Ultrastructural Localization of Carbohydrates in the Cell Walls of Two Pathogenic Fungi: A Comparative Study

ABSTRACT

A survey of major polysaccharides occurring in cell walls of Ophiostoma ulmi and Verticillium alboatrum was performed by means of gold-complexed lectins and glycosidic enzymes. Some differences in wall carbohydrate composition and distribution were noted in these fungi. Both chitin and cellulose were found to occur in the walls of O. ulmi whereas only chitin was present in those of V. albo-atrum. Polygalacturonic acids were identified in both fungi but a greater amount of galactose and N-acetyl-D-galactosamine residues occurred in the walls of V. albo-atrum. In contrast, α-mannosyl and/or α-glucosyl groups were detected only in O. ulmi cell walls. β-glucosides and sialic acid were absent in the walls of both fungi.

Key Words:

• carbohydrates
• ultrastructural localization
• lectins
• glycosidic enzymes
• colloidal gold
• fungal walls