Comparative rickettsial protein profiles during tick infection

描述(申请人提供)：立克次体是落基山斑点热(RMSF)的病原体，落基山斑点热是美国最严重的传染病之一。为了更好地了解立克次体传播给脊椎动物宿主的分子机制，我们将对壁虱载体内的立克次体进行表征。我们的长期目标是利用不同致病力的立克次体之间的差异，并阐明立克次体在硬蜱中的致病机制，以开发控制硬质立克次体疾病的新方法。为了实现这一目标，我们建议使用比较蛋白质组学来评估硬体和硬体传播的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，还将表征斑点热群立克次体通过个体硬虱和整个个体硬体组织传播的速度。在这些目标下的实验将确定：1)从内共生菌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的抗原。研究将通过双向凝胶电泳法评估变色革螨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进行鉴定；候选蛋白将通过质谱学进行鉴定。比较分析将包括与人类疾病无关的立克次体蛋白质组(蒙丹立克次体和贝氏立克次体)。通过鉴定在节肢动物中定义立克次体毒力的分子，立克次体生物学的新方面将被阐明，并随后被用于控制病原体。立克次体是由立克次体斑疹伤寒群和斑点热群成员引起的疾病。致病性立克次体通常通过节肢动物(昆虫和壁虱)传播给人类。为了更好地了解立克次体毒力的机制，该项目试图检查斑点热群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.