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An alternative method for the analysis of melanin production in Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato
Author(s) -
Brilhante Raimunda S. N.,
España Jaime D. A.,
Alencar Lucas P.,
Pereira Vandbergue S.,
CasteloBranco Débora de S. C. M.,
PereiraNeto Waldemiro de A.,
Cordeiro Rossana de A.,
Sidrim José J. C.,
Rocha Marcos F. G.
Publication year - 2017
Publication title -
mycoses
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 69
eISSN - 1439-0507
pISSN - 0933-7407
DOI - 10.1111/myc.12650
Subject(s) - sensu , cryptococcus gattii , cryptococcus neoformans , biology , melanin , cryptococcus , microbiology and biotechnology , agar , cryptococcosis , botany , bacteria , genus , genetics
Summary Melanin is an important virulence factor for several microorganisms, including Cryptococcus neoformans sensu lato and Cryptococcus gattii sensu lato , thus, the assessment of melanin production and its quantification may contribute to the understanding of microbial pathogenesis. The objective of this study was to standardise an alternative method for the production and indirect quantification of melanin in C . neoformans sensu lato and C . gattii sensu lato . Eight C . neoformans sensu lato and three C . gattii sensu lato , identified through URA 5 methodology, Candida parapsilosis ATCC 22019 (negative control) and one Hortaea werneckii (positive control) were inoculated on minimal medium agar with or without L‐ DOPA , in duplicate, and incubated at 35°C, for 7 days. Pictures were taken from the third to the seventh day, under standardised conditions in a photographic chamber. Then, photographs were analysed using grayscale images . All Cryptococcus spp. strains produced melanin after growth on minimal medium agar containing L‐ DOPA . C. parapsilosis ATCC 22019 did not produce melanin on medium containing L‐ DOPA , while H. werneckii presented the strongest pigmentation. This new method allows the indirect analysis of melanin production through pixel quantification in grayscale images, enabling the study of substances that can modulate melanin production.