1-20 OF 165 RESULTS FOR

magnetosomes

Results shown limited to content with bounding coordinates.
Save search
Follow your search
Access your saved searches in your account
Would you like to receive an alert when new items match your search?
Close Modal
Sort by
Journal Article

Environmental parameters affect the physical properties of fast-growing magnetosomes

Damien Faivre, Nicolas Menguy, Mihály Pósfai, Dirk Schüler
Published: 01 February 2008
American Mineralogist (2008) 93 (2-3): 463–469.
DOI: https://doi.org/10.2138/am.2008.2678
...Damien Faivre; Nicolas Menguy; Mihály Pósfai; Dirk Schüler Abstract Magnetotactic bacteria are known to mediate the formation of intracellular magnetic nanoparticles in organelles called magnetosomes. These magnetite crystals are formed through a process called biologically controlled...
FIGURES | View All (5)
View PDF for article title, Environmental parameters affect the physical properties of fast-growing <span class="search-highlight">magnetosomes</span>
Purchase
Add to Citation Manager for Environmental parameters affect the physical properties of fast-growing <span class="search-highlight">magnetosomes</span>
Journal Article

Manganese incorporation into the magnetosome magnetite: magnetic signature of doping

Tanya Prozorov, Teresa Perez-Gonzalez, Carmen Valverde-Tercedor, Concepcion Jimenez-Lopez, Africa Yebra-Rodriguez, André Körnig, Damien Faivre, Surya K. Mallapragada, Paul A. Howse, Dennis A. Bazylinski, Ruslan Prozorov
Published: 01 August 2014
European Journal of Mineralogy (2014) 26 (4): 457–471.
DOI: https://doi.org/10.1127/0935-1221/2014/0026-2388
... bacterium, Magnetospirillum gryphiswaldense strain MSR-1 were grown in the presence of manganese, ruthenium, zinc and vanadium, of which only manganese was incorporated within the magnetosome magnetite crystals. We demonstrate that the magnetic properties of magnetite crystals of magnetotactic bacteria can...
FIGURES | View All (6)
View PDF for article title, Manganese incorporation into the <span class="search-highlight">magnetosome</span> magnetite: magnetic signature of doping
Purchase
Add to Citation Manager for Manganese incorporation into the <span class="search-highlight">magnetosome</span> magnetite: magnetic signature of doping
Image
Model for magnetosome formation and iron biomineralization in magnetotactic bacteria. First, magnetosome vesicles invaginate from the inner cell membrane. Second, vesicles are arranged in chains and magnetite nucleates in empty magnetosomes. Iron is incorporated as reduced (Fe(II)) and/or (Fe(III)) species and stored in the intracellular medium as oxidized iron bound to proteins. Partial reduction of this pool generates Fe(II) for delivery to magnetosomes, in which Fe(II) is partially oxidized for magnetite precipitation. Finally, magnetite size and shape are tightly controlled to provide a magnetic dipole to the bacteria. Green and red arrows point to the reduced (Fe(II)) and oxidized (Fe(III)) pathways, respectively.

Model for magnetosome formation and iron biomineralization in magnetotactic...

Published: 01 August 2023
Figure 4. Model for magnetosome formation and iron biomineralization in magnetotactic bacteria. First, magnetosome vesicles invaginate from the inner cell membrane. Second, vesicles are arranged in chains and magnetite nucleates in empty magnetosomes. Iron is incorporated as reduced (Fe(II
Image
Examples of comparisons between the projected shapes of magnetosomes, as observed in HRTEM images, and morphological models that consist of various expressions of the {111}, {100}, and {110} forms. The models are shown in the same orientation as the corresponding magnetosomes, for which the crystallographic orientation was determined from their FFT values (shown in the second column of the figures). (a) Crystallites, sampled 55 min after Fe induction (scale bar = 4 nm). The crystallites appear rounded and have irregular shapes, making a meaningful identification of their morphologies impossible. The shapes of the crystallites vaguely match almost any of the idealized model morphologies.( b) Mature magnetosomes, sampled 340 min after Fe induction (scale bar = 10 nm). The projected outlines of the magnetosomes are consistent with the cube-like models (c) Reference magnetosomes, formed in continuously growing and Fe-supplemented cells (scale bar = 10 nm). The outlines of the magnetosomes and the thickness fringes in their HRTEM images are consistent with the cuboctahedral models.

Examples of comparisons between the projected shapes of magnetosomes, as ob...

