Collective and individual dynamics of a population of cells from <i>S. carlsbergensis</i> at a cell density of 0.7%.

<p>At = 0 an aliquot of 52 mM glucose was added to the starved and immobilised cells. During the first 350 s of the time-series, the cells start to oscillate and to synchronise to each other. <i>(a)</i> The time-series of the macroscopic, collective fluorescence signal shows well-developed glycolytic oscillations. This coherent signal is generated by all cells of the population. <i>(b)</i> The oscillations of the individual cells show that their normalised amplitudes are highly coherent and synchronised. (The amplitude of oscillations of the cells corresponds to 60–140 photons/s.) Note that the dynamics of every cell is plotted as a thin line and its corresponding normalised amplitude is colour-coded. Cells are numbered randomly, i.e., the numbering does not reflect any spatial arrangement of the cells. At 1800 s the oscillation amplitudes decay and the cells lose synchrony due to exhaustion of glucose. <i>(c)</i> The phases of the oscillations of the individual cells are highly synchronised to each other. Again, for 1800 s the cells desynchronise. <i>(d)</i> The time-dependent Kuramoto order parameter indicates the degree of synchronisation among the cells. For 350 s1800 s the order parameter is almost 1, indicating a very high coherence in the oscillations of the individual cells.