SERINE PROTEASES AND IMMUNITY IN ANOPHELES GAMBIAE

疟疾是一种由疟原虫属寄生原生动物引起的疾病，由蚊子传播给人类。每年有数亿人感染这种生物体，造成2-3百万人死亡，其中大多数是幼儿。这个问题在非洲最为严重，而且由于寄生虫对过去用于预防和控制的廉价药物的抗药性日益增加，现在正在恶化。第二个重要的控制战略，即通过使用杀虫剂减少蚊子数量，也受到威胁，因为杀虫剂抗药性，成本增加和训练有素的人员流失。一个新的研究目标是蚊子和寄生虫之间的相互作用。这里提出的研究的长期目标是了解蚊子和疟原虫之间不相容的分子基础，因为这可能会建议通过遗传或化学操纵媒介蚊子来增强导致不相容的机制。拟议的研究将集中在表征参与蚊子体液免疫反应的蛋白质和基因，这可能导致寄生虫死亡。特别是，丝氨酸蛋白酶是产生两种寄生虫杀死机制，黑色素包囊和抗菌反应的重要酶。在非洲疟疾媒介冈比亚按蚊中，三种丝氨酸蛋白酶基因AgSp 14 D1、AgSp 14 D2和AgSp 14 A在细菌注射或感染疟疾寄生虫后显示转录水平的变化。这些分子将被表征和测试参与体外和体内抗寄生虫的免疫应答。此外，酚氧化酶原激活丝氨酸蛋白酶，这是重要的触发寄生虫黑化，将进行生化纯化，然后克隆和表征。最后，几个A。将在mRNA和蛋白质水平上表征表现出与参与免疫应答的其它酶相似的结构域结构的冈比亚丝氨酸蛋白酶。

Malaria, a disease caused by parasitic protozoans in the genus Plasmodium, is transmitted by mosquitoes to humans. Each year, hundreds of millions of people are infected with this organism and 2-3 million fatalities result, mostly in young children. The problem is most severe in Africa, and is now worsening because of the increasing resistance of parasites to the inexpensive drugs used for prevention and control in the past. A second important strategy for control, reducing mosquito populations through insecticide use, is also threatened because of insecticide resistance, increasing costs and loss of trained personnel. A new target for research has been the interaction between the mosquito and the parasite. The long-term goal of the research presented here is to understand the molecular basis for incompatibility between mosquitoes and malaria parasites because this may suggest ways to enhance mechanisms that cause incompatibility through genetic or chemical manipulation of vector mosquitoes. The proposed research will focus on characterizing proteins and genes that are involved in the mosquito's humoral immune responses, which can lead to the death of parasites. In particular, serine proteases are important enzymes in generation of two parasite-killing mechanisms, melanotic encapsulation and the antimicrobial response. In the African malaria vector, Anopheles gambiae, three serine protease genes, AgSp14D1, AgSp14D2, and AgSp14A, show changes in transcript levels after bacterial injections or infection with malaria parasites. These molecules will be characterized and tested for involvement in immune responses against parasites in vitro and in vivo. In addition, prophenoloxidase activating serine proteases, which are important in triggering parasite melanization, will be biochemically purified and then cloned and characterized. Finally, several A. gambiae serine proteases that exhibit domain structures similar to other enzymes involved in immune responses will be characterized at the mRNA and protein levels.