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Inhibitors of the adhesiveness of enteropathogenic E. coli
Abstract:
The entero-pathogenic strain of E. coli 0125: K 70 was able to adhere to washed guinea-pig erythrocytes and to cause their agglutination. Electron microscopy revealed this strain to be rich in fimbriae. They were able to cause hemagglutination by themselves, generally at protein concentration of 10 to 100 mug per ml. D-mannose and alpha-methylmannoside were able to inhibit hemagglutination by the whole bacteria or their isolated fimbriae at concentrations of 0.003 to 0.012 mg/ml. L-mannose, D-lactose, D-glucose, N-acetylglucosamine, D-galactose, N-acetyl-D-galactosamine, D-fucose, did not exert any inhibiting effect at concentrations as high as 50 mg/ml. N-acetyl-neuraminic acid was also uneffective at concentration as high as 9 mg/ml.
Insights
Enteropathogenic Escherichia coli (E. coli) 0125:K70 strains possess fimbriae that cause hemagglutination. D-mannose specifically inhibits this bacterial adherence and hemagglutination.
Area of Science:
- Microbiology
- Bacteriology
- Cell Biology
Background:
- Enteropathogenic Escherichia coli (E. coli) strains are significant human pathogens.
- Bacterial adherence to host cells is a crucial step in pathogenesis.
- Fimbriae are hair-like appendages on bacterial surfaces involved in adherence.
Purpose of the Study:
- To investigate the adherence and hemagglutination properties of E. coli 0125:K70.
- To identify the role of fimbriae in the observed hemagglutination.
- To determine the specific inhibitors of E. coli-mediated hemagglutination.
Main Methods:
- Hemagglutination assays using guinea-pig erythrocytes.
- Electron microscopy to visualize bacterial fimbriae.
- Inhibition assays with various sugars and derivatives.
Main Results:
- E. coli 0125:K70 adhered to and agglutinated erythrocytes.
- Electron microscopy confirmed the presence of abundant fimbriae on the bacterial strain.
- Isolated fimbriae induced hemagglutination at low protein concentrations (10-100 µg/ml).
- D-mannose and alpha-methylmannoside specifically inhibited hemagglutination by bacteria and fimbriae.
- Other tested sugars, including L-mannose and N-acetyl-neuraminic acid, did not inhibit hemagglutination.
Conclusions:
- Fimbriae are responsible for the hemagglutination activity of E. coli 0125:K70.
- The adherence mechanism mediated by these fimbriae is mannose-sensitive.
- This finding provides insights into the molecular basis of E. coli pathogenesis and potential therapeutic targets.