Permeabilizing action of polyethyleneimine on Salmonella typhimurium involves disruption of the outer membrane and interactions with lipopolysaccharide

Ilkka Helander, Kyösti Latva-Kala, Kari Lounatmaa

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Polyethyleneimine (PEI), a polycationic polymer substance used in various bioprocesses as a flocculating agent and to immobilize enzymes, was recently shown to make Gram-negative bacteria permeable to hydrophobic antibiotics and to detergents.
Because this suggests impairment of the protective function of the outer membrane (OM), the effect of PEI on the ultrastructure of Salmonella typhimurium was investigated. Massive alterations in the OM of PEI-treated and thin-sectioned bacteria were observed by electron microscopy. Vesicular structures were seen on the surface of the OM, but no liberation of the membrane or its fragments was evident.
Since a potential mechanism for the action of PEI could be its binding to anionic LPSs on the OM surface, the interaction of PEI with isolated LPSs was assayed in vitro. The solubility of smooth-type LPSs of Salmonella, regardless of the sugar composition of their O-specific chains, was not affected by PEI, nor was that of Ra-LPS (lacking O-specific chains but having a complete core oligosaccharide).
PEI strongly decreased the solubility of rough-type LPSs of the chemotypes Rb2 and Re, whereas it had only a weak effect on the abnormally cationic Rb2-type pmrA mutant LPS, suggesting that the negative charge to mass ratio of LPS plays a critical role in the interaction.
Original languageEnglish
Pages (from-to)385-390
JournalMicrobiology
Volume144
Issue number2
DOIs
Publication statusPublished - 1998
MoE publication typeA1 Journal article-refereed

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Polyethyleneimine
Salmonella typhimurium
Lipopolysaccharides
Membranes
Solubility
Gram-Negative Bacteria
Oligosaccharides
Salmonella
Detergents
Action Potentials
Electron Microscopy
Polymers
Anti-Bacterial Agents
Bacteria
Enzymes

Cite this

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title = "Permeabilizing action of polyethyleneimine on Salmonella typhimurium involves disruption of the outer membrane and interactions with lipopolysaccharide",
abstract = "Polyethyleneimine (PEI), a polycationic polymer substance used in various bioprocesses as a flocculating agent and to immobilize enzymes, was recently shown to make Gram-negative bacteria permeable to hydrophobic antibiotics and to detergents. Because this suggests impairment of the protective function of the outer membrane (OM), the effect of PEI on the ultrastructure of Salmonella typhimurium was investigated. Massive alterations in the OM of PEI-treated and thin-sectioned bacteria were observed by electron microscopy. Vesicular structures were seen on the surface of the OM, but no liberation of the membrane or its fragments was evident. Since a potential mechanism for the action of PEI could be its binding to anionic LPSs on the OM surface, the interaction of PEI with isolated LPSs was assayed in vitro. The solubility of smooth-type LPSs of Salmonella, regardless of the sugar composition of their O-specific chains, was not affected by PEI, nor was that of Ra-LPS (lacking O-specific chains but having a complete core oligosaccharide). PEI strongly decreased the solubility of rough-type LPSs of the chemotypes Rb2 and Re, whereas it had only a weak effect on the abnormally cationic Rb2-type pmrA mutant LPS, suggesting that the negative charge to mass ratio of LPS plays a critical role in the interaction.",
author = "Ilkka Helander and Ky{\"o}sti Latva-Kala and Kari Lounatmaa",
year = "1998",
doi = "10.1099/00221287-144-2-385",
language = "English",
volume = "144",
pages = "385--390",
journal = "Microbiology",
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Permeabilizing action of polyethyleneimine on Salmonella typhimurium involves disruption of the outer membrane and interactions with lipopolysaccharide. / Helander, Ilkka; Latva-Kala, Kyösti; Lounatmaa, Kari.

In: Microbiology, Vol. 144, No. 2, 1998, p. 385-390.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Permeabilizing action of polyethyleneimine on Salmonella typhimurium involves disruption of the outer membrane and interactions with lipopolysaccharide

AU - Helander, Ilkka

AU - Latva-Kala, Kyösti

AU - Lounatmaa, Kari

PY - 1998

Y1 - 1998

N2 - Polyethyleneimine (PEI), a polycationic polymer substance used in various bioprocesses as a flocculating agent and to immobilize enzymes, was recently shown to make Gram-negative bacteria permeable to hydrophobic antibiotics and to detergents. Because this suggests impairment of the protective function of the outer membrane (OM), the effect of PEI on the ultrastructure of Salmonella typhimurium was investigated. Massive alterations in the OM of PEI-treated and thin-sectioned bacteria were observed by electron microscopy. Vesicular structures were seen on the surface of the OM, but no liberation of the membrane or its fragments was evident. Since a potential mechanism for the action of PEI could be its binding to anionic LPSs on the OM surface, the interaction of PEI with isolated LPSs was assayed in vitro. The solubility of smooth-type LPSs of Salmonella, regardless of the sugar composition of their O-specific chains, was not affected by PEI, nor was that of Ra-LPS (lacking O-specific chains but having a complete core oligosaccharide). PEI strongly decreased the solubility of rough-type LPSs of the chemotypes Rb2 and Re, whereas it had only a weak effect on the abnormally cationic Rb2-type pmrA mutant LPS, suggesting that the negative charge to mass ratio of LPS plays a critical role in the interaction.

AB - Polyethyleneimine (PEI), a polycationic polymer substance used in various bioprocesses as a flocculating agent and to immobilize enzymes, was recently shown to make Gram-negative bacteria permeable to hydrophobic antibiotics and to detergents. Because this suggests impairment of the protective function of the outer membrane (OM), the effect of PEI on the ultrastructure of Salmonella typhimurium was investigated. Massive alterations in the OM of PEI-treated and thin-sectioned bacteria were observed by electron microscopy. Vesicular structures were seen on the surface of the OM, but no liberation of the membrane or its fragments was evident. Since a potential mechanism for the action of PEI could be its binding to anionic LPSs on the OM surface, the interaction of PEI with isolated LPSs was assayed in vitro. The solubility of smooth-type LPSs of Salmonella, regardless of the sugar composition of their O-specific chains, was not affected by PEI, nor was that of Ra-LPS (lacking O-specific chains but having a complete core oligosaccharide). PEI strongly decreased the solubility of rough-type LPSs of the chemotypes Rb2 and Re, whereas it had only a weak effect on the abnormally cationic Rb2-type pmrA mutant LPS, suggesting that the negative charge to mass ratio of LPS plays a critical role in the interaction.

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