IRON UPTAKE AS A VIRULENCE FACTOR IN PATHOGENIC VIBRIOS

这项研究的长期目标是调查遗传学和 一种与毒力相关的性质--质粒铁的分子生物学 摄取，在许多侵袭性疾病的发病机制中起着重要作用 人和家畜的败血症。我们目前使用的是 一种引起末端死亡的鱼类病原菌鳗弧菌的模式系统 出血性败血症。质粒型毒力的特点 行列式使其成为研究宿主细菌的一个非常有吸引力的模型 互动。我们使用了转座诱变、分子克隆和 DNA测序以确定至少四个pJM1组分 质粒介导的铁摄取系统：一个铁载体；一个受体 铁载体复合体，即86kd的外膜蛋白OM2； 调控反式作用因子和RSV1重复序列侧翼 PJM1质粒中的铁摄取区。每一个人扮演的特定角色 这四种成分在铁摄取过程的调节中发挥作用，并 鳗弧菌的毒力将通过建议的 调查。实现这些目标的具体目标是：1. 鳗弧菌铁载体的分离与结构测定。 2.克隆的pJM1铁摄取区的互补分析。3. 克隆的OM2蛋白基因的鉴定。4.克隆和 反式作用调节因子的特征，增强 铁载体活性的产生。5.对犯罪性质的调查 铁载体产量的增加和A V的高吸铁能力。 鳗属分离株及其与One串联复制的关系 在pJM1铁摄取区两侧的两个重复序列中。 重复序列被鉴定为类似IS1的元件，位于铁吸收的侧翼 在人类中发现的另一个与毒力相关的质粒pCo1V-K30的区域 大肠杆菌的侵袭性链条。体内的铁摄取基因 重复序列两侧的区域似乎非常保守 PCo1V-K30和pJM1质粒，以及在其他质粒和 染色体。它们之间的重复序列的存在 毒力决定因素可能对它们的重组做出了贡献 机动性。因此，这个项目不仅将阐明铁的作用 摄取在侵袭性细菌性疾病的发病机制中也会 有助于理解这些毒力产生的机制 这些因素已经在自然界中以流行病的形式传播。

The long term objective of this research is to investigate the genetics and molecular biology of a virulence-associated property, plasmid-mediated iron uptake, which plays an important role in the pathogenesis of many invasive septicemic diseases of man and domestic animals. We are presently using as a model system the fish pathogen Vibrio anguillarum which causes a terminal hemorrhagic septicemia. The features of the plasmid-mediated virulence determinant makes it a very attactive model to study host bacterial interacions. We have used transposition mutagenesis, molecular cloning and DNA sequencing to define at least four components of the pJM1 plasmid-mediated iron uptake system: a siderophore; a receptor for iron-siderophore complexes which is the 86 kd outer membrane protein OM2; a regulatory trans-acting factor and RSV1 repeated sequences that flank the iron uptake region in the pJM1 plasmid. The specific roles that each of these four components play in the regulation of the iron uptake process and virulence in V. anguillarum will be elucidated by the proposed investigation. The specific aims to achieve these objectives are: 1. Isolation and structure determination of the V. anguillarum siderophore. 2. Complementation analysis of cloned pJM1 iron uptake regions. 3. Characterization of the cloned OM2 protein gene. 4. Cloning and characterization of the trans-acting regulatory factor that enhances the production of siderophore activity. 5. Investigation of the nature of the increased siderophore production and high iron uptake proficiency of a V. anguillarum isolate and its relationship to the tandem duplication of one of the two repeated sequences flanking the pJM1 iron uptake region. Repeated sequences identified as IS1-like elements, flank the iron uptake region of another virulence associated plasmid, pCo1V-K30, found in human invasive strins of Escherichia coli. The iron uptake genes within the region flanked by the repeated sequences appeared to be very conserved in both the pCo1V-K30 and the pJM1 plasmids, as well as in other plasmids and chromosomes. The existence of the repeated sequences bracketing these virulence determinants may have contributed to their recombinational mobility. Thus, this project will not only elucidate the role of iron uptake in the pathogenesis of invasive bacterial disease, but will also contribute to the understanding of the mechanisms by which these virulence factors have spread epidemiologically in nature.