Sialic Acid in Pasteurella pestis

Abstract

SIALIC acid is widely distributed in the animal kingdom as a constituent of mucoproteins, mucolipids and mucopolysaccharides^1–3. A search among the bacteria^4–13 has disclosed its occurrence in many Gram-negative bacteria^7,10,11. A polymer of N-acetylneuraminic acid called colominic acid⁴, a neuraminic acid peptide resembling the cell wall constituents and the corresponding uridine nucleotide which is the biosynthetic precursor⁵, and N-acetylneuraminic acid and N: 7-O-diacetylneuraminic acid^6,12 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^8,9. 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)¹¹. Sialic acid appears to be a constituent of the endotoxin^6,12,13, capsular antigen or some surface layers of the cell wall^5,12,13 of some bacteria.