Fig. 2.

PHLG-BIm₄₀ kills bacteria by directly disrupting the bacterial cell membrane. (A) Extent of calcein efflux in neutral vesicles (DOPC/POPC) and negatively charged vesicles (DOPE/DOPG) after treatment with PHDLG-BIm₄₀ (nonhelical, lacking radially amphiphilic structure) or PHLG-BIm₄₀ (helical with radially amphiphilic structure) at various concentrations for 1 h. (B) Flow cytometry analysis of propidium iodide (PI) uptake after incubation with free PI, PI with PHDLG-BIm₄₀, or PI with PHLG-BIm₄₀ at various concentrations. All of the data are represented as average ± SD and analyzed by Student t test (**P ≤ 0.01). (C) The fluorescence microscopy of stained Escherichia coli MG1655 in the absence and presence of PHDLG-BIm₄₀ and PHLG-BIm₄₀ (3.3 µM). (Scale bar, 50 μm.) (D) SEM images of MG1655 after treatment with PBS, PHDLG-BIm₄₀, or PHLG-BIm₄₀. (Scale bar, 1 μm.)