Morphogenesis of Macro-Algae Team

GENERAL AIM

We aim to raise the list of factors which macroalgae have to deal with to build their body.

This includes endogenous factors, like the gene products, the metabolic activity, the energy production and even the communication between the different subcellular compartments, and exogenous factors, like the external osmotic pressure and the mechanical forces, two important physical parameters macroalgae have to respond and adapt to several times a day. Consequently, we use a multidisciplinary approach to identify and study these factors, including genetics, molecular biology, biophysics and cytology.

Brown algae display diverse body architectures with a wide range of morphological complexities involving specialised  organs (stipe, holdfast, pneumatocysts), vascular tissue (kelp) and complex reproductive organs (receptacle).

 

Brown algal vegetative cells are non-motile, are surrounded by a cell wall, and are photosynthetic. At high tide, they are immersed in a liquid medium with a high osmotic pressure (1000 mosmoles) and at low tide, they have to resist to an increase in salt concentration, even dehydration. Because of the density of sea water, the mechanical forces are very strong (compared to what land plants have to experience).

 

To initiate our study, we focused on the filamentous brown alga Ectocarpus siliculosus, because its morphology is simple and basic: a string of cells, which ultimately branches. Re-iteration of this process leads to a bushy organism 1 cm wide.

 

Last edited 02/12/2014