Alkaline phosphatase activity in the preimplantation mouse embryo

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 83-89
Author(s):  
Lincoln V. Johnson ◽  
Patricia G. Calarco ◽  
Margaret L. Siebert
Keyword(s):  
Alkaline Phosphatase ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Mouse Embryos ◽  
Frozen Sections ◽  
Mouse Development ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse Embryo ◽  
Preimplantation Mouse ◽  
Morula Stage

Alkaline phosphatase (AP) activity has been assayed in frozen sections of preimplantation mouse embryos by an azo-dye cytochemical method. The results indicate that during preimplantation mouse development AP activity is first expressed between the 8- and 16-cell stages and develops in all cells by the late morula stage. During blastocyst formation AP activity is lost or greatly reduced in trophoblast cells while activity is maintained in the inner cell mass.

The nature and distribution of serologically detectable alloantigens on the preimplantation mouse embryo

Development ◽  
1976 ◽  
Vol 35 (1) ◽  
pp. 59-72
Author(s):  
Audrey L. Muggleton-Harris ◽  
Martin H. Johnson
Keyword(s):  
Mouse Embryo ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Convincing Evidence ◽  
Mouse Embryos ◽  
Cell Type ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse Embryo ◽  
Preimplantation Mouse

The nature and distribution of surface alloantigens on preimplantation mouse embryos has been examined by immunofluorescence. Non-H-2 alloantigens were detected at allstages examined, from the 2-cell to the 4½-day blastocyst. Cleaving blastomeres, inner cell mass cells and cells of the primary trophectoderm were all positive. In F1 embryos maternalnon-H-2 alloantigens were detectable at all stages, whereas paternal antigens first became evident at the 6- to 8-cell stage. No convincing evidence of the presence of alloantigens associated with the H-2 haplotype was found at any stage or on any cell type, suggesting that if these antigens are present they are in low quantity or are masked.

Changes in the properties of the developing trophoblast of preimplantation mouse embryos as revealed by aggregation studies

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 143-157
Author(s):  
Paul S. Burgoyne ◽  
Thomas Ducibella
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Supporting Cell ◽  
Mouse Embryos ◽  
Mixed Cell ◽  
Time Period ◽  
Preimplantation Mouse Embryos ◽  
Wide Range ◽  
Preimplantation Mouse

Mouse embryos (8-cell to early blastocyst) were denuded with pronase, and apposed in pairs which represented a wide range of stage combinations. These pairs either formed aggregates which differentiated into double-sized blastocysts, or they failed to aggregate. The 8–16-cell stages would not envelop late morulae/early blastocysts to form layered aggregates. This must mean that as the embryo differentiates into a blastocyst, the outer surface of the trophoblast loses its capacity for supporting cell spreading. The aggregation data also demonstrate that embryos almost completely lose their potential for aggregation at a very discrete stage in development – namely, between 8 and 9 h before blastocoel formation. It is argued that this is the stage at which the zonular tight junctional seal is completed, and that it is this physical barrier which prevents aggregation. It has been argued previously that the zonular tight junctional seal allows the creation of the special microenvironment which is necessary for the determination of the inner cells as inner cell mass. The completion of this seal 8–9 h before it is required for the formation of a blastocoel would provide a suitable time period for this cell determination to occur. The results obtained also relate to the technique of chimera production. Since the aim of this technique is to generate mice with mixed cell populations, it is important that the blastocyst formed following aggregation should have both cell lines present in the inner cell mass. This can best be assured by using relatively late morula stages (75 h post-HCG injection) since these will have already segregated their inner cells, but the incomplete seal will still allow aggregation to take place.

