DIMORPHISM AND VIRULENCE IN HISTOPLASMA CAPSULATUM

荚膜组织胞浆菌的二态性和毒力

• 批准号: 3144481
• 负责人: GEORGE S KOBAYASHI
• 金额: $ 16.41万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-05-01 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3144481
• 关键词: environmental adaptation; fungal genetics; gene expression; genetic manipulation; genetic strain; histoplasmosis; laboratory mouse; microorganism sexual dimorphism; molecular cloning; protein biosynthesis; proteins; stress proteins; virulence

Histoplasma capsulatum, a dimorphic fungus, causes disease in humans that has a wide range of clinical manifestations. The long-term goal of this application is to develop an approach towards improving the outcome of histoplasmosis using biochemical and molecular techniques based on our earlier demonstration that virulent infection requires a phase transition at 37 degrees C in the host. We want to elucidate how genes coding for stress proteins and transition-specific (ts) proteins contribute to the morphologic transition and to the different degrees of pathogenicity in isolates from patients and soil. These studies will be of value in development of drugs that interfere with establishment of infection. There are three specific aims: 1. STudy genes involved in the early stages of the phase transition: a. Thermal adaptation - heat shock genes (hsg): clone and characterize the heat shock 83 gene and determine how regulation of its expression and maturation during phase transition at various temperatures in different isolates is related to thermotolerance and pathogenicity. Determine the physiological role the induction of hs proteins play in the different degrees of thermotolerance, morphogenesis, mitochondrial membrane integrity and virulence. b. Phase transition - clone and characterize ts gene that are expressed in the first 6 hrs of the mycelium to yeast differentiation process and determine the pattern of their expression in strains, including the transitional-defective PCMS strain, that show different levels of thermotolerance and pathogenicity. Within this group we expect to find genes that contain heat shock elements in their regulatory regions. 2. Determine the effect of disruption of genes involved in the phase transition and in virulence by: a. Establishing a transformation protocol - design a procedure that will yield an efficient transformation system in order to analyze the role in vitro-mutated genes play in morphogenesis and pathogenicity. b. In vitro mutagenesis to determine its effect on phase transition and adaption - analyze the effect mutagenesis has on the biochemical events that take place after the temperature shift. 3. Determine the role that hs and ts genes play in virulence by: a. Evaluating the in vitro-mutated strains in mice.

囊状组织胞浆菌是一种二相性真菌，可引起人类疾病 具有广泛的临床表现。这样做的长期目标是 应用程序是为了开发一种方法来改善 基于OUR的生化和分子技术在组织胞浆菌病中的应用 早些时候的证据表明，毒力感染需要相变 在37摄氏度的主机中。我们想要阐明基因是如何编码的 应激蛋白和过渡特异(Ts)蛋白有助于 形态转变及对不同致病力的影响 从病人和土壤中分离出来的。这些研究将在 开发干扰感染形成的药物。 具体目标有三个： 1.研究参与相变早期阶段的基因： A.热适应-热休克基因(HSG)：克隆和鉴定 热休克83基因，并确定其表达和调控 不同温度下不同温度下的相变成熟 分离物与耐热性和致病性有关。确定 Hs蛋白的诱导在不同的 耐热性、形态发生、线粒体膜完整性 和致命性。 B.相变-克隆并鉴定表达于 菌丝体向酵母分化过程的前6小时和 确定它们在菌株中的表达模式，包括 过渡性缺陷PCMS菌株，表现出不同水平的 耐热性和致病性。在这个群体中，我们预计会发现 在其调控区域中包含热休克元件的基因。 2.确定参与该阶段的基因中断的影响 通过以下方式转变和致病力： A.建立转换协议-设计一个程序，以便 产生一个有效的转化系统，以便分析在 体外突变基因在形态发生和致病性方面发挥作用。 B.体外诱变以确定其对相变和 适应-分析突变对生化事件的影响 这发生在温度变化之后。 3.通过以下方法确定hs和ts基因在毒力中所起的作用： A.在小鼠身上评估体外突变菌株。