Movie 2.
Transport and acidification of a Cy3/CypHer5-labeled virus in a Chinese hamster ovary (CHO) cell. The fluorescence is false-colored with Cy3 emission in the green channel and CypHer5 emission in the red. The fluorescence image of the virus is overlaid on a static differential interference contrast (DIC) image of the cell. Acidification of the virus is therefore visible as a yellowing or reddening of the fluorescence signal. For clarity, the fluorescence signal has been dimmed outside of a small region surrounding one virus. Time trajectories of transport velocity and pH for this virus are shown in Fig. 4. The three-stage transport behavior is again apparent in this movie. The acidification occurs immediately after the rapid movement towards the perinuclear region. The length of the movie is 450 s. quicktime 6.0 or higher is required.