FIG 1.

Transmission electron micrographs of magnetotactic bacteria isolated from the same sampling bottle collected from the Mediterranean Sea at the Calanque of Méjean near Marseille, France. At least 8 morphotypes were observed, including magnetotactic cocci of a different size that biomineralize one, two, or a cluster of chains of octahedral or elongated prismatic magnetosomes (A to C), a magnetotactic multicellular prokaryote that biomineralizes bullet-shaped magnetosomes (D), curved rods that biomineralize bullet-shaped magnetosomes (E and F), and spirilla or vibrios that biomineralize elongated prismatic magnetosomes (G and H). Note that only magnetite-type magnetosomes were observed. No MTB with magnetosomes resembling greigite were observed in this sample.