FIG 2.

Schematic overview (left) and transmission electron micrograph (right) of a Kuenenia stuttgartiensis cell. The cell plan is divided into three compartments, separated by three bilayer membranes. From outside to inside: surface-layer protein (35), outer membrane, peptidoglycan-containing periplasm (36), cytoplasmic membrane, cytoplasm, anammoxosome membrane, anammoxosome that contains tubule-like structures (white arrowheads), and electron-dense, iron-rich particles (black arrowheads). Note that not all tubule-like structures visible in the micrograph were visualized in the schematic overview. Scale bar, 500 nm.