Satre M, Klein G, Martin J B
Biochimie. 1986 Dec;68(12):1253-61. doi: 10.1016/s0300-9084(86)80077-3.
Phosphorus metabolites and intracellular pH have been examined in the slime mold Dictyostelium discoideum by non-destructive 31P-NMR measurements. In a spectrum from a suspension of aerobic amoebae, the major peaks are inorganic phosphate, nucleotide di- and triphosphates. In the corresponding perchloric acid extract, resonances originating from purine and pyrimidine nucleotides are resolved. Adenine nucleotides are the most abundant components, but the other nucleotides are present in significant amounts. In a spectrum from intact spores in a dormant state, only inorganic phosphate and polyphosphates are detected and nucleotides are no longer present in large amounts. Of particular importance is the ability to observe separately in aerobic amoebae the resonance of inorganic phosphate localized in two different cell compartments: the cytosol and the mitochondria. The cytosolic pH and mitochondrial pH have been measured as 6.7 and 7.7, respectively, on the basis of intracellular inorganic phosphate chemical shifts. They are essentially unaffected over a large range of external pH and they are not modified transiently or permanently during the initiation of the developmental program of the organism. A weak acid, such as propionate, which modifies the progression of differentiation by favoring prestalk cells, perturbs intracellular pH gradients by selectively decreasing mitochondrial pH without any effect on cytosolic pH.
通过非破坏性的³¹P-NMR测量，对黏菌盘基网柄菌中的磷代谢物和细胞内pH进行了检测。在需氧变形虫悬浮液的光谱中，主要峰为无机磷酸盐、核苷酸二磷酸和三磷酸。在相应的高氯酸提取物中，可分辨出来自嘌呤和嘧啶核苷酸的共振峰。腺嘌呤核苷酸是最丰富的成分，但其他核苷酸也大量存在。在处于休眠状态的完整孢子的光谱中，仅检测到无机磷酸盐和多聚磷酸盐，核苷酸不再大量存在。特别重要的是能够在需氧变形虫中分别观察到位于两个不同细胞区室（胞质溶胶和线粒体）中的无机磷酸盐的共振。根据细胞内无机磷酸盐的化学位移，测得胞质溶胶pH和线粒体pH分别为6.7和7.7。在很大范围的外部pH条件下，它们基本不受影响，并且在生物体发育程序启动过程中不会被短暂或永久改变。一种弱酸，如丙酸盐，通过促进前柄细胞来改变分化进程，它通过选择性降低线粒体pH而扰乱细胞内pH梯度，对胞质溶胶pH没有任何影响。
