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

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.

1983 ◽  
Vol 245 (5) ◽  
pp. G681-G689 ◽  
Author(s):  
F. J. Suchy ◽  
W. F. Balistreri ◽  
J. Hung ◽  
P. Miller ◽  
S. A. Garfield

The role of hepatocyte organelles in the intracellular transport and secretion of conjugated bile acids has not been defined. Therefore we studied the transport and observed the subcellular localization of the bile acid analogue 125I-cholylglycyltyrosine by electron microscope autoradiography to further understand the possible compartmentation of bile acids within the hepatocyte. 125I-cholylglycyltyrosine, which retains a net negative charge, exhibited transport properties similar to native bile acids. After portal vein injection, the compound was recovered intact from bile, and the pattern of excretion paralleled that of [14C]cholylglycine. In addition, cholylglycyltyrosine uptake by isolated hepatocytes was sodium dependent. For autoradiography the analogue was injected into the portal vein, and the liver was perfusion fixed after 30 or 300 s. Light microscope autoradiography performed 30 s after isotope injection demonstrated a steep periportal-to-centrilobular gradient for 125I-cholylglycyltyrosine uptake. At 30 s quantitative grain analysis of electron microscope autoradiographs showed predominant labeling of the plasma membrane and the smooth endoplasmic reticulum (SER). The grain distribution over the region of the plasma membrane decreased from 15% at 30 s to 7% by 300 s and was associated with a sevenfold increase in labeling of the Golgi apparatus and a sixfold increase in labeling of the pericanalicular region. Grain distribution over the SER at 300 s was the same as that noted at 30 s. The hypothesis is presented that bile acids move from the sinusoidal plasma membrane to bile via a pathway that includes the SER and Golgi apparatus.


1968 ◽  
Vol 16 (3) ◽  
pp. 162-171 ◽  
Author(s):  
GUILLERMO JAIM ETCHEVERRY ◽  
LUIS MARIA ZIEHER

Blood platelets obtained from normal rabbits and those isolated from reserpine-treated animals and subsequently incubated in vitro with 5-hydroxytryptamine, norepinephrine and histamine were assayed for amine content or processed for examination under the electron microscope. With the glutaraldehyde-dichromate reaction for unsubstituted catechol- and indoleamines, reactive granules were observed in normal platelets. Formaldehyde fixation prior to the glutaraldehyde-dichromate reaction resulted in a similar image under the electron microscope. In platelets obtained from animals treated with reserpine a decrease of the amine content with a corresponding reduction in the number of dense granules was observed. Following incubation with 5-hydroxytryptamine the concentration of the amine increased markedly and the number of dense granules that reacted with both techniques became practically normal. In norepinephrine-incubated platelets dense granules were demonstrated with the glutaraldehyde-dichromate reaction, but no reactive products were observed using prefixation with formaldehyde. Histamine was also incorporated into depleted platelets but gave no reaction. It is concluded that prefixation with formaldehyde renders negative the reaction with catecholamines, leaving unaffected indoleamine-reactive sites. The previous assumption that the dense granules contain 5-hydroxytryptamine has been confirmed by such a cytochemical approach. The possibility that these organelles constitute a common storage site for different amines is discussed.


Author(s):  
M. Bouteille ◽  
E. Delain ◽  
N. Angelier

The LIGOP method of electron microscope autoradiography which consists in a combination of coating Ilford emulsion with the loop technique and developing with gold latensification and phenidon has proved to provide small, compact developed silver grains with high efficiency.This has made it possible to use this technique with very small materials such as isolated molecules of molecular complexes.The method was assayed first with 3H-Thymidine labelled T7 phages DNA molecule with 630,000 cpm/μg specific activity (fig. 1). The molecules were spread using the adsorption technique constrasted by rotatory shadowing with platinum and then subjected to autoradiography. The Labelling was sufficient to obtain quantitative data in which the spread molecules were considered as a material comparable to a “hot line”. The efficiency (45%) and the HD value (1600 Å) were calculated.The method was also applied to transcription units of pleurodeles oocytes nucleoli (fig. 2) labelled in vitro with 3H-Uridine.


1978 ◽  
Vol 76 (2) ◽  
pp. 400-417 ◽  
Author(s):  
D M Nelson ◽  
A C Enders ◽  
B F King

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.


1975 ◽  
Vol 67 (2) ◽  
pp. 320-344 ◽  
Author(s):  
B Meyrick ◽  
L Reid

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.


1981 ◽  
Vol 50 (1) ◽  
pp. 225-243
Author(s):  
S.J. Kimber

The secretion of the 2 main layers (endochorion and exochorion) of the eggshell of the desert locust Schistocerca gregaria was investigated using light and electron microscope autoradiography. Follicles undergoing endochorion secretion were labelled using a 3 min ‘pulse’ of [3H]leucine in vitro followed by a 0-115 min non-radioactive ‘chase’. Immediately after the pulse the silver grains were distributed over the cytoplasm and organelles including rough endoplasmic reticulum, while by 2 and 5 min Golgi bodies contained radioactivity. By 12 min from the beginning of the chase the cell apex containing small secretory vesicles was labelled. By 20 min most of the silver grains were over the endochorion. The half-transport time (t50) was 14–15 min (from mid pulse), the lag time was 9–10 min and the percentage transport rate was 14–15% per min. When a 3 min pulse of [3H]galactose was used to label exochorion precursors, the shorter t50 (11 min) and the clumped grain distribution in light microscope autoradiographs after 0-min chase suggested that galactose was incorporated in Golgi bodies. The secretion of exochorion precursors appears to occur at a similar rate to that of endochorion precursors (approximately 15% per min). The results indicate that the follicle cells are among the fastest secreting cells.


Blood ◽  
1968 ◽  
Vol 31 (2) ◽  
pp. 188-194 ◽  
Author(s):  
MARTHA E. FEDORKO

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.


Author(s):  
Frank A. Rawlins

Several speculations exist as to the site of incorporation of preformed molecules into myelin. The possibility that an autoradiographic analysis of cholesterol-1,2-H3 incorporation at very short times after injection might shed some light in the solution of that problem led to the present experiment.Cholesterol-1,2-H3 was injected intraperitoneally into 24 tenday old mice. The animals were then sacrificed at 10,20,30,40,60,90,120 and 180 min after the injection and the sciatic nerves were processed for electron microscope autoradiography. To analyze the grain distribution in the autoradiograms of cross and longitudinal sections from each sciatic nerve myelin sheaths were subdivided into three compartments named: outer 1/3, middle 1/3 and inner 1/3 compartments.It was found that twenty min. after the injection of cholesterol -1.2-H3 (Figs. 1 and 2), 55% of the total number of grains (t.n.g) found in myelin were within the outer 1/3 compartment, 9% were within the middle 1/3 and 36% within the inner 1/3 compartment


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