen of which 50% was ammonium-N. Modelling the biogeochemical cycle of Ca in this ecosystem proved to be difficult owing to the heterogeneity of the geologic substrate.The cationic denudation occured mostly with bicarbonate ion as a carrier of the base cations towards the streamflow. Seasonal effects on streamwater cationic composition were in relation... |
| Tipo: Journal Article |
Palavras-chave: ECHANGE IONIQUE; CATION; POUVOIR TAMPON. |
| Ano: 1994 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PUB9500003295049081&uri=/notices/prodinra1/2010/11/ |
| |
|
| |
|
| |
|
| |
|
|
| Ferrer, J.L.; Ravanel, S.; Robert, M.; Dumas, R.. |
| Cobalamin-independent methionine synthase (MetE) catalyzes the synthesis of methionine by a direct transfer of the methyl group of N5-methyltetrahydrofolate (CH3-H4PteGlun) to the sulfur atom of homocysteine (Hcy). We report here the first crystal structure of this metalloenzyme under different forms, free or complexed with the Hcy and folate substrates. The Arabidopsis thaliana MetE (AtMetE) crystals reveal a monomeric structure built by two (βα)8 barrels making a deep groove at their interface. The active site is located at the surface of the C-terminal domain, facing the large interdomain cleft. Inside the active site, His647, Cys649, and Cys733 are involved in zinc coordination, whereas Asp605, Ile437, and Ser439 interact with Hcy. Opposite the... |
| Tipo: Journal Article |
Palavras-chave: ARABIDOPSIS THALIANA; STRUCTURE TRIDIMENSIONNELLE; SITE ACTIF; HOMOCYSTEINE; FOLATE; SITE DE LIAISON; ZINC; METHIONINE. |
| Ano: 2004 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PUB0500031912109810&uri=/notices/prodinra1/2010/11/ |
| |
|
| |
|
|
| Curien, G.; Ravanel, S.; Robert, M.; Dumas, R.. |
| The Arabidopsis genome contains two genes predicted to code for bifunctional aspartate kinase-homoserine dehydrogenase enzymes (isoforms I and II). These two activities catalyze the first and the third steps toward the synthesis of the essential amino acids threonine, isoleucine, and methionine. We first characterized the kinetic and regulatory properties of the recombinant enzymes, showing that they mainly differ with respect to the inhibition of the homoserine dehydrogenase activity by threonine. A systematic search for other allosteric effectors allowed us to identify an additional inhibitor (leucine) and 5 activators (alanine, cysteine, isoleucine, serine, and valine) equally efficient on aspartate kinase I activity (4-fold activation). The six... |
| Tipo: Journal Article |
Palavras-chave: VOIE METABOLIQUE; ACIDE AMINE ESSENTIEL; ASPARTATE KINASE HOMOSERINE DEHYDROGENASE; ISOFORME; EFFECTEUR ALLOSTERIQUE; INHIBITION ENZYMATIQUE; THREONINE; ISOLEUCINE; METHIONINE; ACTIVITE ENZYMATIQUE. |
| Ano: 2005 |
URL: http://www.prodinra.inra.fr/prodinra/pinra/doc.xsp?id=PUB9500032200111312&uri=/notices/prodinra1/2010/11/ |
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
| Perignon, Yves; Ardhuin, Fabrice; Cathelain, M.; Robert, M.. |
| Observations of swell dissipation across oceans reveal a significant loss of energy that can be the result of many of processes. Among these candidate mechanisms, this paper examines the properties of the viscous air-sea boundary layer driven by swells in order to characterize the induced atmospheric flow regime and its associated viscous dissipation over swells. A series of 3-D numerical experiments is carried out with a RANS model and appropriate turbulence closure. These experiments reveal a laminar to turbulent transition in the near free-surface region for a common range of characteristic amplitudes and periods of swells under stationary conditions. At low Reynolds number, laminar conditions prevail and computed decay rates conform to the analytical... |
| Tipo: Text |
Palavras-chave: Swell; Dissipation; Shear; Turbulent. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00213/32405/30872.pdf |
| |
| Registros recuperados: 15 | |
|
|
|
