PDF(Pubmed)
Abstract：
Amoebae are micropredators that play an important role in controlling fungal populations in ecosystems. However, the interaction between fungi and their amoebic predators suggests that the pressure from predatory selection can significantly influence the development of fungal virulence and evolutionary processes. Thus, the purpose of this study was to investigate the adaptation of saprotrophic Candida albicans strains during their interactions with Acanthamoeba castellanii. We conducted a comprehensive analysis of survival after co-culture by colony counting of the yeast cells and examining yeast cell phenotypic and genetic characteristics. Our results indicated that exposure to amoebae enhanced the survival capacity of environmental C. albicans and induced visible morphological alterations in C. albicans, particularly by an increase in filamentation. These observed phenotypic changes were closely related to concurrent genetic variations. Notably, mutations in genes encoding transcriptional repressors (TUP1 and SSN6), recognized for their negative regulation of filamentous growth, were exclusively identified in amoeba-passaged isolates, and absent in unexposed isolates. Furthermore, these adaptations increased the exposed isolates\' fitness against various stressors, simultaneously enhancing virulence factors and demonstrating an increased ability to invade A549 lung human epithelial cells. These observations indicate that the sustained survival of C. albicans under ongoing amoebic predation involved a key role of mutation events in microevolution to modulate the ability of these isolates to change phenotype and increase their virulence factors, demonstrating an enhanced potential to survive in diverse environmental niches.
摘要：
变形虫是微捕食者，在控制生态系统中的真菌种群中起着重要作用。然而,真菌与其阿米巴捕食者之间的相互作用表明，捕食性选择的压力可以显着影响真菌毒力和进化过程的发展。因此，这项研究的目的是研究腐生白色念珠菌菌株在与castellanii相互作用期间的适应性。我们通过对酵母细胞进行菌落计数并检查酵母细胞的表型和遗传特征，对共培养后的存活率进行了综合分析。我们的结果表明，暴露于变形虫增强了环境白色念珠菌的生存能力，并诱导白色念珠菌的可见形态改变，特别是通过增加丝状。这些观察到的表型变化与并发遗传变异密切相关。值得注意的是,编码转录抑制因子（TUP1和SSN6）的基因突变，因其对丝状生长的负面调节而受到认可，仅在变形虫传代的分离株中鉴定，并且不存在于未暴露的分离物中。此外，这些适应增加了暴露的隔离株对各种压力源的适应性，同时增强毒力因子，并证明入侵A549人肺上皮细胞的能力增加。这些观察结果表明，在正在进行的阿米巴捕食下，白色念珠菌的持续存活涉及突变事件在微进化中的关键作用，以调节这些分离株改变表型和增加其毒力因子的能力。展示了在不同环境利基中生存的增强潜力。
