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Updated: Jul 31, 2026
Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction
Published on: May 28, 2012
Structural studies on the O-polysaccharide of the lipopolysaccharide produced by Citrobacter rodentium (ATCC 51459)
1Institute for Biological Sciences, National Research Council, Ottawa, Canada.
Abstract:
Citrobacter rodentium is the etiologic agent of transmissible murine colonic hyperplasia (TMCH) and is the only Citrobacter species known to possess virulence factors homologous to human enteropathogenic and enterohemorrhagic Escherichia coli. Members of this species are considered clonal and represent the only known attaching and effacing bacterial pathogen of mice and thus provides a useful animal model for studying the molecular basis of attaching and effacing pathology. The lipopolysaccharide (LPS) produced by C. rodentium has not been previously studied or its possible role as a virulence factor determined. The structure of the LPS has been undertaken as a first step in an investigation of its possible role in pathogenesis. The structure of C. rodentium (ATCC 51459, prototype TMCH isolate, original biotype 4280, previously designated DBS 100) LPS was determined from composition and methylation analyses, mass spectrometry, and two-dimensional nuclear magnetic resonance spectroscopy. The antigenic O-polysaccharide was found to be a high molecular mass branched polymer of repeating pentasaccharide units composed of 2-acetamido-2-deoxy-D-glucose (D-GlcNAc), d-glucose (D-Glc), and L-rhamnose (L-Rha) in the molar ratio 2 : 2 : 1 linked through phosphate, and has the structure: [structure: see text]
Insights
Citrobacter rodentium lipopolysaccharide (LPS) structure was determined for the first time. This research provides a foundation for understanding LPS
Area of Science:
- Microbiology
- Immunology
- Structural Biology
Background:
- Citrobacter rodentium causes transmissible murine colonic hyperplasia (TMCH), a disease relevant to human enteropathogenic Escherichia coli.
- C. rodentium is the only known mouse pathogen exhibiting attaching and effacing (A/E) activity, making it a valuable model for studying A/E pathogenesis.
- The lipopolysaccharide (LPS) of C. rodentium has not been previously characterized, and its role in virulence remains unknown.
Purpose of the Study:
- To determine the structure of C. rodentium LPS as a foundational step in investigating its role in pathogenesis.
- To elucidate the molecular structure of the O-polysaccharide component of C. rodentium LPS.
Main Methods:
- Structural determination of C. rodentium LPS using composition and methylation analyses.
- Mass spectrometry and two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy were employed for detailed structural elucidation.
- Analysis of the antigenic O-polysaccharide structure.
Main Results:
- The O-polysaccharide of C. rodentium LPS is a high molecular mass, branched polymer.
- The polymer consists of repeating pentasaccharide units composed of 2-acetamido-2-deoxy-D-glucose (D-GlcNAc), D-glucose (D-Glc), and L-rhamnose (L-Rha) in a 2:2:1 molar ratio.
- These units are linked via phosphate, forming the antigenic O-polysaccharide.
Conclusions:
- The complete structure of C. rodentium LPS has been determined.
- This structural information is crucial for future studies on the role of LPS in C. rodentium virulence and pathogenesis.
- Understanding the LPS structure may offer insights into host-pathogen interactions and potential therapeutic targets.
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