Figure 7.

Representative images of TEM showing Acanthamoeba isolates containing intracellular bacteria. (A) Overview of an Acanthamoeba trophozoite (Indian corneal isolate) harbouring intracellular bacteria. (A.i-ii) Higher magnification showing rod (white arrow) and cocci (blue arrow) shaped bacteria inside early phagocytic (i) or PV (ii), and bacterial cells were also observed in trophozoite cytoplasm (ii). A bacterium undergoing binary fission (asterisk) and digested bacteria (arrowhead) appear disintegrated surrounded by multiple layers (yellow arrow) (ii). (B) Engulfed bacteria appeared disintegrated and digested inside PV surrounded by multiple layers (Australian water isolate). (C) Rod and spherical shaped bacterial cells close to host NM appears enclosed by double-membranous vacuole and disintegrated (arrowhead). And a bacterial cell is undergoing binary fission (Australian corneal isolate). (D) Engulfed bacteria appeared disintegrated and digested inside PV close to host NM. Both digested and undigested bacteria in the same PV consisting multiple layers of membrane. (E) Digested and undigested cocci bacteria in the same PV. Symbols = EPV: early phagocytic vacuole; PV: phagocytic vacuole; M: mitochondria; N: nucleus; NM: nuclear membrane; NP: nuclear pore; DV: digestive vacuole; CV: contractile vacuole; white arrow: rod bacteria; blue arrow: spherical bacteria; arrowhead: digested bacteria; yellow arrow: surrounded by multiple layers; asterisk (^*): binary fission; alpha (α): electron translucent space. The lengths of bars in the bottom right corner of each image represent 500 nm except A (1 μm), and D (1 μm).