Abstract
Magnetotactic bacteria comprise several aquatic species that orient and migrate along geomagnetic field lines. This behavior is based on the presence of intracellular ferrimagnetic grains of the minerals magnetite (Fe3O4) or greigite (Fe3S4). Whereas the structural and magnetic properties of magnetite magnetosomes have been studied extensively, the properties of greigite magnetosomes are less well known. Here we present a study of the magnetic microstructures, chemical compositions, and threedimensional morphologies and positions of Fe-sulfide crystals in air-dried cells of magnetotactic bacteria. Data were obtained using several transmission electron microscopy techniques that include electron holography, energy-filtered imaging, electron tomography, selected-area electron diffraction, and high-resolution imaging. The studied rod-shaped cells typically contain multiple chains of greigite magnetosomes that have random shapes and orientations. Many of the greigite crystals appear to be only weakly magnetic, because the direction of their magnetic induction is almost parallel to the electron beam. Nevertheless, the magnetosomes collectively comprise a permanent magnetic dipole moment that is sufficient for magnetotaxis. One of the cells, which is imaged at the point of dividing, contains multiple chains of both equidimensional Fe-sulfide and elongated Fe-oxide crystals. The equidimensional and elongated crystals have magnetic properties that are consistent with those of greigite and magnetite, respectively. These results can be useful for obtaining a better understanding of the function of magnetotaxis in sulfide-producing cells, and they have implications for the interpretation of the paleomagnetic signals of greigite-bearing sedimentary rocks.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Low-temperature Zr mobility: An in situ synchrotron-radiation XRF study of the effect of radiation damage in zircon on the element release in H2O + HCl ± SiO2 fluids
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- The arrojadite enigma: I. A new formula and a new model for the arrojadite structure
- The arrojadite enigma: II. Compositional space, new members, and nomenclature of the group
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- The fate of smectite in KOH solutions
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Articles in the same Issue
- Low-temperature Zr mobility: An in situ synchrotron-radiation XRF study of the effect of radiation damage in zircon on the element release in H2O + HCl ± SiO2 fluids
- Magnetic properties, microstructure, composition, and morphology of greigite nanocrystals in magnetotactic bacteria from electron holography and tomography
- Site preference and local geometry of Sc in garnets: Part I. Multifarious mechanisms in the pyrope-grossular join
- Site preference and local geometry of Sc in garnets: Part II. The crystal-chemistry of octahedral Sc in the andradite–Ca3Sc2Si3O12 join
- The arrojadite enigma: I. A new formula and a new model for the arrojadite structure
- The arrojadite enigma: II. Compositional space, new members, and nomenclature of the group
- Single-crystal X-ray diffraction and temperature dependent 57Fe Mössbauer spectroscopy on the hedenbergite-aegirine (Ca,Na)(Fe2+,Fe3+)Si2O6 solid solution
- Stacking structures in pyrophyllite revealed by high-resolution transmission electron microscopy (HRTEM)
- Intensity of quartz cathodoluminescence and trace-element content in quartz from the porphyry copper deposit at Butte, Montana
- The fate of smectite in KOH solutions
- Light-induced changes in molecular arsenic sulfides: State of the art and new evidence by single-crystal X-ray diffraction
- Verifying and quantifying carbon Þ xation in minerals from serpentine-rich mine tailings using the Rietveld method with X-ray powder diffraction data
- Generation of pressures to ~60 GPa in Kawai-type apparatus and stability of MnGeO3 perovskite at high pressure and high temperature
- A model to predict phase equilibrium of CH4 and CO2 clathrate hydrate in aqueous electrolyte solutions
- Raman investigation of H2O molecule and hydroxyl groups in the channels of hemimorphite
- Stacking structure in disordered talc: Interpretation of its X-ray diffraction pattern by using pattern simulation and high-resolution transmission electron microscopy
- Electrical conductivities of pyrope-almandine garnets up to 19 GPa and 1700 °C
- Crystal chemistry and polytypism of tyrolite
- Effect of melt structure on trace-element partitioning between clinopyroxene and silicic, alkaline, aluminous melts
- Analysis of light lithophile elements (Li, Be, B) by laser ablation ICP-MS: Comparison between magnetic sector and quadrupole ICP-MS
- Stornesite-(Y), (Y, Ca)⃞2Na6(Ca,Na)8(Mg,Fe)43(PO4)36, the first terrestrial Mg-dominant member of the fillowite group, from granulite-facies paragneiss in the Larsemann Hills, Prydz Bay, East Antarctica
- Electron paramagnetic resonance spectroscopic study of carbonate-bearing fluorapatite: New defect centers and constraints on the incorporation of carbonate ions in apatites
- EXAFS signature of structural Zn at trace levels in natural and synthetic trioctahedral 2:1 phyllosilicates
- A neutron powder diffraction study of Fe and Ni distributions in synthetic pentlandite and violarite using 60Ni isotope
- Letter. Quantification of amphibole content in expanded vermiculite products from Libby, Montana U.S.A. using powder X-ray diffraction