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Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2020

Vendredi 20 nov. 2020 / IRPHE

publié le

Séminaire IRPHE (candidate CNRS)

Shape and coordinated motion in the simplest multicellular alga

Orateur : Hélène de Maleprade

Abstract : I will start with a short review on my previous research works, and focus on a project from my postdoc in Cambridge.

Microscopic green algae are commonly found in mud, puddles or lakes, and show great diversity in structural complexity. The unicellular Chlamydomonas exhibits two flagella whose beating enables it to swim in a breast stroke towards light, a nowadays widely studied behaviour favouring photosynthesis. One also finds Gonium, an algae made of 16 Chlamydomonas-like cells. It is flat and squared, with all flagella on one side of the plate. This simple algae is a key organism to understand the evolution towards multicellularity.

In the absence of central nervous system, how can each cell adapt its individual photoresponse to efficiently reorient the whole algae ? How crucial is the distinctive squared structure ?

In this talk, I will present our experiments investigating the shape and the phototactic swimming of Gonium, using trajectory tracking and micro-pipette techniques. I will explain our model linking the individual flagella response to the 16-cell colony trajectory. This eventually emphasises the importance of biological noise to succeed swimming towards light.

Date et lieu : Séminaire en ligne sur Zoom, le vendredi 20 novembre à 11h00

Voir en ligne : plus de détails sur l’orateur