Figure 7.

The effect of AZT and metronidazole on G. intestinalis cyst formation and total cell numbers. Treatment with pure encystation medium (control), DMSO, AZT, or metronidazole started at different time points during the encystation process. After completion of the encystation period (28 h) and subsequent treatment, the cells were categorized based on their staining with FDA (measuring metabolic activity) and PI (measuring DNA content). The PI staining requires a leaky membrane, and different genome amplification levels could therefore not be determined in the intact FDA⁺ cysts. Numbers given are normalized to be per 100,000 seeded trophozoites. Intact cysts (FDA⁺, PI⁻) are colored green, whereas the PI⁺ cysts (nearly all of them FDA⁻) are categorized according to their ploidy into 4N (orange), 8N (red), and 16N (black). Cysts that did not stain at all are marked in yellow. AZT, azidothymidine; DMSO, dimethyl sulfoxide; FDA, fluorescein diacetate; PI, propidium iodide.