8-Cell stage embryo

An excellent review of the energy sources utilized by mammalian embryos has been presented by Brinster (1971). His work has shown that the mouse embryo in vitro cannot be supported by glucose until the 8-cell stage of development. The preferred substrates for the culture of 8-cell stage embryos are pyruvate, lactate, and oxalacetate. 

Gautier Yes. One would argue that everything required for apoptosis is present in the egg. If you dissociate the egg and make cell-free extract from the one cell stage embryo, you can in certain conditions have a system to follow apoptosis. 

Fig. 12.4. QD labeling of Xenopus emb os at different stages and specific QD intracellular localizations. (A) Injection of one cell out of an eight-cell-stage embryo resulted in labeling of individual blastomeres. (B) Same embryo shown 1 h later. The daughter cells of the injected blastomere are labeled (C) and at a later stage (D) show two neurula embryos, which were injected into a single cell at the eight-cell-stage in the animal pole. (E)...

Ionizing radiation In utero exposme 3,5,10,15 Gy of Y-rays y-H2AX foci in one-cell stage embryos 30 min after exposure No detection of y-H2AX foci after 3-10 Gy treatment, detection of y-H2AX fbd after 15 Gy treatment 13.3 % of blastomeres were y-H2AX positive 72h after fertilization Adiga et al. 2007... 

Fertilization occurs during the time between release of the oocyte and its entry into the end of the oviduct. Sperm penetrate the follicle-derived vitelline membrane to fertilize the oocyte and the second reduction division occurs. The resultant one-cell stage embryo is called a blastodisc. The requirement for rapid fertiUzation following follicle rupture is met hy the female chicken s ability to store sperm in viable form for a number of weeks. 

For microinjection experiments in fish, a glass needle loaded with DNA solution is used to penetrate the plasma membrane of a one-cell-stage embryo. The injection procedure is performed with the aid of a micromanipulator under a standard dissecting microscope. Once the tip of the needle has entered the cytoplasm, approximately 1-2 nL of DNA solution containing 10 to 10 DNA molecules is injected. 

Laminin is the first ECM protein expressed in two- to four-cell-stage embryos and is a major component of the ECM of the basal laminae in vertebrates [1]. Laminins are a family of heterotrimeric glycoproteins composed of a, (3, and y chains, forming 15 different combinations in human tissues [62]. Laminin-511 consists of the u5, (31, and yl chains and is frequently employed as a coating material on the dishes used to culture hESCs (Table 6.1) [19,62-65]. 

Fig. 1 Microinjection of zebrafish embryos, (a) A typical setup for microinjection. (b) Recently fertilized eggs. The insets show early left) and late right) phases of one-cell-stage embryos, (c) Microinjection plate an acrylic plate with V-shaped grooves for holding embryos, (d) One-cell-stage embryos are arrayed in the grooves for microinjection. Scale bar, 2 mm. (e) DNA constmcts are injected into an embryo by penetrating the blastomere with the micropipette through the chorion. Scale bar, 200 pm...

Fig. 2. Methods for production of identical catde. (a) Embryo spHtting. A microdissection knife is used to cut an early embryo into two identical halves, (b) Embryo cloning. A cell from a morula stage embryo is removed and then inserted into an oocyte that has had its nucleus removed. EoUowing fusion of the two cells the newly produced one-ceU embryo is identical to the original morula. The procedure can be repeated to give multiple copies of the original...

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