Low viscosity in the aqueous domain of cell cytoplasm measured by picosecond polarization microfluorimetry.
Low viscosity in the aqueous domain of cell cytoplasm measured by picosecond polarization microfluorimetry.
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DOI：
10.1083/jcb.112.4.719
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发表时间：
1991-02
期刊：
影响因子：
--
通讯作者：
Verkman AS
中科院分区：
文献类型：
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作者：
Fushimi K;Verkman AS
通过分析引入细胞的小极性分子的旋转运动，可以提供关于含水细胞质的流变学特性的信息。为了确定完整细胞中的流体相细胞质粘度，构建偏振显微镜用于测量细胞质中荧光探针的皮秒各向异性衰减。我们发现，旋转相关时间（tc）的探针，2，7-双-（2-羧乙基）-5-（和-6-）羧基荧光素（BCECF），6-羧基荧光素，和8-羟基芘-1，3，6-三磺酸（HPTS）提供了一个直接测量的流体相细胞质粘度是独立的探针结合。在静止的Swiss 3 T3成纤维细胞中，tc值比在水中长20-40%，表明液相细胞质的粘度仅为水的1.2- 1.4倍。液相细胞质粘度的活化能为4kcal/mol，与水的活化能相近。当加入蔗糖以减小细胞体积、细胞松弛素B以破坏细胞骨架和加压素以激活磷脂酶C时，液相细胞质粘度的变化小于10%。核质和外周细胞质粘度无差异。我们的研究结果建立了一种新的方法来测量流体相细胞质粘度，并表明成纤维细胞的流体相细胞质粘度是类似的自由水。
Information about the rheological characteristics of the aqueous cytoplasm can be provided by analysis of the rotational motion of small polar molecules introduced into the cell. To determine fluid-phase cytoplasmic viscosity in intact cells, a polarization microscope was constructed for measurement of picosecond anisotropy decay of fluorescent probes in the cell cytoplasm. We found that the rotational correlation time (tc) of the probes, 2,7-bis-(2-carboxyethyl)-5-(and-6- )carboxyfluorescein (BCECF), 6-carboxyfluorescein, and 8-hydroxypyrene- 1,3,6-trisulfonic acid (HPTS) provided a direct measure of fluid-phase cytoplasmic viscosity that was independent of probe binding. In quiescent Swiss 3T3 fibroblasts, tc values were 20-40% longer than those in water, indicating that the fluid-phase cytoplasm is only 1.2- 1.4 times as viscous as water. The activation energy of fluid-phase cytoplasmic viscosity was 4 kcal/mol, which is similar to that of water. Fluid-phase cytoplasmic viscosity was altered by less than 10% upon addition of sucrose to decrease cell volume, cytochalasin B to disrupt cell cytoskeleton, and vasopressin to activate phospholipase C. Nucleoplasmic and peripheral cytoplasmic viscosities were not different. Our results establish a novel method to measure fluid-phase cytoplasmic viscosity, and indicate that fluid-phase cytoplasmic viscosity in fibroblasts is similar to that of free water.