Antiphase Synchronization in a Flagellar-Dominance Mutant ofChlamydomonas

Abstract

Groups of beating flagella or cilia often synchronize so that neighboring filaments have identical frequencies and phases. A prime example is provided by the unicellular biflagellate Chlamydomonas reinhardtii, which typically displays synchronous in-phase beating in a low-Reynolds number version of breaststroke swimming. We report the discovery that ptx1, a flagellar-dominance mutant of C. reinhardtii, can exhibit synchronization in precise antiphase, as in the freestyle swimming stroke. High-speed imaging shows that ptx1 flagella switch stochastically between in-phase and antiphase states, and that the latter has a distinct waveform and significantly higher frequency, both of which are strikingly similar to those found during phase slips that stochastically interrupt in-phase beating of the wild-type. Possible mechanisms underlying these observations are discussed.

Hydrodynamics Versus Intracellular Coupling in the Synchronization of Eukaryotic Flagella

“…The potential role of such fibers in the synchronized behavior of C. reinhardtii remains unclear. These cell-internal fibers have been hypothesized to determine and modulate the flagella beating mode [9,21] and have also been suggested to provide the mechanical connection at the origin of synchronization itself [22][23][24]. This last hypothesis is corroborated by our experimental observations of the vfl3 mutant, with impaired mechanical connection between the flagella.…”

“…Experimental work has focused on a model organism for motility: unicellular green alga Chlamydomonas reinhardtii. C. reinhardtii possesses two flagella, the cis and the trans flagellum, which beat in synchrony for long time periods [7,[9][10][11]. Flagella have often been suggested to synchronize due to interflagellar hydrodynamic interactions.…”

Batchelor Prize Lecture Fluid dynamics at the scale of the cell

“…In the mutants, this difference is lost and the two flagella behave nearly identically, frustrating phototaxis. Rüffer & Nultsch (1997) had observed in this mutant a different type of synchrony which, upon modern analysis, turns out to be precise antiphase (AP) synchrony (Leptos et al 2013). As shown in figure 11(a,b) at very high temporal resolution (2000 fps), these cells exhibit stochastic transitions between the in-phase (IP) breaststroke and the AP mode, which is like the human freestyle swimming stroke, corresponding to half-integer jumps in ∆.…”

“…Thus, the mutant behaves normally and the wild type is the outlier! This led us to conjecture (Leptos et al 2013) that wild-type synchrony is controlled by a process internal to the cell, possibly associated with filamentary connections between the bases of the flagella.…”

Forces and shapes as determinants of micro-swimming: effect on synchronisation and the utilisation of drag

“…This suggests that the swimmer has the ability to automatically synchronise its two beating arms for much of the phase space so as to achieve efficient propulsion, and is reminiscent of the phase locking observed in Chlamydomonas agella when elastic connections are included. 42 …”