Developmentally related changes in the production and expression of endo-beta-1,4-glucanases in Aspergillus nidulans

The production and electrophoretic expression of endoglucanase(s) were compared in the wild-type and three developmental mutants of Aspergillus nidulans. In the wild type, the production of endoglucanase and its distribution in extracellular and intracellular fractions varied with the age of the culture and the yield was better in stable cultures (production of conidia and cleistothecia) as compared with shake cultures (vegetative hyphae only). Two developmental mutants, aco-T69 and aco-40, which lack the development of conidia and cleistothecia, produced low levels of endoglucanase enzymes as compared with the wild type grown under similar conditions. On the other hand, in aco-90, a mutant capable of producing cleistothecia but no conidia, endoglucanase production was better. The results indicate a correlation between cleistothecial development and endoglucanase level. The electrophoretic studies revealed the presence of three forms of endoglucanase, i.e., EGI, EGII, and EGIII. The first two were detectable in the wild type as well as in mutant strains when grown under various experimental conditions and at all the stages of development. However, the third form could be observed only during cleistothecial development, indicating that this isozyme is developmentally regulated.