COMPARISON OF METHODS TO ASSAY AMMONIA IN BACTERIAL SUSPENSIONS

In the determination of the concentration of ammonia in the filtrates of Pseudomonas syringae cell suspensions, similar results were obtaine d using the indophenol method, a gas-sensing membrane electrode, and t he L-glutamic dehydrogenase assay. The intracellular ammonia concentra tion was determined using the electrode and estimated to be 17 mM, cor responding to approximately 1/4 of potassium concentration. The result s suggest that ammonium is one of the major intracellular cations in P . syringae cells.