Melanin in Fonsecaea pedrosoi: a trap for oxidative radicals

BMC Microbiology

Research Article

Luana P Borba¹  Sonia Rozental¹  Marcel ML Cunha¹  Wanderley de Souza¹  Marcelo H Herbst²  Ney V Vugman³  Anderson J Franzen⁴  Sergio H Seabra⁴ 

[1] Instituto de Biofísica Carlos Chagas Filho (IBCCF), Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil;Instituto de Ciências Exatas, Departamento de Química, Universidade Federal Rural do Rio de Janeiro, RJ, Brazil;Instituto de Física, Universidade Federal do Rio de Janeiro, RJ, Brazil;Laboratório de Tecnologia em Bioquímica e Microscopia, Centro Universitário da Zona Oeste (UEZO), Rio de Janeiro, Brazil;

关键词: Nitric Oxide;    Electron Spin Resonance;    Electron Spin Resonance Spectrum;    Oxidative Burst;    Paramagnetic Centre;   

DOI  :  10.1186/1471-2180-10-80

 received in 2009-09-02, accepted in 2010-03-16,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe pathogenic fungus Fonsecaea pedrosoi constitutively produces the pigment melanin, an important virulence factor in fungi. Melanin is incorporated in the cell wall structure and provides chemical and physical protection for the fungus.We evaluated the production of nitric oxide (NO) in macrophages, the oxidative burst and the inducible nitric oxide synthase (i-NOS) activity in interactions between activated murine macrophages and F. pedrosoi. Experiments were carried out with or without tricyclazole (TC) treatment, a selective inhibitor of the dihydroxynaphthalene (DHN)-melanin biosynthesis pathway in F. pedrosoi. The paramagnetisms of melanin and the TC-melanin were analysed by electron spin resonance. The fungal growth responses to H2O2 and to S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide donor, were also evaluated.ResultsMelanised F. pedrosoi cells were more resistant to both H2O2 and NO. Nitrite was not detected in the supernatant of macrophages incubated with melanised fungal cells. However, i-NOS expression was unaffected by the presence of either untreated control F. pedrosoi or TC-treated F. pedrosoi. In addition, the inhibition of the DHN-melanin pathway by TC improved the oxidative burst capability of the macrophages.ConclusionThe NO-trapping ability of F. pedrosoi melanin is an important mechanism to escape the oxidative burst of macrophages.

【 授权许可】

Unknown   
© Cunha et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.