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Fig. 3. Neural signals and differentiation in exogastrulae and open-face explants. (A) Pseudoexogastrulae (Xenopus) prepared by microdissection described in Fig. 1. After 24 h the exogastrulae were fixed for whole-mount in situ hybridization with a neural specific f3-tubulin. The signal (neural specific tubulin) is seen only in the intermediate zone between the ectoderm and the endomesoderm farrows). (B) Open-face explant without the superficial/ayer prepared by the technique described in Fig 2. The signal of the neural-specific beta-tubulins seen in the intermediate zone between chordamesoderm and ectoderm (ee) only (arrows). (C) Open-face explant with superficial and inner layers prepared by the technique described in Fig. 2. The signal of the neural specific r3-tubulin is expressed in the intermediate zone between chordamesoderm and ectoderm (ec) only (arrow). The other explant on the left side also shows faint staining in the middle part of the ectoderm (arrowhead). (D) Histological section of an open-face explant contains a few neural cells (neu) in the vicinity of notochord (no) only. ce, cement gland in the ectodermal part of the explant. The blue color in this micrograph represents anilin-blue (normal histology), which has stained the mucous material of the cement gland. tEl A selection of pseudoexogastrulae (Triturus alpestris) prepared by microdissection descnbed under Fig. 1. After 10 days culture at 2OoC the ectoderm has separated from the endomesoderm (end) and has differentiated into atypical (ciliated) epidermis (ec). IF) Histological section of the explant of panel E (arrow) shows that archencephalic brain structures (eye with lens, arrow) have differentiated in the intermediate zone between atypical epldermls(ec) and the endomesodermal area only. Most of the ectodermal parr (only one third is shown) has differentiated into atypical epidermis (ciliated) epidermis only. notochord (no), somites(so). |
