MODELING TEMPERATURE COMPENSATION IN CHEMICAL AND BIOLOGICAL OSCILLATORS

All physicochemical and biological oscillators maintain a balance betw een destabilizing reactions (as, for example, intrinsic autocatalytic or amplifying reactions) and stabilizing processes. These two groups o f processes tend to influence the period in opposite directions and ma y lead to temperature compensation whenever their overall influence ba lances. This principle of ''antagonistic balance'' has been tested for several chemical and biological oscillators. The Goodwin negative fee dback oscillator appears of particular interest for modeling the circa dian clocks in Neurospora and Drosophila and their temperature compens ation. Remarkably, the Goodwin oscillator not only gives qualitative, correct phase response curves for temperature steps and temperature pu lses, but also simulates the temperature behavior of Neurospora frq an d Drosophila per mutants almost quantitatively. The Goodwin oscillator predicts that circadian periods are strongly dependent on the turnove r of the clock mRNA or clock protein. A more rapid turnover of clock m RNA or clock protein results, in short, a slower turnover in longer pe riod lengths.