DIFFERENTIAL EXTRACTION OF N-ACETYLGLUCOSAMINIDASE AND TREHALASE FROMTHE CELL-ENVELOPE OF CANDIDA-ALBICANS

Dithiothreitol (DTT) extraction of N-acetylglucosaminidase and trehala se from intact Candida albicans ATCC 10261 cells was monitored as an i ndex of cell envelope porosity during N-acetylglucosamine-induced morp hogenesis. Trehalase, which is secreted into the cell envelope during starvation and bud-formation, displayed similar extraction kinetics in starved, germ tube-forming, and bud-forming cells, indicating that th e mother cell wall remains largely unchanged during morphogenic outgro wth and that the porosity of bud and mother cell nails is similar. N-a cetylglucosaminidase, which is secreted specifically during morphogene sis, was released eightfold more rapidly from germ tube-forming than b ud-forming cells, reflecting major differences in porosity between bud and germ tube. In addition, by assaying DTT extracts and extracted ce ll residues, it was found that the total extracellular N-acetylglucosa minidase activity increased 2- to 2.5-fold during DTT treatment. Thus, DTT unmasks a cryptic form of N-acetylglucosaminidase. The cryptic ac tivity was associated with the cell wall fraction. (C) 1995 Academic P ress, Inc.