RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan; CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
Exp Eye Res. 2013 Nov;116:395-401. doi: 10.1016/j.exer.2013.09.016. Epub 2013 Oct 3.
Intact eyes of frog and mouse were studied by X-ray diffraction. Light-induced changes in the reflections from the rod outer segments (ROS) were recorded at a time resolution of 0.1 and 1 s in frog and mouse, respectively. Lamellar diffraction from disk membranes was observed to the 10th order. In frog, the intensities of seven reflections were found to change significantly on 7-s intense illumination and the lamellar spacing, which was 30.4 nm in darkness, decreased by 0.5%. Time courses of changes in the intensity and the lamellar spacing were similar, saturating at about 7 s. Most of the intensity changes could be attributable to the spacing change. Thus, the effect of light on the electron density distribution was smaller than previously reported. The decrease in the lamellar spacing is attributed to changes in the intracellular ionic concentrations due to the blockage of the dark current. This may be a useful index to study the ionic movements in the cell. Mouse ROS's had a lamellar spacing larger than frog (32.4 nm). The structural changes after illumination were similar to those in frog ROS. This X-ray diffraction technique may be utilized to study functions of photoreceptor cells in transgenic mice and other animals.
蛙和鼠的完整眼睛被 X 射线衍射研究。在蛙和鼠中，分别以 0.1 和 1 秒的时间分辨率记录光诱导的杆状外段（ROS）反射变化。观察到盘膜的层状衍射可达第 10 级。在蛙中，发现七个反射的强度在 7 秒强光照下显著变化，并且在黑暗中为 30.4nm 的层间距减小了 0.5%。强度和层间距的变化过程相似，在约 7 秒时饱和。大多数强度变化可归因于间距变化。因此，光对电子密度分布的影响小于先前报道的。层间距的减小归因于暗电流阻断导致细胞内离子浓度的变化。这可能是研究细胞中离子运动的有用指标。鼠 ROS 的层间距大于蛙（32.4nm）。光照后的结构变化与蛙 ROS 相似。这种 X 射线衍射技术可用于研究转基因鼠和其他动物中光感受器细胞的功能。
