[Electron microscopic-cytochemical study of succinate dehydrogenase activity of nerve tissue cells of human embryos in vitro].

The ultrastructural localization of succinate dehydrogenase (SDH) activity was revealed in astrocyte-like cells of 26 days old nervous tissue organotypic cultures. The Kerpel-Fronius and Hajos (1968) technique was employed using potassium ferricyanide as an artificial acceptor of electrons. The localization of the reaction product was seen more often in cells with long, thread-like mitochondria.

[Ultrastructural localization of cytochrome oxidase in human embryonic brain cells].

The author studied ultrastructural localization of cytochromoxidase (CO) in neuroectodermic cells (young neurons and glioblasts) of the brain of human embryos and 7--10-week-old fetuses. Use was made of CO determination via cytochrome C with the aid of 3,3'-diaminobenzidine as an electron donor. Intracellular distribution of CO in young neurons did not differ from that in glioblasts.

[Ultrastructural localization of lactate dehydrogenase activity in the brain cells of human embryos].

Results of studying the ultrastructural localization of lactate dehydrogenase (LDH) in the brain neuroectodermal cells of 7-11-week-old human embryos are presented. Young neurons and glioblasts display marked LDH activity. The reaction product is more frequently found in young neurons as compared to glioblasts.

[Light and electron microscopic study of the mitochondria in human embryonic nervous tissue cells in vitro].

After a 5-min heating of isolated Tradescantia leaves at 49 degrees C the granular component in the nucleoli of parenchyma cells disappears and the nucleoli grow more compact and exclusively fibrillar in structure. Simultaneously, the ability of chloroplasts of these cells for phototaxis is completely inhibited. In leaves placed in a moist chamber at room temperature 48 h after heating a normal ultrastructure of nucleoli and the ability of chloroplasts to respond by phototaxis to change in illuminations are restored almost synchronously.