Quantitative determination of the intracellular fate of internalized plasma membrane in dissociated pituitary prolactin cells utilizing a radioiodinated cationic ferritin probe (CFI*) and electron microscopic autoradiography

1984 ◽  
Vol 169 (2) ◽  
pp. 193-206 ◽  
Author(s):  
Lionel J. Rosenzweig ◽  
Yashpal S. Kanwar
Keyword(s):  
Plasma Membrane ◽  
Quantitative Determination ◽  
Prolactin Cells ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Pituitary Prolactin ◽  
Intracellular Fate

scholarly journals Selective uptake of [3H]arachidonic acid into the dense tubular system of human platelets

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 832-837 ◽  
Author(s):  
M Laposata ◽  
CM Krueger ◽  
JE Saffitz
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Human Platelets ◽  
Electron Microscopic ◽  
Selective Labeling ◽  
Electron Microscopic Autoradiography ◽  
Tubular System ◽  
Electron Microscopy Analysis ◽  
Membrane Compartment ◽  
Microscopy Analysis

Abstract We have used quantitative electron microscopic autoradiography to characterize the subcellular distribution of arachidonoyl phospholipids following brief (5 minutes) exposure of unstimulated human platelets to [3H]arachidonic acid. Labeled arachidonate was taken up rapidly and incorporated into phospholipids. Phospholipid radioactivity was preserved and spatially fixed during tissue processing for electron microscopy. Analysis of autoradiographs showed that following a brief exposure to 750 nmol/L [3H]arachidonate, there is selective labeling of an internal membrane compartment composed of the dense tubular system and the open canalicular system. The plasma membrane, platelet granules, and nonmembranous cytoplasm were not labeled. Since the open canalicular system is continuous with the plasma membrane and since phospholipids in continuous membranes are freely diffusible, our observations indicate that [3H]arachidonate was incorporated into phospholipids within the dense tubular system and not the open canalicular system. Thus, the dense tubular system, known to contain cyclooxygenase activity, incorporates arachidonate selectively following brief exposure to this fatty acid, presumably to concentrate it in proximity to enzymes for icosanoid synthesis.

scholarly journals Trypanosoma cruzi: mechanism of entry and intracellular fate in mammalian cells.

1976 ◽  
Vol 143 (6) ◽  
pp. 1402-1420 ◽  
Author(s):  
N Nogueira ◽  
Z Cohn
Keyword(s):  
Plasma Membrane ◽  
Trypanosoma Cruzi ◽  
Mammalian Cells ◽  
Cultured Cells ◽  
Cell Types ◽  
Peritoneal Macrophages ◽  
Electron Microscopic ◽  
Cytoplasmic Matrix ◽  
Mode Of Entry ◽  
Intracellular Fate

The mode of entry and intracellular fate of epimastigotes and trypomastigotes of Trypanosoma cruzi in cultured cells was studied. Electron microscopic observations indicated the uptake by phagocytosis of both forms into mouse peritoneal macrophages and of trypomastigotes and transition forms into other cultured cell types. In each instance the organisms were initially surrounded by a plasma membrane-derived phagosome. Trypsin and chymotrypsin treatment of the macrophages completely abolished attachment and ingestion of both forms, indicating that protease-sensitive structures on the macrophage plasma membrane mediate ingestion. The macrophage Fc or C3b receptors were not essential for uptake of T. cruzi in the conditions used. Cytochalasin B inhibited ingestion but not the attachment of both forms by macrophages. Epimastigotes were not taken up by HeLa, L cells, and calf embryo fibroblasts. In macrophages, epimastigotes were killed and digested within phagolysosomes. In contrast, trypomastigotes and transition forms escaped from the phagocytic vacuole and then multiplied in the cytoplasmic matrix. Amastigotes released from infected cells exhibited properties similar to those of trypomastigotes and were able to enter all cell types studied and multiply intracellularly.

Two action sites of AM-toxin I produced by apple pathotype of Alternaria alternata in host cells: an ultrastructural study

1981 ◽  
Vol 59 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Pyoyun Park ◽  
Syoyo Nishimura ◽  
Keisuke Kohmoto ◽  
Hiroshi Otani ◽  
Kazuyuki Tsujimoto
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Amorphous Materials ◽  
Plasma Membranes ◽  
Host Cells ◽  
Ultrastructural Changes ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography ◽  
Moderately Resistant ◽  
Membrane Cell

The localization of primary action sites of AM-toxin I in host cells was examined by ultrastructural investigation and electron microscopic autoradiography. In susceptible apple leaves, the first effect of the toxin appeared 1 h after treatment in the plasma membranes and chloroplasts of mesophyll and vascular bundle sheath cells and in the plasma membranes of phloem and epidermal cells. Membranes and vesicles which were stained positively with a specific staining solution for grana lamellae were found in the matrix of the chloroplasts, showing that the membranous materials were derived from the disrupted grana. Cell wall lesions were formed around plasmodesmata where plasma membranes were invaginated. The invaginated sites were filled with amorphous materials from degraded cell walls, including membranes derived from plasma membranes and the desmotubules extending from plasmodesmata. The modified chloroplasts and plasma membranes were observed more often as the time after the toxin treatment was prolonged. Modified plastids were not found in the leaf cells. The other cellular membranes appeared normal even 10 h after the treatment. Resistant leaf cells were rarely affected by the toxin. Not all tissues from susceptible apples were sensitive as the toxin caused no necrosis or ultrastructural changes in petal cells. Resistant petal cells were also insensitive to the toxin, but the toxin causes necrosis and ultrastructural changes in moderately resistant petal cells in which the primary effect of the toxin appeared as plasma membrane modifications. Plastids were not affected by the toxin. These results indicate that the action sites of the toxin may be located on the plasma membrane – cell wall association in susceptible leaf cells and in moderately resistant petal cells and also on the chloroplasts of susceptible cells. The results of electron microscopic autoradiography also provided evidence that the action sites of the toxin were present on chloroplasts and the plasma membrane –cell wall association of susceptible leaf cells.

scholarly journals Selective uptake of [3H]arachidonic acid into the dense tubular system of human platelets

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 832-837
Author(s):  
M Laposata ◽  
CM Krueger ◽  
JE Saffitz
Keyword(s):  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Human Platelets ◽  
Electron Microscopic ◽  
Selective Labeling ◽  
Electron Microscopic Autoradiography ◽  
Tubular System ◽  
Electron Microscopy Analysis ◽  
Membrane Compartment ◽  
Microscopy Analysis

We have used quantitative electron microscopic autoradiography to characterize the subcellular distribution of arachidonoyl phospholipids following brief (5 minutes) exposure of unstimulated human platelets to [3H]arachidonic acid. Labeled arachidonate was taken up rapidly and incorporated into phospholipids. Phospholipid radioactivity was preserved and spatially fixed during tissue processing for electron microscopy. Analysis of autoradiographs showed that following a brief exposure to 750 nmol/L [3H]arachidonate, there is selective labeling of an internal membrane compartment composed of the dense tubular system and the open canalicular system. The plasma membrane, platelet granules, and nonmembranous cytoplasm were not labeled. Since the open canalicular system is continuous with the plasma membrane and since phospholipids in continuous membranes are freely diffusible, our observations indicate that [3H]arachidonate was incorporated into phospholipids within the dense tubular system and not the open canalicular system. Thus, the dense tubular system, known to contain cyclooxygenase activity, incorporates arachidonate selectively following brief exposure to this fatty acid, presumably to concentrate it in proximity to enzymes for icosanoid synthesis.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

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