Correlation between electric potential and peristaltic behavior in Physarum polycephalum.

ABSTRACT

Plasmodium of Physarum polycephalum is a model species of eukaryotic microorganisms for studying amoeboid movement. Plasmodium's natural movements are characterized by the rhythmic back-and-forth streaming of cytoplasm peristalsis, which results in the directed locomotion of plasmodium, and the periodic change of the electric potential on the surface of plasmodium. Although it was suggested the causal connection between the cytoplasmic streaming and the electric potential in P. polycephalum, the relationship between its plasmodium peristaltic behavior and the surface electric potential had not been statistically proven. In this study, based on the modern microscopic observation and the new electric potential measurement, we proved the consistence between the frequency spectrums of the electric potential wave and the peristaltic wave during the growth of plasmodium and the synchronization of their waveforms through cross-correlational analysis. And we concluded that the correlation exists between the peristaltic wave and the electric potential wave. This study added new evidence to the hypothesis of the sharing inner biological mechanism between plasmodium's peristaltic behavior and electric potential as previous studies indicated, and brought a new perspective towards the future research on amoeboid movement.