Sexual differentiation in Aspergillus nidulans: the requirement for manganese and its effect on alpha-1,3 glucan synthesis and degradation.

Aspergillus nidulans was grown on media with added amounts of manganese ranging from 0--2.5 muM. Manganese deficiency prevented cleistothecium development, although good vegetative growth was retained. Subsequent analysis of the mycelium produced under Mn2+ deficient growth revealed that alpha-1,3 glucan, the man carbon and energy source for fructification, was virtually absent from the cell wall. Several enzymes related to cell wall composition were investigated. Beta-1,3 glucanase, and very remarkably, alpha-1,3 glucanase reached about the same activity on the Mn2+ deficient and sufficient media, but amylase and protease were about 60 and 75% lower respectively on the Mn2+ deficient media and the correlation of these findings is discussed.