Microscopy studies on uncultivated magnetotactic bacteria

Magnetotactic bacteria are characterized by the magnetosome, a membrane-bound, nano-sized organelle containing a magnetic crystal. This organelle is believed to help the bacteria to navigate along the geomagnetic field lines and find a preferred habitat for survival. The magnetosome is a biomineral structure highly controlled by the bacteria, composed of either magnetite (Fe3O4) or greigite (Fe3S4), and arranged in one or more linear chains in the cell. Most magnetotactic bacteria are not cultivated and studies rely on environmental samples, where microscopy techniques are powerful tools for the structural characterization of the bacteria and their magnetosomes. Here, we show examples of the application of microscopy techniques to the study of uncultivated magnetotactic bacteria