scholarly journals ACTINOMYCIN-D ENHANCEMENT OF GLUTAMINE SYNTHETASE ACTIVITY IN CHICK EMBRYO RETINAS CULTURED IN THE PRESENCE OF CORTISOL

1971 ◽  
Vol 51 (1) ◽  
pp. 303-311 ◽  
Author(s):  
Liane Beif-Lehrer
Keyword(s):  
Chick Embryo ◽  
Glutamine Synthetase ◽  
Actinomycin D ◽  
Synthetase Activity ◽  
Control Mechanisms ◽  
Glutamine Synthetase Activity ◽  
Animal Cells ◽  
Low Levels

Cortisol can prematurely induce glutamine synthetase activity in the chick embryo retina. Under appropriate conditions, this effect can be enhanced by addition of low levels of actinomycin D; this enhancement is reversibly inhibited by cycloheximide. The magnitude of the effect is a function of time of exposure to hormone as well as antibiotic and is also a function of the age of the embryo; within the limits of the present study it did not appear to be a function of actinomycin-D concentration. The data are discussed in terms of current ideas of possible control mechanisms in animal cells.

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.

Excretion of ammonium by Azospirillum brasilense mutants resistant to ethylenediamine

1991 ◽  
Vol 37 (7) ◽  
pp. 549-553 ◽  
Author(s):  
H. B. Machado ◽  
S. Funayama ◽  
L. U. Rigo ◽  
F. O. Pedrosa
Keyword(s):  
Glutamine Synthetase ◽  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Synthetase Activity ◽  
Ammonium Excretion ◽  
Glutamine Synthetase Activity ◽  
Wild Type ◽  
High Concentration ◽  
Low Levels

Several spontaneous ethylenediamine-resistant mutants of Azospirillum brasilense strain FP2 (Sp7, NalR SmR) were isolated. Four mutants, HM053, HM14, HM26, and HM210, were found to fix nitrogen constitutively in the presence of high concentration of NH4+ and to excrete NH4+ derived from nitrogen fixation. They also showed lower rates of NH4+ uptake than the wild-type strain, FP2. All of the mutants were prototrophic for glutamine or glutamate. Their glutamate synthase and glutamate dehydrogenase activities were similar to those of the wild-type strain. However, they presented different patterns of glutamine synthetase activity. Mutant HM14 showed low levels of normally regulated glutamine synthetase activity, while the other mutants showed low levels (HM053) or wild-type levels (HM26 and HM210) of constitutively adenylylated glutamine synthetase activity. The mutants are probably defective in the adenylylation system. Key words: Azospirillum brasilense, ammonium excretion, ethylenediamine resistance, glutamine synthetase.

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
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