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PLoS One. 2014 Apr 15;9(4):e91901. doi: 10.1371/journal.pone.0091901. eCollection 2014.

Pigment production on L-tryptophan medium by Cryptococcus gattii and Cryptococcus neoformans.

Author information

1
Department of Biology, Farmingdale State College, State University of New York, Farmingdale, New York, United States of America.
2
Microscopy Core, New York University Langone Medical Center, New York, New York, United States of America.
3
Laboratory for Macromolecular Analysis & Proteomics, Albert Einstein College of Medicine, Bronx, New York, United States of America.
4
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America.

Abstract

In recent years strains previously grouped within Cryptococcus neoformans have been divided into two species C. neoformans and C. gattii, with Cryptococcus neoformans comprising serotypes A, D, and AD and C. gattii comprising serotypes B and C. Cryptococcus neoformans have also been subdivided into two varieties C. neoformans var. grubii, serotype A, and C. neoformans var. neoformans, serotype D. We analyzed the growth and pigment production characteristics of 139 strains of Cryptococcus spp. in L-tryptophan containing media. Nearly all strains of Cryptococcus, including each variety and serotype tested produced a pink water-soluble pigment (molecular weight of 535.2 Da) from L-tryptophan. Consequently, the partial separation of the species was based on whether the pink pigment was secreted into the medium (extracellular) or retained as an intracellular pigment. On L-tryptophan medium C. neoformans var. grubii and serotype AD produced a pink extracellular pigment. In contrast, for C. gattii, the pink pigment was localized intracellularly and masked by heavy production of brown pigments. Pigment production by C. neoformans var. neoformans was variable with some strains producing the pink extracellular pigment and others retained the pink pigment intracellularly. The pink intracellular pigment produced by strains of C. neoformans var. neoformans was masked by production of brown pigments. Cryptococcus laccase mutants failed to produce pigments from L-tryptophan. This is the first report that the enzyme laccase is involved in tryptophan metabolism. Prior to this report Cryptococcus laccase produced melanin or melanin like-pigments from heterocyclic compounds that contained ortho or para diphenols, diaminobenzenes and aminophenol compounds. The pigments produced from L-tryptophan were not melanin.

PMID:
24736553
PMCID:
PMC3988003
DOI:
10.1371/journal.pone.0091901
[Indexed for MEDLINE]
Free PMC Article

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