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A METHYLAMINE‐RESISTANT MUTANT OF THE BLUE‐GREEN ALGA, NOSTOC MUSCORUM: POSSIBLE INVOLVEMENT OF GLUTAMINE SYNTHETASE IN METHYLAMINE METABOLISM
Author(s) -
VAISHAMPAYAN A.
Publication year - 1982
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1982.tb03339.x
Subject(s) - methylamine , glutamine synthetase , mutant , biochemistry , nostoc , metabolism , biology , glutamine , strain (injury) , enzyme , photosynthesis , cyanobacteria , bacteria , gene , amino acid , genetics , anatomy
S ummary Photoautotrophic growth of the Em‐R het − nif 2 − strain of the blue‐green alga, Nostoc muscorum , is prevented completely by 1 mM methylamine (MA) but a concentration of 2 mM MA is required to inhibit photoheterotrophic or dark heterotrophic growth. From this strain a mutant has been isolated and characterized. The mutant cannot grow photoautotrophically but its heterotrophic growth is resistant to 5 mM MA; moreover, the mutant can use MA as a carbon and nitrogen source for growth. It is suggested that because the mutant is defective in photosynthetic ability it lacks the step that is inhibited by 1 mM MA and, in the absence of such inhibition, is able to show the ability to metabolize MA by an existing enzyme system. Mutant strain Em‐RMSO‐R het + nif + , whose growth is resistant to inhibition by l ‐methionine‐ dl ‐sulphoximine, can grow photoautotrophically in 2 mM MA. Because this mutant is known to contain an altered glutamine synthetase, it is suggested that this enzyme may be responsible for methylamine metabolism.