Cell Cycle Dynamics in the Microalga : Influence of Light Duration and Drugs.

Our investigation into 's cell cycle regulation involved natural and chemical synchronization methods to maximize their proportion at the division phase (G). Hence, cultures were grown under different light/dark cycles (24:0, 12:12, and 8:16 h) to assess the impact of extended dark periods on cell division. Flow cytometry analyses of the cell cycle revealed that extending the dark phase resulted in a higher number of cells entering G.

Optimal resource allocation in micro-organisms under periodic nutrient fluctuations.

Although microorganisms often live in dynamic environments, most studies, both experimental and theoretical, are carried out under static conditions. In this work, we investigate the issue of optimal resource allocation in bacteria growing in periodic environments. We consider a dynamic model describing the microbial metabolism under varying conditions, involving a control variable quantifying the protein precursors allocation.

The paradoxes hidden behind the Droop model highlighted by a metabolic approach.

We propose metabolic models for the haptophyte microalgae with different possible organic carbon excretion mechanisms. These models-based on the DRUM (Dynamic Reduction of Unbalanced Metabolism) methodology-are calibrated with an experiment of nitrogen starvation under day/night cycles, and then validated with nitrogen-limited chemostat culture under continuous light. We show that models including exopolysaccharide excretion offer a better prediction capability.