File:Trypanosome-Motion-Represents-an-Adaptation-to-the-Crowded-Environment-of-the-Vertebrate-Bloodstream-ppat.1003023.s006.ogv

English: High-speed transmitted light videos of persistently swimming trypanosomes. The original recordings at 200, 500 or 1000 fps are shown in real time or slowed down 5x–50x. The elapsed time in milliseconds is shown in the upper left corner. (A) Trypanosome motion on a glass slide in medium with blood viscosity. After 1300 milliseconds, this trypanosome transiently slows down. Following some beat reversals the cell continues to move with similar speed but a different swimming direction. (B) The swimming behavior of trypanosomes in wide microchannels is not fundamentally different from the conditions on glass slides. The planar beat of the free end of the flagellum becomes especially evident in cells that swim along the optical z-axis and thus appear from the depth of the channel. (C) At low viscosity the swimming efficiency of trypanosomes is reduced. This results in decreased average velocity. Compare the 20-times slowed video with the comparable one in (B) to see the direct effect that increased viscosity has on swimming performance.