Effect of Li+ on preimplantation mouse embryos

Development ◽  
1982 ◽  
Vol 67 (1) ◽  
pp. 51-58
Author(s):  
L. Izquierdo ◽  
M. I. Becker
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Preimplantation Mouse Embryos ◽  
Early Embryos ◽  
Preimplantation Mouse

Two-cell mouse embryos were cultured in vitro for different periods in a medium in which NaCl was partially replaced by LiCl at concentrations ranging from 1 to 30 mm. The relative cell number diminished according to increasing LiCl concentrations but the onset of blastulation was not affected, thus resulting in blastulae with fewer cells than normal and with a reduced or absent inner cell mass. Results are discussed in terms of the possible mechanisms involved and are related with the vegetalization induced by Li+ on early embryos of echinoderms and amphibia.

The effects of embryo stage and cell number on the composition of mouse aggregation chimaeras

Zygote ◽  
2000 ◽  
Vol 8 (3) ◽  
pp. 235-243 ◽  
Author(s):  
Pin-chi Tang ◽  
John D. West
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Advanced Embryo ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Cell Embryo ◽  
Embryo Stage

Studies with intact preimplantation mouse embryos and some types of chimaeric aggregates have shown that the most advanced cells are preferentially allocated to the inner cell mass (ICM) rather than the trophectoderm. Thus, differences between 4-cell and 8-cell stage embryos could contribute to the tendency for tetraploid cells to colonise the trophectoderm more readily than the ICM in 4-cell tetraploid[harr ]8 cell diploid chimaeras. The aim of the present study was to test whether 4-cell stage embryos in 4-cell diploid[harr ]8-cell diploid aggregates contributed equally to all lineages present in the E12.5 conceptus. These chimaeras were compared with those produced from standard aggregates of two whole 8-cell embryos and aggregates of half an 8-cell embryo with a whole 8-cell embryo. As expected, the overall contribution of 4-cell embryos was lower than that of 8-cell embryos and similar to that of half 8-cell stage embryos. In the 4-cell[harr ]8-cell chimaeras the 4-cell stage embryos did not contribute more to the trophectoderm than the ICM derivatives. Thus, differences between 4-cell and 8-cell embryos cannot explain the restricted tissue distribution of tetraploid cells previously reported for 4-cell tetraploid[harr ]8-cell diploid chimaeras. It is suggested that cells from the more advanced embryo are more likely to contribute to the ICM but, for technical reasons, are prevented from doing so in simple aggregates of equal numbers of whole 4-cell and whole 8-cell stage embryos.

Preimplantation differentiation in the mouse egg as revealed by microinjection of vital markers

Development ◽  
1972 ◽  
Vol 27 (2) ◽  
pp. 467-479
Author(s):  
I. B. Wilson ◽  
Eleanor Bolton ◽  
Rosemary H. Cuttler
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Bilateral Symmetry ◽  
Cortical Region ◽  
Preimplantation Mouse Embryos ◽  
Physico Chemical ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
A Cell ◽  
Mouse Egg

A microinjection technique has been devised for labelling individual blastomeres of preimplantation mouse embryos with a marker drop of inert silicone fluid placed in the cytoplasm either at the periphery of the egg or at the interface between two blastomeres (i.e. centrally). The following observations were made on blastocysts which developed from injected eggs: (1) All drops derived from peripheral injections (at two-cell to morula stage) were found exclusively in the trophoblast. (2) Drops injected centrally at two- and four-cell stages have been found in both the trophoblast and inner cell mass. (3) Peripheral labelling of one or both members of a pair of eggs (four-cell to morula) fused into a chimaeric blastocyst yielded markers in both trophoblast and inner cell mass. No evidence was found of inherent bilateral symmetry or polarity in the cleaving egg. The results indicate that physico-chemical positional effects determine whether a cell will differentiate into trophoblast or inner cell mass. The results are discussed in the light of current hypotheses relating to early embryonic differentiation in the mammal, and it is suggested that cleavage occurs without spatial disturbance of the cytoplasmic pattern of the egg so that its cortical region is converted directly to the outer cells of the morula and hence to the trophoblast.

