Assessing the membrane pore-forming

Assessing the membrane pore-forming activity of daptomycin. (A) Cellular element concentrations after antibiotic treatment were measured by ICP-OES. Cells were washed with EDTA before resuspension in Tris buffer and were incubated with 3.5 µg/mL daptomycin or 10 µg/mL valinomycin. (B) Depolarization of the B. subtilis 168 cell membrane was measured with the membrane potential-sensitive fluorescent probe DiSC3(5). Gramicidin ABCD was used as positive control. The arrow indicates the time point of antibiotic addition. As a negative control, 2 µg/mL daptomycin without Ca2+ was used. a.u., arbitrary units.