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Diffuse adherence of enteropathogenic Escherichia coli strains.
1Zentrum für Molekulare Biologie Heidelberg, Heidelberg, Germany.
Research in Microbiology
|September 1, 1990
Summary
Researchers identified a key factor, adhesin involved in diffuse adherence (AIDA-I), responsible for diffuse adherence in enteropathogenic Escherichia coli. This 100 kDa protein facilitates bacterial binding to host cells, crucial for understanding infantile diarrhea.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Enteropathogenic Escherichia coli (EPEC) strains cause infantile diarrhea.
- The diffuse adherence (DA) pattern is a characteristic virulence factor of some EPEC strains.
- Identifying the specific factors mediating DA is crucial for understanding EPEC pathogenesis.
Purpose of the Study:
- To identify and characterize the factor(s) responsible for the diffuse adherence (DA) phenotype in enteropathogenic E. coli.
- To clone and express the gene(s) encoding the DA factor.
- To investigate the function and properties of the identified factor.
Main Methods:
- Cloning of an 11-kb DNA fragment from E. coli strain 2787 into the pBR322 vector, creating recombinant plasmids pIB6 and pIB4.
- Transformation of E. coli K12 strains with recombinant plasmids to assess the DA phenotype.
- DNA fragment size reduction to identify the minimal DNA region required for DA expression.
- Western blotting using antiserum against pIB4-encoded proteins to detect surface-associated proteins.
- Isolation and characterization of the 100 kDa protein and assessment of its binding to HeLa cells.
- Inhibition assays using antiserum against C600(pIB4) to confirm the role of the protein in adherence.
Main Results:
- A plasmid-derived 11-kb fragment conferred the DA phenotype on E. coli K12 strains.
- The DNA fragment necessary for DA expression could be reduced to 6.0 kb.
- Western blotting identified a ~100 kDa surface-associated protein recognized by antiserum against pIB4-encoded proteins.
- The isolated 100 kDa protein demonstrated binding to HeLa cells.
- Antiserum against C600(pIB4) inhibited the adherence of E. coli strains expressing the DA phenotype.
Conclusions:
- The identified 100 kDa protein, termed adhesin involved in diffuse adherence (AIDA-I), is responsible for the DA phenotype in enteropathogenic E. coli.
- AIDA-I plays a significant role in the adherence of E. coli to host cells.
- This finding contributes to understanding the molecular mechanisms of E. coli-mediated infantile diarrhea.
- AIDA-I represents a potential target for therapeutic interventions against EPEC infections.