Structure of the disaccharide repeating unit of O-specific polysaccharide isolated from Aeromonas veronii strain Bs8 pathogenic to common carp (Cyprinus carpio).

The O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Aeromonas veronii strain Bs8, which is pathogenic to common carp (Cyprinus carpio), after mild acid hydrolysis followed by gel-permeation chromatography. The high-molecular-mass OPS fraction was investigated using chemical methods, mass spectrometry, and H and C NMR spectroscopy techniques, including 2D homonuclear H,H TOCSY, DQF COSY, NOESY, and heteronuclear H-detected H,C HSQC, and HMBC experiments. The analysis revealed that the O-specific polysaccharide contains sugars with the galacto configuration of the ring and is composed of a disaccharide repeating unit with the following structure.