Physiology and Molecular Biology of Insect Parasitism

寄生虫经常导致其宿主表现出发育和生化异常，从而干扰生物体的正常生长和繁殖。有些影响似乎是由与寄生虫有关的因素，如细菌或病毒，以及寄生虫本身和它们进食和消耗宿主营养物质所带来的压力所介导的。贝克奇博士利用烟草角虫和一种小黄蜂寄生虫作为模型系统，证明了寄生虫将一种病毒注射到宿主体内，刺激了只在被寄生虫寄生的幼虫中才有的新蛋白质的生物合成。这项资助的目的是表征所涉及的蛋白质并研究它们的调控，以确定编码它们合成的基因是否是宿主、寄生虫或病毒基因组的组成部分，并阐明它们的诱导模式。产生蛋白质的组织将被识别，蛋白质的生理作用将被研究，以获得对宿主生理如何被调节以促进成功寄生的发育动力学的新见解。这种寄生蜂，Cotesia congregata，作为几种害虫的生物控制，许多密切相关的物种在农业和森林生态系统中同样重要。因此，本研究获得的信息可能对设计控制各种害虫的新策略具有重要意义，并且可以作为一个有价值的寄生虫学模型，增强我们对宿主-寄生虫界面的宿主生理调节机制的理解。例如，生物技术可用于在未寄生状态下表达正常寄生特异性基因，从而在繁殖之前导致发育停滞。

Parasites frequently cause their host to show developmental and biochemical abnormalities which disturb the normal growth and reproduction of the organism. Some effects appear to be mediated by factors associated with the parasites such as bacteria or viruses, in addition to the parasites themselves and the stress invoed by their feeding and consumption of host nutrients. Using the tobacco hornworm and a braconid wasp parasite as a model system, Dr. Beckage has shown that a virus injected by the parasite into the host stimulates biosynthesis of novel proteins found only in parasitgized larvae. The goal of this grant will be to characterize the proteins involved and study their regulation to determine if the genes encoding for their synthesis are components of the host, parasite, or viral genome (s) and clarify the mode of their induction. The tissues producing the proteins will be identified and the physiological role of the proteins will be studied to gain fresh insights into the developmental dynamics of how the physiology of the host is modulated to facilitate successful parasitism. This parasitic wasp, Cotesia congregata, serves as"a biological control of several insect pests, and many closely related species are similarly important in agricultural and forest ecosystems. Thus the information gained from this study may have important implications for design of novel strategies to control a variety of insect pests in addition to serving as a valuable parasitological model which will enhance our understanding of the mechanisms involved in regulation of host physiology at txe host-parasite interface. Biotechnology could be used to express normally parasitism-specific genes in the unparasitized state, for example, causing developmental arrest prior to reproduction.