Lawaczeck R
Institute of Physical Chemistry, University of Würzburg, F.R.G.
Biochim Biophys Acta. 1988 Dec 8;946(1):165-72. doi: 10.1016/0005-2736(88)90469-5.
The isotopic water exchange across the membrane of a single-cell alga is made visible by optical differences of H2O and 2H2O. In the near infrared (NIR) (1000 to 2500 nm) H2O shows pronounced absorption bands while 2H2O is almost transparent. Results from in vivo experiments on the diffusive water permeation across the membrane of the spherical freshwater alga Eremosphaera viridis are presented. The evaluation of the isotope-exchange kinetics allows the calculation of the permeability coefficient, Pd, and the approximation of the intracellular diffusion constant, D. The extension of H2O/2H2O-exchange measurements to two dimensions opens new ways to study transport pathways up to the spatial resolution of a microscope. First NIR video images demonstrate the capability of the method.
单细胞藻类细胞膜上的同位素水交换通过H₂O和²H₂O的光学差异得以显现。在近红外（NIR）（1000至2500纳米）区域，H₂O呈现出明显的吸收带，而²H₂O几乎是透明的。本文展示了对球形淡水绿藻绿裸藻细胞膜上扩散性水渗透进行的体内实验结果。对同位素交换动力学的评估使得能够计算渗透系数Pd，并估算细胞内扩散常数D。将H₂O/²H₂O交换测量扩展到二维为研究直至显微镜空间分辨率的运输途径开辟了新途径。首批近红外视频图像展示了该方法的能力。
