title: The Pepsin Hydrolysate of Bovine Lactoferrin Causes a Collapse of the Membrane Potential in Escherichia coli O157:H7.
abstract: In the present study, the ability of bovine lactoferrin hydrolysate (LfH) to disrupt the cytoplasmic membrane of Escherichia coli O157:H7 was investigated. Lactoferrin and LfH antimicrobial activities were compared against E. coli O157:H7 and E. coli O157:H7 spheroplasts. The effect of LfH on the cytoplasmic membrane of E. coli O157:H7 cells was determined by evaluating potassium efflux (K(+)), dissipation of ATP and membrane potential (ΔΨ). LfH produced a rapid efflux of potassium ions, a decrease in intracellular levels of ATP coupled with a substantial increase in extracellular ATP levels and a complete dissipation of the ΔΨ. The results suggest that LfH causes a collapse of the membrane integrity by pore formation in the inner membrane, leading to the death of the cell. Moreover, the mechanism of action of LfH on E. coli O157:H7 appears to involve an interference with the inner membrane integrity based on experiments using E. coli O157:H7 spheroplasts.
authors.affiliation: Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ, 08901-8520, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Murdock
authors.affiliation: Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ, 08901-8520, USA.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Chikindas
authors.affiliation: Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ, 08901-8520, USA. matthews@aesop.rutgers.edu.
authors.forename: Karl R
authors.initials: KR
authors.lastname: Matthews
keywords: Antimicrobial peptides; E. coli O157:H7; Lactoferrin; Mode of action