(E, F) Optical section (E) (scale bar: 5 µm) and distribution of the fluorescence signal intensity (F) of A. castellanii infected with mCherry-producing L. pneumophila JR32 (Ptac-mCherry-PflaA-gfp) for 48 h. The plot profile was analyzed for an optical section in the center of an infected host cell and shows the intensity of the green and red channels, respectively (representative of n = 10). The GFP signal mainly localizes to the periphery of the bacterial cluster. 