An Insect Model of Molecular Host-Parasite Relationships

本研究旨在探讨寄生物在寄主体内成功发育的机制。人们经常问这样一个问题：“谁在控制这种关系——寄生虫还是它们的宿主？”在贝克奇博士的实验中，烟草角虫（Manduca sexta）的幼虫与寄生蜂Cotesia congregata一起被用作寄生虫感染的模型。黄蜂将一种病毒连同它的卵一起注射到寄主的幼虫中，并将研究这种病毒在促进成功寄生方面的作用。病毒诱导宿主合成一种新的蛋白质，在存在和不存在这种蛋白质的情况下，将使用血细胞测定法来测试这种蛋白质在抑制宿主免疫反应中的作用，以评估它是否抑制宿主血细胞对外来生物的包封。另一个目标是鉴定编码该蛋白氨基酸序列的基因，并研究其在新寄生幼虫中的调控作用。各种各样的寄生虫都有与之相关的病毒，包括原生动物和变形虫，但在大多数情况下，它们的作用尚未确定。这些病毒可作为节肢动物和寄生虫的遗传转化机制，从而为新的遗传研究和害虫物种和医学上重要的寄生虫的操纵铺平道路。

The purpose of this investigation is to explore the mechanisms whereby parasites achieve successful development in their host. The question is often asked: "Who is in control of this relationship - the parasites or their host?" In Dr. Beckage experiments, larvae of the tobacco hornworm, Manduca sexta, are used as a model of parasitic infection in conjunction with the wasp parasitoid Cotesia congregata. The wasp injects a virus into host larvae along with its eggs, and the role of the virus in facilitating successful parasitism will be examined. The virus induces a new protein to be synthesized by the host, and the role of the protein in suppressing the immune response of the host will be tested using hemocyte assays in the presence and the absence of the protein to assess whether it inhibits encapsulation of foreign organisms by the host's blood cells. Another goal will be to identify the gene encoding the amino acid sequence of the protein and study its regulation in newly parasitized larvae. A variety of parasites have viruses associated with them, including protozoa and amoebae, yet their role has yet to be identified in most cases. The viruses may be developed as mechanisms of genetic transformation of arthropods and parasites, thus paving the way of novel genetic studies and manipulation of pest species and medically important parasites.