(A, C, D) Parts of thin-sectioned cells; scale bar, 200 nm; (B) whole sectioned cell; scale bar, 1 μm. C, cytoplasm; P, periplasm; OM, outer membrane. Arrowheads in (A) show areas of the OM where two lines are visible; the arrow marks a vesicle getting into close contact with the OM. Arrows in (B) show the inner and outer leaflets of the OM, where they are separated. Arrows in (C) show vesicles getting into close contact with the OM, and one vesicle just fusing with the OM. Arrowheads in (D) mark a vesicle blebbing outwards from the OM.