title: Mode of action of novel polyamines increasing the permeability of bacterial outer membrane.
abstract: We have clarified how the polyamines naphthylacetylspermine and methoctramine (N,N'-bis[6-[[(2-methoxyphenyl)methyl]amino]hexyl]-1,8-octanediamine), originally developed as a synthetic analogue of joro spider toxin and a muscarinic receptor antagonist, respectively, can increase the permeability of the outer membrane of Escherichia coli. These polyamines were recently found to be outer membrane permeabilisers, based on investigations of the structure-activity relationship using ion-selective electrodes. In a standard microbiological assay examining membrane-permeabilising ability, these polyamines enhanced the action of hydrophobic antibiotics such as novobiocin and erythromycin, which ineffectively traverse the outer membrane of E. coli, to inhibit the growth of E. coli. This result substantiated the outer membrane-permeabilising ability of these polyamines demonstrated by using ion-selective electrodes. We observed the release of lipopolysaccharide from the outer membrane in the concentration range causing permeabilisation, showing that the action of the polyamines is attributable to disruption of the outer membrane structure.
authors.affiliation: Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Yasuda
authors.forename: Chie
authors.initials: C
authors.lastname: Ohmizo
authors.forename: Takashi
authors.initials: T
authors.lastname: Katsu
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D011073:Polyamines / Q000494:pharmacology*
chemical_list: D011073:Polyamines