AN EXTRACELLULAR POLYSACCHARIDE FROM GIBBERELLA FUJIKUROI (FUSARIUM MONILIFORME)

Abstract

Growth of Gibberellafujikuroi (Fusariummoniliforme) on a glucose medium produced au extracellular polysaccharide containing D-glucose, D-mannose, D-galactose, D-glucuronic acid (molar ratio 1.0:1.1:1.3:0.6), and possibly D-mannuronic acid. Protein was retained tenaciously by the polysaccharide and several deproteinization methods reduced the nitrogen content only slightly. Methylation studies showed that the polysaccharide was highly branched with D-glucose and D-mannose forming the non-reducing ends in the molecule. Most of the D-mannose and D-galactose units were joined by 1 → 2 and 1 → 6 linkages with some branching also at C2and C6positions; D-galactose occurred exclusively in the furanose form. D-Glucose units were joined by 1 → 2 and 1 → 3 linkages. The D-glucuronic acid residues were mainly non-terminal and were attached to both D-galactose and D-mannose units. Periodate oxidation studies supported the foregoing conclusions.