Open-faced explants

Open-faced explants are ones having the inner, deep cells exposed to the medium, often for the purpose of studying deep cell motility (39,46,66,67,70), and thus Danilchik s (DFA) medium is used. A culture chamber for these explants is made by drilling a 20-mm hole in a 60-mm plastic Petri dish and gluing a 1.5, 24-mm coverslip over the hole with silicone high vacuum grease... 

Fig. 7. Time-lapse video microscopy of the inner surface of an open-faced explant shows the tendency of mesodermal cells to migrate animally on the inner surface of the prospective neural tissue. As the bulk of the mesoderm convCTges and extends vegetally (arrows. A), a numba- of individual mesodermal cells break off from the posterior edge of the mesoderm and migrate on the inner surface of the prospective neural ectoderm (pointers. A). In some cases, large tongues of mesodermal cells may migrate animally (white arrows, B) while the rest of the mesoderm converges (C) and extends (E) vegetally (black arrows, B). Photos courtesy of John Shih.

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