scholarly journals Cytological events involved in glycoprotein synthesis in cellular and syncytial trophoblast of human placenta. An electron microscope autoradiographic study of [3H]galactose incorporation.

1978 ◽  
Vol 76 (2) ◽  
pp. 418-429 ◽  
Author(s):  
D M Nelson ◽  
A C Enders ◽  
B F King
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Rough Endoplasmic Reticulum ◽  
Autoradiographic Study ◽  
Leucine Incorporation ◽  
Electron Microscope Autoradiography ◽  
Glycoprotein Synthesis ◽  
Placental Villi ◽  
Syncytial Trophoblast

Electron microscope autoradiography was used to study glycoprotein synthesis in cellular trophoblast (cytotrophoblast) and syncytial trophoblast of term human placental villi incubated in vitro with D-[1-3H]galactose ([3H]gal). Autoradiographs were analyzed using the hypothetical grain analysis of Blackett and Parry (1973. J. Cell Biol. 57:9-15). The results of this study indicated that [3H]gal incorporation into term placental villi was predominantly localized to cytotrophoblast. Utilization of [3H]gal by term syncytial trophoblast was extremely low and yielded too few grains for a quantitative grain analysis. This result is in striking contrast to that found in the preceding study of [3H]leucine incorporation (Nelson, D. M., A. C. Enders, and B. F. King. 1978). Within cytotrophoblast, the rough endoplasmic reticulum incorporated the most [3H]gal into glycoprotein. The Golgi apparatus was another site of [3H]gal incorporation. The vast majority of the [3H]gal incorporated into cytotrophoblast during the pulse incubation remained intracellular through the duration of the experiment. There was little autoradiographic evidence for secretion of tritiated macromolecules. Cytotrophoblast incubated for the longest time period studied (4 h+) showed a substantial concentration of tritiated macromolecules in the Golgi complex and in the ground plasm but not in the rough endoplasmic reticulum.

scholarly journals Cytological events involved in protein synthesis in cellular and syncytial trophoblast of human placenta. An electron microscope autoradiographic study of [3H]leucine incorporation.

1978 ◽  
Vol 76 (2) ◽  
pp. 400-417 ◽  
Author(s):  
D M Nelson ◽  
A C Enders ◽  
B F King
Keyword(s):  
Protein Synthesis ◽  
Electron Microscope ◽  
Autoradiographic Study ◽  
Leucine Incorporation ◽  
Electron Microscope Autoradiography ◽  
Placental Villi ◽  
Microscope Autoradiography ◽  
Syncytial Trophoblast ◽  
Time Point

Electron microscope autoradiography has been used to study protein synthesis in syncytial and cellular trophoblast of term human placental villi incubated in vitro with tritiated leucine ([3H]leu). Autoradiographs were analyzed using the hypothetical grain analysis of Blackett and Parry (1973. J. Cell Biol. 57:9-15). The results of this study demonstrated that both cellular and syncytial trophoblast have marked capacities for protein synthesis. Cellular trophoblast synthesized protein in both its rough endoplasmic reticulum (RER) and its ground plasm which contained abundant free ribosomes. The vast majority of 3H-proteins remained within the cell, with some of the proteins synthesized ultimately appearing in the nucleus. A small percentage of grains was ultimately associated with the trophoblast basement membrane. In syncytial trophoblast, the RER was the dominant site for protein synthesis. The autoradiographic data suggested that, as in the cellular trophoblast, the vast majority of 3H-proteins synthesized by the syncytial trophoblast remained within the syncytial trophoblast throughout the incubation period. The major portion of [3H]leu-labeling present in the syncytial trophoblast of villi incubated the longest times (4 h+) remained in association with the RER. Labeled proteins did not become concentrated in syncytial trophoblast Golgi apparatus, vesicles, or granules. In contrast to cellular trophoblast, the nuclei in the syncytium did not contain 3H-proteins at any time-point studied.

scholarly journals RADIOAUTOGRAPHIC VISUALIZATION OF THE INCORPORATION OF GALACTOSE-3H AND MANNOSE-3H BY RAT THYROIDS IN VITRO IN RELATION TO THE STAGES OF THYROGLOBULIN SYNTHESIS

