Passive electrical properties of microorganisms. II. Resistance of the bacterial membrane.

Studies of the effective, homogeneous, dielectric constants of bacteria are used to show that the resistances of their cytoplasmic membranes are too great to explain the low-frequency conductivities which have been observed for these organisms. This reaffirms the conclusion that at low frequencies the conductivities of bacteria reflect properties of their cell walls. In the organisms studied, the conductivities of the cell wall region are as great as the conductivities of the cytoplasm. This is true even though the ion concentration in the environment is much less than that in the cells. The mobile ions of the wall are presumed to be counterions for fixed charges in this region.