Open AccessThe hydrophobic surface protein layer of enteroaggregative Escherichia coli strains
Author(s) -
Wai Sun Nyunt,
Takade Akemi,
Amako Kazunobu
Publication year - 1996
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1996.tb07960.x
Subject(s) - immunoelectron microscopy , escherichia coli , biology , electron microscope , gel electrophoresis , enterobacteriaceae , microbiology and biotechnology , bacterial outer membrane , electrophoresis , bacteria , antiserum , s layer , biophysics , biochemistry , genetics , physics , gene , antibody , optics
The surface of three strains of enteroaggregative Escherichia coli (EAggEC) and three strains of enteropathogenic E. coli (EPEC) were examined using the freeze‐substitution technique of electron microscopy and as a result an electron dense surface layer was found only on EAggEC strains but not on EPEC strains. The analysis of the outer membrane proteins by polyacrylamide gel electrophoresis revealed the existence of a unique 38 kDa protein in EAggEC strains. The protein could be easily extracted from the bacterial surface with 5 M LiCl treatment at room temperature. The antiserum raised in mice with 38 kDa protein extracted from the electrophoresed gel was immunoreacted with the surface of the bacteria of EAggEC by immunoelectron microscopy. The hydrophobic surface character of the EAggEC strains was lost after the extraction of the protein layer by LiCl. We thus conclude that the surface protein layer therefore plays an important role in the expression of the aggregative phenotype in EAggEC strains.