Symmetry breaking transition towards directional locomotion inPhysarummicroplasmodia
- 19 September 2019
- journal article
- research article
- Published by IOP Publishing in Journal of Physics D: Applied Physics
- Vol. 52 (49), 494004
- https://doi.org/10.1088/1361-6463/ab3ec8
Abstract
True slime mold Physarum polycephalum has been widely used as a model organism to study flow-driven amoeboid locomotion as well as the dynamics of its complex mechanochemical self-oscillations. The aim of this work is to quantify the mechanical aspects of symmetry breaking and its transition into directional flow-driven amoeboid locomotion in small (<similar to 200 mu m) fragments of Physarum polycephalum. To this end, we combined measurements of traction stresses, fragment morphology, and ectoplasmic microrheology with experimental manipulations of cell-substrate adhesion, cortical strength, and microplasmoditun size. These measurements show that initiation of locomotion is accompanied by the symmetry breaking of traction stresses and the polarization of ectoplasmic mechanical properties, with the rear part of the microplasmodium becoming significantly stiffer after the onset of locomotion. Our experimental data suggest that the initiation of locomotion in Physarum could be analogous to an interfacial instability process and that microplasmodial size is a critical parameter governing the instability. Specifically, our results indicate that the instability driving the onset of locomotion is strengthened by substrate adhesiveness and weakened by cortical stiffness. Furthermore, the Fourier spectral analysis of morphology revealed lobe number n = 2 as the consistent dominant mode number across various experimental manipulations, suggesting that the instability mechanism driving the onset of Physarum locomotion is robust with respect to changes in environmental conditions and microplasmodial properties.Funding Information
- National Institutes of Health (R01GM084227)
This publication has 50 references indexed in Scilit:
- Three-Dimensional Quantification of Cellular Traction Forces and Mechanosensing of Thin Substrata by Fourier Traction Force MicroscopyPLOS ONE, 2013
- The role of the cytoskeleton in cellular force generation in 2D and 3D environmentsPhysical Biology, 2011
- Computer Control of Microscopes Using µManagerCurrent Protocols in Molecular Biology, 2010
- Myosin II Is Essential for the Spatiotemporal Organization of Traction Forces during Cell MotilityMolecular Biology of the Cell, 2010
- Anisotropic rheology and directional mechanotransduction in vascular endothelial cellsProceedings of the National Academy of Sciences of the United States of America, 2008
- Locomotive Mechanism of Physarum Plasmodia Based on Spatiotemporal Analysis of Protoplasmic StreamingBiophysical Journal, 2008
- Spatio-temporal analysis of eukaryotic cell motility by improved force cytometryProceedings of the National Academy of Sciences of the United States of America, 2007
- Inhibition of actin polymerization by latrunculin AFEBS Letters, 1987
- Spatial and temporal organization of intracellular adenine nucleotides and cyclic nucleotides in relation to rhythmic motility in Physarum plasmodiumExperimental Cell Research, 1986
- Dynamic aspects of the contractile system inPhysarum Plasmodium: I. Changes in spatial organization of the cytoplasmic fibrils according to the contraction-relaxation cycleCell Motility, 1986