Figure 4

Amoebae invade the locust's flight muscles as well as fat body surrounding the locust brain. Dorsal-longitudinal flight muscle of Acanthamoeba-infected locusts were fixed in 4% paraformaldehyde and stained with Harris' haematoxylin and eosin. To determine infiltration of amoebae into the deep layers of muscle tissues, surface layers were removed and only deep tissues were sectioned. Trophozoites of amoebae (indicated by arrows) were detected in these tissue samples on days 5 (C) and 7 (D) post-infection, but not on day 3 (B), nor in control muscles (A). Degenerative changes of the tissues caused by the amoebae are significant on days 5 and 7. Note that the above images are representative micrographs of the genotype T4, but, similar results were observed with the T1 genotype. Magnification is × 400. (ii) Fat body surrounding the brain of Acanthamoeba-injected locusts was examined on days 3, 5 and 7 after injection. A large numbers of amoebae (pointed by arrowheads) were identified in the fat body on days 5 (C) and 7 (D) after injection. However, they were found in much fewer numbers on day 3 (B). No amoeba was observed in the fat body of control locusts (A). Note that the above images are representative micrographs of the genotype T4, but, similar results were observed with the T1 genotype. Magtnification is × 400.