Principles underlying the complex dynamics of temperature entrainment by a circadian clock
Philipp Burt,
Saskia Grabe,
Cornelia Madeti,
Abhishek Upadhyay,
Martha Merrow,
Till Roenneberg,
Hanspeter Herzel,
Christoph Schmal
Affiliations
Philipp Burt
Institute for Theoretical Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany; Institute for Theoretical Biology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
Saskia Grabe
Institute for Theoretical Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany; Institute for Theoretical Biology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
Cornelia Madeti
Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Goethestrasse 31, 80336 Munich, Germany
Abhishek Upadhyay
Institute for Theoretical Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany; Institute for Theoretical Biology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
Martha Merrow
Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Goethestrasse 31, 80336 Munich, Germany
Till Roenneberg
Institute of Medical Psychology, Faculty of Medicine, LMU Munich, Goethestrasse 31, 80336 Munich, Germany
Hanspeter Herzel
Institute for Theoretical Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany; Institute for Theoretical Biology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
Christoph Schmal
Institute for Theoretical Biology, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany; Institute for Theoretical Biology, Charité Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; Corresponding author
Summary: Autonomously oscillating circadian clocks resonate with daily environmental (zeitgeber) rhythms to organize physiology around the solar day. Although entrainment properties and mechanisms have been studied widely and in great detail for light-dark cycles, entrainment to daily temperature rhythms remains poorly understood despite that they are potent zeitgebers. Here we investigate the entrainment of the chronobiological model organism Neurospora crassa, subject to thermocycles of different periods and fractions of warm versus cold phases, mimicking seasonal variations. Depending on the properties of these thermocycles, regularly entrained rhythms, period-doubling (frequency demultiplication) but also irregular aperiodic behavior occurs. We demonstrate that the complex nonlinear phenomena of experimentally observed entrainment dynamics can be understood by molecular mathematical modeling.
