. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. NUCLEAR TRANSPLANTATION IN TRITON 141. SN FIGURE 1. Diagram of transplantation technique. (A) Diagrammatic optical section of an egg fertilized with irradiated sperm (SN) ; the second maturation spindle (EN) of the egg is near the animal pole; a needle is shown pricking the "egg spot"; nuclei are shown greatly enlarged and are not visible in the living egg. (B) The same egg figured in 1A while the maturation spindle (EN) is being sucked out through the puncture in the egg membrane. The egg will then contain no acti
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. NUCLEAR TRANSPLANTATION IN TRITON 141. SN FIGURE 1. Diagram of transplantation technique. (A) Diagrammatic optical section of an egg fertilized with irradiated sperm (SN) ; the second maturation spindle (EN) of the egg is near the animal pole; a needle is shown pricking the "egg spot"; nuclei are shown greatly enlarged and are not visible in the living egg. (B) The same egg figured in 1A while the maturation spindle (EN) is being sucked out through the puncture in the egg membrane. The egg will then contain no active chromatin but the sperm centrosome (SC) may remain functional. (C) Donor blastula cells (BC) and the method of drawing one cell into the in- jection pipette are shown; note that the cell membrane of the blastula cell is not ruptured at the inner end and that the blastula cell nucleus (BCN) is visible as a small sphere during the injection procedure. (D) Injection of a blastula cell into an enucleated egg which then con- tains a diploid blastula cell nucleus (BCN) and a functional sperm aster (SC). 4. Injection of blastula nuclei Eggs used in the injection experiments were fertilized with irradiated sperm and enucleated in the manner described above. The donor embryo consisted of a young normal diploid blastula (stage 7, Glasner, 1925) which had been re- moved from its jelly capsule and egg membrane. It was placed in the operating dish along with the eggs to be enucleated. A small piece of the donor blastula was then removed by means of a hair or platinum loop (Baltzer, 1941). Always some of the cells along the edge of the excised piece detached from the fragment and these isolated cells were used for injection. Injections were performed im- mediately after enucleating a set of host eggs. Entire donor cells were used and no attempt was made to eliminate the cytoplasm. All injections were carried out free-hand by mouth-pipette. The tip of the injection pipette was a thin-walle
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
