1977 Volume 34 Issue 11 Pages 771-777
It was demonstrated that a liquid ion-exchange membrane (magnesium oleate+ 1-decanol) simulated the electrochemical features of the surface membrane of true slime mold Physarum polycephalum which were closely related to its recognition process. The features simulated were (1) initial (∂E/∂ log C) values were ca. 20 mV irrespective of number of charges of cations z, where E and C are the electromotive force and concentration respectively, (2) Cth (the minimum concentration of each chemical substance required to induce an appreciable change in the membrane potential or in the case of the mold, equivalent to the threshold concentration for chemotaxis) decreased with z-6, and (3) (∂ log Cth/∂T) values were constant irrespective of kinds of chemical substances applied. This indicated that so far as the membrane phenomena were concerned in which the electrostatic force was of predominance, the surface membrane and the liquid ion-exchange membrane behaved in the same manner. Present results also suggested that the electrochemical properties of the surface membrane could be understood in terms of the interfacial phenomena at the cell surface extracellular solution interface.
