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.
