Fig 1. Swimming behaviours of trypomastigote T. brucei procyclic forms and promastigote L. mexicana promastigotes have characteristic differences.

(A,B) Paths followed by swimming trypomastigote T. brucei procyclic forms (A) and promastigote L. mexicana (B), determined from low magnification dark field videomicrographs captured at 5 Hz. Trypomastigotes underwent fast swimming or tumbling, while promastigotes followed curved paths. An example phase contrast image of cell morphology is shown as an inset (scale bar represents 5 μm). (C,D) Swimming speed over time of an example swimming, tumbling and switching trypomastigote T. brucei procyclic form (C) and an example fast, moderate and slow swimming promastigote L. mexicana (D). (E,F) Distributions and cross correlation of swimming velocity and directional persistence for trypomastigote T. brucei procyclic form (E), promastigote L. mexicana (F). The percentage of swimming with directional persistence >0.9 is indicated. Data was pooled from at least three biological replicates with at least 4,000 cell tracks. Point area in the scatter plots is proportional to the length of the cell track to which it corresponds.