Fig. 6

Mechanism of membrane disruption and transcriptomic response to peptide treatment in E. coli strains. (A) Calcein dye leakage assay demonstrating selective membrane permeabilization of bacterial-mimetic POPE/POPG vesicles by the peptide, with minimal leakage observed in mammalian-mimetic POPC/cholesterol vesicles. Values expressed as % dye leakage relative to 0.1% Triton X-100 (100% release) and shown as mean ± SD from three independent experiments, with error bars indicating SD. (B) RNA sequencing analysis showing upregulation of stress response and efflux pump genes and downregulation of growth-related genes in E. coli K-12, UPEC, and MDR strains after sub-MIC peptide exposure. Data presented as log₂ fold change relative to untreated control; mean ± SE of three biological replicates, with error bars indicating SE. (C) KEGG pathway enrichment analysis highlighting activation of stress response and protein folding pathways alongside repression of DNA replication and cell division pathways across the three E. coli strains. Data represent mean enrichment scores ± SD from three replicates, with error bars indicating SD; enrichment significance adjusted by Benjamini–Hochberg correction (FDR < 0.05).