Figure 8

(A) Schematic representation of T. carassii swimming in compact tissues such as those in the fins. Most trypanosomes are directional swimmers and both forward and backward swimming were observed. (B) Selected frame from Video 7 showing the tracks of representative persistent swimmers identified in the fins. (C) In less compact tissues and in capillaries without blood flow, trypanosomes could invert their swimming direction in a ‘whip-like’ motion using the available three-dimensional space of the capillary or tissue. The ‘whip-like’ motion combines the swing of the flagellum along one plane (thin arc arrows), accompanied by a 180°C rotation of the flexible cell body along a third axis (rotational arrows). (D) In tissues where trypanosomes reach dead ends such as the interstitial space between vessels, persistent forward swimming translates into a drilling (auger) movement. Video 7 and Video 8 contain high-speed videos showing all locations and swimming behaviours schematically depicted.