Two rapid pigmentation tests for identification of Cryptococcus neoformans. 1982

C S Kaufmann, and W G Merz

Two tests were developed for the rapid identification of Cryptococcus neoformans based on pigment produced by the organism's phenoloxidase activity. Caffeic acid was incorporated into cornmeal agar, a medium used routinely for yeast identification. When tested on this medium, only C. neoformans isolates produced brown pigment. All other yeasts maintained their normal morphology and did not produce the reaction product. A non-medium-based test was developed for same-day identification of C. neoformans isolates. Paper strips saturated with a buffered L-beta-3,4-dihydroxyphenylalanine-ferric citrate solution were inoculated with isolates and incubated at 37 degrees C. Pigment production occurred only with C. neoformans isolates, many within 60 to 90 min. All other yeasts remained negative.

UI MeSH Term Description Entries
D010088 Oxidoreductases The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9) Dehydrogenases,Oxidases,Oxidoreductase,Reductases,Dehydrogenase,Oxidase,Reductase
D010860 Pigments, Biological Any normal or abnormal coloring matter in PLANTS; ANIMALS or micro-organisms. Biological Pigments
D003454 Cryptococcus A mitosporic Tremellales fungal genus whose species usually have a capsule and do not form pseudomycellium. Teleomorphs include Filobasidiella and Fidobasidium. Torula
D003455 Cryptococcus neoformans A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans. Blastomyces neoformans,Debaryomyces neoformans,Filobasidiella neoformans,Lipomyces neoformans,Saccharomyces neoformans,Torula neoformans,Torulopsis neoformans,Cryptococcus neoformans var. grubii
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man

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