Reverse engineering the euglenoid movement

MARINO ARROYO; LUCA HELTAI; DANIEL MILLÁN; ANTONIO DESIMONE

Providence, RI

Congreso; 50th Annual Technical Meeting of the Society of the Engineering Science (SES 2013); 2013

Society of Engineering Science

Euglenids exhibit an unconventional motility strategy amongst unicellular eukaryotes, consisting of large amplitude highly concerted deformations of the entire body (euglenoid movement or metaboly). A plastic cell envelope called pellicle mediates these deformations. We examine quantitatively video recordings of euglenids executing such motions, which reveals strokes of high uniformity in shape and pace. We interpret the observations with a theory for the pellicle kinematics, providing a precise understanding of the link between local actuation by pellicle shear and shape control. We find that some euglenids execute their stroke at constant body volume, while others exhibit deviations of about 20% from their average volume, challenging current models of low Reynolds number locomotion. We find that metaboly accomplishes locomotion at hydrodynamic efficiencies comparable to those of ciliates and flagellates. Our results suggest new quantitative experiments, provide insight into the evolutionary history of euglenids, and suggest that the pellicle may serve as a model for engineered active surfaces with applications in micro-fluidics.