1969 ◽  
Vol 43 (2) ◽  
pp. 289-311 ◽  
Author(s):  
P. Whur ◽  
Annette Herscovics ◽  
C. P. Leblond
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Light Microscope ◽  
Detectable Effect ◽  
Apical Vesicles ◽  
Rat Thyroid

Rat thyroid lobes incubated with mannose-3H, galactose-3H, or leucine-3H, were studied by radioautography. With leucine-3H and mannose-3H, the grain reaction observed in the light microscope is distributed diffusely over the cells at 5 min, with no reaction over the colloid. Later, the grains are concentrated towards the apex, and colloid reactions begin to appear by 2 hr. With galactose-3H, the reaction at 5 min is again restricted to the cells but it consists of clumped grains next to the nucleus. Soon after, grains are concentrated at the cell apex and colloid reactions appear in some follicles as early as 30 min. Puromycin almost totally inhibits incorporation of leucine-3H and mannose-3H, but has no detectable effect on galactose-3H incorporation during the 1st hr. Quantitation of electron microscope radioautographs shows that mannose-3H label localizes initially in the rough endoplasmic reticulum, and by 1–2 hr much of this reaction is transferred to the Golgi apparatus. At 3 hr and subsequently, significant reactions are present over apical vesicles and colloid, while the Golgi reaction declines. Label associated with galactose-3H localizes initially in the Golgi apparatus and rapidly transfers to the apical vesicles, and then to the colloid. These findings indicate that mannose incorporation into thyroglobulin precursors occurs within the rough endoplasmic reticulum; these precursors then migrate to the Golgi apparatus, where galactose incorporation takes place. The glycoprotein thus formed migrates via the apical vesicles to the colloid.

scholarly journals Polyribosomal attachment to rat liver and hepatoma endoplasmic reticulum in vitro. A method for its study

1971 ◽  
Vol 121 (2) ◽  
pp. 271-278 ◽  
Author(s):  
W. L. Ragland ◽  
T. K. Shires ◽  
H. C. Pitot
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Citric Acid ◽  
Low Temperature ◽  
Rough Endoplasmic Reticulum ◽  
Half Life ◽  
Binding Capacity ◽  
Smooth Endoplasmic Reticulum ◽  
Quantitative Separation

A system for study and measurement of the attachment in vitro of exogenous polyribosomes to membranes has been presented. Its main features are use of low temperature, post-microsomal supernatant, pyrophosphate and citric acid to remove ribosomes from the surface of rough endoplasmic reticulum, and a method for quantitative separation of unattached from membrane-associated polyribosomes. The following were found. (1) Rough endoplasmic reticulum, from which ribosomes had been removed by treatment with pyrophosphate and citrate, bound over 50% of added polyribosomes, whereas the untreated (or control) rough and smooth endoplasmic reticulum and the smooth endoplasmic reticulum treated with pyrophosphate–citrate did not bind polyribosomes. (2) The polyribosome-binding capacity of rough endoplasmic reticulum stripped of its ribosomes decayed upon storage of the membranes at 0–4°C. The half-life of this decay was about 6 days whereas that of the polyribosome-binding capacity of hepatoma stripped rough endoplasmic reticulum was about 1.5 days. (3) Preparations of stripped rough endoplasmic reticulum after reassociation with polyribosomes in vitro were quite similar to preparations of native rough endoplasmic reticulum as viewed with the electron microscope. Evidence is presented to support the contention that association of polyribosomes with membranes was the result of polyribosomal reattachment to the membranes rather than trapping of the polyribosomes between vesicles of the membranes.

scholarly journals In vitro incorporation of (3H)threonine and (3H)glucose by the mucous and serous cells of the human bronchial submucosal gland. A quantitative electron microscope study.

