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Release of Membrane Vesicles Containing Endotoxic Lipopolysaccharide in Escherichia coli O157:H7 Clinical Isolates
Author(s) -
Meno Yuko,
Fujimoto Shuji,
Horikawa Kazumi,
Yoshida Shinichi
Publication year - 2000
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2000.tb02494.x
Subject(s) - vesicle , immunogold labelling , escherichia coli , lipopolysaccharide , biology , negative stain , bacterial outer membrane , polyacrylamide gel electrophoresis , gel electrophoresis , microbiology and biotechnology , biochemistry , sodium dodecyl sulfate , electron microscope , membrane , antibody , enzyme , immunology , physics , gene , optics
Membrane vesicles released by E. coli O157:H7 strains were investigated by immuno‐electron microscopy using anti‐O157 antibody. Anti‐O157 antibody enhanced the negative‐staining of vesicles and we found numerous small vesicles clearly formed around bacterial cells. An immunogold‐electron microscopic examination confirmed that lipopolysaccharide (LPS) including the O‐side chain is present on the surface of the vesicles. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the purified vesicles showed that the vesicles contained LPS consisting of a lipid‐A and an O polysaccharide. In addition, the endotoxic activity of the vesicle was confirmed by a limulus test. These results suggest that the vesicles may play an important role in the pathogenesis of Escherichia coli O157:H7.