Mammalian embryo

Mazur, P. (1977b). Slow-freezing injury in mammalian cells. In The Freezing of Mammalian Embryos. Ciba Foundation Symposium No. 52 (Elliott, K. Whelan, J., eds.), pp. 19-42, Elsevier, Amsterdam. 

Mazur, P. (1990). Equilibrium quasi-equilibrium, and nonequilibrium freezing of mammalian embryos. Cell Biophy. 17, 53-92. 

The very beginning of the first mitotic cell cycle of the mouse embryo seems to be controlled by the mechanisms characteristic for both meiotic and mitotic cell cycles. Active MAP kinase, its substrate p90rsk and the CSF activity itself could influence the cellular processes within the one-cell embryo. Indeed, we have observed that despite the entry into the interphase (as judged by the low activity of MPF) some proteins are actively phosphorylated as during the meiotic M phase (e.g. 35 kDa complex Howlett et al 1986, Szollosi et al 1993), the nuclei and the microtubule interphase network start to form only 1.5 hours after activation (Szollosi et al 1993). This delay in the phenomena characteristic for the interphase could be linked to the mixed meiotic/mitotic character of this early period. This delay probably allows the correct transformation of the sperm nucleus into the male pronucleus. In species like Xenopus or Drosophila the transitional period between the meiotic and the mitotic cell cycle control is probably much shorter since it is proportional to duration of the short first cell cycle of these rapidly cleaving embryos. Mammalian embryos are perhaps the most suitable to study this transition because of the exceptionally long first embryonic cell cycle. 

Interestingly, prolonged duration of the first embryonic M phase is also observed in other mammalian and non-mammalian embryos. It was found in rabbit embryos (X. Yang M. Deng, personal communication) and in sea urchin embryos (J. Z. Kubiak P. Cormier, unpublished observation). Further studies will show whether it is a rule during animal development. 

Nasmyth Presumably the same thing is taking place in the mammalian embryo, when it suddenly breaks symmetry. 

I.K. Glasgow, H.C. Zeringue, D.J. Beebe, S.J. Choi, J.T. Lyman, N.G. Chan, and M.B. Wheeler, Handling individual mammalian embryos using microfluidics. IEEE. Trans. Biomed. Eng. 48, 570-578 (2001). 

Dzierzak, E., Medvinsky, A., and de Bruijn, M. Qualitative and quantitative aspects of haematopoietic cell development in the mammalian embryo, Immunol. Today, 19, 228, 1998. 

Unlike mammalian embryos that are protected within the uterus, amphibian embryos are protected only by a fertilization membrane and jelly coat. Although there is some... 

Blastocyst The mammalian embryo in the post-morula stage in which a fluid-filled cavity, enclosed primarily by trophoblast, contains an inner cell mass which becomes the embryonic disc. [NIH]... 

The ways of SC appliance in veterinary are numerous, including the fundamental biology and applied veterinary. The ESC of different animal species are irreplaceable model for investigating the mammalian embryo-genesis. Since the ESC are totipotent, they can be used as the convenient in vitro model for the investigating of cytodifferentiating processes in the mammalian development. 

New DA (1978) Whole-embryo culture and the study of mammalian embryos during organogenesis. Biol Rev Camb Philos Soc 53(1 ) 81-122... 

Regarding the positive compounds, six out of eight compounds showed a developmental toxicity both in mammalian embryo-fetal studies and in FETAX. Concerning the negative compounds, four out of five chemicals were found negative in both models. There were two false negative compounds, acetylsalicylic acid and dexame-... 

Each candidate compound for entry into development was tested in FETAX. The objective was to give an early alert for developmental toxicity. A standard development plan was followed when FETAX gave negative results. In the case of a positive FETAX result, the mammalian embryo-fetal toxicity studies (preceded by dose-range finding studies) were brought forward (i.e., just after the regulatory repeat-dose toxicity study in rats). 

Concordance FETAX and mammalian embryo-fetal toxicity studies gave the... 

Eight compounds negative in FETAX were found positive in one or both mammalian embryo-fetal toxicity studies. Four were positive in only the rat, two were positive in only the rabbit, and two were positive in both the rat and rabbit. These false negative compounds represented 14% of the 58 drugs tested, with a sensitivity of FETAX reaching 76%. 

Three compounds with adverse effects on morphogenesis in FETAX gave negative results for teratogenic potential in both mammalian embryo-fetal toxicity studies. 

Predictivity. Proportion of compounds giving the same results in FETAX as in the mammalian embryo-fetal toxicity studies (%). 

Detailed procedures of GD9 rat embryo dissection can be found in David Cockroft s book Postimplantation mammalian embryos. A practical approach (4). 

Cockroft DL (1990) Postimplantation mammalian embryos. Oxford University Press, Oxford, A practical approach... 

Squirrell, J. M., Wokosin, D. L., White, J. G., and Bavister, B. D. 1999. Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability. Nat. Biotech. 17 763-67. 

Figure 3.21 The blood supply to the mammalian embryo and placenta.

Mammalian embryos are extremely tolerant of foreign proteins while still in utero, and all substances within the developing organism are accepted as self. This is essential during development to ensure that immune responses are not raised to proteins and peptides produced during this time. Any immunological response to developmental proteins, hormones and growth factors would have disastrous results. 

Sutovsky, P., Moreno, R. D., Ramalho-Santos, J., Dominko, T., Simerly, C., and Schatten, G., Ubiquitinated sperm mitochondria, selective proteolysis, and the regulation of mitochondrial inheritance in mammalian embryos. Biol. Reprod. 63, 582—590 (2000). 

V.H. Ferm, The teratogenic effects of metals on mammalian embryos. Adv. Teratol. 6 51-75, 1972. 

Zucker, R.M.Technical note Whole insects and Mammalian Embryo Imaging with Confocal Microscopy Morphology and Apoptosis. Cytometry 2006 69A 1143- 1152 (COVER). 

Rutledge, J. C. Developmental toxicity induced during early stages of mammalian embryo-genesis. Mutat. Res. 396,113-127,1997. 

STATs play a role in embryonic development, like SMADs. In Dmsophila embryos, STATs seem to have a role in the expression of early genes, like STAT 2 and STAT 3 in mammalian embryos. Defects in a STAT homologue are lethal in the larvae of the fly, and the same is true for mammalian embryos embryos of stat3 knock-out mice die before they ever form mesoderm, and stat2 knock-outs do not reach term... 

Nau H, Scott WJ, Jr. Weak acids may act as teratogens by accumulating in the basic milieu of the early mammalian embryo. Nature. 1986 323(6085) 276-278. 

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