Glycolytic oscillations, biological rhythms

Some of the main examples of biological rhythms of nonelectrical nature are discussed below, among which are glycolytic oscillations (Section III), oscillations and waves of cytosolic Ca + (Section IV), cAMP oscillations that underlie pulsatile intercellular communication in Dictyostelium amoebae (Section V), circadian rhythms (Section VI), and the cell cycle clock (Section VII). Section VIII is devoted to some recently discovered cellular rhythms. The transition from simple periodic behavior to complex oscillations including bursting and chaos is briefly dealt with in Section IX. Concluding remarks are presented in Section X. 

The control by the substrate injection rate of the period, amplitude and very existence of glycolytic oscillations makes these a particularly appropriate model for the study of biological rhythms. Moreover, in contrast with many of these rhythms for which the mechanism of oscillations remains obscure, the molecular basis of glycolytic oscillations is known. This allows the construction of realistic models, which in turn... 

Many models for biochemical oscillations rely on positive feedback, as illustrated in this book by the case of glycolytic (chapter 2), cAMP (chapter 5) or (chapter 9) oscillations. Instabilities can, nevertheless, also arise from negative regulation. Together with the models discussed in chapter 10 for the mitotic oscillator in embryonic cells, for which a combination of positive and negative feedback may contribute to periodic behaviour, the model for circadian oscillations in the period protein in Drosophila supports the view that negative feedback is at the core of some of the most important biological rhythms. 

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