scholarly journals Localization of thyroglobulin antigenicity in rat thyroid sections using antibodies labled with peroxidase or (125)I-radioiodine

1977 ◽  
Vol 74 (3) ◽  
pp. 992-1015 ◽  
Author(s):  
J Paiement ◽  
CP Leblond

In the hope of localizing thyroglobulin within focullar cells of the thyroid gland, antibodies raised against rat thyroglobulin were labeled with the enzyme horseradish peroxidase or with (125)I-radioiodine. Sections of rat thyroids fixed in glutaraldehyde and embedded in glycol methacrylate or Araldite were placed in contact with the labeled antibodies. The sites of antibody binding were detected by diaminobenzidine staining in the case of peroxidase labeling, and radioautography in the case of 125(I) labeling. Peroxidase labeling revealed that the antibodies were bound by the luminal colloid of the thyroid follicles and, within focullar cells, by colloid droplets, condensing vacuoles, and apical vesicles. (125)I labeling confirmed these findings, and revealed some binding of antibodies within Golgi saccules and rough endoplasmic reticulum. This method provides a visually less distinct distribution than peroxidase labeling, but it allowed ready quantitation of the reactions by counts of silver grains in the radioautographs. The counts revealed that the concentration of label was similar in the luminal colloid of different follicles, but that it varied within the compartments of follicular cells. A moderate concentration was detected in rough endoplasmic reticulum and Golgi saccules, whereas a high concentration was found in condensing vacuoles, apical vesicles, and in the luminal colloid. Varying amounts of label were observed over the different types of colloid droplets, and this was attributed to various degrees of lysosomal degradation of thyroglobulin. It is concluded that the concentration of thyroglobulin antigenicity increases during transport from the ribosomal site of synthesis to the follicular colloid, and then decreases during the digestion of colloid droplets which leads to the release of the thyoid hormone.

1969 ◽  
Vol 43 (2) ◽  
pp. 289-311 ◽  
Author(s):  
P. Whur ◽  
Annette Herscovics ◽  
C. P. Leblond

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.


1972 ◽  
Vol 20 (3) ◽  
pp. 220-224 ◽  
Author(s):  
A. HADDAD

Radioactive galactose was injected intravenously into rats and localized in thyroid follicular cells by electron microscopic radioautography at intervals ranging from 2.5 to 30 min after injection. The galactose label was mostly present in the Golgi apparatus at 2.5 min, with some of it in the adjacent rough endoplasmic reticulum. By 30 min, the label was found in apical vesicles and colloid. It was concluded that galactose is added to the carbohydrate side chains of incomplete thyroglobulin molecules during their travel through the cisternae of the endoplasmic reticulum into the Golgi apparatus; the uptake begins as this organelle is approached, but predominates within it. The thyroglobulin molecule which has thus been labeled is transported by the apical vesicles to the colloid.


1971 ◽  
Vol 49 (3) ◽  
pp. 856-882 ◽  
Author(s):  
A. Haddad ◽  
Meredith D. Smith ◽  
Annette Herscovics ◽  
N. J. Nadler ◽  
C. P. Leblond

The incorporation of fucose-3H in rat thyroid follicles was studied by radioautography in the light and electron microscopes to determine the site of fucose incorporation into the carbohydrate side chains of thyroglobulin, and to follow the migration of thyroglobulin once it had been labeled with fucose-3H. Radioautographs were examined quantitatively in vivo at several times after injection of fucose-3H into rats, and in vitro following pulse-labeling of thyroid lobes in medium containing fucose-3H. At 3–5 min following fucose-3H administration in vivo, 85% of the silver grains were localized over the Golgi apparatus of thyroid follicular cells. By 20 min, silver grains appeared over apical vesicles, and by 1 hr over the colloid. At 4 hr, nearly all of the silver grains had migrated out of the cells into the colloid. Analysis of the changes in concentration of label with time showed that radioactivity over the Golgi apparatus increased for about 20 min and then decreased, while that over apical vesicles increased to reach a maximum at 35 min. Later, the concentration of label over the apical vesicles decreased, while that over the colloid increased. Similar results were obtained in vitro. It is concluded that fucose, which is located at the end of some of the carbohydrate side chains, is incorporated into thyroglobulin within the Golgi apparatus of thyroid follicular cells, thereby indicating that some of these side chains are completed there. Furthermore, the kinetic analysis demonstrates that apical vesicles are the secretion granules which transport thyroglobulin from the Golgi apparatus to the apex of the cell and release it into the colloid.


