Alkali-metal ions in the metabolism of
Bact. lactis aerogenes
. I. Experiments on the uptake of radioactive potassium, rubidium and phosphorus
(This paper has been printed in full in Proceedings B, 138, 219) By the use as tracers of 42 K, 86 Rb and 32 P it has been shown that in the metabolism of Bact. lactis aerogenes ladis aerogenes ( a ) the alkali-metal ion enters the cell during oxidation of the carbon substrate (glucose, succinic acid, acetic acid) whether or not a nitrogen source is provided so that growth occurs; in either event the alkali-metal ion subsequently leaves the cell again; ( b ) if the pH is lowered the maximum uptake of the cation by the functioning cell is raised, although increased hydrion concentration first causes displacement of alkali-metal ions from resting cells. ( c ) in the early stages of growth, or of glucose oxidation without growth, the flow into the cell of alkali cations and of phosphate anions takes place in a parallel way.