SIDEROPHORES AND VIRULENCE OF PSEUDOMONAS AERUGINOSA

这项研究的目的是了解假单胞菌是如何 铜绿假单胞菌获得细胞外铁以支持生长 人类感染。我们的长期目标是利用这种理解 向生长抑制或杀菌的方向发展 化合物。要成为成功的病原体，铜绿假单胞菌必须 从无法获得的哺乳动物铁储备、血清中动员铁 转铁蛋白和分泌型乳铁蛋白 可用于细菌新陈代谢。这种细菌依赖于 三种胞外产物可以动员无效的铁。 绿青素是一种还原剂，可以催化脱除 铁(II)来自转铁蛋白。碧萝卜素和吡喃甲素(铁载体) 是以可利用的形式提供铁的铁结合化合物吗？ 到高亲和力的运输系统。Pyoverdin似乎是 最有效的铁载体。这样做的第一个具体目标是 提案将遵循铁和焦油的命运 在运输过程中使用放射性标记研究并比较这些 转运机制与铁蛋白的转运机制相同。这个 所有三种胞外产物的协同活动将是 在运输化验期间进行了调查。高压液体 层析(高效液相色谱)和电泳法将用于 结合运输化验确定参与情况 细菌表面和铁中的蛋白水解酶 转铁蛋白动员。生物合成吡咯烷酮将 通过对分离的色素进行氨基酸分析进行研究 通过等电聚焦和高效液相色谱法，并通过标记形式 含有放射性氨基酸的吡咯烷素。突变株产生 铁载体多肽部分的缩略片段 将被喂食放射性标记的氨基酸及其产品将被 分析得出了多肽形成的顺序观点。 颜料合成的完成将通过以下方式进行研究 将(14C)莽草酸盐掺入喹啉衍生物和 最后转化为二羟基喹啉的吡咯烷酮。核磁共振和质量 光谱学将被用来分析可能的变化 吡喃的二羟基喹啉部分。此信息和 这些化合物将在我们的研究中用于类似物 铁载体和抑制细菌铁的前体 收购。

The goal is this research is to understand how Pseudomonas aeruginosa obtains extracellular iron to support growth during human infections. Our long-term goal is to use this understanding toward the construction of growth-inhibiting or bactericidal compounds. To be a successful pathogen, P. aeruginosa must mobilize iron from unavailable mammalian iron reserves, serum transferrin and secretory lactoferrin into forms which are available to bacterial metabolism. This bacterium depends upon three extracellular products to mobilize unavailable iron. Pyocyanin is a reducing agent which can catalyze the removal of Fe(II) from transferrin. Pyochelin and pyoverdin (siderophores) are iron binding compounds which supply iron in utilizable forms to high affinity transport systems. Pyoverdin appears to be the most effective siderophore. The first specific aim of this proposal will be to follow the fates of both iron and pyoverdin during transport using radiolabelling studies and to compare these transport mechanisms with those used for ferripyochelin. The concerted activities of all three extracellular products will be investigated during transport assays. High pressure liquid chromatography (HPLC) and electrophoresis will be used in conjunction with transport assays to determine the participation of the bacterial surface and of proteolytic enzymes in iron mobilization from transferrin. The biosynthesis of pyoverdin will be investigated by both amino acid analysis of pigments isolated by isoelectric focusing and HPLC, and by labelling the forms of pyoverdin with radioactive amino acids. Mutants which produce abbreviated segments of the peptide portion of the siderophore will be fed radiolabelled amino acids and their products will be analyzed to yield a sequential perspective of peptide formation. Completion of pigment synthesis will be studied by following the incorporation of (14C)shikimate into the quinoline derivatives and finally into the dihydroxyquinoline of pyoverdin. NMR and mass spectroscopy will be employed to analyze possible alteration in the dihydroxyquinoline moiety of pyoverdin. This information and these compounds will be used in our research for analogues of siderophores and precursors which inhibit bacterial iron acquisition.