Sialic acid in pasteurella pestis

Abstract

Sialic acid is widely distributed in the animal kingdom as a constituent of mucoproteins, mucolipids and mucopolysaccharides. A search among the bacteria has disclosed its occurrence in many Gram-negative bacteria. A polymer of N-acetylneuraminic acid called colominic acid, a neuraminic acid peptide resembling the cell wall constituents and the corresponding uridine nucleotide which is the biosynthetic precursor, and N-acetylneuraminic acid and N: 7-O-diacetylneuraminic acid in the hydrolysate of the cell mass with 0.05 N sulphuric acid have been reported in Escherichia coli. From group C Neisseria meningococcus, a group-specific haptenic material has been isolated which contains 3 units of hexosamine and 7 of sialic acid. Citrofactor freundii has yielded a serologically active polysaccharide which contains 36 per cent sialic acid, 21 per cent hexosamine, and the rest unidentified (no uronic acid and only traces of protein). Sialic acid appears to be a constituent of the endotoxin, capsular antigen or some surface layers of the cell wall of some bacteria.