Preimplantation development of gynogenetic diploid mouse embryos

Development ◽  
1982 ◽  
Vol 69 (1) ◽  
pp. 215-222
Author(s):  
Ewa Borsuk
Keyword(s):  
Cytochalasin B ◽  
Polar Body ◽  
Mouse Embryos ◽  
Fertilization In Vitro ◽  
Body Formation ◽  
Male Pronucleus ◽  
Step Procedure ◽  
Gynogenetic Diploid ◽  
Polar Body Formation

Diploid gynogenetic mouse embryos were produced in a three-step procedure: fertilization in vitro, suppression of the 2nd polar body formation by Cytochalasin B, and microsurgical removal of the male pronucleus. The operated eggs were transplanted to the oviduct of recipient females for 72 or 96 h. The overall recovery rate was 73%, but compacted morulae and blastocysts constituted only 28·6% of transplanted eggs. After 72 h blastocysts were rare (3·5%) but 24 h later their incidence increased to 21·2%. In eggs homozygous for T6 chromosome it was possible to prove karyologically that the male pronucleus was effectively removed and that the diploid genome was of purely maternal origin.

In vitro activation of mouse eggs

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 497-512
Author(s):  
C. F. Graham ◽  
Z. A. Deussen
Keyword(s):  
Dna Synthesis ◽  
Culture Medium ◽  
Tritiated Thymidine ◽  
Polar Body ◽  
Similar Time ◽  
Body Formation ◽  
Polar Body Formation ◽  
Second Polar Body ◽  
Mouse Eggs

Unfertilized mouse eggs were activated in vitro with hyaluronidase. Subsequently they were exposed to culture medium at different osmolarities. In full strength White's culture medium they tended to form one pronucleus and a second polar body. The majority of these eggs were haploid. In 4/5 and 3/5 dilutions of this medium, the second polar body formation was suppressed and eggs tended to form with one or two pronuclei. Those with one pronucleus were diploid and those with two pronuclei could either form a diploid or form a haploid mosaic. Old eggs tended to immediately cleave and form haploid mosaics. DNA synthesis was studied in activated eggs using tritiated thymidine and autoradiography. DNA synthesis occurred at a similar time in fertilized and activated eggs.

Changes in actin distribution during fertilization of the mouse egg

Development ◽  
1984 ◽  
Vol 81 (1) ◽  
pp. 211-237
Author(s):  
B. Maro ◽  
M. H. Johnson ◽  
S. J. Pickering ◽  
G. Flach
Keyword(s):  
Structural Changes ◽  
Polar Body ◽  
Cytochalasin D ◽  
Fertilization In Vitro ◽  
Surface Binding ◽  
Con A ◽  
Light Microscope Level ◽  
Body Formation ◽  
Sperm Entry ◽  
Polar Body Formation

Unfertilized mouse oocytes and eggs 1–8 h after fertilization in vitro were examined at the light microscope level for structural changes, distribution of actin (as assessed by both antiactin antibodies and NBD-phallicidin), surface binding of concanavalin A (Con A) and chromosomal distribution and condensation. The influence of cytochalasin D on these events was also assessed. Changes in actin distribution were associated with rotation of the second anaphase spindle, formation of the second polar body, the events following incorporation of the sperm nucleus, and formation and migration of the pronuclei. Cytochalasin D prevented spindle rotation, polar body formation, pronuclear migration and the restoration of Con A binding over the site of sperm entry and the site of polar body formation, but did not affect sperm fusion and entry, the loss of Con A binding at the site of sperm entry and pronuclear formation.

Diploid parthenogenetic mouse embryos produced by heat-shock and Cytochalasin B

Development ◽  
1976 ◽  
Vol 35 (1) ◽  
pp. 25-39
Author(s):  
Hanna Bałakier ◽  
Andrzej K. Tarkowski
Keyword(s):  
Heat Shock ◽  
Cytochalasin B ◽  
Polar Body ◽  
Implantation Rate ◽  
Mouse Embryos ◽  
Activation Rate ◽  
Second Polar Body ◽  
Stage Characteristic ◽  
Parthenogenetic Mouse Embryos

Swiss albino and C57BL/10 eggs from induced ovulations, and spontaneously ovulated A eggs, were activated in vitro by a heat shock of 44 °C for 5 or 7·5 min and cultured in the presence of 10 μg/ml of Cytochalasin B (CB) for 5–8 h. The activation rate was about 70 % in Swiss albino, 40 % in C57BL and 90 % in A eggs. CB suppressed second polar body (2P.B.) formation in over 90 % of activated eggs, with the majority containing two pronuclei. When eggs were placed in CB-free medium their surface became wrinkled and they formed protrusions of various sizes, which in some eggs detached to form enucleate or pronucleate cytoplasmic fragments; some eggs broke down completely into fragments. In most eggs, however, the surface smoothed out in a few hours and suppression of 2P.B. appeared to be permanent. The rate of development of these eggs after transplantation to the oviduct was delayed in terms both of cell divisions and of the time of blastocyst formation. Out of 41 implants collected on the 8th–10th day of pregnancy only two healthy looking egg-cylinders were found on the 8th and 9th day; both were retarded, at the stage characteristic for the 7th day of normal development. The reasons for delayed preimplantation development and low implantation rate are discussed. The present experiments corroborate earlier observations that parthenogenetic mouse embryos, even if diploid, rarely survive in the uterus beyond the egg-cylinder stage.

Memoirs: The Germ-Cell Cycle in Phytophaga destructor Say

1935 ◽  
Vol s2-77 (308) ◽  
pp. 585-604
Author(s):  
MARGOT E. METEALFE
Keyword(s):  
Germ Cells ◽  
Growth Stage ◽  
Germ Line ◽  
Polar Body ◽  
Metaphase Plate ◽  
Body Formation ◽  
Polar Bodies ◽  
Complicated Process ◽  
Female Pronucleus ◽  
Polar Body Formation

1. The somatic cells in both sexes of Phytophaga destructor Say contain four pairs of V-shaped chromosomes, the sex-group being indistinguishable in size or form. 2. The germ-cells in both sexes contain eight pairs of chromosomes. 3. The maturation of the egg follows the normal course of development, eight bivalents being formed. After polar body formation the female pronucleus has eight chromosomes. The polar bodies are never extruded from the egg. 4. Spermatogenesis is a complicated process, the details of which have not been satisfactorily determined. The growth stage appears to take place before the last spermatogonial division. No pairing of chromosome has been observed, and apparently no metaphase plate is formed at meiosis. Eeduction is effected by the expulsion of two buds each containing four chromosomes. Thus only one sperm is produced from each spermatocyte. 5. One or more sperms may enter the egg at fertilization. 6. The germ-line is differentiated from the soma at the eightcell stage. 7. At the fifth cleavage the somatic nuclei eliminate half their number of chromosomes, and are left with eight chromosomes. 8. Migration of the germ nuclei takes place at the sixteencell stage. 9. The relation of the chromosome numbers in the somatic and germ lines is discussed.

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