Biosynthesis and Intracellular Organization of Magnetosomes in Magnetotactic Bacteria

Magnetotactic bacteria are ubiquitous aquatic microorganisms capable of orientation within the earth’s magnetic field. They receive their stunning proficiency from magnetosomes, which are unique organelles used to synthesize nanometer-sized crystals of magnetic iron minerals. Most of these microorganisms cannot be cultivated under laboratory conditions, much less genetically engineered with only few exceptions. However, two Magnetospirillum species have emerged as model organisms to study magnetosome formation and magnetotaxis on genetic level, and within the past decade, much has been revealed about the process of magnetosome biogenesis. In this chapter, we summarize these new insights and place the molecular mechanisms of magnetosome formation in the context of the complex cell biology of Magnetospirillum spp. After giving an overview of magnetosome vesicle synthesis and biomineralization, we focus on recent findings in positioning and dynamics of the organelles and the biological implications of it, which emphasize that magnetotactic spirilla have evolved sophisticated mechanisms to construct, incorporate, and inherit a navigational device perfectly.