1992 ◽  
Vol 40 (3) ◽  
pp. 257 ◽  
Author(s):  
RC Jones ◽  
M Lin

The genital ducts of Heterodontus portusjacksoni are lined by a ciliated epithelium. In the ductuli efferentes the epithelium is low and contains numerous intraepithelial leucocytes which often contain large dense bodies. All epithelial cells are ciliated and are characterised by apical vesicles, vacuoles and glycogen granules, some rough endoplasmic reticulum, dense bodies and lipid droplets, and a Golgi apparatus. The initial segment of the ductus epididymidis is lined by a very tall epithelium of ciliated and non-ciliated cells. The non-ciliated cells contain numerous apical vesicles, a large Golgi apparatus and numerous mitochondria and secretory granules in close association with an extensive endoplasmic reticulum. The terminal segment of the ductus epididymidis is lined by a low columnar epithelium. A proximal region, occupying part of the head of the epididymis, is similar to the epithelium in the ductuli efferentes. Distally, all the epithelial cells are ciliated. They are characterised by considerable dilated endoplasmic reticulum, a Golgi apparatus, apical vesicles, and numerous mitochondria and secretory granules. The secretory tubules of Leydig's glands are lined by a very tall epithelium with non-ciliated cells containing extensive, dilated, rough endoplasmic reticulum, a large Golgi apparatus, and numerous mitochondria and secretory granules. The significance of the structural differentiation of the duct is discussed in relation to the evolution of the mammalian epididymis.


Author(s):  
A. Kent Christensen ◽  
Hayden G. Coon

Thyroglobulin is synthesized in the thyroid gland and is subsequently degraded to provide thyroid hormones. Rat thyroglobulin is made up of two identical 330 kD subunits, and the mRNA for each subunit contains about 8,500 nucleotides. Since polysomes have approximately one ribosome for each 90-100 nucleotides of mRNA, a polysome of about 85-95 ribosomes would be expected for thyroglobulin. We have been interested in how this very large polysomes is organized on the membranes of the rough endoplasmic reticulum (RER).It is well known that bound polysomes assume characteristic shapes on the surface of the RER, resembling beads on a string arranged in circles, spirals, loops, hairpins or other forms. These polysomal shapes can be observed in conventional electron micrographs when the membranes of the RER are seen in surface or en face view, rather than in the usual cross section. Clearcut surface views are infrequent, but the likelihood of seeing them is greatly improved when flattened cells in culture are sectioned in the plane of the cell, since the RER in a flattened cell tends to be oriented in that plane.


1984 ◽  
Vol 98 (5) ◽  
pp. 1705-1709 ◽  
Author(s):  
F Marchi ◽  
C P Leblond

Young rats given an intravenous injection of [3H]proline were killed at successive times from 4 to 80 min later. Fibroblasts from the front foot pad were radioautographed ; silver grains were counted over several of the organelles and the results were expressed as percent radiolabel per unit volume. These percentages reached a peak over rough endoplasmic reticulum cisternae at 4 min, intermediate vesicles and tubules at 10 min, spherical distensions of cis-side Golgi saccules at 20 min, cylindrical distensions of trans-side saccules between 40 and 60 min, and secretory granules at 60 min. It is proposed that the succession of peaks corresponds to the migration pathway of collagen precursor proteins within fibroblasts; that is, the proteins synthesized in rough endoplasmic reticulum are delivered by intermediate vesicles and/or tubules to the spherical distensions of cis-side saccules, somehow pass from there to the cylindrical distensions of trans-side saccules and, finally, are carried by secretory granules to the extracellular space.


