Symmetry breaking transition towards directional locomotion in Physarum microplasmodia

摘要: True slime mold Physarum polycephalum has been widely used as a model organism to study flow-driven amoeboid locomotion well the dynamics of its complex mechanochemical self-oscillations. The aim this work is quantify mechanical aspects symmetry breaking and transition into directional in small (alt;~ 200 µm) fragments polycephalum. To end, we combined measurements traction stresses, fragment morphology, ectoplasmic microrheology with experimental manipulations cell-substrate adhesion, cortical strength microplasmodium size. These show that initiation accompanied by stresses polarization properties, rear part becoming significantly stiffer after onset locomotion. Our data suggests could be analogous an interfacial instability process microplasmodial size critical parameter governing instability. Specifically, our results indicate driving strengthened substrate adhesiveness weakened stiffness. Furthermore, Fourier spectral analysis morphology revealed lobe number n = 2 consistent dominant mode across various manipulations, suggesting mechanism robust respect changes environmental conditions properties.