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Nitrate metabolism in the cyanobacterium Anabaena cycadeae : Regulation of nitrate uptake and reductase by ammonia
Author(s) -
Bagchi Suvendra N.,
Rai Upendra N.,
Rai Amar N.,
Singh Hriday N.
Publication year - 1985
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1985.tb04273.x
Subject(s) - nitrate reductase , glutamine synthetase , nitrate , biochemistry , auxotrophy , glutamine , nitrogen assimilation , reductase , anabaena , metabolism , cyanobacteria , ammonia , biology , chemistry , enzyme , bacteria , amino acid , escherichia coli , ecology , genetics , gene
Nitrogen regulation of nitrate uptake and nitrate reductase (EC 1.7.99.4) was studied in the cyanobacterium Anabaena cycadeae Reinke and its glutamine auxotroph. Development of the nitrate uptake system preceded, and was independent of, the development of the nitrate reductase system. The levels of both systems were several‐fold higher in the glutamine auxotroph lacking glutamine synthetase (EC 6.3.1.2) than in the wild type strain having normal glutamine synthetase activity. The nitrate uptake system was found to be NH4‐repressible and the nitrate reductase system NO 3 − ‐inducible. NH 4 + was the initial repressor signal for the uptake process which was involved in the control of the NO 3 − inducible reductase system.