Rabbit embryos

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found in rabbit embryos (X. Yang M. Deng, personal communication) and in sea urchin embryos (J. Z. Kubiak P. Cormier, unpublished observation).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. 

Pitt JA, Carney EW. Development of a morphologically-based scoring system for postimplantation New Zealand White rabbit embryos. Teratology. 1999 59(2) 88-101. 

McBride WG, Vardy PH, French J. 1982. Effects of scopolamine hydrobromide on the development of the chick and rabbit embryo. Aust. J. Biol. Sci. 35(2) 173-178. 

DeLouis, C., Bonnerot, C., Vernet, M., Nicolas, J.F. (1992). Expression of microinjected DNA and RNA in early rabbit embryos Changes in the permissiveness for expression and transcriptional selectivity. Exp. Cell Res. 207 284-291. 

Rabbit New Zealand White, SPF, Oryctolagus cuniculus female Reproductive studies including range finding studies in pregnant rabbits, embryo-fetal development study, teratogenecity studies... 

There is no net increase in RNA content, per embryo, however, until 72 hours postcoitum at which time there is a marked acceleration of uridine incorporation accompanying the transformation of the morula into a blastocyst as the embryo leaves the oviduct and enters the uterus (Manes, 1969). The qualitative aspects of RNA synthesis in preimplantation rabbit embryos have been investigated by the electrophoretic separation of tritium-labeled embryonic RNA on polyacrylamide gels (Manes, 1971). Labeling of RNA species having migratory properties identical with those of tRNA are detectable from the 2-cell stage onward. 

The small differences in transcriptional patterns displayed by mouse and rabbit embryos may be related to morphological ifferences in the embryos. The rabbit ovum, for example, is about twice the diameter of the mouse ovum, cleaves more rapidly, reaches a morula stage of about 100-130 cells before cavitation begins and retains its zona pellucida throughout the preimplantation period. It is possible that further slight variations in transcriptional patterns will be uncovered as other orders of mammals are studied. 

III. RNA Containing Poly(A) Sequences in Preimplantatian Rabbit Embryos... 

While the significance of these poly (A) sequences in mRNA is still unclear, the sequences can be considered as useful markers for detecting putative mRNA synthesis. As a result, heterogeneous RNA synthesized in rabbit embryos has been assayed for the presence of poly (A) containing RNA in an effort to provide evidence for, and an estimate of. 

Amount of Nuclear and Polysomal Heterogeneous RNA Associated WITH Poly(A) Sequences in the Preimplantation Rabbit Embryo... 

The oxygen consumption of the preimplantation rabbit (Fridhandler, 1961) and mouse embryo (Mills and Brinster, 1967) has been found to be 3.77 / l/mg of dry weight for both species. However, the rabbit embryo during the preblastocyst stages contains about times the voliune of the mouse embryo at the same stages of development. After... 

Pushotten and Pineus (1961) reported that rabbit embryos of two and eight cells grew and developed for 4 days on a protein-free chemically defined medium containing amino acids. However, early blastocysts (72-hour embryos) required an additional medium supplement of 10 serum for successful culture. Daniel and Krishnan (1967), working with somewhat older rabbit blastocysts (5 days), observed that they expanded to a greater extent for the first 36 hours of culture when the defined... 

As previously mentioned, neither the incorporation of radioactive amino acids into embryo proteins nor the presence of amino acids in the immediate environment of the embryo necessarily indicate that free amino acids contribute significantly to the nutritional needs of the embryo. Nevertheless, it should be noted that Mintz (1964), employing autoradiography, observed in the cultured mouse embryo an increase in amino acid incorporation from fertilization to the blastocyst stage. This observation was essentially confirmed (Brinster, 1971) for the mouse when quantitative procedures for the analysis of radioactivity were used. During cleavage of the rabbit embryo in vitro (Manes and Daniel, 1969),... 

It should be noted that Foote and his associates have taken exception to the significance of blastokinin as well as uterine proteins in general. Thus, Kane and Foote (1971) starting with 1-cell rabbit embryos obtained expanded blatocysts on a defined medium supplemented with only bovine serum albumin. Furthermore, it was reported that if was possible to obtain one full term young from a rabbit embryo transferred into a recipient doe after 88 hours of culture on a medium containing only serum (Mauer et al., 1970). 

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