Melanin in a Meristematic Mutant of Fonsecaea monophora Inhibits the Production of Nitric Oxide and Th1 Cytokines of Murine Macrophages
Melanin in a Meristematic Mutant of Fonsecaea monophora Inhibits the Production of Nitric Oxide and Th1 Cytokines of Murine Macrophages
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DOI：
10.1007/s11046-012-9588-x
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发表时间：
2012-10
期刊：
影响因子：
5.5
通讯作者：
Junmin Zhang;Li Wang;L. Xi;Huaiqiu Huang;Yongxuan Hu;Xi-qing Li;Xiao Huang;Sha Lu;Jiufeng Sun
中科院分区：
文献类型：
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作者：
Junmin Zhang;Li Wang;L. Xi;Huaiqiu Huang;Yongxuan Hu;Xi-qing Li;Xiao Huang;Sha Lu;Jiufeng Sun
黑色素是分泌于真菌细胞壁外或构成真菌细胞壁结构的复杂聚合物。它被认为是条件致病真菌的一个重要毒力因子。本研究从一株具有分生组织的真菌突变株CBS 122845出发，获得了一株白化病突变株CBS 125149。透射电子显微镜观察表明，亲株黑色素呈电子致密颗粒状分布于细胞壁表面。我们用碱-酸法从两种不同的菌株中提取细胞壁组分。不同菌株或其细胞壁组分与活化的RAW264.7相互作用。色素菌株及其细胞壁组分在体外均能降低诱导型一氧化氮合酶基因的表达，抑制一氧化氮的合成（P< 0.05）。在活化的RAW 264.7和色素菌株或其细胞壁组分之间的相互作用中发生了Th 2的加剧和Th 1的抑制反应。总的来说，我们的研究结果表明，黑色素在逃避体外氧化爆发的杀伤中起着重要作用。Th 2反应的加剧可能加速了真菌的持续存在。
Melanin is a complex polymer which is secreted outside or constitutes the structure of fungal cell wall. It is considered as an important virulence factor in opportunistic pathogenic fungi. In this study, one albino mutant (CBS 125149) was generated from a parent meristematic mutant (CBS 122845) ofFonsecaea monophora. Transmission electron microscopy profiles showed that melanin in the parent strains appeared as electron-dense granules which located on the cell wall surface. We extracted the cell wall fractions from the two different strains by an alkali–acid method. The different strains or its cell wall fractions were interacted with the activated RAW264.7. The pigmented strain and its cell wall fraction could reduce the expression of inducible nitric oxide synthase gene and inhibit the synthesis of nitric oxide in vitro (P< 0.05). Exacerbated Th2 and inhibited Th1 response occurred in the interaction between activated RAW264.7 and the pigmented strain or its cell wall fraction. Collectively, our results suggest that melanin plays an important role in escaping the killing of oxidative burst in vitro. The exacerbated Th2 response probably accelerates the persistence of the fungus.