Fig. 5.

Daptomycin rigidifies the cell membrane. (A) Spectroscopic measurement of membrane fluidity with laurdan. Laurdan was excited at 330 ± 5 nm, and fluorescence emission was recorded at 460 ± 5 nm and 500 ± 5 nm. The membrane fluidizer benzyl alcohol was used as positive control. (B) B. subtilis 168 was treated with 1 µg/mL daptomycin for 60 min. Laurdan was excited at 360 nm, and fluorescence emission was captured at 522 nm and 450 nm. Color-coded GP maps were generated with Wolfram Mathematica 7. (Scale bars: 2 µm.)