Carwardine S L, Hurd H
Department of Biological Sciences, Keele University, Staffordshire, U.K.
Med Vet Entomol. 1997 Jul;11(3):265-9. doi: 10.1111/j.1365-2915.1997.tb00405.x.
It has been shown previously that infection with Plasmodium yoelii nigeriensis reduces the number of eggs produced by female Anopheles stephensi. Here we examine the mechanism underlying fecundity reduction. Ovaries from infected and uninfected (control) female mosquitoes were examined 12, 24 or 36 h after blood-feeding during the first gonotrophic cycle (replicated) or the second gonotrophic cycle (unreplicated). Follicular development was assessed according to Christophers' stages and the proportions of developing and resorbing follicles per ovary were determined. Resorption of some follicles commenced within 12 h of blood-feeding, affecting significantly more follicles in the infected females: 1.1% v. 3.2%. The difference was greatest 36 h after blood-feeding: 25% reduction (10 v. 35%) in the first cycle; 16% reduction (9 v. 25%) in the second gonotrophic cycle. The mean speed of oogenesis was also found to be significantly retarded in infected mosquitoes. During the second gonotrophic cycle, for example, only 92-94% of follicles reached stage III by 24 h and stage IV by 36 h in infected females, whereas all the developing follicles of uninfected females reached these stages more or less synchronously in the time specified.
先前的研究表明，感染约氏疟原虫尼日尔株会减少斯氏按蚊雌蚊的产卵量。在此，我们研究了产卵量减少背后的机制。在第一个生殖营养周期（重复）或第二个生殖营养周期（未重复）的吸血后12、24或36小时，检查感染和未感染（对照）雌蚊的卵巢。根据克里斯托弗斯阶段评估卵泡发育，并确定每个卵巢中发育中和吸收中的卵泡比例。一些卵泡在吸血后12小时内开始吸收，感染雌蚊中受影响的卵泡明显更多：1.1%对3.2%。吸血后36小时差异最大：第一个周期减少25%（10个对35个）；第二个生殖营养周期减少16%（9个对25个）。还发现感染蚊子的卵子发生平均速度明显减慢。例如，在第二个生殖营养周期中，感染雌蚊中只有92 - 94%的卵泡在24小时时达到III期，在36小时时达到IV期，而未感染雌蚊的所有发育卵泡在规定时间内或多或少同步达到这些阶段。
