[Selective permeability of bacterial membranes for monovalent thallium ions].

Transport of monovalent thallium ions in bacterial cells was studied. An energy-dependent transport of T1+ against electrochemical gradient into the cells of S. faecalis and Micrococcus lysodeikticus, according to the Michaelis-Menten kinetics was observed. T1+, being a K+ analog, is involved into active K+ transport. Unlike K+, T1+ readily penetrates bacterial membranes, reaching the level of stationary distribution between the cells and the medium. This permits to use T1+ as a penetrating cation to study the mechanism of potassium transport in bacteria without the use of ionophores, which can destroy the integrity of cell membranes.