Cryo-TEM visualization of O-IMVs in pathogenic bacteria.

<p>Cryo-electron micrographs showing whole plunge-frozen cells from three pathogenic bacteria, and their derived O-IMVs: (A) <i>N</i>. <i>gonorrhoeae</i>, (B) <i>Pseudomonas</i> PAO1, and (C) <i>A</i>. <i>baumannii</i>. Whole cells with well-defined envelopes are observed in A and B (large black squares show a magnified area of cell envelopes). The new O-IMVs in the three analyzed samples exhibit the same double layer as cells, and are filled with an electron-dense material similar to that seen in the cell cytoplasm (large white squares show a magnified area of the O-IMV). Conventional OMVs are also visualized in images A and C (black arrows). OM: Outer Membrane; PM: Plasma membrane; PG: Peptidoglycan. Bars, 500 nm (A, C) and 250 nm (B). <b> </b>