SIDEROPHORES AND VIRULENCE OF PSEUDOMONAS AERUGINOSA

铜绿假单胞菌导致先天性 防御机制被破坏了 这些患者通常是 烧伤、创伤、免疫抑制和癌症患者。 第一 细菌感染的步骤是定殖和生长。 细菌生长 在组织和血浆中发生在有效的先天防御存在的情况下， 营养免疫机制。 营养免疫力取决于 转铁蛋白阻止细菌吸收必需的铁并阻止其生长。 大多数铜绿假单胞菌菌株对这种生长抑制敏感。 然而，有许多来自人类感染的菌株具有抵抗性， 营养免疫，并在人体血浆中迅速生长。 临床调查 正在进行中的研究被用来研究人类血浆中的生长是否可以 与铜绿假单胞菌菌株的毒力有关。 两 细菌获得铁的细胞外过程， 对抑制最敏感的是铁的铁载体螯合， 铁载体与细菌表面蛋白质结合 运输 这项研究将阐明 铜绿假单胞菌中铁的获得，特别是在那些 抗营养免疫，在人血浆中迅速生长。 两 在此比较期间，将检查铁代谢的各个方面： 运输过程中的铁载体活性和结合。 铜绿假单胞菌产生 两种铁载体绿脓菌螯铁蛋白和绿脓菌荧光素。 高压液相色谱（HPLC）和 将使用薄层（TLC）色谱技术分析 血浆中除铁载体形成外铁载体合成 和媒体 第二，电泳（SDS-PAGE）和层析在高 性能蛋白柱将用于分析铁载体， 细菌表面的铁转铁蛋白结合活性。 这些 技术正在被用来实现支持的长期目标， 通过抑制细菌感染， 增长 目前，我们正在寻找铁载体类似物， 血浆和小鼠中的细菌生长。

Pseudomonas aeruginosa causes serious infections in patients whose innate defense mechanisms are compromised. These patients are typically the burned, traumatized, immunosuppressed, and cancer patients. The first steps in bacterial infection are colonization and growth. Bacterial growth in tissue and plasma occurs in the presence of an effective innate defense mechanism, nutritional immunity. Nutritional immunity depends upon transferrin to withhold essential iron from bacteria and impede growth. Most strains of P. aeruginosa are sensitive to this growth inhibition. However, there are many strains from human infections which resist nutritional immunity and grow rapidly in human plasma. A clinical survey in progress is being used to investigate whether growth in human plasma can be related to the virulence of P. aeruginosa strains. The two extracellular processes in bacterial aqcuisition of iron which would be most sensitive to inhibition are siderophore chelation of iron and ferrisiderophore binding to proteins on the bacterial surface during iron transport. The research in this proposal will elucidate the mechanisms of iron acquisition in P. aeruginosa, particularly in those strains which are resistant to nutritional immunity and grow rapidly in human plasma. Two aspects of iron metabolism will be examined during this comparison: siderophore activity and binding during transport. P. aeruginosa produces two siderophores, pyochelin and pyoverdin. High pressure liquid (HPLC) and thinlayer (TLC) chromatographic techniques will be used to analyze siderophore synthesis in addition to ferrisiderophore formation in plasma and media. Secondly, electrophoresis (SDS-PAGE) and chromatography on high performance protein columns will be used to analyze ferrisiderophore and ferritransferrin binding activities on bacterial surfaces. These techniques are being used to attain the long-term goal of supporting nutritional immunity during infections of patients by inhibiting bacterial growth. Currently we are searching for siderophore analogues which inhibit bacterial growth in plasma and in mice.