Magnetospirillum magnetotacticum
M. magnetotacticum is a motile spirillum, 0.5 x 5 microns, belonging to the alpha-subdivision of the proteobacteria. It is microaerophilic, requires a complex nutrient medium and grows very slowly. Its most interesting property is that it forms single-domain crystals of the mineral magnetite (Fe3O4). The crystals are arranged in long chains called magnetosomes and are oriented so that the magnetic moments are additive and the magnetosome functions as a bar magnet. Magnetite is valuable not only for its magnetic characteristics and hardness as a material, but also for its potential as a geobiological tracer. The organism is being studied in the Paleomagnetic Lab in the Geology Division for its role in the biogenesis of magnetite and the evolution of the magnetotactic response in higher organisms. Our class projects are aimed at understanding how - and why - the organism makes magnetite.
