A Model System For Host-Pathogen Interactions: Drosophila And Its Parasitic Wasps

描述(申请人提供)：尽管黑腹果蝇是先天免疫分子遗传学的模型系统，但对其自然寄生虫的生活史和毒力策略几乎一无所知。在自然种群中，寄生黄蜂感染果蝇幼虫的频率超过50%，并且非常适合实验室和田间研究。Schlenke实验室已经开发出一系列17种活的果蝇黄蜂寄生虫菌株，以及提取和操作它们用来挫败安装在它们卵上的宿主细胞封装反应的毒液鸡尾酒的强大协议。在这项应用中，Schlenke建议使用联合转录和蛋白质组学方法来鉴定10种相关黄蜂物种的毒腺内容物，这些物种非常成功地感染了黑腹果蝇。然后，他将使用两种测试方法来测试每种黄蜂物种的整个毒液的效果：首先，他将在体外测试毒液对黑腹果蝇血细胞结构和功能的影响。其次，他将通过将油滴注射到果蝇体内来测试包裹缺陷，这些油滴很容易被黑色素包裹，与毒液部分混合。对于整个毒液具有的任何免疫抑制作用，施伦克将确定毒液部分和单个毒液蛋白，这些毒液蛋白对这些特有的毒液作用负责。最后，施伦克将使用种群遗传和分子进化方法来揭示毒液如何在与宿主免疫系统的共同进化军备竞赛中保持毒力功能。总之，Schlenke希望将果蝇-黄蜂系统发展为研究真核宿主-病原体相互作用和寄生虫生活史进化的模型。

DESCRIPTION (provided by applicant): Although Drosophila melanogaster is a model system for the molecular genetics of innate immunity, virtually nothing is known about the life history and virulence strategies of its natural parasites. Parasitic wasps can infect Drosophila larvae at frequencies greater than 50% in natural populations, and are highly amenable to laboratory and field study. The Schlenke lab has developed a collection of 17 live wasp parasite strains of Drosophila, and robust protocols for extracting and manipulating the venom cocktails they use to thwart the host cellular encapsulation response mounted against their eggs. In this application, Schlenke proposes to use a joint transcriptomic and proteomic approach to identify the venom gland contents of 10 related wasp species that are highly successful infectors of D. melanogaster. He will then assay the effects of whole venom from each wasp species using two types of assays: First, he will assay the effects of venom on the structure and function of D. melanogaster hemocytes ex vivo. Second, he will assay encapsulation defects in vivo by injecting oil droplets into flies, which are readily melanotically encapsulated, mixed with venom fractions. For any immune suppressive effects that whole venom has, Schlenke will then identify venom fractions and individual venom proteins responsible for these characterized venom effects. Finally, Schlenke will use population genetic and molecular evolution approaches to uncover how venoms maintain virulence function in their co-evolutionary arms race with host immune systems. In sum, Schlenke hopes to develop the Drosophila-wasp system as a model for the study of eukaryotic host-pathogen interactions and for the evolution of parasite life histories.