Fig. 5: Resistance and mode of action test of AMPs on E. coli and the mode of action assays.
a Twenty one days MIC measurement of daily culture passage each day from the cells grown in half-MIC concentrations of AMPs. The MIC values were normalized by the minimum of 21 daily averages for each AMP. Bars are the average of n = 3 independent experiments. See Supplementary Fig. 7 for raw MIC data. b Impact of different AMPs at the concentration of ¼ MIC on the number of E. coli outer membrane vesicles (OMVs) for untreated E. coli (control), (AMP) solvent, and six potent AMPs, and polymyxin B. Bars are the average of independent experiments n = 8 for the control, n = 6 for AMP#3, and n = 3 the rest. Statistics: ordinary one-way ANOVA p < 0.0001 (4.86×10−6), with Polymyxin B as the only significantly different group. c Plate reader measured fluorescence (in arbitrary unit) of propidium iodide with E. coli cells untreated (control) or treated with AMPs. Bars are the average of n = 3 independent experiments. P values are for unpaired t-test of each AMP compared to untreated E. coli control. d Phase-contrast microscopy of E. coli cells untreated or treated with six potent AMPs and Cecropin B (a membrane disruptive AMP) and stained with propidium iodide (red). Source data for a–c and raw images in d (plus six more acquisitions for each, two images of n = 3 biological replicates with similar results) are provided as a Source Data file. Created with BioRender.com.
