Investigation of bacterial resistance to the immune system response: cepacian depolymerisation by reactive oxygen species.

Abstract

Reactive oxygen species (ROS) are part of the weapons used by the immune system to kill and degrade infecting microorganisms. Bacteria can produce macromolecules, such as polysaccharides, that are able to scavenge ROS. Species belonging to the Burkholderia cepacia complex are involved in serious lung infection in cystic fibrosis patients and produce a characteristic polysaccharide, cepacian. The interaction between ROS and bacterial polysaccharides was first investigated by killing experiments, where bacteria cells were incubated with sodium hypochlorite (NaClO) with and without prior incubation with cepacian. The results showed that the polysaccharide had a protective effect towards bacterial cells. Cepacian was then treated with different concentrations of NaClO and the course of reactions was followed by means of capillary viscometry. The degradation products were characterised by size-exclusion chromatography, NMR and mass spectrometry. The results showed that hypochlorite depolymerised cepacian, removed side chains and O-acetyl groups, but did not cleave the glycosidic bond between glucuronic acid and rhamnose. The structure of some oligomers produced by NaClO oxidation is reported.

• Authors: Bruno Cuzzi, Paola Cescutti, Linda Furlanis, Cristina Lagatolla, Luisa Sturiale, Domenico Garozzo, Roberto Rizzo
• Journal: Innate immunity (Innate Immun) Vol. 18 Issue 4 Pg. 661-71 (Aug 2012) ISSN: 1753-4267 [Electronic] United States
• PMID: 22278934 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Free Radical Scavengers
• Polysaccharides, Bacterial
• Reactive Oxygen Species
• cepacian
• Sodium Hypochlorite

Topics

• Bacteriolysis (drug effects)
• Burkholderia Infections (complications, immunology, microbiology)
• Burkholderia cepacia (immunology)
• Carbohydrate Metabolism (drug effects)
• Cystic Fibrosis (complications, immunology, microbiology)
• Free Radical Scavengers (pharmacology)
• Humans
• Immune Evasion
• Magnetic Resonance Spectroscopy
• Mass Spectrometry
• Microbial Viability (drug effects)
• Polysaccharides, Bacterial (chemistry, metabolism)
• Reactive Oxygen Species (chemistry, metabolism)
• Sodium Hypochlorite (chemistry, metabolism)