Changes in Microsporum gypseum mycelial wall and spore coat glycoproteins during sporulation and spore germination

Abstract

Ethylenediamine soluble glycoproteins were extracted from isolated M. gypseum hyphal walls during sporulation and from spore coats before and after germination. This study was carried out to identify a sporulation specific cell wall protein that possibly served as a substrate for the alkaline protease which initiated the macroconidial germination of this fungus. Analysis revealed that water insoluble glycoprotein accounted for 10% of the ungerminated spore coat but only for 4 to 5% of the mycelial wall dry weight. This fraction was modified in its amino acid composition during sporulation, and it decreased in protein content during spore germination. Water soluble glycoprotein, which accounted for approximately 3 to 3.5% of either the spore coat or mycelial wall dry weight, was of similar amino acid composition from both sources and did not decrease in protein content upon spore germination. The water insoluble glycoprotein was found to be rich in leucine, aspartic acid, glycine, glutamic acid, and phenylalanine residues. The water soluble glycoprotein was rich in proline, threonine, glycine, serine, glutamic acid, and alanine.