1975 年 24 巻 2 号 p. 116-120
The effect of some surface active agents on bacteria was morphologically investigated using an electoron microscope.
Cationic, anionic or nonionic surfactant was added to the suspensions of E. coli in physiological solution of sodium chloride and transmittance of the suspension was determined at 560mμ. With the cationics which exhibited a marked antibacterial activity, the transmittance decreased significantly as the concentration of the surfactant increased from 6.25μg/ml to 100μg/ml. The transmittance of the suspensions containing anionics of 100μg/ml was same as that of control suspension containing no surfactant, and the transmittance of the suspension containing cationics showed the lowest. The suspension of E. coli treated with the surfactant was centrifuged in a refrigerated centrifuge to prepare the specimens for an electron microscope observation. According to figures of the electron microscopy, it was found that the cell, especially cell wall and protoplasm, suffered considerable changes such as swelling of cell, disappearance of undulation and bleb formation in cell wall, decrease or granular aggregation of ribosomes, or formation of lamellar structure in the plasma membrane.