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Titolo:
EFFECT OF GLUTAMINE ON THE INDUCTION OF NITRATE REDUCTASE
Autore:
LI XZ; LARSON DE; GLIBETIC M; OAKS A;
Indirizzi:
UNIV GUELPH,DEPT MOLEC BIOL & GENET GUELPH ON N1G 2W1 CANADA UNIV GUELPH,DEPT MOLEC BIOL & GENET GUELPH ON N1G 2W1 CANADA
Titolo Testata:
Physiologia Plantarum
fascicolo: 4, volume: 93, anno: 1995,
pagine: 740 - 744
SICI:
0031-9317(1995)93:4<740:EOGOTI>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
METABOLITE CONTROL; NITROGEN-METABOLISM; MAIZE ROOTS; EXPRESSION; AMMONIUM; LEAVES; CELLS;
Keywords:
GLUTAMINE; INDUCTION, INHIBITION; METHIONINE SULFOXIMINE; NITRATE REDUCTASE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
29
Recensione:
Indirizzi per estratti:
Citazione:
X.Z. Li et al., "EFFECT OF GLUTAMINE ON THE INDUCTION OF NITRATE REDUCTASE", Physiologia Plantarum, 93(4), 1995, pp. 740-744

Abstract

Nitrate reductase (NR, EC 1.6.6.1/2) is a substrate inducible enzyme that could be repressed by its end product glutamine or amino acids. To test this hypothesis, 6-day-old maize seedlings (Zea mays cv. W64A xW182E) were grown hydroponically in a 1/10 strength Hoagland's salt solution modified to contain no nitrogen. Previous experiments had established that after a 24-h induction with NO3- (5 mM KNO3-) the level of NR activity and protein had reached a constant level. In the presentexperiments when glutamine (5 mM) was included together with NO3- there was a significant reduction in NR activity (34% of the control values), NR protein and NR mRNA accumulation in the root. In the shoot, onthe Ether hand, glutamine additions had little or no effect on the levels of either NR activity (81% of control) or NR protein. Inhibition of glutamine synthetase by methionine sulfoximine (MSX) resulted in reduced levels of glutamine in both root and shoot tissues. Contrary to our prediction, however, it had no effect on NR activity and mRNA content in roots. In the shoot, on the other hand, then was a marked reduction of NR activity (34% of the control value) and NR protein, but no apparent effect on NR mRNA. When detached shoots were treated with MSXand other inhibitors of glutamine synthetase (tabtoxinine-beta-lactamor phosphinothricin) the induction of NR activity by NO; was also inhibited. Glutamine additions (5 or 50 mM) to detached shoots had essentially no effect on the induction of NR activity (90% of control). These results demonstrate that the influence of glutamine and MSX on the induction of NR in maize root and shoot tissues, respectively, is very different.

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Documento generato il 14/07/20 alle ore 10:07:04