Encysted embryos (cysts) of the primitive crustacean, Artemia franciscana, are among the most resistant of all animal life history stages to extremes of environmental stress. These embryos, extremophiles of the animal kingdom, are the main focus of this paper. Previous work has revealed the importance of biochemical and biophysical adaptations that provide a significant part of the basis of the...

In 2007, the Human Fertilisation and Embryology Authority in London, UK, published "Hybrids and Chimeras: A Report on the Findings of the Consultation", which summarized a public debate about research on, and suggested policy for, human animal chimeras [4]. The HFEA formulated the report after conducting a series of surveys and debates from earlier in 2007. The HFEA issued a statement in Septem...

Diabetic retinopathy (DR) is the leading cause of blindness among the American working population. The purpose of this study is to establish a new diabetic animal model using a cone-dominant avian species to address the distorted color vision and altered cone pathway responses in prediabetic and early diabetic patients. Chicken embryos were injected with either streptozotocin (STZ), high concen...

To educate its citizens about research into chimeras [3] made from human and non-human animal cells, the United Kingdom's Human Fertilisation Embryology Authority published the consultation piece "Hybrids and Chimeras: A Consultation on the Ethical and Social Implications of Creating Human/Animal Embryos in Research," in 2007. The document provided scientific and legal background, described eth...

Xenopus embryos provide a rich source of pluripotent cells that can be differentiated into functional organs. Since the molecular principles of vertebrate organogenesis appear to be conserved between Xenopus and mammals, this system can provide useful guidelines for the directional manipulation of human embryonic stem cells. Pluripotent Xenopus cells can be easily isolated from the animal pole ...

The mode of zona pellucida denudation and blastocyst proliferation and attachment was investigated in Wistar rats during day 5 of pregnancy and in ovariectomized pregnant animals given 5-0 mg progesterone daily until the 10th day, when 0-2 mug oestradiol was injected together with progesterone. During day 5 of pregnancy, when only 5 empty zonae were detected from 32 animals, zona denudation occ...

The patterns of proteins synthesized in animal and vegetal regions of Xenopus oocytes, eggs and embryos were examined by 2D gel electrophoresis. In oocytes and eggs, the only proteins synthesized asymmetrically along the animal-vegetal axis were a small number of proteins synthesized predominantly in the vegetal hemisphere. At the cleavage stage there were a total of four proteins synthesized u...

Embryonic development offers a unique perspective on the function of many biological processes because of embryos’ heightened sensitivity to environmental factors. This hands-on lesson investigates the effects of elevated vitamin A on the morphogenesis of chicken embryos. The active form of vitamin A (retinoic acid) is applied to shell-less (ex ovo) cultured chick embryos, which are highly acce...

In vitro embryo production is important for research in animal reproduction, embryo transfer, transgenics, and cloning. Yet, in vitro-fertilized (IVF) embryos are generally developmentally delayed and are inferior to in vivo-derived (IVV) embryos; this discrepancy is likely a result of aberrant gene expression. Transcription of three genes implicated to be important in normal preimplantation em...