Adaptation of Candida glabrata to host-associated niches

项目总结 念珠菌病最早是在2500年前被记录下来的，今天仍然是一个全球问题。近几十年来， 非白色念珠菌(NCAC)感染的发病率增加，主要是由于光滑念珠菌， 一种机会主义的真菌病原体。光滑念珠菌具有内在的耐药性，目前仅次于念珠菌。 白念珠菌在临床中的流行情况。虽然众所周知真菌可以适应许多类型的环境，但我们 对人体不同部位如何使光滑毛囊线虫建立感染以及是否 这些不同的宿主生态位限制了有机体随后的进化轨迹。我的首要目标是 确定不同寄主生态位对光肩星天牛生物学的短期和长期影响。具体来说，我 Will将在模拟口腔和尿路两种常见感染部位的培养基中培养光滑毛囊线虫 并将这些处理与两个对照组进行比较：RPMI和合成完整(SC)培养液，后者是 通常用于抗真菌药物敏感性测试。我将追求三个具体目标来实现我的首要目标 进球。首先，为了更好地了解光肩星天牛如何在生理上适应不同的寄主生态位，我将建立 在所有四种条件下的生长模式和全球基因表达。第二，了解……的节奏 进化适应每种情况，我将实验性地进化ATCC建立的复制种群 2001年，通过250代连续传代培养获得菌株。对于每个人口，我将决定如何 种群和克隆的适合度相对于它们共同的祖先发生了变化。第三，揭示 进化适应I将对这些进行全基因组、全种群测序(WGWPS) 种群的世代间隔为50代。在多发性骨髓瘤中反复突变的基因的从头突变 复制和上升到高频率的突变是最有可能有助于适应度增加的突变。 为了建立WGWPS发现的从头突变之间的连锁关系，我们将对一组 来自每个模拟寄主生态位和每个对照的随机克隆。我们还将评估一个 这些克隆的子集，并确定最适合四类抗真菌药物的抗性和敏感性 毒品。这项研究的一个长期目标是发现宿主生态位是否来自于 起源于对增加发病率和死亡率风险的突变的选择。完成这三项工作 特定的目标将提供对作为机会性病原体发生的生理变化的有价值的洞察 最初适应新的宿主生态位，并发现在整个 慢性感染。不断升级的光滑念珠菌感染通常是通过越来越高剂量的抗真菌药物来对抗的 药物，这可能会导致急性毒性。对生理和进化适应的详细知识 发生在不同的感染部位将使我们更接近于开发针对部位的治疗方法， 将这种不想要的副作用降到最低。

PROJECT SUMMARY Candidiasis was first documented 2,500 years ago and remains a global problem today. In recent decades, the incidence of Non-Candida albicans Candida (NCAC) infections has increased chiefly due to Candida glabrata, an opportunistic fungal pathogen. C. glabrata, which has intrinsic drug resistance, is now second only to Candida albicans in clinical prevalence. While it is well-known that fungi can adapt to many types of environments, we know little about how different regions of the human body enable C. glabrata to establish an infection and whether these different host niches constrain the organism’s subsequent evolutionary trajectory. My overarching goal is to determine the short- and long-term influences of different host niches on C. glabrata biology. Specifically, I will culture C. glabrata in media designed to simulate two common sites of infection: the mouth and the urinary tract, and compare these treatments to two controls: RPMI and synthetic complete (SC) medium, which is routinely used in antifungal drug susceptibility testing. I will pursue three Specific Aims to achieve my overarching goal. First, to better understand how C. glabrata adapts physiologically to different host niches I will establish patterns of growth and global gene expression under all four conditions. Second, to understand the tempo of evolutionary adaptation to each condition, I will experimentally evolve replicate populations founded by the ATCC 2001 strain by serially transferring cultures for 250 generations. For each population, I will determine how population and clone fitness change relative to their common ancestor. Third, to uncover the mechanisms of evolutionary adaptation I will carry out whole-genome, whole-population sequencing (WGWPS) on these populations at 50 generation intervals. De novo mutations in genes that are recurrently mutated in multiple replicates and that rise to high frequency are the mutations that are most likely to contribute to fitness increases. To establish linkage relations among de novo mutations discovered by WGWPS we will sequence a set of random clones from each simulated host niche and each control. We will also evaluate the relative fitness of a subset of these clones and determine the resistance and sensitivity of the most fit to four classes of antifungal drugs. A long-term goal of this research is to discover whether the host niche from which a systemic infection originates selects for mutations that confer increased risk of morbidity and mortality. Completion of these three Specific Aims will provide valuable insight into the physiological changes that occur as an opportunistic pathogen initially adapts to a new host niche and discover subsequent evolutionary changes that occur throughout a chronic infection. Escalating C. glabrata infections are typically fought with higher and higher doses of antifungal drugs, which can result in acute toxicity. Detailed knowledge of physiological and evolutionary adaptations that occur at different infection sites will move us closer towards the development of site-specific treatments that minimize such unwanted side-effects.