Suppr超能文献

证明浮萍 6746 表皮细胞质子的电生成外排。

Evidence for electrogenic proton extrusion by subepidermal cells of Lemna paucicostata 6746.

机构信息

Botanisches Institut der Universität für Bodenkultur, Gregor Mendel Straße 33, A-1180, Vienna, Austria.

出版信息

Planta. 1979 Jan;144(4):311-5. doi: 10.1007/BF00391573.

Abstract

The cell potential of Lemna paucicostata 6746 was measured between the vacuole and the external solution. The potential in the dark (-202 mV) could be depolarized with 0.1 mM dicyclohexyl carbodiimide (DCCD) or 1 mM arsenate to-81 mV. The hyperpolarization above the latter value is therefore attributed to an ATP-dependent process. The cell potential showed a significant dependence upon the pH of the external solution. The change in the potential induced by a jump in pH between two certain values, was reversible and independent of the mode of performing the pH change (stepwise or at once). The DCCD-or arsenate-depolarized potential did not respond to external pH changes. A 0.1 mM ammonium chloride solution depolarized the cell potential reversibly to-83 mV. This potential-change could be greatly reduced by simultaneous addition of 5 mM Na isobutyrate. The pH sensitivity of the cell potential is ascribed to changes in the rate of proton extrusion upon altering the proton gradient across the plasmalemma. The effects of ammonium and isobutyrate are interpreted as being the consequence of pH shifts at the inner face of the plasmalemma, caused by the permeation of the undissociated form of the weak acid or base. A critical discussion of an alternative interpretation for the ammonium effect is presented.

摘要

测定了浮萍 6746 细胞的液泡和外液间的点位。暗条件下的点位(-202 mV)可以被 0.1 mM 二环己基碳二亚胺(DCCD)或 1 mM 砷酸盐去极化至-81 mV。因此,超过后一数值的超极化归因于一个 ATP 依赖的过程。细胞点位对外液 pH 值有明显的依赖性。在两个特定 pH 值之间跳变引起的点位变化是可逆的,与执行 pH 值变化的方式(逐步或一次)无关。DCCD 或砷酸盐去极化的点位对外部 pH 值变化没有响应。0.1 mM 氯化铵溶液可逆地将细胞点位去极化至-83 mV。同时添加 5 mM Na 异丁酸盐可以大大降低这种电位变化。细胞点位的 pH 值敏感性归因于改变质膜质子梯度时质子外排率的变化。铵和异丁酸的作用被解释为质膜内表面 pH 值的变化,这是由于弱酸或弱碱基的未离解形式的渗透引起的。对铵效应的另一种解释提出了批判性讨论。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验