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Soluble pig intestinal cell membrane components with affinities for E. coli K88+ antigen
Molecular and Cellular Biochemistry
|January 1, 1983
Summary
Researchers identified a glycoprotein in pig intestinal brush borders as the receptor for K88+ E. coli. This glycoprotein, existing in multimeric forms, binds to the bacteria and is influenced by calcium ions and specific sugars.
Area of Science:
- Gastroenterology
- Microbiology
- Biochemistry
Background:
- Enterotoxigenic Escherichia coli (K88+ E. coli) cause significant disease in piglets.
- Understanding the bacterial adhesion mechanism is crucial for developing preventative strategies.
Purpose of the Study:
- To identify and characterize the intestinal brush border receptor responsible for K88+ E. coli binding.
- To elucidate the molecular properties of this receptor.
Main Methods:
- Radiolabeling of pig intestinal brush borders (BB) via iodination.
- Detergent solubilization and Sepharose CL-4B chromatography.
- In vitro binding assays with K88+ E. coli, inhibition studies with sugars and antibodies, and affinity chromatography.
Main Results:
- K88+ E. coli binding occurred across a wide molecular weight range (690K to 25K daltons) and was saturable.
- Galactose, galactosamine, glucose, and N-acetylglucosamine partially inhibited binding.
- Calcium ions significantly enhanced binding.
- Affinity chromatography identified a glycoprotein (protein:glycoprotein ratio 1:4) with two major subunits (35-32K and 23K daltons) that retained binding activity.
Conclusions:
- The intestinal receptor for K88+ E. coli is a glycoprotein present in multimeric forms on the brush border.
- This glycoprotein plays a key role in bacterial adhesion, with binding modulated by specific sugars and calcium.