Ultrastructural aspects of fragility of Pseudomonas aeruginosa outer membrane devoid of protein F.

The protein F-deficient cells of Pseudomonas aeruginosa were previously found to be more susceptible to osmotic shock than the sufficient cells (Gotoh et al., J. Bacteriol., in press). The protein F-deficient cells were observed by the thin-section method of electron microscopy to determine the effects of osmotic shock. The osmotic shock induced breakage of the protein F-deficient outer membrane, while it had no effect on the protein F-sufficient outer membrane. These results suggested that the cells lost their viability by the osmotic shock caused by fragility of the outer membrane.