Graduate Program in Genetics & Molecular Biology, Emory University.
Department of Biology, Emory University.
J Vis Exp. 2021 May 17(171). doi: 10.3791/62170.
While pathogens can be deadly to humans, many of them cause a range of infection types with non-lethal phenotypes. Candida albicans, an opportunistic fungal pathogen of humans, is the fourth most common cause of nosocomial infections which results in ~40% mortality. However, other C. albicans infections are less severe and rarely lethal and include vulvovaginal candidiasis, impacting ~75% of women, as well as oropharyngeal candidiasis, predominantly impacting infants, AIDS patients and cancer patients. While murine models are most frequently used to study C. albicans pathogenesis, these models predominantly assess host survival and are costly, time consuming, and limited in replication. Therefore, several mini-model systems, including Drosophila melanogaster, Danio rerio, Galleria mellonella, and Caenorhabditis elegans, have been developed to study C. albicans. These mini-models are well-suited for screening mutant libraries or diverse genetic backgrounds of C. albicans. Here we describe two approaches to study C. albicans infection using C. elegans. The first is a fecundity assay which measures host reproduction and monitors survival of individual hosts. The second is a lineage expansion assay which measures how C. albicans infection affects host population growth over multiple generations. Together, these assays provide a simple, cost-effective way to quickly assess C. albicans virulence.
虽然病原体对人类可能是致命的，但它们中的许多都会导致一系列非致死表型的感染类型。白色念珠菌是一种侵袭人类的机会性真菌病原体，是导致约 40%死亡率的第四种最常见的医院获得性感染病原体。然而，其他白色念珠菌感染则不那么严重，很少致命，包括外阴阴道念珠菌病，影响约 75%的女性，以及口咽念珠菌病，主要影响婴儿、艾滋病患者和癌症患者。虽然鼠类模型最常用于研究白色念珠菌的发病机制，但这些模型主要评估宿主的存活率，而且成本高、耗时且复制有限。因此，已经开发了几种微型模型系统，包括黑腹果蝇、斑马鱼、黄粉虫和秀丽隐杆线虫，用于研究白色念珠菌。这些微型模型非常适合筛选白色念珠菌的突变文库或不同的遗传背景。在这里，我们描述了两种使用秀丽隐杆线虫研究白色念珠菌感染的方法。第一种是繁殖力测定，用于测量宿主繁殖并监测个体宿主的存活情况。第二种是谱系扩张测定，用于衡量白色念珠菌感染如何影响宿主种群在多代中的生长。这两种测定方法为快速评估白色念珠菌的毒力提供了一种简单、经济有效的方法。
