Ramasamy M S, Kulasekera R, Wanniarachchi I C, Srikrishnaraj K A, Ramasamy R
Division of Life Sciences, Institute of Fundamental Studies, Kandy, Sri Lanka.
Med Vet Entomol. 1997 Jul;11(3):290-6. doi: 10.1111/j.1365-2915.1997.tb00409.x.
Present understanding of the development of sexual stages of the human malaria parasites Plasmodium vivax and P.falciparum in the Anopheles vector is reviewed, with particular reference to the role of the mosquito midgut in establishing an infection. The sexual stages of the parasite, the gametocytes, are formed in human erythrocytes. The changes in temperature and pH encountered by the gametocyte induce gametogenesis in the lumen of the midgut. Macromolecules derived from mosquito tissue and second messenger pathways regulate events leading to fertilization. In An.tessellatus the movement of the ookinete from the lumen to the midgut epithelium is linked to the release of trypsin in the midgut and the peritrophic matrix is not a firm barrier to this movement. The passage of the P.vivax ookinete through the peritrophic matrix may take place before the latter is fully formed. The late ookinete development in P.falciparum requires chitinase to facilitate penetration of the peritrophic matrix. Recognition sites for the ookinetes are present on the midgut epithelial cells. N-acetyl glucosamine residues in the oligosaccharide side chains of An.tessellatus midgut glycoproteins and peritrophic matrix proteoglycan may function as recognition sites for P.vivax and P.falciparum ookinetes. It is possible that ookinetes penetrating epithelial cells produce stress in the vector. Mosquito molecules may be involved in oocyst development in the basal lamina, and encapsulation of the parasite occurs in vectors that are refractory to the parasite. Detailed knowledge of vector-parasite interactions, particularly in the midgut and the identification of critical mosquito molecules offers prospects for manipulating the vector for the control of malaria.
本文综述了目前对间日疟原虫和恶性疟原虫在按蚊媒介中进行有性生殖阶段发育的理解，特别提及了蚊子中肠在感染确立过程中的作用。疟原虫的有性阶段，即配子体，在人体红细胞中形成。配子体所经历的温度和pH变化会在中肠腔内诱导配子生殖。源自蚊子组织的大分子和第二信使途径调节着导致受精的一系列事件。在鳞斑按蚊中，动合子从肠腔向中肠上皮的移动与中肠中胰蛋白酶的释放有关，而围食膜并非这一移动的坚实屏障。间日疟原虫动合子穿过围食膜的过程可能在围食膜完全形成之前就已发生。恶性疟原虫动合子的后期发育需要几丁质酶来促进其穿透围食膜。中肠上皮细胞上存在动合子的识别位点。鳞斑按蚊中肠糖蛋白和围食膜蛋白聚糖的寡糖侧链中的N - 乙酰葡糖胺残基可能作为间日疟原虫和恶性疟原虫动合子的识别位点。穿透上皮细胞的动合子可能会给媒介带来压力。蚊子分子可能参与基膜中卵囊的发育，并且在对该寄生虫具有抗性的媒介中会发生对寄生虫的包囊化。对媒介 - 寄生虫相互作用的详细了解，特别是在中肠方面以及对关键蚊子分子的鉴定，为通过操控媒介来控制疟疾提供了前景。
