淡色库蚊糖餐定位信息及其作用机理研究

How to deter transmission of mosquito vector diseases has become a front research area in the prevention and control of infectious diseases. To date, most of studies are mainly concentrated on the biology and molecular biology of behaviors of blood-feeding and oviposition of mosquitoes. Sugar feeding as the main energy source for mosquitoes is a critical step in their life cycle, but the information involving in the sugar-feeding behavior of mosquitoes and relevant action mechanism are still limited. The house mosquito Culexs pipiens pallens Coquillett distributing in northern area of China is an important vector of epidemic encephalitis "B" and Bancroft's filariasis. In this project, we take the methods on the botany, behavior biology, analytical chemistry, physiology, biochemistry, and molecular biology, to explore the volatile compound components from plants that involve in the sugar source orientation for C. pipiens pallens, to make clear the structures and functions of key odorant-binding proteins and their receptors responsible for sugar-feeding behavior in C. pipiens pallens, to find out the action mechanism of sugar-feeding orientation information in this mosquito. The results from this project could not only provide theoretical basement for the establishment of new mosquito control strategy, but also offer technical support for the development of new soundly environmentally products for the control of vector-diseases in mosquitoes. Obviously, this project is significantly important for the theory and application in mosquito management, as well as a prospective for mosquito control industry.

如何阻止蚊媒疾病传播是传染病预防和控制研究的前沿领域之一，目前该方面研究主要集中在成蚊血餐和产卵行为的生物学及分子生物学研究上，对维持成蚊生命活动的糖餐及其行为调控机制则很少涉及。淡色库蚊Culex pipiens pallens Coquillett俗称"家蚊"，是我国北方流行性乙型脑炎和班氏丝虫病的重要传播媒介。本项目拟以淡色库蚊为对象，利用植物学、行为生物学、分析化学、生理生化和分子生物学方法，阐明参与糖餐定位的挥发性气味物质组成成分，探明参与糖餐定位行为的关键气味结合蛋白及其受体，解析它们的结构、功能与调控机制，进而系统地揭示淡色库蚊糖餐定位过程中所涉及的信息及其作用机制。本项目研究成果不仅可为蚊虫控制新策略的制定提供理论基础，而且也能为高效、环境友好的蚊媒疾病防控措施的开发提供技术支持。显然，本项研究具有重要的理论意义和现实意义及较大的经济应用前景。

糖餐对成蚊维持生命活动具有十分重要的作用。淡色库蚊是重要的病媒生物，但其对糖餐植物的偏好性及其如何定位糖餐植物迄今不清楚。为了阐明这一科学问题，在过去的四年里我们做了大量的室内外研究工作。结果表明，花的颜色和形状对淡色库蚊成蚊觅糖行为无明显影响。室内测试显示，夹竹桃、糯米条、小叶女贞的花和构树果实与哈密瓜对成蚊具较强引诱力，且对雌蚊的引诱效果强于雄蚊。幼虫期食物丰富度会显著影响成蚊的体型和能量储备，成蚊对糖的趋性与幼虫期食物丰富度呈正相关。进一步研究结果表明，取食偏好糖餐植物的淡色库蚊，其寿命显著延长，产卵量显著提高。利用Y型嗅觉仪测定了淡色库蚊雌蚊对18种开花植物挥发物的行为反应，结果(E)-β-罗勒烯、苯甲醛、己醇、苯乙醇、(Z)-3-己烯-1-醇和芳樟醇等15种化合物及其全组分与简化组分混合物对淡色库蚊均具明显的引诱效果。利用GC-MS对糖餐植物糯米条挥发物所做的测定结果表明，挥发组分包含苯甲醛、α-蒎烯、苯乙醛、苯甲醇、苯乙醇等。糯米条浸提物及相关组分混合物对淡色库蚊雌蚊均具有引诱性。采用分子生物学手段从淡色库蚊成蚊触角中克隆出了10个编码气味结合蛋白的基因和1个编码嗅觉辅助受体的基因，前者主要在触角表达，后者则在触角及雌蚊头部均有表达。室内条件下测定了不同糖诱剂对淡色库蚊成蚊的引诱效果，结果表明构树果实、甜瓜、哈密瓜、水蜜桃和梨等5种果汁糖诱剂均具有良好的引诱效果。室外试验结果表明，淡色库蚊对果汁糖诱剂表现出明显的趋性，且蚊类种群密度随糖诱剂使用时间的延长而呈现下降趋势。对甜瓜、哈密瓜果汁及其糖诱剂的挥发性气味进行收集、分析后发现，与原味果汁相比，发酵后的糖诱剂的挥发物种类及相对含量均发生了一定的变化。淡色库蚊雌蚊对14种果汁及其糖诱剂挥发物具有明显的趋性，且糖诱剂挥发物的引诱效果显著高于果汁挥发物的。上述成果为淡色库蚊防治新技术的开发提供了新的思路。