Fig. 6

Effects of SHH and FGF signal inhibitors on morphology of catfish embryos. Specimens were observed by microscopy (a–c) and SEM (d–f). In the developing catfish, SHH and FGF inhibitors (10 μM of Cyclopamine in b, e and 10 μM of SU5402 in c, f) affect morphogenesis of the craniofacial region. SHH inhibitor induced malformation of mandibular apparatus and reduced the length of maxillary barbels (b, e). In addition, mandibular barbels disappeared in cyclopamine-treated embryos (arrowheads in e). FGF inhibitor caused malformation of maxillary and mandibular barbels (c, f), whereas the craniofacial morphology appeared normal. g shows schematics of the dorsal (left), ventral (middle), and lateral (right) sides of the catfish. i–v are morphological cues used for quantification: i, length of the maxillary barbel; ii, length of the anterior mandibular barbel; iii, length of the posterior mandibular barbel; iv, width of the maxillary region; v, total length. h–q, quantification of the length of barbels (h–j, m–o), width of maxillary region (k, p), and total length (l, q) in cyclopamine-treated embryos (h–l) and SU5402-treated embryos (m–q) at 5 dpf. Inhibition of SHH induced significant abnormality in both maxillary and mandibular barbels (h–j) and maxillary apparatus (k). However, cyclopamine did not affect total length (l). Inhibition of FGFs significantly induced abnormality in both maxillary and mandibular barbels (m–o), while maxillary width and total length appeared normal (p, q). Error bars are standard deviations (SD). Data denoted by the same letter do not differ significantly (* P > 0.05; ** P > 0.01; *** P > 0.001) based on Tukey’s HSD test or the Steel–Dwass test after analysis of homogeneity of variance with Bartlett’s test. mdb, mandibular barbel; mxb, maxillary barbel. Anterior is left in a–c and the upper side in d–f. Scale bars are 500 μm