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.

海洋中，微藻可寄居于宿主细胞内并形成互利共生关系。该共生关系在微量金属生物利用度较低但对微藻代谢至关重要的水域中广泛分布。当前金属S-XRF成像（Metal S-XRF mapping）技术基于经锇染色处理的非天然细胞二维树脂切片，因此对金属分布的解析能力存在局限。为此，本项目旨在揭示并定量分析自由生活型与共生型微藻内的金属分布，并实现天然状态下的三维可视化检测。通过关联X射线相位衬度（X-ray phase-contrast）与X射线荧光层析成像（XRF tomography）技术，可将细胞区室与金属分布信息进行精准叠加，这对阐明铁（Fe）、锰（Mn）、铜（Cu）等关键金属在共生细胞内的区室化分布机制至关重要。本项目将深化我们对金属在海洋共生关系中作用的认知，并为后续开展其他细胞间相互作用（如病原体、病毒）及毒理学领域的研究奠定基础。