Postprint version. Published in Biophysical Journal, Volume 46, Issue 1, July 1, 1984, pages 57-64.
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/10.1016/S0006-3495(84)83998-3.
Diffusive motions of the magnetosomes (enveloped Fe3O4 particles) in the magnetotactic bacterium Aquaspirillum magnetotacticum result in a very broad-line Mössbauer spectrum (T ~ 100 mm/s) above freezing temperatures. The line width increases with increasing temperature. The data are analyzed using a bounded diffusion model to yield the rotational and translational motions of the magnetosomes as well as the effective viscosity of the material surrounding the magnetosomes. The results are <θ2>l/2 < 1.5° and <x2>1/2 < 8.4 Å for the rotational and translational motions, respectively, implying that the particles are fixed in whole cells. The effective viscosity is 10 cP at 295 K and increases with decreasing temperature. Additional Fe3+ material in the cell is shown to be associated with the magnetosomes. Fe2+ material in the cell appears to be associated with the cell envelope.