Membrane fusion during infection of <i>Escherichia coli</i> cells by phage T4

Tarahovsky, Yury S.; Khusainov, A. A.; Deev, A. A.; Kim, Y.V.

doi:10.1016/0014-5793(91)80899-e

Cited by 22 publications

(21 citation statements)

References 13 publications

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“…PMB-induced pores mimic the phage-induced channels in respect to their mode of dissipation of the proton gradient. It has been shown (1,53,54) that the entry of phage T4 DNA into the cytosol occurs through the sites of fusion between the OM and the CM. In such a case the phageinduced pores connect the cytosol directly to the cell exterior.…”

Section: Discussionmentioning

confidence: 99%

Stages of Polymyxin B Interaction with the Escherichia coli Cell Envelope

Daugelavičius

Bakiene

Bamford

2000

Antimicrob Agents Chemother

143

164

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The effects of polymyxin B (PMB) on the Escherichia coli outer (OM) and cytoplasmic membrane (CM) permeabilities were studied by monitoring the fluxes of tetraphenylphosphonium, phenyldicarbaundecaborane, and K ؉ and H ؉ ions. At concentrations between 2 and 20 g/ml, PMB increased the OM permeability to lipophilic compounds and induced a leakage of K ؉ from the cytosol and an accumulation of lipophilic anions in the cellular membranes but did not cause the depolarization of the CM. At higher concentrations, PMB depolarized the CM, forming ion-permeable pores in the cell envelope. The permeability characteristics of PMB-induced pores mimic those of bacteriophage-and/or bacteriocin-induced channels. However, the bactericidal effect of PMB took place at concentrations below 20 g/ml, indicating that this effect is not caused by pore formation. Under conditions of increased ionic strength, PMB made the OM permeable to lipophilic compounds and decreased the K ؉ gradient but was not able to depolarize the cells. The OM-permeabilizing effect of PMB can be diminished by increasing the concentration of Mg 2؉. The major new findings of this work are as follows: (i) the OM-permeabilizing action of PMB was dissected from its depolarizing effect on the CM, (ii) the PMB-induced ion-permeable pores in bacterial envelope were registered, and (iii) the pore formation and depolarization of the CM are not obligatory for the bactericidal action of PMB and dissipation of the K ؉ gradient on the CM.Lipid bilayers usually are quite permeable to lipophilic compounds (15,41,44). However, the outer membrane (OM) of gram-negative bacteria forms a rather effective permeability barrier against various lipophilic substances, including antibiotics. At least 10-to 100-fold slower rates of lipophilic compound permeation through the OM bilayer compared to those through the cytoplasmic membrane (CM) are observed because of the highly charged lipopolysaccharide (LPS)-formed outer monolayer and the stabilization of this layer by divalent cations (20, 39). These compounds also cannot traverse the porins, the narrow channels for inorganic ions and small hydrophilic nutrients (19,38).Polymyxin B (PMB) is a decapeptide antibiotic characterized by a heptapeptide ring containing four 2,4-diaminobutyric acids. An additional peptide chain covalently bound to the ␥-amino group carries an aliphatic chain attached to the peptide through an amide bond. The molecule carries five positively charged residues of diaminobutyric acid (52). Due to its molecular mass (about 1,200 Da), charge, and amphiphilicity, PMB should be excluded by the OM. However, several polycationic compounds, including PMB, are known to penetrate the OM using pathways other than porins. Although the detailed mechanism of the OM permeability barrier disruption remains undetermined, complex formation by PMB with LPS is expected to be the first stage (26,50,56,60). Being bulkier than the inorganic divalent cations that it displaces, PMB changes the packing order of LPS and increases the permeabi...

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Section: Discussionmentioning

confidence: 99%

Stages of Polymyxin B Interaction with the Escherichia coli Cell Envelope

Daugelavičius

Bakiene

Bamford

2000

Antimicrob Agents Chemother

143

164

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“…⌬p is commonly used in gram-negative bacteria to drive the transport of macromolecules into or across the membrane(s) (for reviews see Dreiseikelmann, 1994;Palmen et al, 1994). The translocation of phage T4 genome into the host cytosol depends on phage-induced, ⌬p-dependent fusion of the OM and PM at the site of phage adsorption (Tarahovsky et al, 1991). The insertion of channel-forming colicins into the bacterial PM occurs through an electrostatic binding to the membrane surface, spontaneous insertion of hydrophobic hairpin into the membrane, and ⌬⌿-driven insertion of amphiphilic helices (Cramer et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

A Novel Virus–Host Cell Membrane Interaction

Poranen

Daugelavičius

Ojala

et al. 1999

The Journal of Cell Biology

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Studies on the virus–cell interactions have proven valuable in elucidating vital cellular processes. Interestingly, certain virus–host membrane interactions found in eukaryotic systems seem also to operate in prokaryotes (Bamford, D.H., M. Romantschuk, and P.J. Somerharju, 1987. EMBO (Eur. Mol. Biol. Organ.) J. 6:1467–1473; Romantschuk, M., V.M. Olkkonen, and D.H. Bamford. 1988. EMBO (Eur. Mol. Biol. Organ.) J. 7:1821–1829). φ6 is an enveloped double-stranded RNA virus infecting a gram-negative bacterium. The viral entry is initiated by fusion between the virus membrane and host outer membrane, followed by delivery of the viral nucleocapsid (RNA polymerase complex covered with a protein shell) into the host cytosol via an endocytic-like route. In this study, we analyze the interaction of the nucleocapsid with the host plasma membrane and demonstrate a novel approach for dissecting the early events of the nucleocapsid entry process. The initial binding of the nucleocapsid to the plasma membrane is independent of membrane voltage (ΔΨ) and the K+ and H+ gradients. However, the following internalization is dependent on plasma membrane voltage (ΔΨ), but does not require a high ATP level or K+ and H+ gradients. Moreover, the nucleocapsid shell protein, P8, is the viral component mediating the membrane–nucleocapsid interaction.

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“…Phages of the family Myoviridae (for classification of tailed phages, see reference 5), including T4, P1, and P2, have contractile tails, in which the contraction of the sheath is thought to bring the central hollow tube through the OM (431). Some morphological studies suggest that this insertion of the tail core occurs at, or induces the formation of, the OM-inner membrane fusion structure (649). The structure of the central, needle-like device which is used by T4 to puncture the OM was solved recently (317).…”

Section: Entry Of Colicins and Phage Nucleic Acidsmentioning

confidence: 99%

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Nikaido

2003

Microbiol Mol Biol Rev

3,790

3,800

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Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions

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Membrane fusion during infection of Escherichia coli cells by phage T4

Abstract: Phage T4 infection of Eschericlriu co/i was studied by thin-section and freeze-fracture electron microscopy. It was found that phage T4 induces the formation of a bridge between the outer and inner membranes of E. co/i. A membrane fusion during the infection is suggested.

Cited by 22 publications

References 13 publications

Stages of Polymyxin B Interaction with the Escherichia coli Cell Envelope

Stages of Polymyxin B Interaction with the Escherichia coli Cell Envelope

A Novel Virus–Host Cell Membrane Interaction

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

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