The occurrence of alpha (1----2) linked N-acetylperosamine--homopolymer in lipopolysaccharides of non-O1 Vibrio cholerae possessing an antigenic factor in common with O1 V. cholerae.

Chemical analysis was carried out on lipopolysaccharides from Vibrio cholerae bio-serogroup Hakata 487-85. The O-specific chain of the phenol-soluble lipopolysaccharides was demonstrated by 13C-NMR spectroscopy and methylation analysis to contain a linear homopolymer of alpha(1----2) linked N-acetylperosamine (4-acetamido-4,6-dideoxy-D-mannopyranose), which was closely similar to but not identical to a linear alpha(1----2) linked N-3-deoxy-L-glycerotetronyl (S-2,4-dihydroxybutyryl) perosamine-homopolymer constituting that of O1 Vibrio cholerae lipopolysaccharides.