Structure, Morphology and Crystal Growth of Bacterial Magnetite

Author Info

Stephen Mann, University of Oxford
Richard B. Frankel, Massachusetts Institute of TechnologyFollow
Richard P. Blakemore, University of New Hampshire

Recommended Citation

Postprint version. Published in Nature, Volume 310, Issue 5976, August 2, 1984, pages 405-407.

NOTE: At the time of publication, the author Richard B. Frankel was not yet affiliated with Cal Poly.

The definitive version is available at https://doi.org/10.1038/310405a0.

Abstract

Recent high-resolution transmission electron microscopy (HRTEM) studies of the structure and morphology of bacterial magnetite (Fe₃O₄) crystals isolated from a magnetotactic coccus¹ and from an unidentified bacterium extracted from sediment² have shown the crystals to be well ordered single-domain particles with a morphology based on a hexagonal prism of {011} faces truncated by specific low index planes. We report here a HRTEM study of intact magnetite crystals (magnetosomes) in the microaerophilic bacterium Aquaspirillum magnetotacticum, grown in pure culture^3,4. Our aim has been to investigate the structure, morphology and crystal growth of the magnetite particles in the light of a recent Mossbauer spectroscopy study of this organism⁵ which indicated, in addition to magnetite, the presence of hydrated iron(III) oxide phases together with the magnetosomes. Our results show that the mature particles are well ordered single-domain crystals of magnetite with a morphology very different from previously studied crystals and based on an octahedral prism of {111} faces truncated by {100} faces. We also show the first direct evidence for both crystalline and non-crystalline phases within individual magnetosomes. The results are important in aiding elucidation of the crystal growth mechanisms of biogenic magnetite.

Disciplines

Physics

Copyright

1984 Nature Publishing Group.