Ion, water and ammonia regulation in aquatic insects

*这项研究计划调查淡水(FW)水生昆虫幼虫基本的生理过程调节其内部离子和水位的机制，并使它们能够有效地排泄代谢废物氨。在这方面，我的研究的长期目标是显着提高水和离子调节以及FW水生昆虫幼虫排氨的机制知识。这些机制是在环境污染物、盐和氨的背景下利用蚊子和蚂蚁的幼虫进行研究的。埃及伊蚊在世界热带和亚热带地区传播登革热、基孔肯雅热和寨卡等虫媒病毒疾病。在FW中，幼虫面临体液稀释，因为它们在血淋巴(血液)中保持相对较高的离子(盐)水平，导致梯度分别有利于离子损失和从栖息地获得水分。然而，最近在被海水污染的栖息地和氨含量较高的化粪池中发现了这些蚊子。这些栖息地与旱季疾病的流行有关，因为旱季传统的FW栖息地稀少。这项研究涉及在受盐和氨污染的水中饲养埃及伊蚊幼虫，并检查和比较特定蛋白质的存在和功能，这些蛋白质参与通过参与调节体液成分的上皮组织细胞运输水、离子和氨。我们还研究了调节上皮组织中细胞间隙的渗透性的蛋白质。硬纹夜蛾的若虫(幼虫)阶段生活在浅水FW湖泊(例如伊利湖)底部的沉积物中，在那里它是食物网的重要组成部分，也是生态系统健康的重要指标。最近的一项研究跟踪了北美300多个FW湖泊的盐分水平，并注意到这些湖泊的盐分水平持续上升，并预测其中许多湖泊的盐分水平将在未来50年内达到7 mmoL L-1。被认为适合饮用和维持生态系统的FW通常含有约0.7mmoL L-1的盐。这对水生生物构成了威胁，硬纹夜蛾是研究这些影响的极佳模式生物。这项研究涉及将硬纹夜蛾若虫暴露在被盐污染的FW中，并对蚊子幼虫进行与上述类似的评估。*这项研究解决了重要的现实社会问题。这项研究提供了关于使埃及伊蚊能够开发新的栖息地(受盐和氨污染的水)的基本生理学信息，以及FW的盐碱化将如何影响水生FW动物。这有可能为蚊子控制计划提供信息，并将为保护内陆FW来源的政策制定者提供信息。**

*** This research program investigates the mechanisms that underly fundamental physiological processes that freshwater (FW) aquatic insect larvae possess to regulate their internal ion and water levels, and that allow them to efficiently excrete the metabolic waste, ammonia. In this respect the long-term goal of my research is to significantly advance mechanistic knowledge of water and ion regulation as well as ammonia excretion in FW aquatic insect larvae. These mechanisms are studied in the context of the environmental contaminants, salt and ammonia, utilizing larvae of mosquitoes and mayflies.****** The mosquito Aedes aegypti spreads arboviral diseases like dengue, chikungunya and zika in tropical and sub-tropical regions of the world. In FW the larvae face dilution of body fluids because they maintain relatively high levels of ions (salt) in their hemolymph (blood) causing a gradient that favours ion loss and water gain to and from their habitat, respectively. However, recently these mosquitoes have been found in habitats contaminated with seawater and in septic tanks which are high in ammonia. These habitats are implicated in the prevalence of disease during dry seasons when traditional FW habitats are scarce. The research involves raising A. aegypti larvae in salt and ammonia contaminated water and examining and comparing the presence and function of specific proteins that are involved in transporting water, ions and ammonia through cells of epithelial tissues that are involved in regulating body fluid composition. We also examine proteins that regulate the permeability of the space between the cells in epithelial tissues.****** The nymph (larvae) stage of the mayfly Hexagenia rigida lives in sediment at the bottom of shallow FW lakes (e.g. Lake Erie) where it is an important part of the food web and an important indicator of ecosystem health. A recent study tracked salt levels of over 300 FW lakes in North America and noted sustained increases in salt levels in these lakes and predicted that levels would reach a concentration of 7 mmol l-1 within the next 50 years in many of these lakes. FW deemed suitable for drinking and for sustaining the ecosystem typically contains around 0.7 mmol l-1 of salt. This poses a threat to aquatic life and H. rigida nymphs are an excellent model organism to study these effects. This research involves exposing nymphs of H. rigida to FW contaminated with salt and performing assessments similar to that described above for the mosquito larvae.*** *** This research addresses important real-life societal problems. The research provides essential information about the underlying physiology that allow the disease vector A. aegypti to exploit new habitats (salt and ammonia contaminated water), and how salination of FW will affect aquatic FW animals. This has the potential to inform mosquito control programs and will inform policy makers contributing to the protection of inland sources of FW. **