Alteration of cyanobacterial glutamine synthetase activity in vivo in response to light and NH 4 +

1979 ◽  
Vol 120 (3) ◽  
pp. 195-200 ◽  
Author(s):  
P. Rowell ◽  
M. J. A. M. Sampaio ◽  
J. K. Ladha ◽  
W. D. P. Stewart
Keyword(s):  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity

Regulation of in vivo glutamine synthetase activity by glucocorticoids in the developing rat brain

1983 ◽  
Vol 10 (1) ◽  
pp. 83-91 ◽  
Author(s):  
A.J. Patel ◽  
A. Hunt ◽  
C.S.M. Tahourdin
Keyword(s):  
Glutamine Synthetase ◽  
Rat Brain ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Developing Rat

scholarly journals In Vivo Regulation of Glutamine Synthetase Activity in the Marine Chlorophyll b-Containing CyanobacteriumProchlorococcus sp. Strain PCC 9511 (Oxyphotobacteria)

2001 ◽  
Vol 67 (5) ◽  
pp. 2202-2207 ◽  
Author(s):  
Sabah El Alaoui ◽  
Jesús Diez ◽  
Lourdes Humanes ◽  
Fermı́n Toribio ◽  
Frédéric Partensky ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Starvation ◽  
Glutamate Synthase ◽  
Nitrogen Sources ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Protein Determination ◽  
Physiological Regulation ◽  
Gs Protein

ABSTRACT The physiological regulation of glutamine synthetase (GS; EC6.3.1.2 ) in the axenic Prochlorococcus sp. strain PCC 9511 was studied. GS activity and antigen concentration were measured using the transferase and biosynthetic assays and the electroimmunoassay, respectively. GS activity decreased when cells were subjected to nitrogen starvation or cultured with oxidized nitrogen sources, which proved to be nonusable forProchlorococcus growth. The GS activity in cultures subjected to long-term phosphorus starvation was lower than that in equivalent nitrogen-starved cultures. Azaserine, an inhibitor of glutamate synthase, provoked an increase in enzymatic activity, suggesting that glutamine is not involved in GS regulation. Darkness did not affect GS activity significantly, while the addition of diuron provoked GS inactivation. GS protein determination showed that azaserine induces an increase in the concentration of the enzyme. The unusual responses to darkness and nitrogen starvation could reflect adaptation mechanisms of Prochlorococcus for coping with a light- and nutrient-limited environment.

Encapsulation of glutamine synthetase in mouse erythrocytes: a new procedure for ammonia detoxification

2008 ◽  
Vol 86 (6) ◽  
pp. 469-476 ◽  
Author(s):  
Elena A. Kosenko ◽  
Natalia I. Venediktova ◽  
Andrey A. Kudryavtsev ◽  
Fazoil I. Ataullakhanov ◽  
Yury G. Kaminsky ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Cell Recovery ◽  
Ammonia Detoxification ◽  
Neurological Alterations

There are a number of pathological situations in which ammonia levels increase leading to hyperammonemia, which may cause neurological alterations and can lead to coma and death. Currently, there are no efficient treatments allowing rapid and sustained decrease of ammonia levels in these situations. A way to increase ammonia detoxification would be to increase its incorporation in glutamine by glutamine synthetase. The aim of this work was to develop a procedure to encapsulate glutamine synthetase in mouse erythrocytes and to assess whether administration of these erythrocytes containing glutamine synthetase (GS) reduce ammonia levels in hyperammonemic mice. The procedure developed allowed the encapsulation of 3 ± 0.25 IU of GS / mL of erythrocytes with a 70% cell recovery. Most metabolites, including ATP, remained unaltered in glutamine synthetase-loaded erythrocytes (named ammocytes by us) compared with native erythrocytes. The glutamine synthetase-loaded ammocytes injected in mice survived and retained essentially all of their glutamine synthetase activity for at least 48 h in vivo. Injection of these ammocytes into hyperammonemic mice reduced ammonia levels in the blood by about 50%. The results reported indicate that ammocytes are able to keep their integrity, normal energy metabolism, the inserted glutamine synthetase activity, and can be useful to reduce ammonia levels in hyperammonemic situations.

Glutamine synthetase activity in vivo and in primary cell cultures of rat hypothalamus

1979 ◽  
Vol 33 (4) ◽  
pp. 953-957 ◽  
Author(s):  
D. E. Vaccaro ◽  
S. E. Leeman ◽  
L. Reif-Lehrer
Keyword(s):  
Glutamine Synthetase ◽  
Cell Cultures ◽  
Primary Cell ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Rat Hypothalamus ◽  
Primary Cell Cultures

scholarly journals Glutamine synthetase in muscle and kidney

1970 ◽  
Vol 119 (2) ◽  
pp. 145-156 ◽  
Author(s):  
Khalid Iqbal ◽  
J. H. Ottaway
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Optimum Conditions ◽  
Muscle Enzyme ◽  
Tissue Extracts ◽  
Kidney Enzyme

1. Glutamine synthetase activity has been determined in extracts of rat cardiac and skeletal muscle and kidney, after treatment to ensure that the rate of synthesis was proportional to time of incubation and to amount of extract added. The activity was measured by two methods, with hydroxylamine as substrate. 2. No activity was detected in rat heart extract by either method. The activity in skeletal muscle was of the order of 20μmol of glutamylhydroxamate synthesized/h per g of tissue under optimum conditions. The activity in kidney extracts was 180μmol/h per g of tissue when measured as ferric hydroxamate. 3. The activity in both skeletal-muscle and kidney extracts was inhibited by Pi. The inhibition is competitive for the muscle enzyme, with a Ki of 12mm. For the kidney enzyme the inhibition is non-competitive, and less marked. Possible enzyme mechanisms that would lead to these types of inhibition are discussed. 4. Several observations are reported that suggest that the enzymes from muscle and kidney are not identical. 5. Growth hormone, either in vivo or in vitro, did not affect the measured glutamine synthetase activity of tissue extracts.

Unchanged glutamine synthetase activity and increased NMDA receptor density in epileptic human neocortex: Implications for the pathophysiology of epilepsy

2005 ◽  
Vol 47 (6) ◽  
pp. 379-384 ◽  
Author(s):  
Marc Steffens ◽  
Hans-Jürgen Huppertz ◽  
Josef Zentner ◽  
Emmanuelle Chauzit ◽  
Thomas J. Feuerstein
Keyword(s):  
Nmda Receptor ◽  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Receptor Density ◽  
Human Neocortex

scholarly journals Induction of Glutamine Synthetase Activity in Nonnodulated Roots of Glycine max, Phaseolus vulgaris, and Pisum sativum

1992 ◽  
Vol 100 (1) ◽  
pp. 525-528 ◽  
Author(s):  
Inger Hoelzle ◽  
John J. Finer ◽  
Michael D. McMullen ◽  
John G. Streeter
Keyword(s):  
Glycine Max ◽  
Phaseolus Vulgaris ◽  
Pisum Sativum ◽  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity

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

Strain- and sex-specific variations in hepatic glutamine synthetase activity and distribution in rats and mice

2008 ◽  
Vol 16 (3) ◽  
pp. 166-173 ◽  
Author(s):  
Hüseyin Sirma ◽  
Gary M. Williams ◽  
Rolf Gebhardt
Keyword(s):  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Rats And Mice
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