Related Experiment Video

Updated: Jul 24, 2026

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction
05:31

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction

Published on: May 28, 2012

The lipopolysaccharide of moraxella catarrhalis structural relationships and antigenic properties

T Holme1, M Rahman, P E Jansson

  • 1Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden.

European Journal of Biochemistry
|October 3, 1999
PubMed

Insights

Moraxella catarrhalis lipopolysaccharide (LPS), lacking an O-chain, exhibits unique structures across serogroups A, B, and C. These common structural features may aid bacterial survival in human hosts.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Structural Biology

Background:

  • Moraxella catarrhalis is increasingly recognized as a significant pathogen.
  • Lipopolysaccharide (LPS) is a key virulence factor in Gram-negative bacteria.
  • Previous understanding of M. catarrhalis LPS structure and function was limited.

Purpose of the Study:

  • To investigate the structural characteristics of Moraxella catarrhalis LPS.
  • To explore the potential role of LPS structure in bacterial survival and host colonization.
  • To compare LPS structures across different M. catarrhalis serogroups (A, B, and C).

Main Methods:

  • Structural analysis of M. catarrhalis lipopolysaccharide (LPS).
  • Serological characterization of LPS from different M. catarrhalis strains.
  • Comparative analysis of LPS structures with other Gram-negative bacteria.

Main Results:

  • M. catarrhalis LPS lacks the O-chain (polysaccharide portion).
  • Specific structural features of LPS were identified for serogroups A, B, and C.
  • Common structural elements, including a galabiosyl unit, were found across serogroups.
  • LPS structures share similarities with those of other Gram-negative nonenteric bacteria.

Conclusions:

  • The unique, O-chain-deficient LPS structure of M. catarrhalis is serogroup-specific.
  • Common structural motifs in M. catarrhalis LPS may contribute to its survival and colonization of the human host.
  • Further research into LPS structure-function relationships is warranted for understanding M. catarrhalis pathogenesis.

More Related Videos

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria12:57

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria

Published on: September 17, 2013

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii10:24

Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii

Published on: April 10, 2020

Related Concept Videos

Cross-reactivity00:42

Cross-reactivity

Overview
Outer Layers of the Cell Envelope01:18

Outer Layers of the Cell Envelope

The outermost layers of prokaryotic cells play a critical role in their survival, virulence, and interaction with the environment. These layers, often composed of polysaccharides, polypeptides, or proteins, form protective and adhesive structures that vary in organization and function.Capsules and Slime LayersCapsules are highly organized, tightly bound layers that firmly attach to the bacterial cell wall. Capsules are usually made of polysaccharides, though some are made of polypeptides. These...
Formation of Lipopolysaccharides01:19

Formation of Lipopolysaccharides

Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin, triggering...
Bacterial Toxins01:12

Bacterial Toxins

Bacterial toxins are sophisticated virulence factors that enable pathogenic bacteria to interact with, invade, and damage host tissues. These toxins fall broadly into two types: protein exotoxins, which are secreted into the environment and target specific host receptors, and lipopolysaccharide endotoxins, which are structural components of the bacterial outer membrane released primarily during bacterial lysis or membrane shedding. Exotoxins generally act more selectively, binding to cell...
Streptococcal Pharyngitis01:27

Streptococcal Pharyngitis

Streptococcal pharyngitis, commonly known as “strep throat,” is an acute infection of the oropharyngeal tissues caused by the Gram‑positive Group A Streptococcus (Streptococcus pyogenes). Transmission occurs primarily through respiratory droplets expelled during coughing, sneezing, or talking.Mechanisms of Host Entry and Immune EvasionUpon entering the host, S. pyogenes adheres to the mucosal epithelial cells of the pharynx via surface proteins, notably lipoteichoic acid and the antiphagocytic...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...