Structural characterization of a cell wall polysaccharide from Penicilliumvermoesenii: chemotaxonomic application

The water-soluble polysaccharides (F1SS) obtained from the alkali extracts of the cell wall of two strains of Penicillium vermoesenii Biourge, Fusariu m javanicum Koorders, Fusarium solani (Martius) Saccardo, and Fusarium oxys porum Schlechtendahl represented 8.7 to 10.7% of the dry cell wall material . All polysaccharides were composed of galactose (22.0-27.4%), glucose (18. 4-30.3%), mannose (7.8-23.1%), and glucuronic acid (3.0-6.0%, except in F. oxysporum that contained 16.8%). Methylation analysis and H-1-NMR spectra o f the polysaccharides of these fungi were similar except for F. oxysporum, which showed a higher peak of glucuronic acid than of glucose. The chemical and structural analyses performed indicated that F1SS polysaccharides of t he species studied have a skeleton of beta-(1->6) galactofuranose, fully su bstituted at positions O-2 by a single residue of glucopyranose or by short side chains containing one glucuronic acid residue and beta-mannopyranose. This polysaccharide is linked to a mannose core consisting of a short chai n of alpha-(1->6)-linked D-mannopyranose. Immunological methods confirm the structural relatedness among these polysaccharides. No similarities were f ound with the H-1-NMR spectra of F1SS polysaccharides from other species of Penicillium or Gliocladium. These results show that P. vermoesenii is clos er to the genus Fusarium than to Penicillium or Gliocladium.