(G) Transmission electron micrographs of A. castellanii infected with L. pneumophila. A. castellanii was infected (MOI 5, 42 h) with L. pneumophila wild-type strain JR32 and subjected to high-pressure freezing and electron microscopy. Many LCVs were still intact at 42 h post infection (left panel; arrow: intact LCV membrane, arrowhead plasma membrane), and occasionally, the bacteria were flagellated (middle panel, arrow). Some LCVs were already ruptured, and the bacteria were released into the host cell cytosol (right panel; arrows: ruptured LCV membrane). Scale bars: 2 µm, 0.5 µm (insets). 