Published: 01 February 2008
F igure 3. Examples of comparisons between the projected shapes of magnetosomes, as observed in HRTEM images, and morphological models that consist of various expressions of the {111}, {100}, and {110} forms. The models are shown in the same orientation as the corresponding magnetosomes
Image
Examples of comparisons between the projected shapes of magnetosomes, as observed in HRTEM images, and morphological models that consist of various expressions of the {111}, {100}, and {110} forms. The models are shown in the same orientation as the corresponding magnetosomes, for which the crystallographic orientation was determined from their FFT values (shown in the second column of the figures). (a) Crystallites, sampled 55 min after Fe induction (scale bar = 4 nm). The crystallites appear rounded and have irregular shapes, making a meaningful identification of their morphologies impossible. The shapes of the crystallites vaguely match almost any of the idealized model morphologies.( b) Mature magnetosomes, sampled 340 min after Fe induction (scale bar = 10 nm). The projected outlines of the magnetosomes are consistent with the cube-like models (c) Reference magnetosomes, formed in continuously growing and Fe-supplemented cells (scale bar = 10 nm). The outlines of the magnetosomes and the thickness fringes in their HRTEM images are consistent with the cuboctahedral models.

Examples of comparisons between the projected shapes of magnetosomes, as ob...

Published: 01 February 2008
F igure 3. Examples of comparisons between the projected shapes of magnetosomes, as observed in HRTEM images, and morphological models that consist of various expressions of the {111}, {100}, and {110} forms. The models are shown in the same orientation as the corresponding magnetosomes
Image
Electron holography of a magnetotactic bacterium showing magnetic field lines associated with the magnetosomes. (top) transmission electron micrograph of an unstained cell of Magnetospirillum magnetotacticum showing chain of magnetite magnetosomes. (bottom) Magnetic field lines generated from the magnetic contribution to the holographic phase overlaid onto the positions of the magnetosomes. Note that most of the magnetic field lines run parallel to the magnetosome chain showing that that the chain acts as a single magnetic dipole. (Figure adapted from Dunin-Borkowski et al. 1998).

Electron holography of a magnetotactic bacterium showing magnetic field lin...

Published: 03 January 2003
Figure 5. Electron holography of a magnetotactic bacterium showing magnetic field lines associated with the magnetosomes. ( top ) transmission electron micrograph of an unstained cell of Magnetospirillum magnetotacticum showing chain of magnetite magnetosomes. ( bottom ) Magnetic field lines
Image
Transmission electron micrograph of a thin-section of several magnetite magnetosomes within a lysing cell of the marine coccus strain MC-1. Arrows denote the electron-dense magnetosome membrane surrounding each crystal. Note that magnetosome membrane is adjacent to cytoplasmic membrane.

Transmission electron micrograph of a thin-section of several magnetite mag...

Published: 03 January 2003
Figure 7. Transmission electron micrograph of a thin-section of several magnetite magnetosomes within a lysing cell of the marine coccus strain MC-1. Arrows denote the electron-dense magnetosome membrane surrounding each crystal. Note that magnetosome membrane is adjacent to cytoplasmic membrane.
Image
Transmission electron micrographs obtained with high-angle annular dark-field detector (HAADF) and EDS spectra for (a) magnetite-containing magnetosomes from lysed cells of Magnetospirillum gryphiswaldense strain MSR-1 grown in the presence of 50 μM MnCl2 and 50 μM ferric citrate. The EDX spectra collected on individual magnetosomes clearly demonstrate the presence of manganese in the magnetosomes magnetite; (b) magnetosomes from lysed cells of Magnetospirillum gryphiswaldense strain MSR-1 grown only with 50 μM ferric citrate. No manganese was detected in these magnetosomes, despite that the area in these measurements (~65,000 nm2) was several times larger compared to that depicted in (a) (~100 nm2). Top right: SAED pattern. Note: the significant Cu signal in the EDS spectra originates from the copper grids. The occasional Si signal is attributed to Si escape peaks from the solid-state EDX detector. (Online version in color)

Transmission electron micrographs obtained with high-angle annular dark-fie...

Published: 01 August 2014
Fig. 1 Transmission electron micrographs obtained with high-angle annular dark-field detector (HAADF) and EDS spectra for (a) magnetite-containing magnetosomes from lysed cells of Magnetospirillum gryphiswaldense strain MSR-1 grown in the presence of 50 μM MnCl 2 and 50 μM ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image

Features of cells and magnetosomes produced by cells of Magnetospirillum g...

Published: 01 August 2014
Table 1 Features of cells and magnetosomes produced by cells of Magnetospirillum gryphiswaldense strain MSR-1 grown with 50 μM ferric citrate and 50 μM of an addition metal. Cells for the inoculum for all cultures were pregrown in medium lacking the major source of iron, ferric citrate
Image
Magnetic states of magnetofossils visualized with electron holography. Colors indicate the direction of flux line inside the magnetosomes (see color wheel on the left). (A) Single-domain (SD) state of an isolated magnetosomal magnetite particle. (B) Two double chains of prismatic magnetosomal magnetite particles in a freshwater coccus. The lower double chain is in an SD state, while the upper double chain is in a partial flux-closure state as seen by the opposed magnetization of the right half of the upper strand. Image credits available at http://doi.org/10.5281/zenodo.8023370.

