https://doi.org/10.1140/epje/s10189-021-00076-z
Regular Article - Living Systems
Reconstruction of the three-dimensional beat pattern underlying swimming behaviors of sperm
1
Center of Advanced European Studies and Research (caesar), Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
2
Theoretical Physics of Living Matter, Institute of Biological Information Processing and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425, Jülich, Germany
3
Biological Algorithms Group, TU Dresden, Cluster of Excellence ‘Physics of Life’ and Center for Advancing Electronics Dresden (cfaed), Helmholtzstr. 18, 01069, Dresden, Germany
d
U.B.Kaupp@caesar.de
g
luis.alvarez@caesar.de
Received:
6
March
2021
Accepted:
6
May
2021
Published online:
1
July
2021
The eukaryotic flagellum propels sperm cells and simultaneously detects physical and chemical cues that modulate the waveform of the flagellar beat. Most previous studies have characterized the flagellar beat and swimming trajectories in two space dimensions (2D) at a water/glass interface. Here, using refined holographic imaging methods, we report high-quality recordings of three-dimensional (3D) flagellar bending waves. As predicted by theory, we observed that an asymmetric and planar flagellar beat results in a circular swimming path, whereas a symmetric and non-planar flagellar beat results in a twisted-ribbon swimming path. During swimming in 3D, human sperm flagella exhibit torsion waves characterized by maxima at the low curvature regions of the flagellar wave. We suggest that these torsion waves are common in nature and that they are an intrinsic property of beating axonemes. We discuss how 3D beat patterns result in twisted-ribbon swimming paths. This study provides new insight into the axoneme dynamics, the 3D flagellar beat, and the resulting swimming behavior.
© The Author(s) 2021
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