A Model System for Host Pathogen Interaction: Drosophila and Its Parasitic Wasps

描述（由申请人提供）：尽管黑腹果蝇是先天免疫分子遗传学的模型系统，但对其天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，寄生蜂感染果蝇幼虫的频率超过50%，并且非常适合实验室和实地研究。Schlenke实验室已经收集了17种活的果蝇寄生蜂寄生虫菌株，并制定了可靠的方案，用于提取和操纵它们用来阻止宿主细胞对其卵的封装反应的毒液鸡尾酒。在这个应用中，Schlenke提出使用联合转录组学和蛋白质组学的方法来鉴定10种相关的黄蜂物种的毒液腺内容，这些黄蜂物种是黑腹瓢虫的高度成功的感染者。然后，他将使用两种类型的分析方法来分析每种黄蜂的整个毒液的影响：首先，他将分析毒液对体外黑腹大黄蜂血细胞结构和功能的影响。其次，他将通过向苍蝇体内注射油滴来检测体内的封装缺陷，这些油滴很容易被黑化封装，并与毒液混合。对于整个毒液具有的任何免疫抑制作用，Schlenke将识别毒液的部分和单个毒液蛋白质，负责这些特征的毒液作用。最后，Schlenke将使用群体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-黄蜂系统发展成为研究真核宿主-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.