Date:
Wed, 15/11/202310:00-11:30
Location:
Danciger B building – Seminars Room
Lecturer: Dr. Eldad Afik (Caltech)
Abstract:
Caulerpa brachypus is a marine green alga consisting of organ-like regions, resembling leaves, stems and roots. While an individual can exceed a meter in size, it is a multinucleated single cell. Hence Caulerpa challenges central paradigms in developmental biology.
The experiments presented in this talk reveal self-organised waves of greenness that propagate throughout the alga. These waves exhibit anticipatory behavior, typically preceding the night and day light states transitions. Dynamical systems analysis, namely power spectra, shows that this anticipation is explained by entrainment --- adjustment of the rhythm of a self-sustained oscillator by interaction with another oscillator, here the driving illumination.
Using a scalable and affordable experimental system, varying two control parameters --- the temporal period of the illumination and its intensity --- we identify distinct dynamical states of the self-organised waves. Under constant conditions light intensity affects the natural period, and a transition to states of increased temporal disorder is found under higher illumination intensities. Moreover, distinct morphologies arise depending on light temporal patterns, thus development depends not only on the average photon flux but also on its temporal distribution.
The results suggest waves of chlorophyll could link synchronization of biological oscillators to metabolism and morphogenesis in this giant unicellular organism.
Abstract:
Caulerpa brachypus is a marine green alga consisting of organ-like regions, resembling leaves, stems and roots. While an individual can exceed a meter in size, it is a multinucleated single cell. Hence Caulerpa challenges central paradigms in developmental biology.
The experiments presented in this talk reveal self-organised waves of greenness that propagate throughout the alga. These waves exhibit anticipatory behavior, typically preceding the night and day light states transitions. Dynamical systems analysis, namely power spectra, shows that this anticipation is explained by entrainment --- adjustment of the rhythm of a self-sustained oscillator by interaction with another oscillator, here the driving illumination.
Using a scalable and affordable experimental system, varying two control parameters --- the temporal period of the illumination and its intensity --- we identify distinct dynamical states of the self-organised waves. Under constant conditions light intensity affects the natural period, and a transition to states of increased temporal disorder is found under higher illumination intensities. Moreover, distinct morphologies arise depending on light temporal patterns, thus development depends not only on the average photon flux but also on its temporal distribution.
The results suggest waves of chlorophyll could link synchronization of biological oscillators to metabolism and morphogenesis in this giant unicellular organism.