scholarly journals Does Lowering Glutamine Synthetase Activity in Nodules Modify Nitrogen Metabolism and Growth of Lotus japonicus?

2003 ◽  
Vol 133 (1) ◽  
pp. 253-262 ◽  
Author(s):  
Judith Harrison ◽  
Marie-Anne Pou de Crescenzo ◽  
Olivier Sené ◽  
Bertrand Hirel
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Metabolism ◽  
Lotus Japonicus ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity

In vitro proof of direct regulation of glutamine synthetase by GlnK proteins in the extreme halophilic archaeon Haloferax mediterranei

2011 ◽  
Vol 39 (1) ◽  
pp. 259-262 ◽  
Author(s):  
Laia Pedro-Roig ◽  
Mónica Camacho ◽  
María José Bonete
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Metabolism ◽  
Model Organism ◽  
Methanogenic Archaea ◽  
Ammonium Assimilation ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Haloferax Mediterranei ◽  
Pii Proteins

Haloferax mediterranei is an extreme halophilic micro-organism belonging to the Archaea domain that was isolated from the Santa Pola solar salterns (Alicante, Spain) in 1983. The biochemistry of the proteins involved in nitrogen metabolism is being studied, but the knowledge of their regulation is very scarce at present. The PII superfamily is constituted by major regulators of nitrogen metabolism, which are widespread in prokaryotic and eukaryotic organisms. These trimeric proteins (12 kDa per subunit) have in Escherichia coli long been known to regulate GS (glutamine synthetase) activity via its adenylyltransferase/adenylyl-removing enzyme and, more recently, to be able to interact directly with this enzyme in methanogenic archaea. We have tested the possible role of PII proteins in the regulation of ammonium assimilation in our model organism and the results clearly indicate that the direct influence of GS by PII proteins can also take place in halophilic archaea, starting with the comprehension of nitrogen regulation in those organisms.

Respective effects of glucose and glutamine on the glutamine synthetase activity of human skin fibroblasts

1991 ◽  
Vol 102 (2) ◽  
Author(s):  
Th�ophile Soni ◽  
Claire Wolfrom ◽  
Samia Guerroui ◽  
Nicole Raynaud ◽  
Jos�phine Poggi ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Human Skin ◽  
Skin Fibroblasts ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Human Skin Fibroblasts

Control of nitrogen assimilation in Stichococcus bacillaris by growth conditions

1987 ◽  
Vol 65 (3) ◽  
pp. 432-437 ◽  
Author(s):  
Iftikhar Ahmad ◽  
Johan A. Hellebust
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Continuous Light ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Cell Carbon ◽  
Stichococcus Bacillaris ◽  
Mixotrophic Conditions

Stichococcus bacillaris Naeg. (Chlorophyceae) grown on a 12 h light: 12 h dark cycle divides synchronously under photoautotrophic conditions and essentially nonsynchronously under mixotrophic conditions. Photoassimilation of carbon under photoautotrophic conditions was followed by a decline in cell carbon content during the dark period, whereas under mixotrophic conditions cell carbon increased throughout the light–dark cycle. The rates of nitrogen assimilation by cultures grown on either nitrate or ammonium declined sharply during the dark, and these declines were most pronounced under photoautotrophic conditions. Photoautotrophic cells synthesized glutamine synthetase and NADPH – glutamate dehydrogenase (GDH) exclusively in the light, whereas in mixotrophic cells about 20% of the total synthesis of these enzymes during one light–dark cycle occurred in the dark. NADH–GDH was synthesized almost continuously over the entire light–dark cycle. In the dark, both under photoautotrophic and mixotrophic conditions, the alga contained more than 50% of glutamine synthetase in an inactive form, which was reactivated in vitro in the presence of mercaptoethanol and in vivo after returning the cultures to the light. The thermal stability of glutamine synthetase activity was less in light-harvested cells than in dark-harvested cells. The inactivation of glutamine synthetase did not occur in cultures growing either heterotrophically in continuous darkness or photoautotrophically in continuous light. This enzyme appears to be under thiol control only in cells grown under alternating light–dark conditions, irrespective of whether this light regime results in synchronous cell division or not.

scholarly journals Hydrocortisone requirement for the induction of glutamine synthetase in chick-embryo retinas

1968 ◽  
Vol 106 (2) ◽  
pp. 425-430 ◽  
Author(s):  
Liane Reif-Lehrer ◽  
Harold Amos
Keyword(s):  
Chick Embryo ◽  
Glutamine Synthetase ◽  
Messenger Rna ◽  
Active Component ◽  
Calf Serum ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity

Hydrocortisone has been found to induce glutamine synthetase activity in chick-embryo retinas in culture. Evidence is presented to show that the hydrocortisone is definitely required for transcription; its requirement for translation has not been ruled out. The possible identity of hydrocortisone with an active component of calf-serum diffusate reported earlier is discussed. The data also indicate that the glutamine synthetase messenger RNA is stable for at least several hours.

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