整合转录组学和形态学表征揭示脉冲电场对大肠杆菌O157:H7细胞包膜的胁迫机制

Abstract

PEF damaged the E. coli O157 envelope, with greater disruption at higher intensities. • RNA-seq revealed regulation of two-component, peptidoglycan, phospholipid and LPS pathways. • Upregulation of lpp , ompC and pal suggests envelope repair and permeability regulation. • Differential plsY and pgsA expression indicates phospholipid remodeling under PEF. • lpxC downregulation and lpt gene induction suggest coordinated LPS homeostasis under PEF. Escherichia coli O157:H7 is a major foodborne pathogen capable of surviving diverse environmental stresses. Pulsed electric field (PEF) is an effective non-thermal inactivation technology; however, envelope-level responses of Gram-negative bacteria under electric-field exposure remain unclear. This study integrated morphological characterization and transcriptomic profiling to elucidate cell envelope responses of E. coli O157:H7 subjected to low- and high-intensity PEF treatments (LEFI and HEFI). Electron microscopy revealed intensity-dependent structural disruption, including outer membrane deformation, rupture, cytoplasmic leakage, and partial cellular collapse, accompanied by reduced viability. Transcriptomic analysis identified 2967 and 3008 differentially expressed genes in LEFI and HEFI groups, respectively, with coordinated regulation of pathways related to outer membrane assembly, LPS biosynthesis and transport, peptidoglycan remodeling, phospholipid metabolism, and two-component systems. Differential expressions of lpp , pal , omp C, and omp F suggests dynamic modulation of membrane integrity, permeability, and envelope stabilization, while pls Y repression and pgs A upregulation indicate transcriptional remodeling of membrane lipid metabolism. Comparative analysis demonstrated intensity-dependent amplification of structural damage and transcriptional reprogramming. Collectively, these findings establish an envelope-centered mechanistic framework linking PEF-induced structural disruption with