scholarly journals Differential Role of Glutamate Dehydrogenase in Nitrogen Metabolism of Maize Tissues

1984 ◽  
Vol 76 (2) ◽  
pp. 536-540 ◽  
Author(s):  
Victor Manuel Loyola-Vargas ◽  
Estela Sanchez de Jimenez
1991 ◽  
Vol 95 (2) ◽  
pp. 509-516 ◽  
Author(s):  
Sharon A. Robinson ◽  
Annette P. Slade ◽  
Gary G. Fox ◽  
Richard Phillips ◽  
R. George Ratcliffe ◽  
...  

PLoS ONE ◽  
2013 ◽  
Vol 8 (12) ◽  
pp. e84452 ◽  
Author(s):  
Albertus J. Viljoen ◽  
Catriona J. Kirsten ◽  
Bienyameen Baker ◽  
Paul D. van Helden ◽  
Ian J. F. Wiid

2012 ◽  
Vol 24 (10) ◽  
pp. 4044-4065 ◽  
Author(s):  
Jean-Xavier Fontaine ◽  
Thérèse Tercé-Laforgue ◽  
Patrick Armengaud ◽  
Gilles Clément ◽  
Jean-Pierre Renou ◽  
...  

1981 ◽  
Vol 1 (2) ◽  
pp. 158-164
Author(s):  
N S Dunn-Coleman ◽  
E A Robey ◽  
A B Tomsett ◽  
R H Garrett

Glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. Glutamate synthase activity has been determined in a number of Neurospora crassa mutant strains with various defects in nitrogen metabolism. Of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutamate requiring) background. These mutants, i and en-am, are so-called enhancers of am; they have been redesignated herein as en(am)-1 and en(am)-2, respectively. Although glutamate synthase levels in en(am)-1 were essentially wild type, the en(am)-2 strain was devoid of glutamate synthase activity under all conditions examined, suggesting that en(am)-2 may be the structural locus for glutamate synthase. Regulation of glutamate synthase occurred to some extent, presumably in response to glutamate requirements. Glutamate starvation, as in am mutants, led to enhanced activity. In contrast, glutamine limitation, as in gln-1 mutants, depressed glutamate synthase levels.


2020 ◽  
Vol 202 (7) ◽  
Author(s):  
Prabhat Ranjan Singh ◽  
Anil Kumar Vijjamarri ◽  
Dibyendu Sarkar

ABSTRACT Mycobacterium tuberculosis retains the ability to establish an asymptomatic latent infection. A fundamental question in mycobacterial physiology is to understand the mechanisms involved in hypoxic stress, a critical player in persistence. Here, we show that the virulence regulator PhoP responds to hypoxia, the dormancy signal, and effectively integrates hypoxia with nitrogen metabolism. We also provide evidence to demonstrate that both under nitrogen limiting conditions and during hypoxia, phoP locus controls key genes involved in nitrogen metabolism. Consistently, under hypoxia a ΔphoP strain shows growth attenuation even with surplus nitrogen, the alternate electron acceptor, and complementation of the mutant restores bacterial growth. Together, our observations provide new biological insights into the role of PhoP in integrating nitrogen metabolism with hypoxia by the assistance of the hypoxia regulator DosR. The results have significant implications on the mechanism of intracellular survival and growth of the tubercle bacilli under a hypoxic environment within the phagosome. IMPORTANCE M. tuberculosis retains the unique ability to establish an asymptomatic latent infection. To understand the mechanisms involved in hypoxic stress which play a critical role in persistence, we show that the virulence regulator PhoP is linked to hypoxia, the dormancy signal. In keeping with this, phoP was shown to play a major role in M. tuberculosis growth under hypoxia even in the presence of surplus nitrogen, the alternate electron acceptor. Our results showing regulation of hypoxia-responsive genes provide new biological insights into role of the virulence regulator in metabolic switching by sensing hypoxia and integrating nitrogen metabolism with hypoxia by the assistance of the hypoxia regulator DosR.


2013 ◽  
Vol 69 (1) ◽  
pp. 114-126 ◽  
Author(s):  
Anne-Marie Davila ◽  
François Blachier ◽  
Martin Gotteland ◽  
Mireille Andriamihaja ◽  
Pierre-Henri Benetti ◽  
...  

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