Nucleolus

About: Nucleolus is a research topic. Over the lifetime, 5873 publications have been published within this topic receiving 232435 citations. The topic is also known as: GO:0005730 & cell nucleolus.

Ultrastructural localization of nuclei acids by the use of enzyme-gold complexes.

Abstract: A cytochemical technique for the ultrastructural localization of substrates using enzyme-gold complexes is reported. RNase A and DNase I have been labeled with gold particles. The RNase-gold and dNase-gold complexes obtained were applied on thin sections of glutaraldehyde-fixed and Epon-embedded tissues. Different cellular compartments were labeled by these enzyme-gold complexes. Using the RNase-gold complex the rough endoplasmic reticulum appeared decorated with gold particles. The gold marker was also present over the nucleus, especially over the nucleolus; mitochondria were weakly labeled. Using the DNase-gold complex, gold particles were concentrated over the euchromatin of the nucleus and the mitochondria. The heterochromatin and the nucleolus showed a less intense labeling. For both enzyme-gold complexes, the Golgi area, the secretory granules and the extracellular space appeared free of label. In those control conditions where the substrates were added to the enzyme-gold complexes a major reduction...

Electron microscopic morphology of oogenesis.

Abstract: Publisher Summary This chapter discusses the electron microscopic morphology of oogenesis. The nucleus plays a very important role in regulation of cell life processes. In accordance with the theory that the nucleolus controls the synthesis of cytoplasmic RNA, it is noted in studies of oocyte nuclei that the nucleolus often shows signs of emitting granules into the nucleoplasm. In vitro nucleolar emission is observed in oocytes of the roach and this finding was correlated with a reticulate rim of the nucleolus as seen in the electron microscope. Two processes visibly affect the nuclear envelope during oogenesis. One is concerned with the partial or complete perforation of the envelope, possibly facilitating the passage of nuclear material to the cytoplasm; the other is the enlargement of the nuclear membrane area as well as its area relative to nuclear volume. 2. The literature on oogenesis makes little mention of smooth endoplasmic reticulum. It is generally accepted that this type of cytomembrane plays only a limited role in oocytes. The controversy in interpretation of Golgi structure and function may be equally applied to oogenetical studies. Electron microscopy has so far been the most reliable means for studying Golgi material.