1975 ◽  
Vol 67 (2) ◽  
pp. 320-344 ◽  
Author(s):  
B Meyrick ◽  
L Reid
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Golgi Apparatus ◽  
Secretory Granules ◽  
Mucous Cell ◽  
Submucosal Gland ◽  
Electron Microscope Autoradiography ◽  
Serous Cell ◽  
Relationship Of

Incorporation of [3H]threonine and [3H]glucose by the mucous and serous cells of the human bronchial submucosal gland has been studied over 8 h using, for the first time in vitro pulse labeling and electron microscope autoradiography. In assessing the autoradiographs, two methods were compared, the circle analysis and the recently described hypothetical grain analysis. Preliminary studies showed formaldehyde to be the most suitable fixative. Chemical analysis of tissue revealed that [3H]threonine was incorporated into the polypeptide moiety of the bronchial gland product and that metabolites of [3H]-glucose were incorporated into the carbohydrate. Tritiated threonine was first localized in the endoplasmic reticulum of both mucous and serous cells and later migrated to the Golgi apparatus, while metabolites of [3H]glucose localized first mainly in the Golgi apparatus. From here, both radioactive precursors were next identified in vacuoles and, finally, in secretory granules. The mucous cell incorporated strikingly more of both radioactive precursors than the serous cell. Thus, it seems that oligosaccharides of mucous and serous cell glycoproteins are synthesized mainly in the Golgi apparatus and added there to the polypeptide core which is synthesized in the endoplasmic reticulum. The relationship of the mucous cell to the serous cell is discussed. It seems that under "normal" conditions each cell represents a different line but that injury may transform a serous cell into a mucous cell.

scholarly journals Formation of Cytoplasmic Granules in Human Eosinophilic Myelocytes: An Electron Microscope Autoradiographic Study

Blood ◽  
1968 ◽  
Vol 31 (2) ◽  
pp. 188-194 ◽  
Author(s):  
MARTHA E. FEDORKO
Keyword(s):  
Bone Marrow ◽  
Electron Microscope ◽  
Golgi Complex ◽  
Autoradiographic Study ◽  
Electron Microscope Autoradiography ◽  
Cytoplasmic Granules ◽  
Microscope Autoradiography ◽  
Intracellular Amino Acids ◽  
Flow Through

Abstract The intracellular flow of tritiated lysine in human eosinophilic myelocytes was studied by electron microscope autoradiography so that information could be obtained on the formation of eosinophil granules. Bone marrow particles obtained from a patient with a marked increase in the number of bone marrow eosinophils were incubated in vitro for periods up to 150 minutes. The percentage of cytoplasmic grains over the Golgi complex rose from 11 percent at 5 minutes to 28 percent by 30 minutes and fell to 15 percent at 150 minutes. Grains over cytoplasmic granules steadily rose to 37 percent by 150 minutes. These results are statistically significant and demonstrate that: human eosinophilic myelocytes are able to form cytoplasmic granules under the in vitro conditions employed, and that intracellular amino acids or proteins flow through the Golgi complex before incorporation into granules.

scholarly journals Electron microscope autoradiographic study of intestinal absorption of decanoic and octanoic acids in the rat.

1975 ◽  
Vol 65 (2) ◽  
pp. 383-397 ◽  
Author(s):  
H Carlier ◽  
J Bezard
Keyword(s):  
Fatty Acids ◽  
Electron Microscope ◽  
Intestinal Absorption ◽  
Common Duct ◽  
Autoradiographic Study ◽  
Electron Microscope Autoradiography ◽  
Blood Capillaries ◽  
Medium Chain ◽  
Medium Chain Fatty Acids ◽  
Chain Fatty Acids

Intestinal absorption of [3H]octanoic acid and [3H]decanoic acid was investigated in the rat by electron microscope autoradiography. The common duct (bile and pancreatic common duct) of the rats was diverted and a loop of the duodenum was cannulated 24 h later. The lipid mixture to be investigated was introduced into each experimental loop, and after 15 min or less the loop was removed. One part of each loop was used to determine the distribution of radioactivity in different lipid fractions, and an autoradiographic study was performed on the other part of the loop. Radioactivity distribution studies confirmed that medium chain fatty acids are absorbed in their nonesterified form and established that these fatty acids are absorbed much more rapidly than oleic acid. Autoradiographic studies indicated that the medium chain fatty acids are taken up in a molecular or aggregate molecular form, leave the epithelial cells by way of the lateral plasma membrane, and are next found in the blood capillaries. Our results suggest that the Golgi complex does not play an important role in the absorption of unesterified fatty acids.

