Synthesis of melanin-like pigments by Sporothrix schenckii in vitro and during mammalian infection

Rachael Morris-Jones, Sirida Youngchim, Beatriz L. Gomez, Phil Aisen, Roderick J. Hay, Joshua D. Nosanchuk, Arturo Casadevall, Andrew J. Hamilton

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Abstract

Melanin has been implicated in the pathogenesis of several important human fungal pathogens. Existing data suggest that the conidia of the dimorphic fungal pathogen Sporothrix schenckii produce melanin or melanin-like compounds; in this study we aimed to confirm this suggestion and to demonstrate in vitro and in vivo production of melanin by yeast cells. S. schenckii grown on Mycosel agar produced visibly pigmented conidia, although yeast cells grown in brain heart infusion and minimal medium broth appeared to be nonpigmented macroscopically. However, treatment of both conidia and yeast cells with proteolytic enzymes, denaturant, and concentrated hot acid yielded dark particles similar in shape and size to the corresponding propagules, which were stable free radicals consistent with identification as melanins. Melanin particles extracted from S. schenckii yeast cells were used to produce a panel of murine monoclonal antibodies (MAbs) which labeled pigmented conidia, yeast cells, and the isolated particles. Tissue from hamster testicles infected with S. schenckii contained fungal cells that were labeled by melanin-binding MAbs, and digestion of infected hamster tissue yielded dark particles that were also reactive. Additionally, sera from humans with sporotrichosis contained antibodies that bound melanin particles. These findings indicate that S. schenckii conidia and yeast cells can produce melanin or melanin-like compounds in vitro and that yeast cells can synthesize pigment in vivo. Since melanin is an important virulence factor in other pathogenic fungi, this pigment may have a similar role in the pathogenesis of sporotrichosis.

Original languageEnglish (US)
Pages (from-to)4026-4033
Number of pages8
JournalInfection and Immunity
Volume71
Issue number7
DOIs
StatePublished - Jul 1 2003

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Sporothrix
Melanins
Fungal Spores
Infection
Yeasts
Sporotrichosis
Cricetinae
In Vitro Techniques
Monoclonal Antibodies
Virulence Factors
Agar
Free Radicals
Testis
Digestion
Peptide Hydrolases
Fungi

ASJC Scopus subject areas

  • Immunology

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Synthesis of melanin-like pigments by Sporothrix schenckii in vitro and during mammalian infection. / Morris-Jones, Rachael; Youngchim, Sirida; Gomez, Beatriz L.; Aisen, Phil; Hay, Roderick J.; Nosanchuk, Joshua D.; Casadevall, Arturo; Hamilton, Andrew J.

In: Infection and Immunity, Vol. 71, No. 7, 01.07.2003, p. 4026-4033.

Research output: Contribution to journalArticle

Morris-Jones, R, Youngchim, S, Gomez, BL, Aisen, P, Hay, RJ, Nosanchuk, JD, Casadevall, A & Hamilton, AJ 2003, 'Synthesis of melanin-like pigments by Sporothrix schenckii in vitro and during mammalian infection', Infection and Immunity, vol. 71, no. 7, pp. 4026-4033. https://doi.org/10.1128/IAI.71.7.4026-4033.2003
Morris-Jones, Rachael ; Youngchim, Sirida ; Gomez, Beatriz L. ; Aisen, Phil ; Hay, Roderick J. ; Nosanchuk, Joshua D. ; Casadevall, Arturo ; Hamilton, Andrew J. / Synthesis of melanin-like pigments by Sporothrix schenckii in vitro and during mammalian infection. In: Infection and Immunity. 2003 ; Vol. 71, No. 7. pp. 4026-4033.
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