Video shows a single cell from a human cancer cell line which is fluorescently labeled on the growing tips of its microtubules, revealing where these microtubules are being built up. At the beginning of the video, before the cell is treated, you can see that microtubules are very dynamic structures, rapidly shooting around the cell like comets, in complex and constantly changing patterns.
A photostatin compound is then added to the cell. Over the rest of the video, the scientists apply alternating pulses of blue and green light to the cell using a microscope; this switches the photostatin on and off, which then stops and restarts the dynamics of microtubules (the comets pause, then resume, then pause, then resume). The photostatin acts as a precise and powerful interface connecting the researcher in the lab, with the tiny but critical internal structures that cells and tissues rely on for their function and survival.