Electrical properties and molecular architecture of the channel formed by Escherichia coli hemolysin in planar lipid membranes

1989 ◽  
Vol 985 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Monica Ropele ◽  
Gianfranco Menestrina
Keyword(s):  
Escherichia Coli ◽  
Electrical Properties ◽  
Lipid Membranes ◽  
Molecular Architecture ◽  
Planar Lipid Membranes ◽  
Escherichia Coli Hemolysin

Bacterial hemolysins and leukotoxins affect target cells by forming large exogenous pores into their plasma membrane. Escherichia coli hemolysin a as a case example

1995 ◽  
Vol 15 (6) ◽  
pp. 543-551 ◽  
Author(s):  
Gianfranco Menestrina ◽  
Mauro Dalla Serra ◽  
Cecilia Pederzolli ◽  
Monica Bregante ◽  
Franco Gambale
Keyword(s):  
Escherichia Coli ◽  
Immune Response ◽  
Plasma Membrane ◽  
Virulence Factors ◽  
Lipid Membranes ◽  
Model Membranes ◽  
Target Cells ◽  
Planar Lipid Membranes ◽  
Escherichia Coli Hemolysin

Many bacteria include among their virulence factors exoproteins which exert leukocidal and cytolytic functions and have the ability to form pores in model membranes. We show that, at least in the case of the RTX hemolysin produced by Escherichia coli (HlyA), formation of pores in planar lipid membranes is parallelled by opening of strikingly similar channels in the plasma membrane of exposed macrophages. Formation of such lesions in leukocytes can give rise to a variety of effects leading altogether to a diminished immune response towards the invasive bacteria.

Voltage-dependent gating properties of the channel formed by E. coli hemolysin in planar lipid membranes

1989 ◽  
Vol 9 (4) ◽  
pp. 465-473 ◽  
Author(s):  
Gianfranco Menestrina ◽  
Monica Ropele
Keyword(s):  
Lipid Membranes ◽  
Ph Dependence ◽  
Phospholipid Bilayer ◽  
Bilayer Membranes ◽  
E Coli ◽  
Simple Physical Model ◽  
Voltage Dependent ◽  
Planar Lipid Membranes ◽  
Escherichia Coli Hemolysin ◽  
Gating Process

Escherichia coli hemolysin forms cation selective, ion-permeable channels of large conductance in planar phospholipid bilayer membranes. The pore formation mechanism is voltage dependent resembling that of some colicins and of diphtheria toxin: pores open when negative voltages are applied and close with positive potentials. The pH dependence of this gating process suggests that it is mediated by a negative fixed charge present in the lumen of the pore. A simple physical model of how the channel opens and closes in response to the applied voltage is given.

In vivo effects of intravascularly applied Escherichia coli hemolysin: dissociation between induction of granulocytopenia and lethality in monkeys

1993 ◽  
Vol 182 (1) ◽  
Author(s):  
Dierk Vagts ◽  
Hans-Peter Dienes ◽  
PeterJ. Barth ◽  
Hansj�rg Ronneberger ◽  
Klaus-Dieter Hungerer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Escherichia Coli Hemolysin ◽  
In Vivo Effects
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