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Adherence of Shigella dysenteriae 1 to human colonic mucin
P S Sudha1, H Devaraj, N Devaraj
1Department of Biochemistry and Molecular Biology, University of Madras, Guindy Campus, Chennai-600 025, India.
Abstract:
The pathogenic potential of Shigella is correlated with the ability of the organism to invade and multiply within the cells of colonic epithelium. Although invasion is the ultimate event, a preceding step is adherence. Shigella dysenteriae 1 preferentially adhered to colonic mucin and not to small intestinal mucin. The pathogen showed a very strong adherence pattern to human colonic mucin when compared with guinea pig and rat mucin. The adherence pattern of S. dysenteriae 1 was not altered on preincubation with monosaccharides present in mucins, suggesting that the receptor for the pathogen is not a simple sugar. Binding of S. dysenteriae 1 to human colonic mucin was not by weak hydrophobic forces. The bacterium also adhered to glycolipids, emphasizing the role of glycoconjugates as receptors for S. dysenteriae 1.
Insights
Shigella dysenteriae 1 preferentially adheres to human colonic mucin, not small intestinal mucin. This bacterial adherence to colonic glycoconjugates, like glycolipids, is crucial for infection.
Area of Science:
- Microbiology
- Pathogenesis
- Gastroenterology
Background:
- Shigella pathogenesis involves invasion and multiplication within colonic epithelial cells.
- Bacterial adherence to host cells precedes invasion and is critical for infection establishment.
Purpose of the Study:
- To investigate the adherence properties of Shigella dysenteriae 1 to host mucins.
- To identify the specific host molecules involved in Shigella dysenteriae 1 adherence.
Main Methods:
- Assessing adherence of Shigella dysenteriae 1 to human, guinea pig, and rat colonic and small intestinal mucins.
- Evaluating the effect of monosaccharide preincubation on bacterial adherence.
- Testing bacterial binding to glycolipids to determine receptor types.
Main Results:
- Shigella dysenteriae 1 demonstrated preferential adherence to human colonic mucin over small intestinal mucin.
- Adherence was significantly stronger to human colonic mucin compared to rodent mucins.
- Bacterial adherence was not affected by monosaccharides, indicating non-simple sugar receptors.
- Shigella dysenteriae 1 also adhered to glycolipids, suggesting glycoconjugates are key receptors.
Conclusions:
- Human colonic mucin and its glycoconjugates, particularly glycolipids, serve as primary receptors for Shigella dysenteriae 1 adherence.
- Understanding these interactions is vital for elucidating Shigella pathogenesis and developing targeted interventions.