MACROSCOPIC OSCILLATIONS OF THE REPRESSILATOR
A bacterial strain containing the repressilator was streaked out to obtain colonies originating from single cells, and imaged in the fluorescence (reporting the oscillations). Because bacterial colonies grow mainly from the outer diameter while keeping the inner part frozen in phase, the repressilator form a pattern similar to rings found in tree stumps, where the oscillator plays the role of the seasons in the tree growth.
Using the repressilator with a fluorescent reporter for each of the three repressors, we can observe (below) the three phases of the oscillations alternating in green, blue and red. These images were taken with a microscope with a large field-of-view.
The oscillations can also be observed in flasks, where billions of cells oscillate in synchrony.