483—Monitoring cell potential of Escherichia coli with use of an electrode sensitive to tetraphenyl phosphonium: Change by addition of various sugars

An electrode sensitive to tetraphenyl phosphonium cation (TPP⁺) was applied to the determination of the membrane potential of E. coli (strain B, IAM 1268). This strain did not require EDTA (ethylenediamine tetraacetic acid)-treatment for accumulation of TPP⁺. As reported previously, some part of the TPP⁺-uptake was due to the binding to cell envelopes. The time course of TPP⁺-uptake by cells on addition of sugars was analysed, and the result indicated that the additional binding of TPP⁺ no longer occured. The change in the membrane potential on addition of various sugars was evaluated.