Development of the human dispermic embryo.

In a recent CD-ROM, we portrayed the microstructure of the pre-implantation human embryo (Sathananthan et al., 1999), which was a multimedia production with computer colour-enhanced electron micrographs of mainly monospermic embryos. This disk portrays light and electron micrographs of over 250 tripronuclear (3PN), dispermic, human embryos during pre-implantation development, viewed in thick and thin Araldite sections, as well as appearances of whole embryos flat embedded in Araldite blocks visualized with the light microscope.

inheritance of sperm centrioles and centrosomes in bovine embryos.

Immature cumulus oocyte complexes (COCs) were aspirated from ovarian follicles of slaughtered cow and matured for 24 h in TCM 199 medium with hormones. Eighty-five percent of oocytes matured with subsequent abstriction of the polar body. Matured COCs were then inseminated with frozen-thawed semen (2 x 10(6)/mL final concentration).

Centrifugation of bovine oocytes for nuclear micromanipulation and sperm microinjection.

The reproductive biotechnologies of intracytoplasmic sperm microinjection, nuclear transfer and DNA microinjection require the visualization of cytoplasmic components and nuclei of oocytes and early embryonic cells. Bovine oocytes were matured and fertilized in vitro, and then centrifuged at the germinal vesicle, metaphase II and pronuclear stages and at syngamy. These (n = 536) were examined using light and transmission electron microscopy.