Whenever fundamental features of living systems and their molecular basis are reviewed, the problem of timing, of time setting or free open-end running times is only marginally on the desk of research agendas, although the finite ageing as one of the features resulting from time markers is known since long. With the discovery of cellular and most important of cellfree oscillatory processes new concepts and experimental techniques were designed to approach these questions more directly leading not only to a better understanding of timing but strongly contributed to concepts for spatial pattern generation. As given in the list of contents major items in the field of intracellular and intercellular periodic reactions are reviewed in Sections 2–7 in terms of specific properties of various systems and in Section 8 in summing important features common to all oscillatory stems in chemistry and biology. Section 9 draws attention to the problem of patterning in the mesoscopic domains of living systems, which is so basic in terms of the volume dimensions specific for the cellular and subcellular reaction compartments in biology. The last chapter sets some marks on urgent problems currently approached by the combined methods of molecular genetics, biochemistry and computer technologies.

1. INTRODUCTION AND HISTORY 122

2. PERIODIC GLYCOLYSIS: TEMPORAL AND SPATIAL OSCILLATIONS 123

2.1 Cell-free glycolysis 123

2.2 Intact cells 128

2.2.1 Yeast 128

2.2.2 Myocytes 130

2.2.3 β-Cells of the islets of pancreas 131

3. CALCIUM OSCILLATIONS 131

3.1 Temporal oscillations 131

3.2 Calcium waves 136

3.3 Physiology 138

4. MICROTUBULE OSCILLATIONS 140

5. THE MITOTIC OSCILLATOR 141

6. DICTYOSTELIUM DISCOIDEUM 144

7. CARDIOMUSCULAR NETWORK 150

8. GENERAL PROPERTIES OF DYNAMIC SPATIAL PATTERNS 152

9. MICROSCOPIC PATTERNS 156

10. PERSPECTIVES 162

11. ACKNOWLEDGEMENTS 163

12. REFERENCES 163