PHYSIOLOGY OF INSECT POTASSIUM ION TRANSPORT

中肠模型解释了管腔、细胞和血液的恒定性 (K)就泵泄漏稳定状态而言。K从高脚杯中移开 球状细胞顶端的细胞通向管腔和生电K泵 膜(GCAM)使管腔呈碱性。K会泄漏回来， 沿着它的电化学梯度，通过氨基进入柱状细胞 酸性钾在柱状细胞顶膜(CCAM)表达。K 柱状细胞和杯状细胞之间通过侧向连接扩散 并通过K通道从血液进入细胞。一起类似的K泵泄漏 稳定状态驱动昆虫唾液腺和 马氏管，在昆虫感官中开发受体潜力 在哺乳动物的听力过程中，可能潜水K流。我们的 目标是描述这种昆虫细胞K的动态平衡和 利用它的破坏作用进行环境安全的昆虫控制。 在前一段时间里，我们已经溶解并表征了 GCAM的K-ATPase活性及鉴定的亚基蛋白。我们 已证明Ba2阻断CCAM中K通道的作用 苏云金杆菌库尔斯塔基变种(BTK)毒素并逆转 醉酒的过程。我们的第一个目标是纯化K-ATPase 并显示它位于portasome中，在那里它是一个键 K泵的组件。利用生物化学和分子 生物学上，我们将对编码ATPase的基因进行测序 推导出该酶的一级结构。vbl.使用 免疫组织化学我们将研究K的分布 中肠和其他钾转运上皮细胞中的门静脉小体。我们的 第二个目标是研究中肠K的动态平衡。我们会 使用短路电流、放射性标记离子通量。和水泡 测定比阳离子渗透率的传输技术 CCAM的活性状态和被BTK中毒时的情况 内毒素。中肠K动态平衡在科学上很重要，因为 昆虫胃肠和感官功能的模型。 BTK等药物对中肠钾稳态的破坏作用 在CCAM中选择性地形成离子通道提供了基础 对环境安全的虫害防治。

The midgut model explains the constancy of lumen, cell and blood (K+) in terms of a pump-leak steady state. K+ moves from goblet cells to lumen via and electrogenic K+ pump in globet cell apical membrane (GCAM) rendering the lumen alkaline. K+ leaks back, down its electrochemical gradient, into columnar cells via amino acid-K+ symports in columnar cell apical membrane (CCAM). K+ diffuses between columnar and goblet cells via lateral junctions and from blood to cells via K+ channels. A similar K+ pump-leak steady state drives secretion by insect salivary glands and Malpighian tubules, develops receptor potentials in insect sensory epithelia, and may dive K+ flow during mammalian hearing. Our goal is to characterize this insect cellular K+ homeostasis and to exploit its disruption for environmentally safe insect control. During the prior period we have solubilized and characterized the K+ ATPase activity of GCAM and identified subunit proteins. We have shown that Ba2+ blocks the K+ channels induced in CCAM by Bacillus thuringiensis var kurstaki (Btk) toxin and reverses the intoxication process. Our first aim is to purify the K+ ATPase and to show that it is localized in portasomes where it is a key component of the K+ pump. Using biochemistry and molecular biology we will sequence the gene coding for the ATPase and deduce the primary structure of the enzyme. Using immunohistochemistry we will study the distribution of K+ portasomes in midgut and other K+ transporting epithelia. Our second aim is to characterize the midgut K+ homeostasis. We will use the short circuit current, radiolabelled ion fluxes. and vesicle transport techniques to determine specific cation permeabilities of CCAM in its active state and when it is intoxicated with Btk endotoxin. Midgut K+ homeostasis is important scientifically as a model for insect gastrointestinal, and sensory function. Disruption of midgut K+ homeostasis by Btk and other agents which selectively form ion channels in CCAM provides the basis for enviromentally safe insect control.