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A study of the dynamical ultramicromorphology of differentiating cow early embryo nucleoli in embryos collected in the area of chronic irradiation near Tchernobyl

PIVKO J, BARAN V, GRAFENAU P, KOPECNY V, PELECHATYJ NS, BONDARCUK VN, KOZUCH AJ, KOVALCIK LM
Veterinarni Medicina 42, 1997, 33-38

Ultrastructural morphology and immunoelectron microscopy of the nucleus and nucleologenesis in early preimplantation cow embryos were applied in an attempt to demonstrate a possible radiation injury to that early stage of development due to chronical irradiation of the animals in the Tchernobyl area. Mostly eight cell embryos as well as morulae were collected from superovulated cows which were previously constantly kept in zones of different levels of radioactive irradiation. In addition to the normometric status of reproductive organs in no case was it possible to detect an apparent deviation in the nuclear morphology or in the process of nucleologenesis as compared to the physiological situation (Kopecny et al., 1989b, 1991, 1996). This observation was supported by an immunoelectron microscope study of DNA association and penetration in the differentiated nucleolus in the late 8-cell stage. These observations show that the otherwise demonstrated radiation injury localized in the genome does not probably influence markedly the early events of the developing embryo and that the aberrant cytoplasmic command of the nuclear events known in other types of oocyte/early cow embryo impairment (review Kopecny and Niemann, 1993


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