C-F. Immunofluorescence images of esg-GFP and Delta (Dl) staining with the midgut section from the R4 region of 14-day Drosophila (C), 26-day Drosophila (D), 40-day Drosophila (E), and 40-day Drosophila in response to 0.5 mM ALA administration, which started at day 26 after eclosion (F). esg-GFP (green) identifies ISCs and their differentiating cells. Dl staining (red) was used to visualize ISCs. Data information: DAPI stained nuclei are shown in blue. 