The expression of secreted aspartyl proteinases of Candida species in human whole saliva

The expression of secreted aspartyl proteinases (Saps) by clinical isolates of Candida albicans, C, tropicalis and C, parapsilosis in human saliva sup plemented with glucose and in a proteinase-inducing medium (YCB-BSA), was i nvestigated. Also, yeast growth, pH fluctuation and total protein concentra tion of the saliva cultures during incubation were measured. Sap expression was assessed by evaluating the enzyme activity as well as the antigen conc entration. Saps were expressed well in human saliva supplemented,vith gluco se by all three Candida species, although greater expressions was found in YCB-BSA medium. C, albicans isolates were significantly more proteolytic th an the non-albicans isolates. In general, for all three species, the rate o f yeast growth, pH fluctuation and percentage reduction of total salivary p rotein concentration concurred with the degree of expression of Saps. These data strongly suggest that Saps of C, albicans, C, tropicalis and C, parap silosis may play an active role in the progression of oral candidoses, part icularly with regard to the abundance of low pH microenvironments in the or al cavity, which are regularly replenished with dietary environments carboh ydrates.