Peschek G A, Czerny T, Schmetterer G, Nitschmann W H
Biophysical Chemistry Group, Institute of Physical Chemistry, University of Vienna, Währingerstrasse 42, A-1090 Vienna, Austria.
Plant Physiol. 1985 Sep;79(1):278-84. doi: 10.1104/pp.79.1.278.
The transmembrane proton electrochemical potential gradient Deltamu(H+) in whole cells of Anacystis nidulans was measured in aerobic and anaerobic dark conditions using the distribution, between external medium and cell interior, of radioactively labeled weak acids (acetylsalicyclic acid, 5,5-dimethyloxazolidine-2,4-dione) or bases (imidazole, methylamine), and permeant ions (tetraphenylphosphonium cation, thiocyanate anion), as determined by flow dialysis. Alternatively, the movements across the plasma membrane of DeltapH-indicating atebrin or 9-aminoacridine, and of DeltaPsi-indicating 8-anilino-l-naphthalenesulfonate were qualitatively followed by fluorescence measurements. Attempts were made to discriminate between the individual chemiosmotic gradients across the cytoplasmic (plasmalemma) and the intracytoplasmic (thylakoid) membranes. By use of the ionophores nigericin, monensin, and valinomycin, the components of the proton motive force, namely the proton concentration gradient DeltapH and the electric membrane potential DeltaPsi were shown to be mutually exchangeable within the range of external pH values tested (3.2-11.0). Both components were depressed by the uncoupler carbonylcyanide m-chlorophenylhydrazone, though inhibition of DeltapH was much more pronounced than that of DeltaPsi, notably in the alkaline pH(0) range. The total proton electrochemical gradient across the plasma membrane was significantly higher in aerobic than in anaerobic cells and increased markedly (i.e. became more negative) towards lower pH(0) values. This increase was paralleled by a similar increase in the rate of endogenous respiration of the cells. At the same time the ATPase inhibitor dicyclohexylcarbodiimide only slightly affected the proton motive force across the plasma membrane of aerobic cells. The results will be discussed in terms of a respiratorily competent plasma membrane in Anacystis nidulans.
在需氧和厌氧黑暗条件下，使用放射性标记的弱酸（乙酰水杨酸、5,5-二甲基恶唑烷-2,4-二酮）或碱（咪唑、甲胺）以及渗透性离子（四苯基鏻阳离子、硫氰酸根阴离子）在外部介质和细胞内部之间的分布，通过流动透析测定了集胞藻（Anacystis nidulans）全细胞中的跨膜质子电化学势梯度Δμ(H+)。另外，通过荧光测量定性跟踪了指示ΔpH的阿的平或9-氨基吖啶以及指示ΔΨ的8-苯胺基-1-萘磺酸盐跨质膜的移动。尝试区分跨细胞质（质膜）和胞质内（类囊体）膜的各个化学渗透梯度。通过使用离子载体尼日利亚菌素、莫能菌素和缬氨霉素，质子动力的组成部分，即质子浓度梯度ΔpH和膜电位ΔΨ，在测试的外部pH值范围（3.2 - 11.0）内显示是可以相互交换的。两种成分都被解偶联剂羰基氰化物间氯苯腙抑制，尽管对ΔpH的抑制比对ΔΨ的抑制更明显，特别是在碱性pH(0)范围内。需氧细胞中跨质膜的总质子电化学梯度明显高于厌氧细胞，并且随着pH(0)值降低而显著增加（即变得更负）。这种增加与细胞内源性呼吸速率的类似增加平行。同时，ATP酶抑制剂二环己基碳二亚胺仅轻微影响需氧细胞跨质膜的质子动力。将根据集胞藻中有呼吸活性的质膜来讨论这些结果。
