Cellular rhythms

A. Goldbeter, Biochemical Oscillations and Cellular Rhythms The Molecular Bases of Periodic and Chaotic Behaviour, Cambridge University Press, Cambridge, United Kingdom (1997). 

A. Goldbeter, Computational approaches to cellular rhythms. Nature 420, 238 245 (2002). 

E. Stochastic Versus Deterministic Models for Circadian Rhythms The Cell-Cycle Clock Newly Discovered Cellular Rhythms... 

New examples of cellular rhythms have recently been uncovered (Table II). These include periodic changes in the intracellular concentration of the transcription factor NF-KB and of the tumor suppressors p53, stress-induced oscillations in the transport of the transcription factor Msn2 between cytoplasm and nucleus in yeast, the segmentation clock that is responsible for the... 

Biological Regulations and Examples of Associated Cellular 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. 

Glycolytic oscillations in yeast cells provided one of the first examples of oscillatory behavior in a biochemical system. They continue to serve as a prototype for cellular rhythms. This oscillatory phenomenon, discovered some 40 years ago [36, 37] and still vigorously investigated today [38], was important in several respects First, it illustrated the occurrence of periodic behavior in a key metabolic pathway. Second, because they were soon observed in cell extracts, glycolytic oscillations provided an instance of a biochemical clock amenable to in vitro studies. Initially observed in yeast cells and extracts, glycolytic oscillations were later observed in muscle cells and evidence exists for their occurrence in pancreatic p-cells in which they could underlie the pulsatile secretion of insulin [39]. 

Only deterministic models for cellular rhythms have been discussed so far. Do such models remain valid when the numbers of molecules involved are small, as may occur in cellular conditions Barkai and Leibler [127] stressed that in the presence of small amounts of mRNA or protein molecules, the effect of molecular noise on circadian rhythms may become significant and may compromise the emergence of coherent periodic oscillations. The way to assess the influence of molecular noise on circadian rhythms is to resort to stochastic simulations [127-129]. Stochastic simulations of the models schematized in Fig. 3A,B show that the dynamic behavior predicted by the corresponding deterministic equations remains valid as long as the maximum numbers of mRNA and protein molecules involved in the circadian clock mechanism are of the order of a few tens and hundreds, respectively [128]. In the presence of molecular noise, the trajectory in the phase space transforms into a cloud of points surrounding the deterministic limit cycle. 

A. Goldbeter. Biochemical Oscillations and Cellular Rhythms. Cambridge University Press, 1995. 

Goldbeter, A. (1996) Biochemical Oscillations 1032. and Cellular Rhythms The Molecular Basis of... 

Glycolytic oscillations and cAMP oscillations were, respectively, discovered around 1965 and 1975. Might there be a rough periodicity of some 10 years in progress on biochemical and cellular rhythms The field of biochemical oscillations has indeed changed drastically due to the discovery in 1985 of intracellular Ca oscillations that occur in a variety of cells, either spontaneously or as a result of stimulation by an external signal such as a hormone or a neurotransmitter. Since their... 

As indicated in section 1.3, cytosolic Ca oscillations, which occur in a variety of cell types as a result of stimulation by hormones or neurotransmitters, are among the most widespread of cellular rhythms, besides oscillations driven by periodic variations of the membrane potential in electrically excitable cells. These oscOlations, whose period varies from seconds to minutes depending on the cell type, sometimes occur spontaneously. Part V is devoted to this phenomenon, which clearly represents the most significant addition to the field of biochemical oscillations over the last decade, in addition to the evidence that has acciunulated to show that a continuous biochemical oscillator controls the eukaryotic cell cycle (see below). Experimental work on Ca oscillations has increased so much over the last years that it is by now the most studied biochemical rhythm. 

The study of biochemical oscillations thus extends in many directions, from simple and complex periodic behaviour to chaotic dynamics, and from cellular rhythms to chronopharmacology. It is the purpose of this book to explore the molecular bases of these oscillatory phenomena and the richness of their physiological implications. 

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