Further Evidence for the Existence of a Membrane Potential in Trypanosoma brucei brucei

SUMMARY: The distribution of 137Cs+, in the presence of valinomycin, has been used to measure the magnitude of the membrane potential (Δ) in bloodstream forms of Trypanosoma brucei brucei. Values of the Δ falling in the range −100 mV to −160 mV were observed and the maintenance of this Δ was sensitive to certain ionophores and protonophores.