Journal ArticleDOI
Ultrastructural and autoradiographic studies of mouse cleavage stages
Nina Hillman,Richard J. Tasca +1 more
TLDR
Beginning at the 8-cell stage, re-incubation in nonradioactive medium results in a significant decrease in nucleolar labeling and an increase in cytoplasmic labeling suggesting that more ribosomal RNA is transferred from the nucleus to the cy toplasm at the later cleavage stages.Abstract:
Studies of cleavage stage mouse embryos are reported, with particular emphasis upon nucleolar fine structural and functional changes. Multiple fibrillar primary nucleoli are present in the early 2-cell embryo. In late 2-cell embryos, some of these nucleoli acquire a peripheral zone of granules, while others reticulate, forming nucleoli composed of fibrillo-granular cortices and fibrillar cores. The nucleoli of early 4-cell embryos are composed only of fibrils. In the middle of the 4-cell stage, some of the nucleoli acquire a peripheral granular zone, while others reticulate. The reticulated nucleoli of both the late 2-cell and 4-cell embryos can be considered, on the basis of their fine structure, to be definitive nucleoli. Early 8-cell and morula embryos usually contain only two definitive nucleoli per nucleus. 3H-5-uridine-pulsed embryos contain label localized in the nucleus, particularly over definitive nucleoli. Nucleolar labeling increases at each successive developmental stage. Beginning at the 8-cell stage, re-incubation in nonradioactive medium results in a significant decrease in nucleolar labeling and an increase in cytoplasmic labeling suggesting that more ribosomal RNA is transferred from the nucleus to the cytoplasm at the later cleavage stages.read more
Citations
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Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability
TL;DR: In this article, the dynamics of mitochondrial distribution in hamster embryos at frequent intervals over 24 hours using two-photon microscopy (1,047 nm) while maintaining blastocyst, and even fetal, developmental competence.
Journal ArticleDOI
Long-term two-photon fluorescence imaging of mammalian embryos without compromising viability
TL;DR: Long-term fluorescence observations of the dynamics of three-dimensional cytoarchitecture in highly photosensitive specimens such as mammalian embryos are made using two-photon microscopy and confocal microscopy.
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Mitochondrial distribution and function in oocytes and early embryos
TL;DR: Detailed studies with hamster oocytes and early embryos reveal a pattern of active mitochondria migrating to surround the pronuclei to form a pattern that persists through the early cleavage stages, which may provide insights into the regulation of normal embryo development.
Journal ArticleDOI
Oxidative Phosphorylation-Dependent and -Independent Oxygen Consumption by Individual Preimplantation Mouse Embryos
James R. Trimarchi,Lin Liu,Lin Liu,D. Marshall Porterfield,Peter K. Smith,David L. Keefe,David L. Keefe +6 more
TL;DR: Results validate the self-referencing electrode technique for analyzing oxygen consumption and utilization by preimplantation embryos and demonstrate that changes in oxygen consumption accompany important physiological events, such as development, response to medium metabolites, or cell death.
Journal ArticleDOI
Mitochondrial transfer between oocytes: potential applications of mitochondrial donation and the issue of heteroplasmy.
TL;DR: The results demonstrate the feasibility of isolating and transferring mitochondria between oocytes, an apparent increase in net ATP production in the recipients, and the persistence of activity in the transferred mitochondria.
References
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Journal ArticleDOI
The relation of a particular chromosomal element to the development of the nucleoli in Zea mays
TL;DR: The nucleolus is organized in the telophase through the activity of a distinct deep-staining body having a definite position in one chromosome (the satellited chromosome) of the monoploid complement through a reciprocal translocation which broke this body into two parts.
Journal ArticleDOI
RNA synthesis during the development of Xenopus laevis, the South African clawed toad
Donald D. Brown,Elizabeth Littna +1 more
TL;DR: Methods have been described for radioactive-labeling, purification and characterization of high molecular weight RNA from eggs and embryos of Xenopus laevis, the South African clawed toad, and the following sequence of developmental events has been described.
Journal ArticleDOI
Absence of ribosomal rna synthesis in the anucleolate mutant of xenopus laevis.
Donald D. Brown,John B. Gurdon +1 more
TL;DR: It was apparent that magnesium-starved embryos were to some extent phenocopies of the homozygous mutants (0-nu) since retardation of embryogenesis and growth occurred in both groups of embryos at about the same developmental stage.
Journal ArticleDOI
A method for in vitro cultivation of mouse ova from two-cell to blastocyst.
TL;DR: A method for relatively large-scale in vitro experiments on the early cleavage divisions of the mouse embryo has been developed in this laboratory and is now being used in several types of study.
Journal ArticleDOI
Ribosomal cistrons and the nucleolar organizer.
H. Wallace,M.L. Birnstiel +1 more
TL;DR: This finding strongly suggests that the anucleolate Xenopus is a deletion mutant, and supports the hypothesis that ribosomal cistrons are located at the nucleolar organizer region.
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