Carbohydrate Composition of Endotoxins from R-type Isogenic Mutants of Shigella sonnei Studied by Capillary Electrophoresis and GC-MS

Sa？etak The carbohydrate composition of the rough-type endotoxins (lipopolysaccharides, LPSs) from Shigella sonnei mutant strains (Shigella sonnei phase II - 4303, 562H, R41 and 4350) was investigated by capillary electrophoresis and GC-MS. The monosaccharides obtained by hydrolysis were determined by capillary electrophoresis combined with laser induced fluorescence detection (CE-LIF) after labeling with 8-aminopyrene-1,3,6-trisulfonic acid (APTS) and by GC-MS as alditol-acetate derivatives. It was obtained that the lipopolysaccharides of the isogenic rough mutants are formed in a step-like manner, containing no heptose (4350), one D-glycero-D-mannoheptose (562H), or two or three L-glycero-Dmannoheptoses (R41, 4303, respectively) in the deep core region. Besides the heptoses, the longest LPS from the mutant Shigella sonnei 4303 contains hexoses, such as glucoses and galactoses, in a proportion of approximately 3:2. This study provides a comprehensive comparison of the variability in the carbohydrate part of the rough endotoxins extracted from Shigella sonnei isogenic mutants. (doi: 10.5562/cca1795