INTRACELLULAR PH HOMEOSTASIS IN MALPIGHIAN TUBULES

马氏管细胞内 pH 稳态

基本信息

批准号：
2414892
负责人：
DAVID H. PETZEL
金额：
$ 5.47万
依托单位：
CREIGHTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1995
资助国家：
美国
起止时间：
1995-05-01 至 1999-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/2414892
关键词：
Aedes acid base balance cyclic AMP excretion fluorimetry hormone regulation /control mechanism intracellular invertebrate endocrinology laboratory mouse

项目摘要

Fluid transport in insects is dependent on hydrogen ions. Vacuolar-type H+-ATPase pumps energize insect epithelial membranes in a manner similar to that of the ubiquitous Na/K-ATPase pump. Insects secrete fluid from hemolymph through cells into the lumen of the Malpighian tubule. The energy derived from the H + -ATPase pump allows for secondary transport that leads to this transport of fluid. The secretion of fluid is the first step in generation of urine in insects and regulation of the composition of their extracellular fluid. Despite the crucial role played by the H+-ATPase in urine formation, no information to date is available as to the nature of intracellular regulation of hydrogen ions in Malpighian tubules. Questions which arise are: What is the source of the hydrogen ions for the H+-ATPase? How is the pH of the Malpighian tubule cell cytoplasm maintained? Which acid/base transporter is activated during diuresis? The goals of the proposed research are to 1) determine the primary mechanism(s) of intracellular hydrogen ion homeostasis m isolated Mosquito Malpighian tubules and 2) determine the influence of intracellular and extracellular messenger molecules including cyclic AMP and diuretic hormones on intracellular hydrogen ion homeostasis. Preliminary data indicate that mosquito Malpighian tubules regulate their intracellular pH through at least two acid extrusion mechanisms, and two acid loading mechanism. Additionally, intracellular hydrogen and bicarbonate generation are under the control of carbonic anhydrase. Finally, cyclic AMP increases acid extrusion after an acute acid load suggesting a link between acid extrusion and cAMP-mediated diuresis. The proposed experiments will measure fluid secretion and hydrogen ion secretion rates in isolated mosquito Malpighian tubules in order to establish dose response relationships between inhibition of specific acid-base transporters and fluid and hydrogen ion secretion rates in insects. Intracellular pH will be measured using micro-fluorometric techniques which allow for real time recording of changes in quantities of cellular hydrogen ions. We will characterize the effects of inhibition and stimulation of the acid extruding and acid loading mechanism with respect to steady-state intracellular pH, recovery rates after acute acid loading, acid or base flux rates and Km and Vmax of the transporters. The results from the proposed experiments will, for the first time, describe in detail the underlying mechanism(s) for fluid secretion in Malpighian tubules. This body of knowledge will lead to potential insight into physiological processes that enable mosquitoes to be effective in resisting pesticide intervention and efficient vectors of pathogens.

昆虫中的流体转运取决于氢离子。液泡型 H+-ATPase以类似的方式泵送昆虫上皮膜到无处不在的Na/k-ATPase泵。昆虫分泌液体通过细胞进入马尔皮亚小管的腔。这源自H + -ATPase泵的能量允许进行二次运输这导致了这种流体的运输。液体的分泌是昆虫中尿液产生的第一步和调节其细胞外液的组成。尽管起着至关重要的作用尿形成中的H+-ATPase，迄今为止没有任何信息可用至于氢离子细胞内调节的性质马尔皮亚小管。出现的问题是：什么是 H+-ATPase的氢离子？马尔皮亚小管的pH值如何维持细胞细胞质？激活哪种酸/碱基转运蛋白在利尿期间？拟议研究的目标是1）确定主要分离的细胞内氢离子稳态M的机理蚊子马皮亚小管，2）确定细胞内和细胞外信使分子，包括环状AMP 以及细胞内氢离子稳态上的利尿激素。初步数据表明蚊子马尔皮亚小管调节其细胞内pH通过至少两个酸挤出机制，两个酸负荷机制。另外，细胞内氢和碳酸氢盐的产生在碳酸酐酶的控制之下。最后，环状AMP在急性酸负荷后增加酸挤出提示酸挤出与cAMP介导的利尿之间有联系。提出的实验将测量流体分泌和氢离子孤立蚊子马尔皮亚小管中的分泌率是为了建立抑制特定的剂量反应关系酸碱转运蛋白，流体和氢离子分泌速率昆虫。细胞内pH将使用微荧光学测量允许实时记录数量变化的技术细胞氢离子。我们将表征抑制的影响并用尊重稳态的细胞内pH，急性酸后的恢复速率转运蛋白的加载，酸或碱磁通速率以及km和vmax。提议的实验的结果将首次详细描述流体分泌的基本机制马尔皮亚小管。这种知识将导致潜在的见识进入生理过程，使蚊子能够有效抵抗农药干预和病原体的有效向量。

项目成果

期刊论文数量（3）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Na(+)/H(+) exchange in mosquito Malpighian tubules.

蚊子马尔皮基小管中的 Na( )/H( ) 交换。

DOI：
10.1152/ajpregu.2000.279.6.r1996
发表时间：
2000
期刊：
American journal of physiology. Regulatory, integrative and comparative physiology
影响因子：
0
作者：
Petzel,DH
通讯作者：
Petzel,DH

Characterization of a leucokinin binding protein in Aedes aegypti (Diptera: Culicidae) Malpighian tubule.

埃及伊蚊（双翅目：库蚊科）马氏小管中白细胞激肽结合蛋白的表征。