Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1978 Aug;62(2):299–304. doi: 10.1104/pp.62.2.299

Initial Organic Products of Assimilation of [13N]Ammonium and [13N]Nitrate by Tobacco Cells Cultured on Different Sources of Nitrogen 1

Thomas A Skokut 1,2, C Peter Wolk 1, Joseph Thomas 1,3, John C Meeks 1,4, Paul W Shaffer 1, W-S Chien 2
PMCID: PMC1092110  PMID: 16660506

Abstract

Glutamine is the first major organic product of assimilation of 13NH4+ by tobacco (Nicotiana tabacum L. cv. Xanthi) cells cultured on nitrate, urea, or ammonium succinate as the sole source of nitrogen, and of 13NO3− by tobacco cells cultured on nitrate. The percentage of organic 13N in glutamate, and subsequently, alanine, increases with increasing periods of assimilation. 13NO3−, used for the first time in a study of assimilation of nitrogen, was purified by new preparative techniques. During pulse-chase experiments, there is a decrease in the percentage of 13N in glutamine, and a concomitant increase in the percentage of 13N in glutamate and alanine. Methionine sulfoximine inhibits the incorporation of 13N from 13NH4+ into glutamine more extensively than it inhibits the incorporation of 13N into glutamate, with cells grown on any of the three sources of nitrogen. Azaserine inhibits glutamate synthesis extensively when 13NH4+ is fed to cells cultured on nitrate. These results indicate that the major route for assimilation of 13NH4+ is the glutamine synthetase-glutamate synthase pathway, and that glutamate dehydrogenase also plays a role, but a minor one. Methionine sulfoximine inhibits the incorporation of 13N from 13NO3− into glutamate more strongly than it inhibits the incorporation of 13N into glutamine, suggesting that the assimilation of 13NH4+ derived from 13NO3− may be mediated solely by the glutamine synthetase-glutamate synthase pathway.

Full text

PDF
299

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bauer A., Urquhart A. A., Joy K. W. Amino Acid metabolism of pea leaves: diurnal changes and amino Acid synthesis from N-nitrate. Plant Physiol. 1977 May;59(5):915–919. doi: 10.1104/pp.59.5.915. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Dougall D. K. Evidence for the presence of glutamate synthase in extracts of carrot cell cultures. Biochem Biophys Res Commun. 1974 Jun 4;58(3):639–646. doi: 10.1016/s0006-291x(74)80466-3. [DOI] [PubMed] [Google Scholar]
  3. ELLIOTT W. H. Isolation of glutamine synthetase and glutamotransferase from green peas. J Biol Chem. 1953 Apr;201(2):661–672. [PubMed] [Google Scholar]
  4. Ferrari T. E., Yoder O. C., Filner P. Anaerobic nitrite production by plant cells and tissues: evidence for two nitrate pools. Plant Physiol. 1973 Mar;51(3):423–431. doi: 10.1104/pp.51.3.423. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Filner P. Regulation of nitrate reductase in cultured tobacco cells. Biochim Biophys Acta. 1966 May 5;118(2):299–310. doi: 10.1016/s0926-6593(66)80038-3. [DOI] [PubMed] [Google Scholar]
  6. Filner P. Semi-conservative replication of DNA in a higher plant cell. Exp Cell Res. 1965 Aug;39(1):33–39. doi: 10.1016/0014-4827(65)90004-2. [DOI] [PubMed] [Google Scholar]
  7. Gersberg R., Krohn K., Peek N., Goldman C. R. Denitrification Studies with 13N-Labeled Nitrate. Science. 1976 Jun 18;192(4245):1229–1231. doi: 10.1126/science.192.4245.1229. [DOI] [PubMed] [Google Scholar]
  8. Heimer Y. M., Filner P. Regulation of the nitrate assimilation pathway in cultured tobacco cells. 3. The nitrate uptake system. Biochim Biophys Acta. 1971 Feb 23;230(2):362–372. doi: 10.1016/0304-4165(71)90223-6. [DOI] [PubMed] [Google Scholar]
  9. Lea P. J., Miflin B. J. Alternative route for nitrogen assimilation in higher plants. Nature. 1974 Oct 18;251(5476):614–616. doi: 10.1038/251614a0. [DOI] [PubMed] [Google Scholar]
  10. Meeks J. C., Wolk C. P., Thomas J., Lockau W., Shaffer P. W., Austin S. M., Chien W. S., Galonsky A. The pathways of assimilation of 13NH4+ by the cyanobacterium, Anabaena cylindrica. J Biol Chem. 1977 Nov 10;252(21):7894–7900. [PubMed] [Google Scholar]
  11. Miflin B. J., Lea P. J. Glutamine and asparagine as nitrogen donors for reductant-dependent glutamate synthesis in pea roots. Biochem J. 1975 Aug;149(2):403–409. doi: 10.1042/bj1490403. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. O'Neal D., Joy K. W. Glutamine synthetase of pea leaves. I. Purification, stabilization, and pH optima. Arch Biochem Biophys. 1973 Nov;159(1):113–122. doi: 10.1016/0003-9861(73)90435-9. [DOI] [PubMed] [Google Scholar]
  13. O'Neal D., Joy K. W. Localisation of glutamine synthetase in chloroplasts. Nat New Biol. 1973 Nov 14;246(150):61–62. doi: 10.1038/newbio246061a0. [DOI] [PubMed] [Google Scholar]
  14. O'neal D., Joy K. W. Glutamine synthetase of pea leaves: divalent cation effects, substrate specificity, and other properties. Plant Physiol. 1974 Nov;54(5):773–779. doi: 10.1104/pp.54.5.773. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Thomas J., Meeks J. C., Wolk C. P., Shaffer P. W., Austin S. M. Formation of glutamine from [13n]ammonia, [13n]dinitrogen, and [14C]glutamate by heterocysts isolated from Anabaena cylindrica. J Bacteriol. 1977 Mar;129(3):1545–1555. doi: 10.1128/jb.129.3.1545-1555.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Thomas J., Wolk C. P., Shaffer P. W., Austin S. M., Galonsky A. The initial organic products of fixation of 13N-labeled nitrogen gas by the blue-green alga Anabaena cylindrica. Biochem Biophys Res Commun. 1975 Nov 17;67(2):501–507. doi: 10.1016/0006-291x(75)90840-2. [DOI] [PubMed] [Google Scholar]
  17. Webster G. C. Enzymatic Synthesis of Glutamine in Higher Plants. Plant Physiol. 1953 Oct;28(4):724–727. doi: 10.1104/pp.28.4.724. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Wolk C. P., Austin S. M., Bortins J., Galonsky A. Autoradiographic localization of 13N after fixation of 13N-labeled nitrogen gas by a heterocyst-forming blue-green alga. J Cell Biol. 1974 May;61(2):440–453. doi: 10.1083/jcb.61.2.440. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Wolk C. P., Thomas J., Shaffer P. W., Austin S. M., Galonsky A. Pathway of nitrogen metabolism after fixation of 13N-labeled nitrogen gas by the cyanobacterium, Anabaena cylindrica. J Biol Chem. 1976 Aug 25;251(16):5027–5034. [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES