Chemical Composition of the Hyphal Wall from Fusarium graminearum

Abstract

Barbosa, I. P., and Kemmelmeier, C. 1993. Chemical composition of the hyphal wall from Fusarium graminearum. Experimental Mycology 17, 274-283. Hyphal cell walls of Fusarium graminearum (zearalenone producer strain) were isolated, purified, and subjected to chemical analysis, enzymatic degradation, and electron microscopy. Chemical analysis revealed that the cell wall contained 74.5% carbohydrate, 4.5% protein, 3.0% lipid, 4.5% ash, and 0.3% phosphorus. The major cell wall component, N-acetylglucosamine (31%), is in the form of chitin, as shown by infrared spectroscopy. Glucose constituted 21.5% of the cell wall while mannose, galactose, arabinose, and glucuronic acid accounted for 22% of the cell wall. Glucuronic acid seems to be predominantly linked to galactose in the intact wall. Electron microscopy studies showed that the isolated cell wall consisted of two distinct layers, an outer electron-dense layer and a broader electron-transparent inner layer. Furthermore, intact cells showed an additional outer mucilaginous layer. The cell wall was shown to be susceptible to enzymatic degradation with the gastric juice from the snail Megalobulimus paranaguensis.