[Synchronization of mechanochemical auto-oscillations within the Physarum polycephalum plasmodium by periodical...

Amoeboid locomotion of huge unicellular organism, the Physarum polycephalum plasmodium, is stipulated by endoplasmic flow, which is produced by spatially highly coordinated rhythmic contractions of the ectoplasm. To describe the self-organization of the plasmodial contractile activity, we proposed a mathematical model, which is based on the hypothesis of positive feedback between the deformation of the cytoskeleton and release of a chemical regulator of the active contraction. A nonautonomous analogue of this model was used to study the synchronization of mechanochemical auto-oscillations by periodic gradient of the external pressure. Numerical computations of the system of differential equations obtained revealed a dependency of the synchronization band on the amplitude of the external pressure oscillations. On the basis of this dependence and experimental data on the band of synchronization of the shuttle endoplasmic flow by the periodic gradient of temperature obtained with the help of the laser Doppler anemometer, relative efficiency of external synchronizing action of temperature and pressure was evaluated.