Ion, water and ammonia regulation in aquatic insects

本研究计划探讨淡水（FW）水生昆虫幼虫调节其内部离子和水水平的基本生理过程的机制，并使它们能够有效地排出代谢废物氨。在这方面，我的研究的长期目标是显著推进水和离子调节以及FW水生昆虫幼虫氨排泄的机制知识。利用蚊子和蜉蝣的幼虫，在环境污染物、盐和氨的背景下研究了这些机制。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性疾病。在FW中，幼虫面临体液的稀释，因为它们的血淋巴（血液）中保持相对高水平的离子（盐），造成一种梯度，分别有利于离子的损失和水分的获得。然而，最近在受海水污染的生境和氨含量高的化粪池中发现了这些蚊子。在干旱季节，传统的FW栖息地稀缺时，这些栖息地与疾病的流行有关。这项研究包括在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空间通透性的蛋白质。刚性五月蝇（hexenia rigida）的若虫（幼虫）期生活在浅水湖泊（如伊利湖）底部的沉积物中，是食物网的重要组成部分，也是生态系统健康的重要指标。最近的一项研究追踪了北美300多个FW湖泊的盐含量，并注意到这些湖泊的盐含量持续增加，并预测在未来50年内，这些湖泊的盐含量将达到7毫摩尔-1。被认为适合饮用和维持生态系统的FW通常含有约0.7 mmol -1的盐。这对水生生物构成了威胁，刚性水蛭若虫是研究这些影响的一个很好的模式生物。本研究涉及将刚性僵虫若虫暴露于受盐污染的FW中，并对蚊子幼虫进行类似于上述的评估。这项研究解决了现实生活中重要的社会问题。该研究提供了有关疾病媒介埃及伊蚊开发新栖息地（盐和氨污染的水）的潜在生理学以及FW的盐化如何影响水生FW动物的基本信息。这有可能为蚊子控制项目提供信息，并将为政策制定者提供信息，以保护FW的内陆来源。

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.