Determination of bacterial ammonia pools using Myxococcus virescens as an example.

Samples (150 microliters) from liquid cultures of known cell density of Myxococcus virescens (Myxobacterales) were used for the determination of the intracellular NH3/NH+4 concentrations (= total ammonia). The cells were separated from the culture broth within 30 s by centrifugation through a silicone layer and were lysed immediately with 20 microliters of a disintegration liquid at the bottom of the centrifugation tube. The ammonia concentrations of the lysates were determined with a Dohrmann nitrogen analyzer. The intracellular ammonia concentrations were calculated after corrections for trapped supernatant had been made by adding radioactive glucose, which cannot be taken up by the organism. Control experiments with permeabilized cells and radioactive methylamine corroborated the reliability of the method.