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Magnetosomes could be protective shields against metal stress in magnetotactic bacteria

Abstract: Magnetotactic bacteria are aquatic microorganisms with the ability to biomineralise membrane-enclosed magnetic nanoparticles, called magnetosomes. These magnetosomes are arranged into a chain that behaves as a magnetic compass, allowing the bacteria to align in and navigate along the Earth's magnetic field lines. According to the magneto-aerotactic hypothesis, the purpose of producing magnetosomes is to provide the bacteria with a more efficient movement within the stratified water column, in search of the optimal positions that satisfy their nutritional requirements. However, magnetosomes could have other physiological roles, as proposed in this work. Here we analyse the role of magnetosomes in the tolerance of Magnetospirillum gryphiswaldense MSR-1 to transition metals (Co, Mn, Ni, Zn, Cu). By exposing bacterial populations with and without magnetosomes to increasing concentrations of metals in the growth medium, we observe that the tolerance is significantly higher when bacteria have magnetosomes. The resistance mechanisms triggered in magnetosome-bearing bacteria under metal stress have been investigated by means of x-ray absorption near edge spectroscopy (XANES). XANES experiments were performed both on magnetosomes isolated from the bacteria and on the whole bacteria, aimed to assess whether bacteria use magnetosomes as metal storages, or whether they incorporate the excess metal in other cell compartments. Our findings reveal that the tolerance mechanisms are metal-specific: Mn, Zn and Cu are incorporated in both the magnetosomes and other cell compartments; Co is only incorporated in the magnetosomes, and Ni is incorporated in other cell compartments. In the case of Co, Zn and Mn, the metal is integrated in the magnetosome magnetite mineral core.

 Autoría: Muñoz D., Marcano L., Martín-Rodríguez R., Simonelli L., Serrano A., García-Prieto A., Fdez-Gubieda M.L., Muela A.,

 Fuente: Scientific Reports, 2020, 10, 11430

 Editorial: Nature Publishing Group

 Fecha de publicación: 10/07/2020

 Nº de páginas: 12

 Tipo de publicación: Artículo de Revista

 DOI: 10.1038/s41598-020-68183-z

 ISSN: 2045-2322

 Proyecto español: MAT2017-83631-C3-R

 Url de la publicación: https://doi.org/10.1038/s41598-020-68183-z

Autoría

MUÑOZ RODRÍGUEZ, DAVID

MARCANO PRIETO, LOURDES

SIMONELLI BEAMLINE, LAURA

SERRANO RUBIO, AIDA

ANA GARCIA PRIETO

FERNÁNDEZ GUBIEDA, MARÍA LUISA

MUELA BLAZQUEZ, ALICIA