Open AccessThe secreted aspartate proteinase of Candida albicans: physiology of secretion and virulence of a proteinase-deficient mutant
Author(s) -
Ian K. Ross,
Flavia De Bernardis,
George W. Emerson,
Antonio Cassone,
Patrick A. Sullivan
Publication year - 1990
Publication title -
journal of general microbiology/journal of general microbiology
Language(s) - English
Resource type - Journals
eISSN - 2059-9323
pISSN - 0022-1287
DOI - 10.1099/00221287-136-4-687
Subject(s) - secretion , candida albicans , virulence , intracellular , mutant , enzyme , biology , yeast , biochemistry , strain (injury) , microbiology and biotechnology , secretory protein , corpus albicans , gene , anatomy
It was established that Candida albicans grew rapidly in a simple medium containing yeast extract (0.2%, w/v) plus glucose (2%, w/v). These cultures were in or near to a state of nitrogen limitation and the concentration of secreted aspartate proteinase increased rapidly (within 3-4 h) on addition of BSA. Synthesis and secretion were apparently controlled both positively (induction by albumin or, more probably, the peptides produced from it) and negatively (repression by NH4Cl). A small intracellular pool of the enzyme was detected during production of the enzyme and this pool decreased with the cessation of synthesis and secretion. A stable mutant, IR24, was isolated which secreted less than 0.3% of the amount of the proteinase exported by the parent strain ATCC 10261. The LD50 values for mutant IR24 and the parent strain administered intravenously to mice were greater than 1.0 x 10(9) and 1.6 x 10(6) c.f.u. kg-1 respectively.