Showing papers on "Cellular compartment published in 1980"

Quantitative immunocytochemical localization of pancreatic secretory proteins in subcellular compartments of the rat acinar cell.

Abstract: The recently developed protein A-gold technique for the detection of intracellular antigenic sites on thin sections was utilized to localize nine different secretory proteins in the rat exocrine pancreas. Amylase, chymotrypsinogen, trypsinogen, lipase, elastase, carboxypeptidases A and B, RNase and DNase, were detected at the level of the rough endoplasmic reticulum, the Golgi area, and the zymogen granules of the acinar cells, as well as in the acinar lumen. A quantitative evaluation of the labeling showed that its intensity was not identical for all enzymes studied nor in all cellular compartments analyzed. An increasing gradient of the labeling from the rough endoplasmic reticulum to the Golgi and to the zymogen granules was found for amylase, carboxypeptidases A and B, chymotrypsinogen, trypsinogen, and RNase, while a comparable low degree of labeling in the Golgi apparatus and in the zymogen granules was observed for DNase, lipase, and elastase. These results suggest that the nine enzymes are processed through the same intracellular compartments, but that they may be concentrated to different degrees in the zymogen granules before being released in the acinar lumen.

Plastid DNA-the plastome.

Abstract: The development of autotrophic eukaryotic organisms results from a close cooperation between three distinct cellular compartments (using the compartment definition of Schnepf 1966), of nucleus/cytosol, plastids, and mitochondria, each of which contains its own genetic machinery. Understanding the nature of this cooperation and its evolution is a fundamental problem in biology. This chapter focuses primarily on genetic elements of plastids.

Saccharide Traffic Signals in Receptor-Mediated Endocytosis and Transport of Acid Hydrolases

Abstract: Endocytosis is a transport process which allows cells to interiorize extracellular material (1). Endocytic vesicles form when segments of the plasma membrane invaginate, pinch off, and enclose a volume of extracellular fluid. Fusion of plasma membrane to plasma membrane seals the neck of the vesicles (2) and the sites from which they invaginate. Fusion of the endocytic vesicle with another membrane permits the transport of the contents of the vesicle to another cellular compartment, or to the cell exterior.

Reaction patterns of cell organelles in vitamin B6 deficiency: Ultrastructural-morphometric analysis of the liver parenchymal cell

Abstract: Summary Under the influence of seven weeks of vitamin B 6 -free nutrition, the hepatocyte single volume is diminished in the face of an unchanged nuclear single volume, posing the question of whether there is proportional atrophy of all cell organelles or single organelle atrophy with counterregulatory hyperplasia in other cellular compartments. The nucleoli hypertrophy, as the result of segregation and protein synthesis inhibition. The rough endoplasmic reticulum experiences hypoplasia, but the ultrastructural-morphometric analysis does not determine which metabolic steps are attacked. By contrast one observes hyperplasia in the smooth endoplasmic reticulum, which may be regarded as a counter-regulatory mechanism to the choking of protein synthesis. As with the rough endoplasmic reticulum, the mitochondria also show hypoplasia. This is due to the dependency of the mitochondria upon the endoplasmic protein synthesis. The disturbed functional output of the endoplasmic reticulum is seen in the reduced number of orthoperoxisomes as well. The Golgi apparatus experiences hypoplasia as a result of B6 hypovitaminosis, and this must be considered in the context of fatty change in the liver.

Endoplasmic Reticulum, Golgi Complexes and Secretory Vesicles

Abstract: During the 1950s an avalanche of electron microscopic (E.M.) studies showed that the cytoplasm of most plant and animal cells contained a complex membrane system of canaliculi and cisternae. This was named the endoplasmic reticulum (ER) by Palade and was divided into rough ER, characterized by ribosomes on the outer surfaces of the cisternae, and smooth ER, which was devoid of ribosomes (figure 6.1). The rough ER was 40–50 nm wide, approximately half the width of the smooth ER elements. A third membrane system, known as the Golgi body or apparatus, since it was first reported by Golgi in 1898, was confirmed by E. M. and shown to be a relatively discrete interconnected fretwork of flattened sacs (saccules), tubules and vesicles that could fairly be termed an organelle. The finding that ER and Golgi bodies were particularly well developed in synthetically active cells like exocrine pancreas, liver, collagen-secreting fibroblasts and polymer-secreting plant cells, suggested that they were involved in synthetic and secretory activity. Subsequent investigations brilliantly vindicated these predictions.