Fig. 1

(a₁–d₁) DCFH-DA reveals the gut lumen formation process at 2–4.5 dpf in the lateral view. (a₂–d₂) The dorsal view of the pattern of a₁–d₁ at 2–4.5 dpf. The red arrows in a₁–d₂ represent the intestinal lumen formation processes, which initially show a dashed line pattern (boxed region in a₁–b₁, red arrows in a₂) at 2 dpf and merge thereafter. The red arrowheads in a₁ to d₂ indicate the formation of the intestine bulb from 2 dpf, which increases in size at 2.5 dpf (b₁ and b₂), 3.5 dpf (c₁ and c₂) and 4.5 dpf (d₁ and d₂). (e₁–f₄) The staining patterns of DCFH-DA at later stages, 5 dpf (e₁–e₄) and 6 dpf (f₁–f₄). e₁–e₂ are lateral with regard to the gut after staining, and e₂ is the image of e₁ merged with DIC. The blue arrows in e₁ and e₂ indicate that the dye marks the pronephric ducts in addition to the gut lumen, as indicated by red arrows. e₃–e₄ shows the dorsal view of the pattern, which indicates that the dye clearly labels the gallbladder (white arrows). e₄ is the image of e₃ merged with DIC. f₁–f₄ are the lateral views of the gut at 6 dpf, and f₂ and f₄ are the images of f₁ and f₃ merged with DIC. f₃ and f₄ are high magnifications of the boxed images in f₁ and f₂. The white arrowheads in f₃ and f₄ indicate the folding of the gut epithelium during the formation of crypt-like architecture. (g–h) The dye emitting from the mouth (g) and anus (h). The red arrows represent the circular signals of the emitting dye under the GFP channel.