Image analysis of chromatin in cells of reimplantation mouse embryos.

Mouse two-celled embryos and blastulae were Feulgen stained and the DNA content of their nuclei was measured with an integrating microdensitometer. The cells considered on the basis of their nuclear DNA content to be in G(1), S, and G(2) phases of the cell cycle were selected and their total chromatin area and chromatin areas at different gray levels were measured by the image analyzing computer, Quantimet. The measurements were aimed at quantitation of several features of the chromatin morphology of cells in different functional states.

Uptake of heterologous genome by mammalian spermatozoa and its transfer to ova through fertilization.

Simian virus 40 (SV40) adsorbs on rabbit spermatozoa but does not penetrate the cells, as indicated by the absence of radioactive material seen on autoradiography of spermatozoa exposed to [(3)H]thymidine-labeled SV40. In contrast, after exposure of spermatozoa to labeled SV40 DNA, radioactive material was found in the postacrosomal area of the spermatozoa. Furthermore, when spermatozoa exposed to SV40 DNA were fused with cells of the CV-1 line of African green monkey kidney cells, infectious SV40 was isolated.