| Sujet | acid; acylation; amide; Bordetella; Bordetella bronchiseptica; Bordetella pertussis; carbohydrate conformation; chemical; chemistry; chromatography, gel; chromatography, thin layer; comparative study; component; desorption mass spectrometry; disaccharide; electrophoresis, polyacrylamide gel; endotoxin; esters; fatty acids; glucosamine; isolation & purification; laser; linkages; lipid; lipid A; Lipopolysaccharide; liquid chromatography/mass spectrometry; magnetic; magnetic resonance spectroscopy; mass fragmentography; mass spectrometry; methods; models, molecular; molecular; NMR; nuclear; Parapertussis; plasma; silicon dioxide; species specificity; spectrometry, mass, matrix-assisted laser desorption-ionization; spectrum analysis, mass; structure; Support, Non-U. S. Gov't |
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| Résumé | Bordetella hinzii has recently been isolated from immunocompromised human hosts. The structure of the lipid A of its endotoxin was investigated using chemical analyses, nuclear magnetic resonnance (NMR), gas liquid chromatography/mass spectrometry (GC/MS), plasma desorption mass spectrometry (PDMS) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The lipid A contains the classical bisphosphorylated beta-(1-->6)-linked D-glucosamine disaccharide with hydroxytetradecanoic acid (C14OH) in amide linkages. The lipid A components of B. pertussis, B. bronchiseptica, and B. parapertussis all differ in their acylation pattern but share a residue of tetradecanoyl-3-hydroxytetradecanoic acid in amide linkage at the C-2' position. However, in the B. hinzii species, the tetradecanoic acid (C14) is stoichiometrically replaced by a 2-hydroxytetradecanoic acid (2-C14OH). In the few reported examples of a hydroxylated fatty acid in this position, the substitutions were only partial. The B. hinzii lipid A differs from that of B. pertussis also by replacement of the hydroxydecanoic acid (C10OH) by hydroxydodecanoic acid (C12OH) and by the presence of a hexadecanoic acid (C16) to give a sixth fatty acid. The lipid A was heterogeneous, being composed of three major molecular species: tetra-, penta- and hexaacylated. The fatty acids in ester linkage were localized by PDMS of the native and alkali-treated lipid A. The lipid A components isolated from the O-chain-linked lipopolysaccharides (LPSs) were shown to be more acylated than those from the O-chain-free LPSs |
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