Entrainment to external Ca2+ oscillation in ionophore-treated Physarum plasmodium

Area of Science:

• Cellular Biology
• Biophysics

Background:

• The Physarum plasmodium exhibits complex intracellular chemical rhythms.
• Understanding the interplay of these rhythms is crucial for deciphering cellular coordination.

Purpose of the Study:

• To investigate the mutual interaction mechanism of intracellular chemical rhythms in Physarum plasmodium.
• To determine how external calcium (Ca2+) oscillations influence internal cellular rhythms and tension generation.

Main Methods:

• Applied external Ca2+ oscillations to an ionophore-treated plasmodial strand.
• Measured the resulting tension oscillations to analyze entrainment and phase-locking phenomena.

Main Results:

• Tension oscillations in the plasmodium were successfully entrained and phase-locked to the applied external Ca2+ oscillations.
• Two stable phase relationships (in-phasic and anti-phasic) were observed between the internal and external oscillations.
• Transitions between these stable phase relationships were documented.

Conclusions:

• Cytosolic Ca2+ oscillations play a key role in the mutual entrainment of intracellular rhythms that control tension generation in Physarum plasmodium.
• The interaction of these rhythms is characterized by two distinct and stable phase relationships.