Séminaire/Seminar - The magnetosome organelle: its role in a magnetotactic holobiont and a model system to study magnetite biomineralization - Dan Chevrier

June 6th at 11 AM

IMPMC - Sorbonne Université - 4 place Jussieu - 75005 Paris - Barre 22-23, 4e étage, salle 401

Dan Chevrier (CNRS researcher, CEA)

Abstract

Magnetotactic bacteria (MTB) are a diverse type of motile, single-cell prokaryote well known for their capacity to biomineralize chains or clusters of magnetosome organelles that contain magnetic nanocrystals of magnetite or greigite [1]. They are ubiquitously found in micro-/anaerobic conditions and can easily locate such habitats thanks to the collective magnetic moment of their magnetosomes, which is referred to as magnetotaxis. This talk will first present a biophysical study of a magnetotactic holobiont – a symbiosis between a motile eukaryotic host and magnetosome-producing bacteria – that describes how chains of magnetosomes are optimized for magnetic-field guided motility of the host cell [2]. Secondly, new approaches using scanning X-ray microscopy to study magnetite biomineralization by MTB will be presented [3]; including the application of microfluidic sample environments to measure hydrated cells at the synchrotron.

 [1] Faivre, D. & Schüler, D. Magnetotactic bacteria and magnetosomes. Chem. Rev. 108, 4875–4898 (2008)

[2] Chevrier, D. M. et al. Collective magnetotaxis of microbial holobionts is optimized by the three-dimensional organization and magnetic properties of ectosymbionts. Proc. Natl. Acad. Sci. U. S. A. 120, e2216975120 (2023)

[3] Chevrier, D. M. et al. Synchrotron-Based Nano-X-Ray Absorption Near-Edge Structure Revealing Intracellular Heterogeneity of Iron Species in Magnetotactic Bacteria. Small Sci. 2, 2100089 (2021)