Detection of Iss and Bor on the surface of Escherichia coli.
OBJECTIVE
To confirm the presence of Iss and Bor on the outer membrane of Escherichia coli using Western blots of outer membrane protein (OMP) preparations and fluorescence microscopy, and explore the use of fluorescence microscopy for the detection of avian pathogenic E. coli (APEC) and diagnosis of avian colibacillosis.


RESULTS
Knockout mutants of iss and bor were created using a one-step recombination of target genes with PCR-generated antibiotic resistance cassettes. Anti-Iss monoclonal antibodies (Mabs) that cross-react with Bor protein were used to study the mutants relative to the wild-type organism. These Mabs were used as reagents to study OMP preparations of the mutants with Western blotting and intact E. coli cells with fluorescence microscopy. Iss and Bor were detected in Western blots of OMP preparations of the wild type. Also, Iss was detected on Deltabor mutants, and Bor was detected on Deltaiss mutants. Iss and Bor were also detected on the surface of the intact, wild-type cells and mutants using fluorescence microscopy.


CONCLUSIONS
These results demonstrate that Bor and Iss are exposed on E. coli's outer membrane where they may be recognized by the host's immune system.


CONCLUSIONS
To our knowledge, this is the first report confirming Iss' location in the outer membrane of an E. coli isolate. Such surface exposure has implications for the use of these Mabs for APEC detection and colibacillosis control.
Lynne
A M
AM
Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Skyberg
J A
JA
Logue
C M
CM
Nolan
L K
LK
D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D015153:Blotting, Western / Q000379:methods; D004926:Escherichia coli / Q000737:chemistry*; D004927:Escherichia coli Infections / Q000175:diagnosis / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000032:analysis*; D017353:Gene Deletion; D008856:Microscopy, Fluorescence / Q000379:methods; D009154:Mutation; D011201:Poultry Diseases / Q000175:diagnosis / Q000382:microbiology; D011506:Proteins / Q000032:analysis*; D014764:Viral Proteins / Q000032:analysis*
D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; C409210:Iss protein, E coli; D011506:Proteins; D014764:Viral Proteins; C065503:bor protein, Bacteriophage lambda