Molecular order of carbohydrate components in cell walls of bacteria, fungi and algae according to the topo-optical reaction of the vicinal OH groups.

Selective topo-optical staining of vicinal OH groups with aldehyde-bisulphite-toluidine blue (ABT) has been used for studying the molecular structural order of polysaccharide components in microbial cell walls and capsules. (i) By intensive metachromatic staining in the light microscope, the method demonstrates carbohydrates, containing free vicinal OH or acylaminohydroxyl groups. (ii) The birefringence induced by oriented toluidine blue binding of the ABT reaction, provides information about the linear order of the reacting carbohydrate chains, a possibility not offered by other ultrastructural methods. Furthermore the different optical character of birefringence induced by ABT is indicative of the presence of (a) tangentially oriented polysaccharide chains in the cell wall of the molds and bacterial capsules; or (b) radially oriented OH groups suggesting helical glycan chains of peptidoglucomannane and mucopeptide in the yeasts and bacterial cell walls.