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Figure 7 | Frontiers in Zoology

Figure 7

From: How the pilidium larva feeds

Figure 7

Rhodomonas tries to escape the pilidium. (A) Rhodomonas lens (CCMP739) illustrating several rows of large ejectisomes (ej) lining the gullet from which the two flagella (fl) emerge; cv = contractile vacuole. (B) Rhodomonas just after an abrupt jump; ejectisome filament(s) (arrowhead) remain along the path of the jump. (C) Another cryptomonad, Storeatula sp. (CCMP1868), trapped between slide and coverslip; four successive frames, 1 ms each, from high-speed video sequence in which a single ejectisome fired (because the cell was trapped, the filament extended away from the cell instead of making the cell move). Bottom row is contrast-enhanced to reveal the filament; arrowheads mark filament tip, which extends 26 μm in the time spanned by the two exposures (1.625 ms). Inset shows boxed region at 3x; hollow arrowhead points out the ejectisome which, because it changes from first to second frame, is apparently the one that fired. (D) High-speed video sequence of M. alaskensis pilidium maneuvering Rhodomonas up the buccal funnel (Additional file 11: Video 11); the kymograph was made by straightening the broad band indicated in the first of five frames shown below. Short arrows along the kymograph indicate the times of frames shown below. The dark streak is the path of the cell; the stomach entrance is at the bottom of the graph; thus the vertical distance represents distance from the stomach. Abrupt vertical excursions represent escape attempts, some of which correspond to multiple jumps in sequence. Most jumps are initiated when the cell is near the stomach entrance. Note the beat of the buccal ridges, which appears at middle height in the kymograph; a dramatic increase in beat frequency at ~1.5 s is associated with onset of a draught which sucks the cell back up the funnel.

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