On the Relation between Chemical Oscillations and Self-Replication

Area of Science:

• Origin of Life Studies
• Biophysics
• Theoretical Biology

Background:

• Cellular self-replication is fundamental to life, with proposed mechanisms involving biochemical oscillations or simpler non-oscillatory processes.
• Existing protocell models present diverse assumptions, complicating the determination of whether chemical oscillations are essential for self-replication.

Purpose of the Study:

• To compare cellular self-replication with and without chemical oscillations within a unified whole-cell model.
• To identify universal requirements and specific constraints for self-replication in both stationary and oscillatory protocell models.

Main Methods:

• Developed a whole-cell model integrating a chemical reaction network (CRN) for constituent synthesis and membrane dynamics.
• Utilized nonlinear differential equations to couple chemical concentrations and surface-area-to-volume ratio, analyzing asymptotic trajectories.
• Determined cellular shape by minimizing membrane bending energy and investigated oscillatory CRN dynamics.

Main Results:

• Cellular self-replication is achievable in both stationary (non-oscillatory) and oscillatory protocell models.
• A minimum spontaneous membrane curvature is a universal requirement for cell division in both scenarios.
• Oscillatory models introduce additional constraints: integer doubling time to oscillation period ratio and a maximum spontaneous curvature limit.

Conclusions:

• Chemical oscillations are not strictly required for early cellular self-replication.
• The stringent constraints of oscillatory replication suggest non-oscillatory mechanisms were likely favored initially.
• Biochemical oscillations in modern cells may have evolved later for metabolic advantages, requiring additional feedback for robustness.