Leakage of cellular contents and morphological changes in resting Escherichia coli B cells exposed to an alternating current.

An alternating current (AC) causes lethal or sublethal damage to Escherichia coli cells under either aerobic or anaerobic conditions.12) Recently, we reported that the surface charges and physiological properties of E. coli cells, e.g.respiratory rate and stainability with crystal violet, vary when the cells are anaerobically exposed to AC, and inferred that the permeability of the cell membrane is modified on AC-exposure.3)However, little evidence has been obtained in bacterial cells exposed to ACas to the membrane damage causing modification of the permeability, and morphological investigation of ACexposed cells has rarely been reported.We present here results which show that AC causes the release of the intracellular contents of E. coli cells together with changes in the electron micrographic appearance of cellular materials located in the nucleus region within cells.Resting E. coli B (IFO 13168) cells were suspended in a