Wed December 4th 2019
16:00 – 17:00
Seminar Decoding coordinated motion in the simplest multicellular algae
Hélène de Maleprade


Microscopic green algae are commonly found in mud, puddles or lakes, and show great diversity in structural complexity. One encounters the unicellular Chlamydomonas, exhibiting two flagella whose beating enables it to swim in a breast stroke towards light, a behaviour favouring photosynthesis. One also finds Gonium, an algae made of 16 Chlamydomonas-like cells, already differentiated. As one of the first multicellular algae, Gonium is therefore a key organism to understand the evolution towards multicellularity.
In the absence of centralised communication, how can each cell adapt its individual behaviour to efficiently steer the whole algae to light? In this talk, I will present our experiments investigating the phototactic swimming of Gonium, from trajectory tracking under various light conditions to micro-pipette experiments offering access to the flagella description. I will explain our model linking the flagella response to the colony trajectory, upgrading the response to light of Chlamydomonas to a multicellular dynamics. This eventually emphasises the importance of biological noise to succeed swimming towards light.
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The 10th Complex Motion in Fluids 2021
Max Planck Gesellschaft
Centre for Scientific Computing