DIMORPHISM AND VIRULENCE IN HISTOPLASMA CAPSULATUM

荚膜组织胞浆菌的二态性和毒力

• 批准号: 3144482
• 负责人: GEORGE S KOBAYASHI
• 金额: $ 17.49万
• 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/3144482
• 关键词: cell transformation; environmental adaptation; fungal genetics; gene expression; genetic manipulation; genetic strain; histoplasmosis; laboratory mouse; microorganism genetics; 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.

二态真菌的组织囊肿囊肿会导致人类疾病 具有广泛的临床表现。 这个长期目标 应用是开发一种改善结果的方法 基于我们的生化和分子技术，组织质质病基于我们 较早的证明有毒感染需要相变 在主机中的37度c。 我们想阐明基因如何编码 应力蛋白和过渡特异性（TS）蛋白有助于 形态学转变和不同程度的致病程度 从患者和土壤中分离出来。 这些研究将具有价值 开发干扰建立感染的药物。 有三个特定的目标： 1。研究基因涉及相变早期阶段： 一个。热适应 - 热休克基因（HSG）：克隆并表征 热休克83基因，并确定其表达和如何调节 在不同温度的不同温度下，在不同的温度下的成熟 分离株与耐热性和致病性有关。 确定 生理作用HS蛋白在不同的 耐热度，形态发生，线粒体膜完整性 和毒力。 b。相变 - 克隆和表征在中表达的TS基因 菌丝体到酵母分化过程的前6个小时和 确定其在菌株中表达的模式，包括 过渡缺陷性PCMS菌株，显示不同的水平 温耐和致病性。 在这个组中，我们希望找到 在其调节区域中包含热冲击元件的基因。 2。确定相关基因破坏的影响 过渡和毒力通过： 一个。建立转换协议 - 设计一个将 产生有效的转换系统，以分析 体外突变基因在形态发生和致病性中发挥作用。 b。体外诱变，以确定其对相变的影响和 适应性 - 分析诱变对生化事件的影响 这是在温度变化后发生的。 3。确定HS和TS基因在毒力中的作用： 一个。评估小鼠体外突破性菌株。