Observations on follicular lactate concentrations and the influence of granulosa cells on oocyte maturation in the rat (including data on second polar body formation)

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.

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Polar Body Formation in Tubifex Eggs

Annals of the New York Academy of Sciences ◽

10.1111/j.1749-6632.1990.tb21685.x ◽

1990 ◽

Vol 582 (1 Cytokinesis) ◽

pp. 260-272 ◽

Cited By ~ 18

Author(s):

TAKASHI SHIMIZU

Keyword(s):

Polar Body ◽

Body Formation ◽

Polar Body Formation

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Memoirs: The Germ-Cell Cycle in Phytophaga destructor Say

Journal of Cell Science ◽

10.1242/jcs.s2-77.308.585 ◽

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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Preimplantation development of gynogenetic diploid mouse embryos

Development ◽

10.1242/dev.69.1.215 ◽

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.

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