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Rev. Inst. Med. trop. S. Paulo vol.41 n.3 São Paulo May 1999
Re: Constitutive melanin in the cell wall of the etiologic agent of Lobos disease
São Paulo, April 26, 1999.
We read with interest the paper by TABORDA et al. Constitutive melanin in the cell wall of the etiologic agent of Lobos disease, recently published in the Revista do Instituto de Medicina Tropical de São Paulo1.
The authors investigated the presence of melanin in P. loboi and P. brasiliensis, using the Fontana-Masson stain, and reported that P. loboi contains constitutive melanine as opposed to P. brasiliensis.
However some authors have looked at melaninogenesis in Cryptococcus neoformans and have concluded that silver-reducing compounds in the fungal cell wall, as demonstrated by the Fontana-Masson technique, are unlikely to be melanin. They may be catecholamine oxidation products, which do not undergo postenzymatic polymerization to form typical eumelanin2.
Therefore we wonder whether the data on the in vivo production of melanin by P. loboi should not be reviewed.
1. TABORDA, V.B.A.; TABORDA, P.R.O. & McGINNIS, M.R. - Constitutive melanin in the cell wall of the etiologic agent of Lobos disease. Rev. Inst. Med. trop. S. Paulo, 41: 9-12, 1999.
2. LIU, L.; WAKAMATSU, K.; ITO, S. & WILLIAMSON, P.R. - Catecholamine oxidative products, but not melanin, are produced by Cryptococcus neoformans during neuropathogenesis in mice. Infect. Immun., 67: 108-112, 1999.
Prof. Marcello F. Franco
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