Evidence for a common genetic regulation of glutamine synthetase and nitrate uptake and reductase in the cyanobacterium Anabaena cycadeae

Summary Nitrate uptake and reductase activities of the cyanobacterium Anabaena cycadeae and its mutant, lacking glutamine synthetase, (the glutamine auxotroph) were measured. The levels of both these enzymes were up to 25-fold higher in the mutant than in the parent (Anabaena cycadeae). the data indicate operation of a common genetic regulatory mechanism controlling the loss of the primary ammonia assimilating enzyme, glutamine synthetase, and derepression of the nitrate uptake and reductase systems.Abbreviations Chl Chlorophyll - GS Glutamine Synthetase - HEPES 4-(2-hydroxyethyl)-1-piperazine ethanesulphonic acid - MSX l-methionine-dl-sulphoximine - SDS sodium dodecyl sulphate - Tricine N-tris(hydroxymethyl) methyl glycine - Tris Tris(hydroxymethyl) aminomethane