Comparative rickettsial protein profiles during tick infection

描述（由申请人提供）：立克次体立克次体是美国最严重的传染病之一落基山斑疹热的病原体。为了更好地了解立克次体传播到脊椎动物宿主的分子机制，我们将在蜱媒介中描述立克次体的特征。我们的长期目标是利用不同致病性的立克次体之间的差异，阐明蜱中立克次体的发病机制，以开发控制蜱传立克次体疾病的新方法。为了达到这个目的，我们建议使用比较蛋白质组学来评估蜱和蜱传立克次体之间的分子相互作用。这些研究的目的除了确定与传播事件有关的立克次体衍生分子外，还将确定斑点热组立克次体通过单个蜱虫和整个单个蜱虫组织传播的速率。在这些目标下的实验将确定：1)从内共生体到病原体的物种差异，2)不同组织中立克次体蛋白表达谱的差异，以及3)脊椎动物宿主识别的保守和独特抗原。研究将通过二维凝胶电泳评估变异性革螨蜱唾液腺和卵巢中的立克次体蛋白质组。此外，抗原蛋白将通过免疫印迹分析鉴定；候选蛋白将通过质谱法鉴定。比较分析将包括与人类疾病无关的立克次体的蛋白质组学（山立克次体和贝利氏体）。通过鉴定确定立克次体在节肢动物中毒力的分子，立克次体生物学的新方面将被阐明，并随后用于病原体的控制。立克次体病是由立克次体斑疹伤寒组和斑点热组成员引起的疾病。致病性立克次体通常通过节肢动物（昆虫和蜱虫）传播给人类。为了更好地了解立克次体毒力的机制，该项目旨在研究斑点热组立克次体和媒介蜱之间的相互作用。

DESCRIPTION (provided by applicant): Rickettsia rickettsii is the causative agent of Rocky Mountain spotted fever (RMSF), one of the most severe infectious diseases in the United States. To better understand the molecular mechanisms by which rickettsiae undergo transmission to vertebrate hosts, we will characterize rickettsiae inside the tick vector. Our long term goal is to exploit the differences between rickettsiae of varying pathogenicity and elucidate the mechanisms of rickettsial pathogenesis in ticks in order to develop novel approaches to control tick-borne rickettsial diseases. Towards this objective, we propose to use comparative proteomics to assess the molecular interactions between ticks and tick-borne rickettsiae. Aims of these studies will characterize the rate at which spotted fever group Rickettsia spread through individual ticks and throughout individual tick tissues, in addition to identifing Rickettsia-derived molecules that are involved in transmission events. Experiments under these aims will identify: 1) differences in species ranging from endosymbionts to pathogens, 2) differences in rickettsial protein expression profiles in various tissues, and 3) conserved and unique antigens recognized by the vertebrate host. Studies will assess proteomes of Rickettsia rickettsii in the salivary glands and ovaries of Dermacentor variabilis ticks by two-dimensional gel electrophoresis. Additionally, antigenic proteins will be identified by immunoblot analysis; candidate proteins will be identified by mass spectrometry. Comparative analysis will include proteomes of rickettsiae not associated with human disease (R. montanensis and R. bellii). By identifying molecules which define the virulence of rickettsiae in arthropods, novel aspects of rickettsial biology will be elucidated and subsequently exploited for control of the pathogen. Rickettsioses are diseases caused by members of the typhus group and spotted fever group of Rickettsia. Pathogenic Rickettsia are typically transmitted to humans by arthropods (insects and ticks). To better understand the mechanisms of rickettsial virulence, this project seeks to examine the interplay between spotted fever group Rickettsia and the vector tick.