IRON UTILIZATION BY BACTEROIDES GINGIVALIS

厌氧口腔细菌牙龈类杆菌已被牵连 作为成人牙周炎的主要病原体。营养需求是最重要的 牙龈假单胞菌在牙龈定位中的生态学意义 缝隙地带。牙龈假单胞菌生长需要氯化血红素，但实际上并非如此。 知道其他铁化合物是否能满足这一营养需求。 这项研究旨在确定铁的获取和机制 利用，并评估它们在牙龈假单胞菌致病中的作用。 拟议项目的目标是确定铁的要求。 牙龈假单胞菌的体外生长及其与体内生长的关系。 铁源将包括与转铁蛋白、乳铁蛋白、白蛋白、 结合珠蛋白和血凝素，这是体内常见的来源。其作用机制 参与铁获取的人将通过1)确定B. 牙周炎可以利用其他生物产生的铁载体； 牙龈菌确实会产生自己的铁载体； 牙龈菌产生特定的蛋白质，这些蛋白质受铁的生长调节- 条件有限。将采取遗传方法来检查更多 通过构建牙龈假单胞菌菌株来接近对铁的需求 唯一不同的是利用氯化血红素生长的能力。Tn4351 转座诱变将被用于构建这些菌株。 将在我们的小鼠模型中使用等基因菌株来评估该病毒的毒力 这些菌株。我们将克隆相应的铁利用基因 使用特定的Tn4351-B。牙周炎突变株基因组DNA作为探针的研究 基因组文库。此外，牙龈假单胞菌生长在铁充足和 铁缺乏的介质将被评估其引起感染的能力 在小鼠皮下腔模型中。这些研究将允许 评价铁利用在芽孢杆菌致病性中的作用。 牙周炎。

The anaerobic oral bacterium, Bacteroides gingivalis, has been implicated as a major pathogen in adult periodontitis. Nutritional needs are of prime ecological importance in the localization of B. gingivalis to the gingival crevice area. B. gingivalis requires hemin for growth, however it is not known if other iron-compounds can fulfill this nutritional requirement. This study is designed to identify the mechanism of iron acquisition and utilization, and to assess their role in pathogenicity of B. gingivalis. The objectives of the proposed project are to define the iron requirements of B. gingivalis for growth in vitro and to relate these to growth in vivo. Iron sources will include iron bound to transferrin, lactoferrin, albumin, haptoglobin and hemopexin, sources commonly found in vivo. The mechanisms involved in iron acquisition will be examined by 1) determining if B. gingivalis can utilize siderophores produced by other organisms, 2) if B. gingivalis does indeed produce its own siderophores, and 3) if B. gingivalis produces specific proteins that are regulated by growth in iron- limited conditions. A genetic approach will be taken to examine more closely the requirement for iron, by constructing strains of B. gingivalis differing only in the ability to utilize hemin for growth. Tn4351 transpositional mutagenesis will be used to construct these strains. Isogenic strains will be used in our mouse model to assess the virulence of these strains. We will clone the corresponding genes for iron utilization using specific Tn4351-B. gingivalis mutant genomic DNA as probes in total genomic libraries. In addition, B. gingivalis grown in iron-sufficient and iron-deficient medium will be evaluated for its ability to cause infection in the mouse subcutaneous chamber model. These studies will allow for the evaluation of the role of iron utilization in the pathogenicity of B. gingivalis.