1971 ◽  
Vol 51 (1) ◽  
pp. 162-175 ◽  
Author(s):  
Judy M. Strum ◽  
Janice Wicken ◽  
John R. Stanbury ◽  
Morris J. Karnovsky

Iodination within the thyroid follicle is intimately associated with a thyroid peroxidase. In order to locate the in vivo site of iodination, the initial cytochemical appearance of this enzyme has been determined in fetal rat thyroid and its presence correlated with the onset of iodinated thyroglobulin synthesis. Peroxidase first appears in follicular cells during the 18th day of gestation. It is seen first in the perinuclear cisternae, the cisternae of the endoplasmic reticulum, and within the inner few Golgi lamellae. These organelles presumably represent sites of peroxidase synthesis. During the 19th and 20th days of gestation, there is a tremendous increase in peroxidase activity. In addition to the stained sites described, there are now many peroxidase-positive apical vesicles in the follicular cells. Newly forming follicles stain most conspicuously for peroxidase, the reaction product being heavily concentrated at the external surfaces of apical microvilli and in the adjacent colloid. Iodinated thyroglobulin becomes biochemically detectable in thyroids during the 19th day of gestation and increases greatly during the 20th day. The parallel rise in peroxidase staining that just precedes, and overlaps, the rise in iodinated thyroglobulin, suggests that apical vesicles and the apical cell membrane are the major sites of iodination within the thyroid follicle.


1983 ◽  
Vol 61 (2) ◽  
pp. 603-625 ◽  
Author(s):  
Gordon Beakes

The ultrastructural development of encystment vesicles (formerly bar bodies) and the outer cyst coat has been examined in primary and secondary spores of a range of isolates of Saprolegnia, mostly from the S. diclina – parasitica complex, of both saprophytic and fish-lesion origin. The development of both primary encystment vesicles (PEVs) in zoosporangia and secondary encystment vesicles (SEVs) in primary cysts appears essentially similar. The vesicles are probably derived from the rough endoplasmic reticulum system. The tubular primary spines and solid secondary boathooks seem to form autonomously within the vesicle matrix. Upon settling all of the preformed encystment vesicles are liberated from the zoospores to give rise to an electron-dense, amorphous, outer cyst coat, in which the spines are embedded. Fish-lesion isolates of S. parasitica have longer tubules on their primary cysts than saprophytic isolates and have distinctive bundles of long (<10 μm) boathooks on their secondary cysts compared with the single short (< 1.0 μm) boathooks typical of the saprophytes. However, even in fish-lesion isolates considerable variation in SEV and boathook sizes was observed. Staining by the Thiéry procedure revealed a high concentration of polysaccharidelike material with both the encystment vesicle cortex layer and spines, although treatment with various glucanases and proteases failed to digest either component. Spherical fibrous vesicles also appear in primary cysts and their contents are partially removed by protease digestion. These appear morphologically similar to the glycoprotein adhesive vesicles described in other oomycetes and appear to be discharged by secondary zoospores. The complex encystment apparatus in Saprolegnia is compared with that described in other oomycete and chytridiomycete fungi and the possible phylogenetic significance discussed. The role of the long boathook spines in relation to the infection of fish is also considered.


1986 ◽  
Vol 84 (1) ◽  
pp. 41-52
Author(s):  
N. Chegini ◽  
C.V. Rao

The electron microscopic autoradiographic studies described here revealed the presence of specific silver grains over nuclei, lysosomal vesicles, rough endoplasmic reticulum and Golgi apparatus after incubation of placental tissue for 2 h at 38 degrees C with 1 nM-[125I]EGF. Three-step mask analysis, which corrects for radiation spread, showed that the relative grain density was the highest in nuclei, followed by lysosomal vesicles, then Golgi and rough endoplasmic reticulum, equally. The nuclear grain density, however, was lower than that in microvillus plasma membranes. There were very few grains in basolateral plasma membranes, none in the basement membrane area and a considerable number in capillary endothelial cells. The present results demonstrating the association of internalized [125I]EGF with a variety of intracellular organelles raise the possibility of EGF acting on the intracellular sites in addition to cell surface sites.


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