PARASITIC CASTRATION IN SNAILS--ROLE OF BIOGENIC AMINES

描述：（改编自申请人摘要）：寄生性 吸虫幼虫对蜗牛的阉割，表现为 性腺的组织病理学变化和/或产卵减少， 代表了一个最引人注目的例子， 改变宿主的内部环境以利于它们自身的生长 和繁殖。 然而，这种现象的分子基础是 仍然未知。 初步调查结果显示曼氏血吸虫 光滑双脐螺的感染导致 产卵和并发在几个寄主生物源水平 中枢神经系统和/或血浆中的胺，包括左旋多巴、多巴胺，和 血清素 由于这些生物胺调节其他动物的生殖活动， 软体动物，这项研究建议解决的假设，寄生 幼虫体的阉割作用部分是由于寄生虫的调节 蜗牛宿主的生物胺水平或负责它们的酶 合成. 使用分析方法的组合来量化 体内蜗牛组织中的生物胺水平和酶活性 抑制实验和测定生物胺与 寄主生殖器官和幼虫S. mansoni调查员会 解决四个具体目标：1）确定干扰的影响 感染对中枢神经系统（CNS）中生物胺水平的影响， 蜗牛的性腺、白蛋白腺和无细胞血淋巴（血浆） 主机，B。glabrata，2）以确定幼虫感染对关键 参与CNS中生物胺合成途径的酶，3）评估 体内和体外单胺处理对生殖的影响 感染和未感染蜗牛的活动，以及4）评估 吸收和代谢，或抑制活性 的宿主生物胺。 了解生物胺在蜗牛中的作用 以及寄生虫如何干扰它们的活动可能导致 涉及基于代谢破坏的生物防治的新方法， 媒介蜗牛的产卵量。

DESCRIPTION: (Adapted from the Applicant's Abstract): Parasitic castration of snails by larval trematodes, which manifests itself as histopathological changes in the gonads and/or lowered oviposition, represents one of the most dramatic examples of how parasites are capable of modifying the host's internal environment to favor their own growth and reproduction. However, the molecular basis for this phenomenon is still unknown. Preliminary findings show that Schistosoma mansoni infection of the snail Biomphalaria glabrata leads to a depression in oviposition and concurrently in the levels of several host biogenic amines in the CNS and/or plasma, including L-dopa, dopamine, and serotonin. Since these bioamines regulate reproductive activity in other molluscs, this research proposal addresses the hypothesis that parasitic castration by larval schistosomes is due in part to parasite modulation of snail host bioamine levels or enzymes responsible for their synthesis. Using a combination of analytical methods to quantify bioamine levels and enzyme activities in snail tissues, in vivo inhibition experiments, and assays measuring bioamine interaction with host reproductive organs and larval S. mansoni, the investigator will address four specific aims: 1) to determine the effects of schistosome infection on bioamine levels in the central nervous system (CNS), gonads, albumin gland, and cell-free hemolymph (plasma) of the snail host, B. glabrata, 2) to determine the impact of larval infection on key enzymes involved in bioamine synthetic pathways in the CNS, 3) to assess effects of in vivo and in vitro monoamine manipulations on reproductive activity of infected and noninfected snails, and 4) to assess the ability of larval schistosomes to take up and metabolize, or inhibit activity of, host bioamines. Understanding the role of bioamines in snail reproduction and how parasites interfere with their activity may lead to novel methods of biological control based on metabolic disruption of egg production in the vector snail.