Xenbase Image ID: 49543

Fig. 8. Tail organizer activity persists in the chordoneural hinge. All embryos shown here result from the transplantation of tissue fragments into the blastocoele of early gastrulae by the Einsteck procedure. (A) Chordoneural hinge (bottom embryo) and prechordal plate (middle embryo) grafts from early tailbud (stage 25) embryos and a sham-operated embryo (top embryo) are shown. (B) contribution of FDA-labelled chordoneural hinge to the =induced secondary tail. The graft formed only a a small part of the induced tail; by histological analysis the labelled cells formed chordoneural hinge, notochord and some neural tissue ( not shown). (C) Low power view of the same embryo shown in B, showing the orientation of the secondary tail with respect to the host embryo. Note the presence of well-formed dorsal and ventral fins in the secondary tail. (D) Section of a secondary tail resulting from implantation of the tip of the tail of a 2-day tadpole ( stage 35); note the presence of notochord ( No) muscle blocks ( Mu) and neural tube (NT). (E) Graft of the tip of the tail of an unlabelled donor into a host embryo whose cytoplasm was labelled with rhodamine dextran; the majority of the induced tail structures , in particular the notochord and muscle, are red and therefore derived from the host. The tip pf the secondary tail ( outline indicated with arrowheads), and the neural tissue are unlabelled and presumably derived from the graft. The histology of the region indictated by brackets of the same embryo is shown in D. (F) Graft fragment of a rhodamine dextran marked neural tissue obtained from the hindbrain of a stage 30 embryo; (F') Histological section through a similar graft. Hindbrain grafts fail to induce structures. (G) Implanted rhodamine dextran-labelled notochord (stage 30, from the middle third of the embryo and of a similar size to the implant in B); (G') histological section through a similar graft. Notochord does not induce significant structures in the Einstick assay. Cg, cement gland; CNH, chordoneural hinge; DF dorsal fin; VF ventral fin; 1', primary tail, 2', secondary tail; Ne neural tissues; No, notochord. Image published in: Gont LK et al. (1993) Copyright © 1993. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View

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