SKM 2023 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 3: Active Matter I (joint session BP/CPP/DY)
DY 3.11: Talk
Monday, March 27, 2023, 12:30–12:45, TOE 317
Active phase fluctuations of Chlamydomonas axonemes — •Abhimanyu Sharma1, Benjamin M. Friedrich2, and Veikko F. Geyer1 — 1B CUBE - Center for Molecular Bioengineering, TU Dresden, Dresden, Germany — 2Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
Cilia and eukaryotic flagella generate periodic beat patterns by the activity of dynein motors. Earlier studies revealed active fluctuations in the ciliary beat arising presumably from small number fluctuations in the collective dynamics of the molecular motors that drive the beat. A theoretical model of the beating cilium as a system of coupled motors predicts that the fluctuations measured in terms of the quality factor of the oscillations scale with the number of beat-generating-motors.
To measure those fluctuations experimentally, we use in situ reactivated axonemes, the mechanical core of motile cilia isolated from the green alga Chlamydomonas. To modulate the number of motors in beating axonemes, we make use of motor mutants or partially extract molecular motors biochemically.
Using shape mode analysis and limit-cycle reconstruction, we characterize the phase fluctuations in the beat and report for the first time the relation between beat parameters and the motor number in Chlamydomonas axonemes. We experimentally infer scaling relations for the beat frequency, mean beat amplitude, and the quality factor. Further, using mass spectrometry, we identify specific dynein motors and infer their role in regulating the beat fluctuations.