An Electron-Microscope Study of the in vitro Transformation of Human Leucocytes

1967 ◽  
Vol 2 (3) ◽  
pp. 359-370
Author(s):  
J. A. CHAPMAN ◽  
M. W. ELVES ◽  
J. GOUGH
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Messenger Rna ◽  
Human Peripheral Blood ◽  
Limited Extent ◽  
Single Particles ◽  
Blast Cells ◽  
Protein Secreting

Electron-microscope studies of cultured small lymphocytes from human peripheral blood transforming into larger blastoid cells in the presence of phytohaemagglutinin (PHA) show that the transformed cell possesses the preliminary stages of development of a protein-synthesizing system. The transformed blastoid cell has abundant ribosomes, although, in contrast with in vivo protein-secreting cells, many of these occur as single particles with only a small proportion Linked in polysomal clusters. Endoplasmic reticulum membranes occur to a very limited extent and with a marked paucity of attached ribosomal particles; the few attached particles are usually located in groups. Some endoplasmic reticulum membranes revealed degenerative changes in otherwise normal cells. A moderately well-developed Golgi apparatus was a characteristic feature of the cells. Apart from the relatively low proportion of polysomes, in vitro PHA-transformed blastoid cells are identical in fine structure to in vivo blast cells (otherwise known as immunoblasts, haemocytoblasts, etc.) occurring in the immune response. It is suggested that messenger-RNA production in PHA-stimulated transformed cells may be reduced and that this could explain the limited number of polysomes and the restricted development of the endoplasmic reticulum.

Synthesis and Localization of Sulphated Mucopolysaccharide in Megakaryocytes and Platelets of the Rat, An Analysis by Electron-Microscope Autoradiography

1972 ◽  
Vol 10 (3) ◽  
pp. 705-717
Author(s):  
G. G. MacPHERSON
Keyword(s):  
Electron Microscope ◽  
Golgi Apparatus ◽  
Blood Platelets ◽  
Total Activity ◽  
Electron Microscope Autoradiography ◽  
Dense Granules ◽  
Level Of Activity ◽  
Microscope Autoradiography ◽  
Almost All

Electron-microscope autoradiography has been used to investigate the synthesis and localization of sulphated mucopolysaccharide in megakaryocytes and blood platelets. Following 10-min incubation of bone marrow with 35S-sulpahte in vitro the majority of the activity in megakaryocytes was associated with the Golgi apparatus, but a substantial proportion was associated with other cytoplasmic organelles, suggesting either rapid transport or sulphation of mucopolysaccharide outside the Golgi apparatus. Three hours after the intravenous injection of 35SO4 only a small proportion of the total activity was associated with the Golgi apparatus, most being associated with demarcation membranes and dense granules, while 12 h after injection almost all the activity was associated with demarcation membranes and granules. A rising proportion of activity localized solely on the demarcation membranes suggested that they may possess some activity of their own. Autoradiographs of blood platelets prepared 72 h after the injection of 35SO4 were analysed. It was shown that most of the activity was associated with the α-granules, but there was strong evidence that the platelet membrane possessed a low level of activity.

Autoradiographic study of macromolecular synthesis in the fusion epithelium of the developing rat primary palate in vitro

Development ◽  
1979 ◽  
Vol 50 (1) ◽  
pp. 145-154
Author(s):  
Alvaro A. Figueroa ◽  
Robert M. Pratt
Keyword(s):  
Autoradiographic Study ◽  
Whole Embryo Culture ◽  
Glycoprotein Synthesis ◽  
Palate Development ◽  
Molecular Events ◽  
Secondary Palate ◽  
Primary Palate ◽  
Epithelial Fusion ◽  
Developing Rat

The facial processes involved in primary palate formation undergo epithelial fusion in a manner morphologically analogous to that observed during secondary palate formation. We have used whole embryo culture to analyze the synthesis of macromolecules (DNA, protein, glycoprotein) in the primary palate, based on the incorporation of various labeled precursors. The results of this study demonstrate that changes in the synthesis of macromolecules occur during the fusion of the facial processes, which resemble those previously reported to occur during secondary palate development. These changes include cessation of DNA synthesis in cells in a restricted zone of the epithelium, concomitant with maintenance of glycoprotein synthesis. These findings indicate that the molecular events underlying the development of the primary and secondary palate may be similar.

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