Hydrodynamics of Euglena Gracilis during locomotion

• DOI: 10.1007/s42241-021-0007-y
• Publication Date: 2021-02-27T05:25:16Z
• Authors: Fahrettin Gökhan ...
• Keywords: Euglena gracilis; Bluff; Piston (optics)

The hydrodynamics and locomotion mechanism of Euglena Gracilis (E. Gracilis) is investigated using microscopic shadow imaging and micro particle image velocimetry (MicroPIV). Three distinct locomotion modes were observed: translation, spin, and left/right turn. Since the flagellum was not possible to image, the strokes were identified by evaluating the flow field around the protist. The flow field information is obtained using a phase-separated PIV evaluation, which uses a histogram-thresholding based dynamic masking approach. The temporal resolution of the experiment was sufficient to identify the sequence of two modes, translation and spin, and the stroke-pulling frequency. The flow field result during a stroke is compared with existing Stokeslet dipole theories and flow disturbance decay with distance is investigated. The results indicate that the organism has a complex locomotion technique that allows the change of direction, axial orientation and propulsion.