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Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii
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Structural characterization of Haemophilus parainfluenzae lipooligosaccharide and elucidation of its role in

Angela Pollard1, Frank St Michael, Lynn Connor

  • 1Division of Biomedical Sciences, Department of Biological Sciences, Illinois State University, Campus Box 4120, Normal, IL 61790, USA. ampollard@wisc.edu

Canadian Journal of Microbiology
|November 11, 2008
PubMed

Insights

Haemophilus parainfluenzae lipooligosaccharide structure is similar to nontypeable Haemophilus influenzae. This bacterial lipooligosaccharide is crucial for adherence and colonization of human bronchial epithelial cells.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Glycobiology

Background:

  • Haemophilus parainfluenzae is an opportunistic pathogen residing in the human oropharynx.
  • Lipooligosaccharide (LOS) structure is critical for bacterial adherence and colonization.

Purpose of the Study:

  • To characterize the oligosaccharide structure of lipooligosaccharide from two clinical isolates of H. parainfluenzae.
  • To investigate the role of H. parainfluenzae LOS in adherence to bronchial epithelial cells.

Main Methods:

  • Isolation and purification of core oligosaccharide from lipooligosaccharide.
  • Structural elucidation using monosaccharide analysis, methylation analysis, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry.
  • Adherence assays using a human bronchial epithelial cell line and a mutant lacking the outer core of LOS.

Main Results:

  • Detailed structures of the H. parainfluenzae LOS core oligosaccharide were determined, revealing similarities to nontypeable Haemophilus influenzae LOS.
  • Strain 4282 LOS contained a beta-galactose substituent, while strain 4201 had no substituent on the distal glucose.
  • H. parainfluenzae exhibited similar adherence to bronchial epithelial cells as nontypeable H. influenzae.
  • A mutant lacking the outer core of LOS showed reduced adherence, indicating its importance in tissue colonization.

Conclusions:

  • The structural characterization of H. parainfluenzae LOS provides insights into its interactions with host cells.
  • H. parainfluenzae LOS plays a significant role in the adherence and potential colonization of human respiratory tissues.
  • Findings highlight the importance of LOS in the pathogenesis of H. parainfluenzae infections.

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