Although we have aspired to observe dynamic changes in fluorescent images at the cellular level for a long time, the commercially available video cameras are not at all suitable for this purpose because of their low frame rates and photosensitivity. The present work tackles this issue and describes our attempt to find a solution by using our high-speed video camera and an ultrabright illumination system. We used light sources with considerably higher energy because conventional mercury lamps cannot produce sufficient brightness for our video cameras working a rate of more than 4,500 fps to obtain fluorescent images of cells. We observed that the flagellar movement of mice sperms ceased and multiple kinks developed in their tails when exposed to 2.7W of laser illumination for 1 s. In contrast, no significant alterations could be detected when the sperms were subjected to the same amount of energy by intermittent illumination. Since we found that cells can survive short-duration exposure to high-energy light, we attempted to construct an ultrabright Xenon-strobe illumination system. Our fluorescence studies are currently being extended to other types of animal cells, e.g., observation of the conduction of action potentials in the peripheral nerves of frog.
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