Magnetite Crystal Orientation in Magnetosome Chains

Körnig, André; Winklhofer, Michael; Baumgartner, Jens; González, Teresa María Perandones; Fratzl, Peter; Faivre, Damien

doi:10.1002/adfm.201303737

Cited by 49 publications

(54 citation statements)

References 44 publications

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“…30 We proceed similarly with our immobilized cells. The living bacteria are mounted in a way that the direction of alignment is perpendicular to the beam (Figure 1N).…”

Section: Organized Magnetotactic Bacteria Display Textured Xrd Patternmentioning

confidence: 99%

Probing the Mechanical Properties of Magnetosome Chains in Living Magnetotactic Bacteria

et al. 2014

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The mechanical properties of cytoskeletal networks are intimately involved in determining how forces and cellular processes are generated, directed, and transmitted in living cells. However, determining the mechanical properties of subcellular molecular complexes in vivo has proven to be difficult. Here, we combine in vivo measurements by optical microscopy, X-ray diffraction, and transmission electron microscopy with theoretical modeling to decipher the mechanical properties of the magnetosome chain system encountered in magnetotactic bacteria. We exploit the magnetic properties of the endogenous intracellular nanoparticles to apply a force on the filament-connector pair involved in the backbone formation and stabilization. We show that the magnetosome chain can be broken by the application of external field strength higher than 30 mT and suggest that this originates from the rupture of the magnetosome connector MamJ. In addition, we calculate that the biological determinants can withstand in vivo a force of 25 pN. This quantitative understanding provides insights for the design of functional materials such as actuators and sensors using cellular components.

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“…30 We proceed similarly with our immobilized cells. The living bacteria are mounted in a way that the direction of alignment is perpendicular to the beam (Figure 1N).…”

Section: Organized Magnetotactic Bacteria Display Textured Xrd Patternmentioning

confidence: 99%

Probing the Mechanical Properties of Magnetosome Chains in Living Magnetotactic Bacteria

et al. 2014

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“…The magnetosomes are membrane-enclosed compartments that contain a crystalline magnetic nanoparticle, which consists of the iron oxide magnetite, Fe 3 O 4 . In M. gryphiswaldense MSR-1, the nanocrystals are aligned with the 111 direction parallel to the chain axis [15]. Furthermore, this axis is also the easy axis of magnetization and corresponds to the direction of the magnetic moment.…”

Section: Magnetotactic Bacteriamentioning

confidence: 99%

Magnetotactic bacteria

Klumpp

Faivre

2016

Eur. Phys. J. Spec. Top.

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Abstract. Magnetotactic bacteria are aquatic microorganisms with the ability to swim along the field lines of a magnetic field, which in their natural environment is provided by the magnetic field of the Earth. They do so with the help of specialized magnetic organelles called magnetosomes, vesicles containing magnetic crystals. Magnetosomes are aligned along cytoskeletal filaments to give linear structures that can function as intracellular compass needles. The predominant viewpoint is that the cells passively align with an external magnetic field, just like a macroscopic compass needle, but swim actively along the field lines, propelled by their flagella. In this minireview, we give an introduction to this intriguing bacterial behavior and discuss recent advances in understanding it, with a focus on the swimming directionality, which is not only affected by magnetic fields, but also by gradients of the oxygen concentration.

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“…Our comprehensive TEM observations demonstrate that whatever the initial growth directions, the final elongation direction is always [001]. It is still unknown whether the kinking growth of MYR-1 magnetite originates from the kinked shape of magnetosome membrane or/and multiple-step regulation by specific protein(s) [6,37], or other nonbiological influence such as magnetic interactions [21,43,44]. An alternative hypothesis is that the usual cubo-octahedral equilibrium shape of magnetite is related to the fastest growth direction of magnetite, i.e.…”

Section: Crystal Growth and Molecular Mechanismsmentioning

confidence: 99%

Crystal growth of bullet-shaped magnetite in magnetotactic bacteria of theNitrospiraephylum

Menguy

Gatel

et al. 2015

J. R. Soc. Interface.

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Magnetotactic bacteria (MTB) are known to produce single-domain magnetite or greigite crystals within intracellular membrane organelles and to navigate along the Earth's magnetic field lines. MTB have been suggested as being one of the most ancient biomineralizing metabolisms on the Earth and they represent a fundamental model of intracellular biomineralization. Moreover, the determination of their specific crystallographic signature (e.g. structure and morphology) is essential for palaeoenvironmental and ancient-life studies. Yet, the mechanisms of MTB biomineralization remain poorly understood, although this process has been extensively studied in several cultured MTB strains in the Proteobacteria phylum. Here, we show a comprehensive transmission electron microscopy (TEM) study of magnetic and structural properties down to atomic scales on bullet-shaped magnetites produced by the uncultured strain MYR-1 belonging to the Nitrospirae phylum, a deeply branching phylogenetic MTB group. We observed a multiple-step crystal growth of MYR-1 magnetite: initial isotropic growth forming cubo-octahedral particles (less than approx. 40 nm), subsequent anisotropic growth and a systematic final elongation along [001] direction. During the crystal growth, one major f111g face is well developed and preserved at the larger basal end of the crystal. The basal f111g face appears to be terminated by a tetrahedral-octahedral-mixed iron surface, suggesting dimensional advantages for binding protein(s), which may template the crystallization of magnetite. This study offers new insights for understanding magnetite biomineralization within the Nitrospirae phylum.

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Magnetite Crystal Orientation in Magnetosome Chains

Cited by 49 publications

References 44 publications

Probing the Mechanical Properties of Magnetosome Chains in Living Magnetotactic Bacteria

Probing the Mechanical Properties of Magnetosome Chains in Living Magnetotactic Bacteria

Magnetotactic bacteria

Crystal growth of bullet-shaped magnetite in magnetotactic bacteria of theNitrospiraephylum

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