Magnetic states of magnetofossils visualized with electron holography. Colo...

Published: 01 August 2023
Figure 2. Magnetic states of magnetofossils visualized with electron holography. Colors indicate the direction of flux line inside the magnetosomes (see color wheel on the left). ( A ) Single-domain (SD) state of an isolated magnetosomal magnetite particle. ( B ) Two double chains of prismatic
Image
Contoured image derived from the difference in holographic phase images of Itaipu 1 magnetosomes after application of applied fields as indicated by double-headed arrow. The density of flux lines for smaller Itaipu 3 magnetosomes indicates magnetic reversal for these crystals. See text for discussion of contour pattern in larger Itaipu 1 magnetosomes.

Contoured image derived from the difference in holographic phase images of ...

Published: 01 July 2001
Fig. 4. Contoured image derived from the difference in holographic phase images of Itaipu 1 magnetosomes after application of applied fields as indicated by double-headed arrow. The density of flux lines for smaller Itaipu 3 magnetosomes indicates magnetic reversal for these crystals. See text
Image
Electron microscopy images of multicellular magnetotactic prokaryotes (MMPs) isolated from sediments of the Mediterranean Sea near Marseille, France. (A) Scanning electron microscopy (SEM) image of an MMP observed at low voltage (1.00 kV) to show the surface of the cells (black arrowheads point the flagella). (B) SEM image of an MMP observed at high voltage (15.00 kV), using a backscattered electron detector, showing discontinuous aligned magnetosome chains inside the cells (white structures). (C) Transmission electron microscopy (TEM) image of an MMP showing the abundance of flagella on the cell surface (black arrowheads). Note that the magnetosomes inside the cells are not visible when the thick spherical structure is conserved during sample preparation. (D) TEM image of disaggre-gated cells of the MMP allows the observation of magnetosomes (here greigite magnetosomes) inside the cells (dark structures inside the cell). All scale bars represent 1 µm. Arrowheads point to flagella on the organism’s surface in (A) and (C).

Electron microscopy images of multicellular magnetotactic prokaryotes (MMPs...

Published: 01 August 2023
arrowheads point the flagella). ( B ) SEM image of an MMP observed at high voltage (15.00 kV), using a backscattered electron detector, showing discontinuous aligned magnetosome chains inside the cells (white structures). ( C ) Transmission electron microscopy (TEM) image of an MMP showing the abundance
Image
Transmission electron micrograph of: (a) purified magnetite magnetosomes released from cells of strain MV-1 negatively stained with 0.5% uranyl acetate; “halo” around crystals represents magnetosome membrane while material at arrows might indicate additional membranes holding chains together; (b) the same magnetosomes after treatment with 1% sodium deodecyl sulfate, a detergent that removes lipids.

Transmission electron micrograph of: (a) purified magnetite magnetosomes re...

Published: 03 January 2003
Figure 8. Transmission electron micrograph of: (a) purified magnetite magnetosomes released from cells of strain MV-1 negatively stained with 0.5% uranyl acetate; “halo” around crystals represents magnetosome membrane while material at arrows might indicate additional membranes holding chains
Image
Transmission electron microscopy (TEM) observations of magnetite grains in a magnetosome chain from hydrogenetic ferromanganese crust sample SCS-02 (A, South China Sea, 15°09′N, 117°23′E, water depth 2430 m) and a single magnetite magnetosome from sample PO-01 (D, Pacific Ocean 20°19′N, 174°10′E, water depth 2355 m); high-resolution TEM observations (B, E) and their corresponding diffraction pattern (fast Fourier transform) (C, F) for the magnetosomes in A and D, respectively. d(111) represents the interplanar spacing of the (111); that is, the distance between two nearest lattice planes (the parallel dashed lines shown in B and E). (G,H) Energy dispersive X-ray spectroscopy (EDS) spectra of single magnetosomes (selected areas of EDS analysis are indicated by the yellow and red rectangles in A and D).

Transmission electron microscopy (TEM) observations of magnetite grains in ...

Published: 03 January 2020
Figure 1. Transmission electron microscopy (TEM) observations of magnetite grains in a magnetosome chain from hydrogenetic ferromanganese crust sample SCS-02 (A, South China Sea, 15°09′N, 117°23′E, water depth 2430 m) and a single magnetite magnetosome from sample PO-01 (D, Pacific Ocean 20°19′N