Chestnut M H, Siegel D P, Burns J L, Talmon Y
Procter and Gamble Company, Cincinnati, OH 45239-8707.
Microsc Res Tech. 1992 Jan 1;20(1):95-101. doi: 10.1002/jemt.1070200110.
We describe a temperature-jump device that permits time-resolved studies of thin cryo-transmission electron microscopy specimens. The specimen is rapidly heated to induce a change in microstructure just prior to cryo-fixation. The apparatus consists of a xenon arc lamp equipped with a shutter controlled by timing circuitry, used in conjunction with an environmental specimen preparation chamber. The specimen is heated by exposure to focused light from the lamp, and then plunged into cryogen. Using a thermocouple constructed from an electron microscope grid, we show that temperature jumps of 30-60 K are achieved with exposure times of 150-450 milliseconds. Micrographs of dimyristoyl phosphatidylcholine (DMPC) vesicles and n-docosane films, subjected to these exposures, show that the specimens are still at least 20-30 K above their initial temperature when they contact the cryogen. This method could be applied to a variety of biological and chemical systems which undergo structural changes activated by a rise in temperature.
我们描述了一种温度跃升装置，该装置可用于对低温透射电子显微镜薄样品进行时间分辨研究。在进行冷冻固定之前，将样品快速加热以诱导微观结构的变化。该装置由配备有由定时电路控制的快门的氙弧灯组成，与环境样品制备室配合使用。样品通过暴露于来自灯的聚焦光而被加热，然后投入冷冻剂中。使用由电子显微镜网格构建的热电偶，我们表明在150 - 450毫秒的曝光时间内可实现30 - 60 K的温度跃升。经过这些曝光处理的二肉豆蔻酰磷脂酰胆碱（DMPC）囊泡和正二十二烷薄膜的显微照片显示，当样品接触冷冻剂时，其温度仍比初始温度至少高20 - 30 K。这种方法可应用于各种因温度升高而发生结构变化的生物和化学系统。
