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BP: Fachverband Biologische Physik

BP 16: Focus Session: Nonlinear Dynamics in Biological Systems II (joint session DY/BP)

BP 16.1: Hauptvortrag

Dienstag, 18. März 2025, 14:00–14:30, H43

Mechanistic origins of temperature scaling in the early embryonic cell cycle — •Lendert Gelens — Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat, 49, Leuven, Belgium

Temperature profoundly impacts organismal physiology and ecological dynamics, particularly affecting ectothermic species and making them especially vulnerable to climate shifts. Even though complex physiological processes usually involve dozens of enzymes, empirically it is found that the rates of these processes often obey the Arrhenius equation, which was originally derived for single enzyme-catalyzed reactions. Here we have examined the temperature scaling of the early embryonic cell cycle, with the goal of understanding why the Arrhenius equation approximately holds, and why it breaks down at temperature extremes.

Using experimental data from different frog, fish, fly, and worm species, we find that the apparent activation energies for the early embryonic cell cycle for diverse ectotherms are all similar. Computational modeling and experiments with frog egg extracts show that the non-Arrhenius scaling can be accounted for by biphasic temperature scaling in critical individual components of the cell cycle oscillator circuit, in combination with imbalances in the activation energies for different partially rate-determining enzymes. These findings provide mechanistic insights into the dynamic interplay between temperature and complex biochemical processes, and into why biological systems fail at extreme temperatures.

Keywords: Temperature; Cell division cycle; Embryonic development; Biochemical oscillations; Arrhenius scaling