Ion transport and motility in larval mosquito stomach

描述(申请人提供)：幼虫最突出的器官是胃，它构成了胃肠道的主要部分。这个器官对离子、体积和酸/碱的动态平衡非常重要。前胃活跃地分泌碱当量，产生极高的PH值，这对消化很重要，但也对生物控制剂，如苏云金芽孢杆菌内毒素的敏感性。在胃的后部，通过恢复碱当量，pH几乎恢复到中性。最有可能的是，这个循环涉及酸/碱当量以及钠和氯离子的高周转。对蚊子幼虫胃内离子转运的过程、它们的调节以及它们与蠕动的协调还知之甚少。该项目旨在了解两种蚊子的这些过程：黄热病蚊子(埃及伊蚊)和撒哈拉以南非洲冈比亚按蚊的疟疾蚊子。具体地说，我们将确定：1。参与前胃碱化的离子转运机制。2.胃后酸化的离子转运机制。3.调节前胃和后胃离子转运的机制。4.前胃和后胃离子转运与蠕动的协调机制。这些研究将主要使用五种不同的方法进行：1.使用传统的跨上皮技术和微电极对跨离体胃节段离子传输及其调节的电生理学表征2。使用pH指示器和/或灌流液中的pH敏感微电极分析离体胃节段的管腔pH变化。受累转运蛋白和调节单位/系统的组织化学和免疫组织化学定位转运蛋白活性的生化测定及其激素/非激素因素的调节。用电生理技术和图像分析技术分析蠕动及其调节。该项目的结果将提供有关蚊子控制剂开发的具体目标的信息。

DESCRIPTION (provided by applicant): The most prominent organ of larval mosquitoes is the stomach, which makes up the major part of the gastrointestinal tract. This organ is of prominent importance for ionic, volume and acid/base homeostasis. The anterior stomach actively secretes alkali equivalents, generating a compartment of extremely high pH which is of importance for digestion, but also for the susceptibility to biological control agents such as Bacillus thuringienis endotoxin. In the posterior stomach the pH returns to almost neutral values by recovery of alkali equivalents. Most likely, this cycle involves a high turnover of acid/base equivalents as well as of sodium and chloride ions. The processes of ion transport, their regulation and their coordination with peristalsis in the stomach of larval mosquitoes are poorly understood. The project is directed at understanding these processes in two mosquito species: the yellow fever mosquito (Aedes aegypti) and the malaria mosquito of subsaharan Africa Anopheles gambiae. Specifically we will determine: 1. the ion transport mechanisms involved in alkalization of the anterior stomach. 2. the ion transport mechanisms involved in reacidification of the posterior stomach. 3. the mechanisms of regulation of ion transport in the anterior and posterior stomach. 4. the mechanisms of coordination of ion transport with peristalsis in the anterior and posterior stomach. The studies will be carried out, using mainly five different methodological approaches: 1.) Electrophysiological characterization of ion transport across isolated stomach segments and its regulation, using conventional transepithelial techniques and microelectrodes 2.) Analyses of luminal pH changes with isolated stomach segments, using pH indicators and/or pH sensitive microelectrodes in the perfusate 3.) Histochemical and immunhistochemical localization of involved transporters and regulative units/systems 4.) Biochemical determination of transporter activities and their regulation by hormonal/non-hormonal factors 5.) Analyses of peristalsis and its regulation with electrophysiological techniques and image analyses. The results of this project will provide information about specific targets for the development of mosquito control agents.