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Adhesion of a human fecal Escherichia coli strain to mouse colonic mucus
Abstract:
Escherichia coli F-18 isolated from the feces of a healthy human is an excellent colonizer of the CD-1 mouse colon. In the present investigation, adhesion of E. coli F-18 to CD-1 mouse colonic mucus and bovine serum albumin (BSA), immobilized on polystyrene, was studied. Adhesion of E. coli F-18 to mucus was two- to sixfold greater than to either BSA or polystyrene. E. coli F-18 lipopolysaccharide specifically blocked adhesion of E. coli F-18 to mucus and mimicked adhesion of E. coli F-18 to mucus, BSA, and polystyrene. Purified capsule also blocked adhesion of E. coli F-18 to mucus, but this inhibition was found to be entirely nonspecific. The specific E. coli F-18 receptor in mucus appeared to be a glycoprotein, containing sugars normally found in mucins and having a maximum molecular weight of between 1.25 X 10(5) and 2.5 X 10(5).
Insights
Escherichia coli F-18 readily colonizes mouse colons. Its adhesion to mucus is mediated by a specific glycoprotein receptor, distinct from lipopolysaccharide and capsule interactions.
Area of Science:
- Microbiology
- Gastroenterology
- Biochemistry
Background:
- Escherichia coli F-18, a human fecal isolate, demonstrates effective colonization of the CD-1 mouse colon.
- Understanding bacterial adhesion mechanisms is crucial for addressing gastrointestinal colonization and infections.
Purpose of the Study:
- To investigate the adhesion properties of Escherichia coli F-18 to colonic mucus.
- To identify specific molecular interactions involved in E. coli F-18 adhesion to the mouse colon.
Main Methods:
- Studied adhesion of E. coli F-18 to immobilized CD-1 mouse colonic mucus and bovine serum albumin (BSA) on polystyrene.
- Utilized E. coli F-18 lipopolysaccharide and purified capsule to probe adhesion mechanisms.
- Characterized the molecular properties of the mucus receptor.
Main Results:
- E. coli F-18 exhibited significantly higher adhesion to mucus (2-6 fold) compared to BSA or polystyrene.
- E. coli F-18 lipopolysaccharide specifically blocked mucus adhesion and mimicked adhesion to mucus, BSA, and polystyrene.
- Purified capsule showed nonspecific inhibition of mucus adhesion.
- Identified a specific glycoprotein receptor in mucus (MW 1.25-2.5 x 10^5 Da) containing mucin-like sugars.
Conclusions:
- The specific adhesion of E. coli F-18 to mouse colonic mucus is mediated by a distinct glycoprotein receptor.
- Lipopolysaccharide plays a role in specific adhesion, while the capsule's role appears nonspecific.
- This interaction provides insight into bacterial colonization of the gastrointestinal tract.