title: 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.affiliation: Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Cuzzi
authors.forename: Paola
authors.initials: P
authors.lastname: Cescutti
authors.forename: Linda
authors.initials: L
authors.lastname: Furlanis
authors.forename: Cristina
authors.initials: C
authors.lastname: Lagatolla
authors.forename: Luisa
authors.initials: L
authors.lastname: Sturiale
authors.forename: Domenico
authors.initials: D
authors.lastname: Garozzo
authors.forename: Roberto
authors.initials: R
authors.lastname: Rizzo
mesh_terms: D001433:Bacteriolysis / Q000187:drug effects; D019121:Burkholderia Infections / Q000150:complications / Q000276:immunology* / Q000382:microbiology; D016956:Burkholderia cepacia / Q000276:immunology*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D003550:Cystic Fibrosis / Q000150:complications / Q000276:immunology* / Q000382:microbiology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D057131:Immune Evasion; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D050296:Microbial Viability / Q000187:drug effects; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000378:metabolism*; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D011135:Polysaccharides, Bacterial; D017382:Reactive Oxygen Species; C487212:cepacian; D012973:Sodium Hypochlorite