Chick embryo grafting

Lakshml treated primitive-streak stage embryos with CN to study the effect on Hensen s node (related to the organization of the embryo). The embryos were incubated for 3 h after treatment the nodes were then excised, washed, and grafted to host chick embryos at the same stage. The results showed an inverse relation between the capacity for Induction of Hensen s node and exposure to CN. 

Saunders, J.W., Gasseling, M.T., Cairns, J.M. (1959). Differentiation of prospective thigh mesoderm grafted beneath the apical ectodermal ridge of the wing in the chick embryo. Dev Biol. 1,281 -301. 

Follow the method in section 18.2.2.2 to place a chick embryo in modified New (6) cnlture as if to receive a graft. 

Here the host emhryo is operated in ovo, which is suitahle with ease only for embryos older than about 36 8 h incubation. As an example, the operation described here consists of a graft of presomitic mesoderm (segmental plate) with a quail embryo as the donor and a chick embryo as the host. An identical procedure can be followed to transplant paraxial mesoderm that has already formed somites, but it should be remembered that this is much easier when it... 

Examples of the application of neural grafting in chick embryos have been to explore the role of a signaling region by transplanting it to an ectopic site... 

Fig. 2. Scheme of the orthotopic quail/chick neural tube transplantation. A chick embryo in ovo (Al) is microsurgicaUy deprived of its neural tube (A2) at the level of the last formed somites. The corresponding fragment of blastoderm of a quail at the same stage (Bl) is enzymatically dissociated. The isolated quaU neural tube (B2) is orthotopically grafted into the chick embryo (A3). 

Fig. 3. Scenario of the orthotopic graft of brain vesicles. (A) 12-somite chick embryo in ovo after injection of a solution of Indian ink under the blastoderm. Brain vesicles are well delineated. (B) Longitudinal incisions are made between the cephalic neural tube and the head mesenchyme to delimit the brain excision (arrows). (C) After a transversal section at the level of the mesencephalo-metencephalic constriction, the prosencephalon and the mesencephalon are separated from the head mesoderm and endoderm. The notochord (N) is then visible. (D) The excised chick brain vesicles are discarded. (E) The equivalent quail brain vesicles (Q) are grafted into the chick host. Pro prosencephalon Mes mesencephalon Met metencephalon S12 somite 12. A bar = 0.05 mm B, C, D, E bar = 0.05 mm.

Any avian or mammalian cells that perform at 38-39°C can be grafted into the chick anbryo. It is advisable to use adhering cell lines to prevent the dispersal of the grafts. As for the protein-loaded beads, the cells can be placed anywhere in the embryo. 

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