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Karsenti Group (Visiting)

Planctonic ecosystems in TARA OCEANS expedition

Karsenti Group

Karsenti Group

Figure 1: Artificial spindle assembled in a frog egg extract (above) and the Ran pathway involved in spindle assembly (below)

Karsenti Group

Figure 2: The TARA OCEANS expedition 
Please click on the pictures for a larger version.

Previous and current research

Assembly of the mitotic spindle in large eukaryotic cells is driven by a signaling pathway that generates a gradient of microtubule nucleation and stabilization activity around chromosomes. My group has been studying the biochemical composition of this signaling pathway as well as the physico-chemical processes associated with it, leading to the self-organisation of microtubules into a bipolar spindle.

More generally, this raised important questions about self-organisation events in biology: how ensemble of molecules, cells, or “agents”, organize themselves into functional wholes? We began to address such questions in the case of the mitotic spindle with François Nédélec and I am presently working in collaboration with Lars Hufnagel and Daren Gilmour on the organisation principles underlying the formation of the lateral line in the Zebra fish.

Future projects and goals

Over the past 4 years, I have been working on the organisation of an expedition about life in the oceans. Finally, a collaboration with the TARA Expeditions group in Paris has been formalised, allowing the organisation of an oceanographic expedition to explore microscopic marine ecosystems world wide (Figure 2). The TARA OCEANS expedition led by myself, a group of scientific coordinators and Etienne Bourgois, the owner of the schooner TARA, left Lorient on 5 September 2009.

The mission of the expedition is to bring back quantitative and qualitative data on the composition of these ecosystems as a function of geographic position and environmental conditions. The goal of this collection of samples and data is 3 fold:

  1. to feed morpho-genomic analyses of marine ecosystems in order to better understand the nature of the organisms and genes expressed in a given oceanic environment,
  2. to better understand the evolution of marine organisms and
  3. to feed models of the co-evolution of these ecosystems with the hydro-climate.

TARA Oceans Expedition website

In addition to coordinating the expedition, I will interact with Jan Ellenberg (Ellenberg Group) at EMBL to develop high throughput imaging of protists and small metazoans, with Detlev Arendt (Arendt Group) on the biogeography and evolution of marine annelids and with Peer Bork (Bork Group) for genome analyses.