scholarly journals ELABORATION OF THE MATRIX GLYCOPROTEIN OF ENAMEL BY THE SECRETORY AMELOBLASTS OF THE RAT INCISOR AS REVEALED BY RADIOAUTOGRAPHY AFTER GALACTOSE-3H INJECTION

1971 ◽  
Vol 51 (1) ◽  
pp. 26-51 ◽  
Author(s):  
Alfred Weinstock ◽  
C. P. Leblond
Keyword(s):  
Golgi Apparatus ◽  
Phosphotungstic Acid ◽  
Secretory Granules ◽  
Low Ph ◽  
Enamel Matrix ◽  
Rat Incisor ◽  
Golgi Region ◽  
The Matrix

The elaboration of enamel matrix glycoprotein was investigated in secretory ameloblasts of incisor teeth in 30–40-g rats. To this end, the distribution of glycoprotein was examined histochemically by the use of phosphotungstic acid at low pH, while the formation of glycoprotein was traced radioautographically in animals sacrificed 2.5–30 min after galactose-3H injection. Histochemically, the presence of glycoprotein is observed in ameloblasts as well as in the enamel matrix; in ameloblasts glycoprotein occurs within the Golgi apparatus in amounts increasing from the outer to the inner face of the stacks of saccules, and is concentrated in condensing vacuoles and secretory granules; in the enamel matrix, glycoprotein is observed within linear subunits. Radioautographs at 2.5 min after injection demonstrate the uptake of galactose-3H label by Golgi saccules, indicating that galactose-3H is incorporated into glycoprotein within this organelle. After 5–10 min, the label collects in the condensing vacuoles and secretory granules of the Golgi region. By 20–30 min, the label appears in the secretory granules of the apical (Tomes') processes, as well as in the enamel matrix (next to the distal end of the apical processes, and at the tips of matrix prongs). In conclusion, galactose contributes to the formation of glycoprotein within the Golgi apparatus. The innermost saccules then distribute the completed glycoprotein to condensing vacuoles, which later evolve into secretory granules. These granules rapidly migrate to the apical processes, where they discharge their glycoprotein content to the developing enamel.

scholarly journals Synthesis, Secretion, Degradation, and Fate of Ameloblastin During the Matrix Formation Stage of the Rat Incisor as Shown by Immunocytochemistry and Immunochemistry Using Region-specific Antibodies

1997 ◽  
Vol 45 (10) ◽  
pp. 1329-1340 ◽  
Author(s):  
Takashi Uchida ◽  
Chikage Murakami ◽  
Kazuyoshi Wakida ◽  
Takahiro Satoda ◽  
Naofumi Dohi ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Matrix Protein ◽  
Core Protein ◽  
Secretory Granules ◽  
Protein Band ◽  
Enamel Matrix ◽  
Rat Incisor ◽  
Formation Stage ◽  
The Matrix ◽  
Secretory Ameloblast

Rat ameloblastin is a recently cloned tooth-specific enamel matrix protein containing 422 amino acid residues. We investigated the expression of this protein during the matrix formation stage of the rat incisor immunohistochemically and immunochemically, using anti-synthetic peptide antibodies that recognize residues 27–47 (Nt), 98–107 (M-1), 224–232 (M-2), 386–399 (M-3), and 406–419 (Ct) of ameloblastin. Immunohistochemical preparations using antibodies Nt and M-1 stained the Golgi apparatus and secretory granules of the secretory ameloblast and the entire thickness of the enamel matrix. Only M-1 intensely stained the peripheral region of the enamel rods. Immunostained protein bands were observed near 65, 55, and below 22 kD. Immunohistochemical preparations using antibodies M-2 and Ct stained the Golgi apparatus and secretory granules of the ameloblast and the immature enamel adjacent to the secretion sites, but not deeper enamel layers. Immunostaining using M-2 and Ct revealed protein bands near 65 and 40–56 kD, and 65, 55, 48, 36, and 25 kD, respectively. M-3 stained the cis side of the Golgi apparatus but not the enamel matrix. This antibody recognized a protein band near 55 kD, but none larger. After brefeldin A treatment, immunoreaction of the 55-kD protein band intensified, and dilated cisternae of rER of the secretory ameloblast contained immunoreactive material irrespective of the antibodies used. These data indicate that ameloblastin is synthesized as a 55-kD core protein and then is post-translationally modified with O-linked oligosaccharides to become the 65-kD secretory form. Initial cleavages of the 65-kD protein generate N-terminal polypeptides, some of which concentrate in the prism sheath, and C-terminal polypeptides, which are rapidly degraded and lost from the enamel matrix soon after secretion.

scholarly journals SYNTHESIS, MIGRATION, AND RELEASE OF PRECURSOR COLLAGEN BY ODONTOBLASTS AS VISUALIZED BY RADIOAUTOGRAPHY AFTER [3H]PROLINE ADMINISTRATION

1974 ◽  
Vol 60 (1) ◽  
pp. 92-127 ◽  
Author(s):  
Melvyn Weinstock ◽  
C. P. Leblond
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Phosphotungstic Acid ◽  
Secretory Granules ◽  
Low Ph ◽  
Collagen Fibrils ◽  
Dentin Collagen ◽  
Odontoblast Process ◽  
High Radioactivity

