Growth of Cryptococcus neoformans on uric acid agar.

Effect of certain low molecular nitrogen substances, namely uric acid, eura and creatinine as sole source of nitrogen was studied on 31 strains of Cryptococcus neoformans as well as on a rough looking isolate recovered from the brain of a mouse inoculated with a mucoid strain of C. neoformans. Uric acid as a nitrogen source caused striking alterations in the morphology of C. neoformans. In view of the facts that uric acid is a common end-product of human and animal metabolism, it is abundantly present in the avian faecal matter and is capable of inducing mucoid growth and capsule formation in dry growing non-encapsulated strains or in an otherwise rough looking hypha forming isolate, its role in studying the phylogenesis of C. neoformans and its pathogenicity seems to be an important proposition.