THE EFFECT OF WHEAT-GERM-AGGLUTININ ON DINITROGEN FIXATION, GLUTAMINE-SYNTHETASE ACTIVITY AND AMMONIA EXCRETION IN AZOSPIRILLUM-BRASILENSE SP-245

Wheat germ agglutinin was found to increase glutamine synthetase and n itrogenase activities and excretion of N2-fixation product (NH4+) in A zospirillum brasilense Sp 245. Each effect had a similar pattern and c orrelated well with each other. They were dynamic, had maxima in the m iddle of the exponential phase of growth, and were due to N-acetyl-D-g lucosamine specificity of wheat germ agglutinin, since its preincubati on with 10% N-acetyl-D-glucosamine caused the disappearance of the eff ects. When wheat germ agglutinin was replaced with Ulex europaeus aggl utinin II possessing the same carbohydrate binding specificity all the above effects remained, replacing wheat germ agglutinin with concanav alin A with a different sugar specificity, or with bovine serum albumi n led to their disappearance.