3D Metal imaging in planktonic symbiosis from the ocean

In the ocean, microalgae can live inside host cells and establish a mutualistic interaction. This partnership is abundant in waters where trace metals are poorly available yet essential for the metabolism of the microalgae. Metal S-XRF mapping is currently based on 2D resin sections of non-native cells (i.e. osmium staining), thus offering a limited understanding of metal distribution. Therefore, this proposal aims to unveil and quantify the metal distribution in free-living and symbiotic microalgae, and so in 3D and in native state. Correlated X-ray phase-contrast and XRF tomography will superimpose cellular compartments of cells and metals distribution, which is essential to understand how key metals are compartmentalized in symbiotic cells (e.g. Fe, Mn, Cu). This project will improve our knowledge of the role of metals in oceanic symbiosis and will pave the way for more investigations on other cell-cell interactions (e.g. pathogens, viruses) and in toxicology.