Fig 3.

(A) Phylogenetic tree of 16S rRNA gene sequences, constructed based on the neighbor-joining method. Bootstrap values at each node are based on 1,000 replicates. (B to D) The same microscopic field after staining with DAPI (B), after hybridization with 5′-6-carboxyfluorescein (FAM)-labeled bacterial universal probe EUB338 (C), and after hybridization with a 5′-Cy3-labeled probe SRB385Db (D). Arrows indicate MTB vibrios and MTB cocci as negative controls. (E) TEM images of magnetite and greigite magnetosome-mineralizing rod-shaped bacteria from the Xi'an city moat. (F) The rod-shaped bacteria synthesize both irregular rectangular and bullet-shaped magnetosomes. (G and H) HRTEM analyses of an irregular rectangular magnetosome and a bullet-shaped magnetosome, respectively. (I and J) EDX analyses of the irregular rectangular magnetosome and the bullet-shaped magnetosome shown in panels G and H, respectively. EDX analyses and HRTEM imaging on individual particles indicate that the mineral phase of irregular rectangular and bullet-shaped magnetosomes is greigite and magnetite, respectively.