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Evaluation of laccases and melanization in clinical and environmental Cryptococcus neoformans samples by non-denaturing PAGE.
Pereira, Cristiane B; Bueno, Frank L; Dias, Amanda L T; Brigagão, Maísa R P L; Paula, Claudete R; Siqueira, Antonio M.
Afiliação
  • Pereira CB; Departamento de Ciências Biológicas, Laboratório de Microbiologia e Imunologia, Universidade Federal de Alfenas, Alfenas, MG, Brazil.
  • Bueno FL; Departamento de Ciências Biológicas, Laboratório de Microbiologia e Imunologia, Universidade Federal de Alfenas, Alfenas, MG, Brazil.
  • Dias ALT; Departamento de Ciências Biológicas, Laboratório de Microbiologia e Imunologia, Universidade Federal de Alfenas, Alfenas, MG, Brazil.
  • Brigagão MRPL; Departamento de Ciências Biológicas, Laboratório de Bioquímica, Universidade Federal de Alfenas, Alfenas, MG, Brazil.
  • Paula CR; Departamento de Microbiologia, Laboratório de Micologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo (USP), São Paulo, Brazil.
  • Siqueira AM; Departamento de Ciências Biológicas, Laboratório de Microbiologia e Imunologia, Universidade Federal de Alfenas, Alfenas, MG, Brazil.
J Med Microbiol ; 58(Pt 5): 563-566, 2009 May.
Article em En | MEDLINE | ID: mdl-19369516
The increased incidence of infections caused by the opportunistic pathogen Cryptococcus neoformans, which mainly affects immunocompromised patients but can also infect immunocompetent individuals, has needed additional studies on this micro-organism's pathogenicity and factors related to virulence, such as enzyme production, for a better understanding of the aetiology of cryptococcosis. The aim of this study was to verify the applicability of non-denaturing PAGE for analysis of laccases by quantification of the amount of melanin pigment produced by clinical and environmental strains of C. neoformans. After incubation of the gel with the substrate L-dopa, strains produced melanin spots of a bright brown to black colour. Quantification of these spots was performed by densitometry analysis and the amount of melanin produced was calculated and compared among the strains. All strains showed laccase activity. Serotype B strains showed a higher melanin intensity than serotype A strains. Over half of the clinical strains (56.2%) showed the lowest melanin intensities, suggesting that melanin production may not be the main virulence factor against host defence. The clinical strain ICB 88 revealed two melanin spots on the gel, indicating the presence of two laccase isoforms. The environmental strains showed the highest values of melanin intensity, which may be related to previous exposure to environmental stress conditions.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Criptococose / Cryptococcus neoformans / Lacase / Melaninas Limite: Humans País/Região como assunto: America do sul / Brasil Idioma: En Revista: J Med Microbiol Ano de publicação: 2009 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Criptococose / Cryptococcus neoformans / Lacase / Melaninas Limite: Humans País/Região como assunto: America do sul / Brasil Idioma: En Revista: J Med Microbiol Ano de publicação: 2009 Tipo de documento: Article