Tools to investigate transepithelial ammonia transports

在我的NSERC资助的研究项目中，对氨的上皮性运输机制进行了研究，氨是蛋白质代谢产生的一种剧毒代谢废物，重点是两栖动物和无脊椎动物，包括浮游动物、昆虫、甲壳类、环节动物和线虫。要彻底研究运输过程，必须采取综合办法。所需的工具是一个高度通用的6通道电压-电流钳位/Ussing腔系统。该系统可以测定特定运输上皮的电生理特性，包括组织产生的跨上皮电压差、产生的电流和离子渗透性(电导)，但也可以同时用于特定离子和溶质的跨上皮流量测量。Ussing小室本身允许使用各种不同孔径(约1cm2到1mm2)的不同组织支架。因此，它适合于不同大小的上皮细胞的研究，以便例如蝴蝶幼虫的肠道或青蛙皮肤的肠道可以安装和研究。由于该系统已经有几套定制的纸巾托架，因此在此应用中，需要用于安装蛙皮(0.9 cm2)和裂开蟹鳃薄片(1 Mm2)的托架。所要求的设备填补了我使用活体动物进行的研究和分子水平上的研究之间的空白，允许检查运输上皮中的运输动力学、电学性质和运输机制以及它们的调节，使用的是“接近体内”的设置。与所需设备相同的型号是我研究的基本要素，并参与了由7总部执行的几个当前项目。然而，目前到位的仪器是从德国研究基金会(DFG)借来的，必须立即归还给德国。因此，所要求的系统是必要的，以确保我的研究计划的继续，确保我作为国家和国际研究人员的竞争力，并允许我的学生及时完成他们正在进行的项目。

In my NSERC funded research program the mechanisms responsible for the epithelial transport of ammonia, a highly toxic metabolic waste product from protein metabolism, is investigated with the focus on amphibians and invertebrates including planarians, insects, crustaceans, annelids and nematodes. For a thorough study of transport processes an integrative approach is imperative. The requested tool is a highly versatile 6-channel Voltage-Current Clamp/Ussing chamber system. This system allows the determination of the electrophysiological properties of a given transport epithelium including the tissue-generated transepithelial voltage difference, the produced electrical current and the ion permeability (conductance) but can simultaneously also be used for transepithelial flux measurements of specific ions and solutes. The Ussing chamber itself allows the usage of a wide variety of different tissue holders with different apertures (ca. 1 cm2 to 1 mm2). It is therefore suitable for the investigation of epithelia of different sizes, so that e.g. the intestine of butterfly larvae or frog skin can be mounted and investigated. Since several sets of custom-made tissue holders are already at hand for this system, in this application, holders for mounting frog skin (0.9 cm2) and split crab gill lamella (1 mm2) are requested. The requested equipment fills the gap between my studies using the living animal and investigations on the molecular level by allowing the examination of transport kinetics, electric properties, and transport mechanisms and their regulation in the transporting epithelium employing a "near in-vivo" set-up. The same model as the requested equipment is an essential element in my research and involved in several current projects which are conducted by 7 HQP. However, the apparatus in place right now is on loan from the German Research Foundation (DFG) and must be returned to Germany immediately. Therefore the requested system is necessary to ensure the continuation of my research program, my competitiveness as a researcher on a national and international level and also to allow my students to finish their ongoing projects in a timely manner.