1887

Abstract

Two mutants of that cannot grow with nitrate as nitrogen source have been examined biochemically. Each mutant differs from the wild-type strain by a single mutation in a Mendelian gene. One mutant (14/15) carries a mutation in a gene designated This organism took up nitrate and converted nitrate-nitrogen to insoluble-nitrogen; nevertheless no enzymic activities associated with nitrate reductase (NADH-nitrate reductase, reduced benzyl viologen nitrate reductase or inducible NADH-cytochrome reductase) could be demonstrated in frozen/thawed cells or cell-free extracts. At high nitrate concentrations (5 mM) the rate of nitrate uptake by this mutant [ 59 nmol (mg dry wt) h] was considerably lower than that of wild-type [ 920 nmol (mg dry wt) h]. It is concluded that is probably a regulatory gene for nitrate reductase. The other mutant (17/4) has a mutation in a gene designated This organism did not take up nitrate and had no NADH-nitrate reductase or inducible NADH-cytochrome reductase activities. Frozen/thawed cells and cell-free extracts had reduced benzyl viologen nitrate reductase activity. The enzyme from the mutant eluted from a Sepharose 4B column later than wild-type enzyme; it was therefore probably of lower molecular weight. The mutation of closely resembles the mutation of and, like this mutation, it probably results in loss of the NADH combining sub-unit of nitrate reductase. Strain 137c of had no enzymic activities associated with nitrate reductase and did not take up nitrate. This organism may have mutations in both the and loci.

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1978-09-01
2022-01-22
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References

  1. Barea J. L., Maldonado J. M., Cardenas J. 1976; Further characterization of nitrate and nitrite reductases from Chlamydomonas reinhardii. Physiologia plantarum 36:325–332
    [Google Scholar]
  2. Beevers L., Hageman R. H. 1969; Nitrate reduction in higher plants. Annual Review of Plant Physiology 20:495–522
    [Google Scholar]
  3. Bliss G. I., James A. T. 1966; Fitting the rectangular hyperbola. Biomztrics 22:573–602
    [Google Scholar]
  4. Butz R. G., Jackson W. A. 1976; A mechanism for nitrate transport and reduction. Phyto-chemistry 16:409–417
    [Google Scholar]
  5. Coddington A. 1976; Biochemical studies on the nit mutants of Neurospora crassa. Molecular and General Genetics 145:195–206
    [Google Scholar]
  6. Conway E. J. 1947 Microdiffusion Analysis and Volumetric Error London: Crosby Lockwood & Son;
    [Google Scholar]
  7. Cove D. J., Coddington A. 1965; Purification of nitrate reductase and cytochrome c reductase from Aspergillus nidulans. Biochimica et bio-physica acta 110:312–318
    [Google Scholar]
  8. Hartree E. F. 1972; A modification of the Lowry method that gives a linear photometric response. Analytical Biochemistry 48:422–427
    [Google Scholar]
  9. Hipkin C. R., Syrett P. J. 1973; Enzymic determination of nitrate by use of frozen/thawed Chlorella cells. New Phytologist 72:47–49
    [Google Scholar]
  10. Levine R. P., Goodenough U. 1970; The genetics of photosynthesis and of the chloroplast in Chlamydomonas reinhardi. Annual Review of Genetics 4:397–408
    [Google Scholar]
  11. MacDonald D. W., Cove D. J., Coddington A. 1974; Cytochrome c reductases from wild-type and mutant strains of Aspergillus nidulans. Molecular and General Genetics 128:187–199
    [Google Scholar]
  12. Massey V. 1959; The microestimation of succinate and the extinction coefficient of cytochrome c. Biochimica et biophysica acta 34:255–256
    [Google Scholar]
  13. Medina A., Nicholas D. J. D. 1957; Interference by reduced pyridine nucleotides in the diazotization of nitrite. Biochimica et biophysica acta 33:440–442
    [Google Scholar]
  14. Milner H. W., Lawrence N. S., French C. S. 1950; Colloidal dispersion of chloroplast material. Science 111:633–634
    [Google Scholar]
  15. Nichols G. L., Syrett P. J. 1978; Nitrate reductase deficient mutants of Chlamydomonas reinhardii. Isolation and genetics. Journal of General Microbiology 108:71–77
    [Google Scholar]
  16. Pateman J. A., Cove D. J., Rever B. M., Roberts D. B. 1964; A common co-factor for nitrate reductase and xanthine dehydrogenase which also regulates the synthesis of nitrate reductase. Nature, London 201:58–60
    [Google Scholar]
  17. Ross P. J., Martin A. E. 1970; A rapid procedure for preparing gas samples for nitrogen-15 determination. Analyst 95:817–822
    [Google Scholar]
  18. Schloemer R. H., Garrett R. H. 1974; Nitrate transport system in Neurospora crassa. Journal of Bacteriology 118:259–269
    [Google Scholar]
  19. Shehata S. A. M. 1977 Mechanisms for the uptake and metabolism of nitrate by Chlamy-domonas. Ph.D. thesis University of Wales;
    [Google Scholar]
  20. Solomonson L. P. 1975; Purification of NADH-nitrate reductase by affinity chromatography. Plant Physiology 56:853–855
    [Google Scholar]
  21. Sueoka N. 1960; Mitotic replication of deoxy-ribonucleic acid in Chlamydomonas reinhardi. Proceedings of the National Academy of Sciences of the United States of America 4683–91
    [Google Scholar]
  22. Thacker A., Syrett P. J. 1972; Disappearance of nitrate reductase activity from Chlamydomonas reinhardi. New Phytologist 71:435–441
    [Google Scholar]
  23. Thompson S. T., Cass K. H., Stellwegen E. 1975; Blue dextran-Sepharose: an affinity column for the dinucleotide fold in proteins. Proceedings of the National Academy of Sciences of the United States of America 72669–672
    [Google Scholar]
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