a State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences , Beijing , China.
b University of Chinese Academy of Sciences , Beijing , China.
Virulence. 2016 Apr 2;7(3):230-42. doi: 10.1080/21505594.2015.1135287. Epub 2015 Dec 29.
Candida dubliniensis is closely related to Candida albicans, a major causative agent of candidiasis, and is primarily associated with oral colonization and infection in human immunodeficiency virus (HIV)-positive patients. Despite the high similarity of genomic and phenotypic features between the 2 species, C. dubliniensis is much less virulent and less prevalent than C. albicans. The ability to change morphological phenotypes is a striking feature of Candida species and is linked to virulence. In this study, we report a novel phenotype, the gray phenotype, in C. dubliniensis. Together with the previously reported white and opaque cell types, the gray phenotype forms a tristable phenotypic switching system in C. dubliniensis that is similar to the white-gray-opaque tristable switching system in C. albicans. Gray cells of C. dubliniensis are similar to their counterparts in C. albicans in terms of several biological aspects including cellular morphology, mating competence, and genetic regulatory mechanisms. However, the gray phenotypes of the 2 species have some distinguishing features. For example, the secreted aspartyl protease (Sap) activity is induced by bovine serum albumin (BSA) in gray cells of C. albicans, but not in gray cells of C. dubliniensis. Taken together, our results demonstrate that the biological features and regulatory mechanisms of white-gray-opaque tristable transitions are largely conserved in the 2 pathogenic Candida species.
都柏林假丝酵母与白假丝酵母菌密切相关，白假丝酵母菌是假丝酵母菌病的主要病原体，主要与人类免疫缺陷病毒（HIV）阳性患者的口腔定植和感染有关。尽管这两种物种在基因组和表型特征上非常相似，但都柏林假丝酵母的毒力和普遍性都比白假丝酵母菌低得多。形态表型改变的能力是假丝酵母菌属的一个显著特征，与毒力有关。在这项研究中，我们报告了都柏林假丝酵母的一种新型表型，即灰色表型。与之前报道的白色和不透明细胞类型一起，灰色表型在都柏林假丝酵母中形成了一个三稳态表型转换系统，类似于白-灰-不透明三稳态转换系统在白假丝酵母菌中。在细胞形态、交配能力和遗传调控机制等几个生物学方面，都柏林假丝酵母的灰色细胞与白假丝酵母菌中的灰色细胞相似。然而，这两个物种的灰色表型具有一些区别特征。例如，牛血清白蛋白（BSA）诱导白假丝酵母菌灰色细胞中的分泌天冬氨酸蛋白酶（Sap）活性，但不诱导都柏林假丝酵母灰色细胞中的 Sap 活性。总之，我们的结果表明，白-灰-不透明三稳态转换的生物学特征和调控机制在这两种致病性假丝酵母菌中是高度保守的。
