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Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters
Published on: September 27, 2012
Noise-induced coherence in multicellular circadian clocks
Ekkehard Ullner1, Javier Buceta, Antoni Díez-Noguera
1Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Terrassa, Spain. ekkehard.ullner@gmail.com
Biophysical Journal
|May 6, 2009
Summary
Light fluctuations can surprisingly generate circadian rhythms in organisms, even when constant light normally causes arrhythmicity. This noise-induced rhythm shows a resonance effect, highlighting cooperative effects in biological clocks.
Area of Science:
- * Chronobiology
- * Systems Biology
- * Biophysics
Background:
- * Circadian rhythms in higher organisms rely on multicellular genetic clocks synchronized by light-dark cycles.
- * Previous research often assumes perfectly periodic light cycles, neglecting natural light fluctuations.
- * Organisms experience variable light intensities daily, impacting circadian oscillator dynamics.
Purpose of the Study:
- * To investigate the impact of light fluctuations and intercellular coupling on collective rhythm dynamics.
- * To model a large ensemble of nonidentical, globally coupled cellular clocks using Goodwin oscillators.
- * To explore the inverse relationship between cell-cell coupling strength and light intensity.
Main Methods:
- * Simulation of Goodwin oscillators representing cellular clocks.
- * Introduction of noise (light fluctuations) to the system.
- * Varying noise intensity and light levels to observe rhythm generation and coherence.
- * Analysis of collective rhythm and individual oscillator behavior.
Main Results:
- * Noise-induced rhythm generation observed at light intensities where the system is typically arrhythmic without noise.
- * A resonance-like phenomenon in rhythm coherence as a function of noise intensity.
- * Enhanced coherence is apparent in the collective rhythm, not individual oscillators.
- * Cooperative effects of noise, coupling, and synchronization enhance overall rhythmicity.
Conclusions:
- * Light fluctuations can be crucial for generating robust circadian rhythms, especially under constant light conditions.
- * Intercellular coupling and noise interact synergistically to produce emergent rhythmic behavior.
- * The study reveals a novel mechanism for rhythm generation and synchronization in biological systems.
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