Cell constituents of mycelia and conidia of Aspergillus fumigatus

Abstract Cell-wall components of mycelia and conidia of Aspergillus fumigatus contain alkali-soluble polysaccharides comprised of d -galacto- d -mannans which coprecipitated with small proportions of a d -glucan, tentatively identified as glycogen. The fine structures of the d -galacto- d -mannans varied as a function of the cell type. In a 5-day-old mycelium, the polysaccharide consisted of a main chain of (1→6)-linked α- d -mannopyranose residues substituted at O-2 by 1 to 3 α- d -mannopyranosyl units that are (1→2)-interlinked. β- d -Galactofuranosyl units are (1→6)-linked to the d -mannan core, being components of side-chains of average length of ∼6 units, which are (1→5)-interlinked. The 10-day-old mycelium had a similar d -galacto- d -mannan, but the proportion of glycogen was smaller. Conidia contain polysaccharides of different structure, as shown by the 13 C-n.m.r. spectrum and by methylation analysis. Side chains composed of a single unit of β- d -galactofuranosyl linked (1→6) to adjacent d -mannopyranosyl units were identified with a minor proportion of 6- O -substituted d -galactofuranosyl units. Also present were nonreducing d -galacto-pyranosyl end-groups and 2-amino-2-deoxyglycosyl units. The glucan component was not glycogen. Conidial walls have much less protein than mycelial walls. Predominant amino acids in the latter were aspartic and glutamic acids, tyrosine, alanine, and glycine. Fatty acids C 16 , C 18 , C 18:1 , and C 18:2 were present in the mycelial and conidial walls, C 18:2 was present in minor amounts in the mycelial wall, but was a major component of the lipid fraction from whole cells.