Jahan N, Hurd H
Department of Biological Sciences, Keele University, Staffordshire, UK.
J Med Entomol. 1998 Nov;35(6):956-61. doi: 10.1093/jmedent/35.6.956.
Our previous studies demonstrated a significant reduction in the egg production and survival of Anopeles stephensi Liston infected with Plasmodium yoelii nigeriensis Killick-Kendrick. We investigated the physiological mechanism underlying the malaria-induced curtailment of reproductive fitness. Polyclonal antibodies were raised against An. stephensi vitellin (Vn) and used in an enzyme immunoassay to quantify ovarian Vn and hemolymph vitellogenin (Vg) at 8, 12, 16, 20, 24, and 48 h postblood feeding in infected and noninfected mosquitoes. Initially, the concentration of Vg in the hemolymph and the accumulation of Vn in the ovaries of infected females were identical to females fed on noninfected mice, indicating that the synthesis of yolk protein by the fat bodies was initiated normally. However, there was a significant reduction in ovarian Vn at 24 and 48 h postblood feeding and a significant accumulation of Vg at 20 and 24 h postblood feeding in the hemolymph of infected mosquitoes. This increase in concentration of Vg in the hemolymph just before Vn reduction in the ovaries of infected mosquitoes indicated that synthesis at the fat body level may not be affected, but that sequestration of Vg by ovarian follicles of malaria-infected mosquitoes may be affected before resorbing follicles lose protein.
我们之前的研究表明，感染约氏疟原虫尼日尔株（Killick-Kendrick）的斯氏按蚊（Anopeles stephensi Liston）的产卵量和存活率显著降低。我们研究了疟疾导致生殖适应性下降的生理机制。制备了针对斯氏按蚊卵黄磷蛋白（Vn）的多克隆抗体，并用于酶免疫测定，以量化感染和未感染蚊子在吸血后8、12、16、20、24和48小时卵巢中的Vn和血淋巴中的卵黄原蛋白（Vg）。最初，感染雌蚊血淋巴中Vg的浓度以及卵巢中Vn的积累与吸食未感染小鼠血液的雌蚊相同，这表明脂肪体中卵黄蛋白的合成正常启动。然而，在吸血后24和48小时，感染蚊子卵巢中的Vn显著减少，而在吸血后20和24小时，感染蚊子血淋巴中的Vg显著积累。在感染蚊子卵巢中Vn减少之前，血淋巴中Vg浓度的这种增加表明，脂肪体水平的合成可能未受影响，但疟疾感染蚊子的卵巢卵泡对Vg的隔离可能在吸收卵泡失去蛋白质之前就受到了影响。
