Figure 1. Model for magnetosome dynamics and scenarios of chain formation.

(A) The basic scenario: Magnetosomes are described by their position, the volume of the magnetite crystal they contain (brown circles) and the direction of their magnetic momentum (indicated by small red and green arrows). They move diffusively with diffusion coefficient D in one dimension, constrained by the cytoskeletal magnetosome filament along the cell axis, and interact through magnetic dipole-dipole interactions (A), which may either be attractive or repulsive (blue arrows). In other scenarios we simulate, the dynamics is modified by introducing a binding zone (dashed grey), in which diffusion is reduced by binding to the cytoskeleton (B), or active movement towards the center of the cell (C).