title: Bovine abnormal preimplantation embryos: analysis of segregated cells occurring in the subzonal space and/or blastocoele cavity for their nuclear morphology and persistence of RNA synthesis.
abstract: Bovine embryos in the early blastocyst/blastocyst stage were analysed by [5-3H]uridine labelling followed by electron microscopic autoradiography. In normal control embryos an intact zona pellucida, evenly developed blastomeres and a transparent perivitelline space were seen. In this group, the blastomeres of the trophoblast and embryoblast showed high homogeneous labelling localised in the nucleoplasm and even more intense labelling in the nucleolus. On the contrary, in addition to evident cytoplasmic disintegration, a clearly different labelling pattern and a low labelling intensity were observed in the nuclei of the segregated cells in the subzonal space and in those free in the blastocoele cavity. A typical nuclear morphological feature of these blastomeres was chromatin marginalisation, similar to that observed in embryos treated with actinomycin D for transcription inhibition. It is concluded that the segregated cells are arrested in their further differentiation.
authors.affiliation: Research Institute of Animal Production, Institute for Genetics and Reproduction, Nitra, Slovak Republic. pivko@vuzv.sk
authors.forename: J
authors.initials: J
authors.lastname: Pivko
authors.forename: P
authors.initials: P
authors.lastname: Grafanau
authors.forename: E
authors.initials: E
authors.lastname: Kubovicová
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D001757:Blastomeres / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D002417:Cattle; D002467:Cell Nucleus / Q000473:pathology*; D046508:Culture Techniques; D003609:Dactinomycin / Q000494:pharmacology; D012313:RNA / Q000096:biosynthesis; D014158:Transcription, Genetic
chemical_list: D003609:Dactinomycin; D012313:RNA