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Synchronization of circadian clocks to diurnal cycles: from microscopic algae in changing weather to meal timing.
To anticipate periodic changes due to the alternation of days and nights, most living organisms rely on biological oscillators which serve as clocks and orchestrate many biological functions. The importance of these clocks in biology has been highlighted by the Nobel prize 2017 in physiology or medecine. To keep time, these clocks synchronize to the day/night cycle by locking their frequency to an external signal. We will present two clock synchronization problems. In the first case, we will see how a small microscopic alga and other organisms manage to keep time even in the face of large daylight fluctuations. In the second case, we will discuss how the liver clock in mammals synchronizes to feeding and fasting cycles, how perturbations of these cycles (nutritional stress) may lead to clock disruption, and how mathematical modeling can suggest chronotherapeutic protocols to rescue normal clock oscillations in such cases.
Friday, Jan 12th 2018