Ultrastructural effects of antimicrobial peptides from bovine lactoferrin on the membranes of Candida albicans and Escherichia coli

Antimicrobial peptides allegedly exert their action on microbial membranes. Bovine lactoferrin enfold two antimicrobial domains, lactoferricin B (LFcin B) and lactoferrampin (LFampin). Effects of representative peptides thereof on the membranes of Candida albicans and Escherichia coli were investigated. Confocal laser scanning microscopy revealed that these peptides were internalized within a few minutes, concurrently with disrupting membrane integrity as indicated by freeze-fracture transmission electron microscopy. The most striking findings were induction of distinct vesicle-like structures in the membrane of C. albicans by the LFampin peptide, and detachment of the outer membrane and surface protrusions in E. coli by the LFcin B peptide.