Dynamic aspects of the contractile system in physarum plasmodium. IV. Local asynchronism in the generation cycle of actomyosin fibrils and its relationship to the shuttle streamomg.

Abstract

The cyclic generation-degeneration of actomyosin fibrils, which coincides with the cyclic contraction-relaxation of the plasmodium, was documented quantitatively in the two half regions of dumbbell-shaped fragments of Physarum plasmodium by polarizing microscopy and image analysis, with simultaneous monitoring of the direction and velocity of the shuttle streaming in the central isthmus region. Examination of the phase relationships between those periodic changes showed that the shuttle streaming arises in correspondence with local asynchronism in the fibrillar generation cycles.