Embryo structure reorganisation reduces the probability of apoptosis in preimplantation mouse embryos

2021 ◽  
Vol 33 (12) ◽  
pp. 725
Author(s):  
Dawid Winiarczyk ◽  
Anna Piliszek ◽  
Silvestre Sampino ◽  
Marek Lukaszewicz ◽  
Jacek Andrzej Modliński
Keyword(s):  
Cell Volume ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Lineage ◽  
Cell Number ◽  
Blastocyst Stage ◽  
Mammalian Development ◽  
Mouse Development ◽  
Preimplantation Mouse ◽  
Morula Stage

Programmed cell death plays a key role in mammalian development because the morphological events of an organism’s formation are dependent on apoptosis. In the mouse development, the first apoptotic waves occur physiologically at the blastocyst stage. Cell number and the mean nucleus to cytoplasm (N/C) ratio increase exponentially throughout subsequent embryo cleavages, while cell volume concurrently decreases from the zygote to blastocyst stage. In this study we tested the hypothesis that reorganisation of the embryo structure by manipulating cell number, the N/C ratio and the cell volume of 2-cell embryos may result in the earlier and more frequent occurrence of apoptosis. The results indicate that doubling (‘Aggregates’ group) or halving (‘Embryos 1/2’ group) the initial cell number and modifying embryo volume, ploidy (‘Embryos 4n’ group) and the N/C ratio (‘Embryos 2/1’ group) reduce the probability of apoptosis in the resulting embryos. There was a higher probability of apoptosis in the inner cell mass of the blastocyst, but apoptotic cells were never observed at the morula stage in any of the experimental groups. Thus, manipulation of cell number, embryo volume, the N/C ratio and ploidy cause subtle changes in the occurrence of apoptosis, although these are mostly dependent on embryo stage and cell lineage (trophectoderm or inner cell mass), which have the greatest effect on the probability of apoptosis.

Aggregation between teratocarcinoma cells and preimplantation mouse embryos

Development ◽  
1980 ◽  
Vol 58 (1) ◽  
pp. 289-302
Author(s):  
Colin Stewart
Keyword(s):  
Embryonal Carcinoma ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Mouse Embryos ◽  
Embryonic Cells ◽  
Teratocarcinoma Cells ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Ec Cells ◽  
Derivatives Of

The ability of two embryonal carcinoma (EC) cell lines, F9 and PCI3, to aggregate with preimplantation 8-cell mouse embryos is described. Both adhere to the embryonic cells and subsequently compact with the embryos. The aggregates form blastocysts in culture. The blastocysts sometimes contain the EC cells, located almost always in their inner cell mass. Differentiated derivatives of EC cells, namely PYS-1 and PYS-2, as well as STO fibroblasts do not aggregate with embryos.

Cytoplasmic and nuclear protein synthesis in preimplantation mouse embryos

Development ◽  
1979 ◽  
Vol 52 (1) ◽  
pp. 209-225
Author(s):  
C. C. Howe ◽  
D. Solter
Keyword(s):  
Protein Synthesis ◽  
Gel Electrophoresis ◽  
Nuclear Protein ◽  
Inner Cell Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cell Mass ◽  
Mouse Embryos ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Specific Proteins

Cytoplasmic and nuclear proteins synthesized by mouse embryos at different stages of preimplantation development were analyzed by two-dimensional polyacrylamide gel electrophoresis. Several nuclear-specific proteins (i.e. proteins more abundant in the nucleus than in the cytoplasm) and numerous cytoplasmic-specific proteins were observed. The trends of changes in the nuclear and cytoplasmic protein synthesis are similar. Moderate changes occur between the unfertilized egg and the zygote. Striking changes characterized by the disappearance of numerous major oocyte-specific proteins and the appearance of a large number of new, stage-specific proteins occur between the zygote and the 4- to 8-cell stages. In contrast, between the 4- to 8-cell and early blastocyst periods, only a few new proteins appear, and a small number of oocyte-specific or other stage-specific proteins disappear. Minor differences in protein synthesis were observed between the trophoblast and inner cell mass.

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