Fig. 5: B. subtilis membranes during the stationary growth phase bind daptomycin less effectively, therefore membrane depolarisation occurs at higher concentrations.
From: The last resort antibiotic daptomycin exhibits two independent antibacterial mechanisms of action
Phase contrast and fluorescence microscopy images of B. subtilis cells in (a) exponential and c stationary growth phase stained with 1 µM DiSC3(5), untreated or treated with different daptomycin concentrations for 20 min. Daptomycin fluorescence was detected based on kynurenine autofluorescence (DAP). The channel-forming peptide gramicidin was used as a positive control for membrane depolarisation (10 µM, 5 min). Scale bar, 3 µm. b, d Quantification of DiSC3(5)- and DAP-fluorescence for individual cells from the datasets shown in (a) and (c), respectively (n = 40–176). Median fluorescence intensity is indicated with a cyan line, together with P values of a one-way, unpaired ANOVA. **** represents p < 0.0001, ns, not significant. Strain used: B. subtilis 168 (WT). For details about the sample size and statistical significance, see Supplementary Table 2.
