de Andrade Iara Bastos, Araújo Glauber Ribeiro de Sousa, Brito-Santos Fábio, Figueiredo-Carvalho Maria Helena Galdino, Zancopé-Oliveira Rosely Maria, Frases Susana, Almeida-Paes Rodrigo
Laboratório de Micologia, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
Laboratório de Biofísica de Fungos, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Front Microbiol. 2022 Apr 25;13:876611. doi: 10.3389/fmicb.2022.876611. eCollection 2022.
Melanin is one of the most studied virulence factors in pathogenic fungi. This pigment protects them from a series of both environmental and host stressors. Among basidiomycetes, and are known to produce melanin in the presence of phenolic precursors. Other species from the Trichosporonaceae family also produce this pigment, but the extent to this production among the clinically relevant species is unknown. For this reason, the aim of this study was to verify the production of melanin by different Trichosporonaceae species of clinical interest and to compare their pigments with the ones from and , which are more prevalent in human infections. Melanin was produced in a minimal medium supplemented with 1 mM L-dihydroxyphenylalanine (L-DOPA). Pigment was evaluated using scanning electron microscopy, Zeta potential measurements, and energy-dispersive X-ray spectroscopy. It was found that, besides and , , , , , , and also produce melanin-like particles in the presence of L-DOPA. Melanin particles have negative charge and are smaller than original cells. Variations in color, fluorescence, and chemical composition was noticed between the studied strains. All melanins presented carbon, oxygen, sodium, and potassium in their composition. Melanins from the most pathogenic species also presented iron, zinc, and copper, which are important during parasitism. Biophysical properties of these melanins can confer to the Trichosporonaceae adaptive advantages to both parasitic and environmental conditions of fungal growth.
黑色素是致病真菌中研究最多的毒力因子之一。这种色素可保护它们免受一系列环境和宿主应激源的影响。在担子菌中，已知在酚类前体存在的情况下会产生黑色素。丝孢酵母科的其他物种也会产生这种色素，但临床相关物种中这种色素的产生程度尚不清楚。因此，本研究的目的是验证具有临床意义的不同丝孢酵母科物种产生黑色素的情况，并将它们产生的色素与在人类感染中更常见的和产生的色素进行比较。黑色素是在添加了1 mM L - 二羟基苯丙氨酸（L - DOPA）的基本培养基中产生的。使用扫描电子显微镜、Zeta电位测量和能量色散X射线光谱对色素进行了评估。结果发现，除了和之外，、、、、和在L - DOPA存在的情况下也会产生黑色素样颗粒。黑色素颗粒带负电荷，且比原始细胞小。在所研究的菌株之间发现了颜色、荧光和化学成分的差异。所有黑色素的组成中都含有碳、氧、钠和钾。致病性最强的物种产生的黑色素中还含有铁、锌和铜，这些在寄生过程中很重要。这些黑色素的生物物理特性可以赋予丝孢酵母科在真菌生长的寄生和环境条件方面的适应性优势。
