Clostridium perfringens Epsilon Toxin Induces a Rapid Change of Cell Membrane Permeability to Ions and Forms Channels in Artificial Lipid Bilayers

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作者：

L Petit，E Maier，M Gibert，MR Popoff，R Benz

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摘要：

Epsilon toxin is a potent toxin produced by types B and D, which are responsible for a rapidly fatal enterotoxemia in animals. One of the main properties of epsilon toxin is the production of edema. We have previously found that epsilon toxin causes a rapid swelling of Madin-Darby canine kidney cells and that the toxin does not enter the cytosol and remains associated with the cell membrane by forming a large complex (Petit, L., Gibert, M., Gillet, D., Laurent-Winter, C., Boquet, P., and Popoff, M. R. (1997) 179, 6480–6487). Here, we report that epsilon toxin induced in Madin-Darby canine kidney cells a rapid decrease of intracellular K, and an increase of Cland Na, whereas the increase of Caoccurred later. The entry of propidium iodide that was correlated with the loss of cell viability monitored by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test indicates that epsilon toxin formed large pores. In artificial lipid bilayers, epsilon toxin caused current steps with a single-channel conductance of 60 pS in 100 mKCl, which represented general diffusion pores. The channels were slightly selective for anions, but cations could also penetrate. Epsilon toxin formed wide and water-filled channels permeable to hydrophilic solutes up to a molecular mass of at least 1 kDa, which probably represents the basic mechanism of toxin action on target cells.

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关键词：

Bacterial Toxins Cell Membrane Cell Membrane Permeability Lipid Bilayers 细菌毒素类细胞膜细胞膜渗透性脂双层