Peptide Autoinducers of Staphylococcal Pathogenicity

葡萄球菌致病性肽自诱导剂

• 批准号: 6615490
• 负责人: Richard P. Novick
• 金额: $ 19.22万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-15 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6615490
• 关键词: Staphylococcus aureus; Staphylococcus infection; antigen presentation; bacteria infection mechanism; bacterial genetics; biological signal transduction; gene induction /repression; laboratory mouse; microorganism interaction; microorganism metabolism; mutant; peptides; protein purification; receptor expression; transcription factor; virulence

DESCRIPTION (provided by applicant): The agr locus encodes the central regulatory system for staphylococcal pathogenesis and other stress-related functions. It is a quorum-sensing system that contains a two-component signal transduction module, encoded by agrA and C, and a peptide autoinducer, encoded by agrD, that is the activating ligand. Natural variants exist that cross inhibit agr autoinduction in heterologous combinations, thus blocking pathogenesis. This is the continuation of a long-term program whose overall goal is to understand the mechanism of agr autoinduction, the role of the agr autoinduction circuit in the pathogenesis of staphylococcal disease, and the biological significance of agr variants and their biotypes. Specific Aims for this period are: 1. To determine the mechanism of autoinducing peptide biosynthesis and the mechanism by which the mature secreted peptide interacts with its receptor, including both activation by cognate peptides and inhibition by heterologous ones. 2. To determine the role of the agr system in the pathogenesis of staphylococcal disease by following the expression of specific genes in vivo, the consequences of certain mutations, and the effects of the inducing or inhibiting peptides on the course of an experimental infection. 3. To characterize the agr specificity groups for traits or genes that are shared within a group and divergent between groups, with respect to pathogenic adaptations of the organism. Design and Methods: A direct ligand-binding assay using radioactive peptide will be developed to analyze receptor-ligand interactions. Variant peptides will be synthesized to delineate the structural and sequence requirements for receptor activation and inhibition. Other variants will be synthesized to enhance stability and activity in vivo to maximize the therapeutic efficacy of inhibiting virulence. Certain bacterial genes will be fused to a luciferase reporter, which will permit the monitoring of their expression as well as of the fate and persistence of infecting organisms in a murine infection model, by means of a luciferase-detecting imaging camera. This camera will monitor the effects of in vivo agr inhibition on the infecting organisms and on gene expression in vivo. Agr group-specific biotypes will be delineated to identify group-specific traits that may be correlated with pathogenic behavior - site and type of lesion, level of virulence, antibiotic resistance, etc..

描述（由申请人提供）：AGR基因座编码用于葡萄球菌发病机理和其他与压力相关功能的中央调节系统。它是一个群体感应系统，其中包含由Agra和C编码的两个组件信号转导模块，以及由Agrd编码的肽自动引导者，即激活的配体。存在自然变体，可以跨差异组合中的AGR自动诱导，从而阻断发病机理。这是一个长期计划的延续，其总体目标是了解AGR自动诱导的机制，AGR自动诱导电路在葡萄球菌疾病发病机理中的作用以及AGR变体及其生物型的生物学意义。在此期间的具体目的是：1。确定自身诱导肽生物合成的机制以及成熟的分泌肽与其受体相互作用的机制，包括同源肽的激活和异源肽的抑制作用。 2。通过遵循体内特定基因的表达，某些突变的后果以及诱导或抑制肽在实验感染过程中的影响，确定AGR系统在葡萄球菌疾病的发病机理中的作用。 3。表征在群体中共享的特异性或基因的AGR特异性基团，并且在组之间存在分歧，相对于生物体的致病性适应。设计和方法：将开发使用放射性肽的直接配体结合测定，以分析受体配体相互作用。将合成变体肽以描绘受体激活和抑制的结构和序列要求。其他变体将被合成以增强体内稳定性和活性，以最大程度地提高抑制毒力的治疗功效。某些细菌基因将融合到荧光素酶报告基因，这将允许通过荧光素酶检测成像摄像机监测其表达以及在鼠感染模型中感染生物的命运和持久性。该相机将监测体内AGR抑制对感染生物的影响以及体内基因表达。 AGR组特异性生物型将被划定，以识别可能与致病行为相关的组特异性性状 - 部位和病变的类型，毒力水平，抗生素耐药性等。