FIG. 5.

Comparison of cell-wall thickness and TRG in the presence of vancomycin among the test strains after cultivation (or incubation) in BHI medium and RM. (A and B) Comparison of cell-wall thicknesses of the test strains cultivated in BHI medium (A) and after further incubation in RM (B). The values under each panel are mean ± SD thicknesses (in nanometers). The bacterial cultures at an OD₆₀₀ of 0.7 in BHI medium were divided into two portions. One of them was directly subjected to electron microscopy (A). The other portion was washed twice with RMg−, further incubated in RM at 37°C for 2 h, and then subjected to electron microscopic examination (B). (C and D) TRG was compared among the cell preparations shown in panels A (C) and B (D). (C) Vancomycin was added to a final concentration of 30 mg/liter when the culture (inoculated with the cells shown in p1anel A at an initial concentration of 10⁶ cells/ml) reached an OD₆₀₀ of 0.4. (D) Cells incubated in RM were spun down and resuspended in BHI medium containing vancomycin at 30 mg/liter.