The elaboration of dentin collagen precursors by the odontoblasts in the incisor teeth of 30–40-g rats was investigated by electron microscopy, histochemistry, and radioautography after intravenous injection of tritium-labeled proline. At 2 min after injection, when the labeling of blood proline was high, radioactivity was restricted to the rough endoplasmic reticulum, indicating that it is the site of synthesis of the polypeptide precursors of collagen, the pro-alpha chains. At 10 min, when the labeling of blood proline had already declined, radioactivity was observed in spherical portions of Golgi saccules containing entangled threads, and, at 20 min, radioactivity appeared in cylindrical portions containing aggregates of parallel threads. The parallel threads measured 280–350 nm in length and stained with the low pH-phosphotungstic acid technique for carbohydrate and with the silver methenamine technique for aldehydes (as did extracellular collagen fibrils). The passage of label from spherical to cylindrical Golgi portions is associated with the reorganization of entangled into parallel threads, which is interpreted as the packing of procollagen molecules. Between 20 and 30 min, prosecretory and secretory granules respectively became labeled. These results indicate that the cylindrical portions of Golgi saccules transform into prosecretory and subsequently into secretory granules. Within these granules, the parallel threads, believed to be procollagen molecules, are transported to the odontoblast process. At 90 min and 4 h after injection, label was present in predentin, indicating that the labeled content of secretory granules had been released into predentin. This occurred by exocytosis as evidenced by the presence of secretory granules in fusion with the plasmalemma of the odontoblast process. It is proposed that pro-alpha chains give rise to procollagen molecules which assemble into parallel aggregates in the Golgi apparatus. Procollagen molecules are then transported within secretory granules to the odontoblast process and released by exocytosis. In predentin procollagen molecules would give rise to tropocollagen molecules, which would then polymerize into collagen fibrils.

Relationship between golgi apparatus and axonal reticulum in sympathetic ganglion cells

1978 ◽  
Vol 36 (2) ◽  
pp. 598-599
Author(s):  
J. Quatacker ◽  
W. De Potter
Keyword(s):  
Golgi Apparatus ◽  
Sympathetic Ganglion ◽  
Phosphotungstic Acid ◽  
Ganglion Cells ◽  
Low Ph ◽  
Dense Core ◽  
Dense Core Vesicles ◽  
Large Dense Core Vesicles ◽  
Cervical Ganglia ◽  
Axoplasmic Reticulum

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).

scholarly journals THE CYTOLOGY OF THE NORMAL PARATHYROID GLANDS OF MAN AND VIRGINIA DEER

1963 ◽  
Vol 16 (2) ◽  
pp. 379-400 ◽  
Author(s):  
Bryce L. Munger ◽  
Sanford I. Roth
Keyword(s):  
Golgi Apparatus ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Blood Stream ◽  
Chief Cells ◽  
Cytoplasmic Organelles ◽  
Golgi Region ◽  
Capillary Endothelial Cells ◽  
Transitional Cells ◽  
Two Phases

The normal parathyroids of six humans and a Virginia deer were studied by light and electron microscopy. The parenchyma of the deer parathyroid is composed of uniform chief cells, which contained 100 to 400 mµ electron-opaque, membrane-limited granules, presumed to be secretory granules, in addition to the usual cytoplasmic organelles. Desmosomes are present between adjacent cells, and rare cilia are observed protruding from the chief cells into the intercellular space. The human parathyroids contain chief cells in two phases—active and inactive—as well as oxyphil cells. Active chief cells have a large Golgi apparatus, sparse glycogen, numerous secretory granules, and rare cilia. Inactive chief cells contain a small Golgi apparatus, abundant glycogen, and few secretory granules. Both forms have the usual cytoplasmic organelles and, between adjacent cells, desmosomes. Oxyphil cell cytoplasm is composed of tightly packed mitochondria and glycogen granules, with rare secretory granules. Cells with cytoplasmic characteristics intermediate between chief and oxyphil cells, possibly representing transitional cells, have been observed. Secretory granules of both man and deer are composed of 100 to 200 A particles and short rods, and the granules develop from prosecretory granules in the Golgi region of the cell. The human secretory granules are smaller and more variable in shape than those of the deer. The granules are iron and chrome alum hematoxylin-positive, argyrophilic, and aldehyde fuchsin-positive, permitting light microscopic identification. They are also found in the capillary endothelial cells of the parathyroid and in its surrounding connective tissue. The secretory granules of the parathyroid cells can thus be followed from their formation in the Golgi apparatus almost to their extrusion into the blood stream.

scholarly journals Distribution of basal lysosomes in exocrine acinar cells.

1987 ◽  
Vol 35 (5) ◽  
pp. 565-570 ◽  
Author(s):  
C Oliver ◽  
Y Yuasa
Keyword(s):  
Acid Phosphatase ◽  
Golgi Apparatus ◽  
Guinea Pig ◽  
Secretory Granules ◽  
Acinar Cells ◽  
The Other ◽  
Basal Region ◽  
Golgi Region ◽  
Basal Portion ◽  
Two Populations

We examined the distribution of trimetaphosphatase (TMPase)-positive basal lysosomes in pancreas, parotid, submandibular, sublingual, and exorbital lacrimal glands from rats, rabbits, and guinea pigs. The location of the basal lysosomes was compared to that of the acid phosphatase (AcPase)-positive lysosomes. In all of the tissues examined from rat and rabbit, AcPase activity was localized primarily to the Golgi region. Reaction product was localized in GERL, immature secretory granules, and lysosomes lying adjacent to the Golgi apparatus. TMPase activity was found in basal lysosomes and in occasional elongated lysosomes adjacent to the Golgi apparatus. In guinea pig, the distribution of TMPase activity was identical to that seen in the other two species, but a significant number of lysosomes in the basal region of the cells also contained AcPase activity. These results confirm and extend our previous finding (J Histochem Cytochem 31:1209, 1983) that exocrine acinar cells possess two distinct populations of lysosomes. The lysosomes in the Golgi region contain both AcPase and TMPase activity, whereas those in the basal portion of the cells are reactive predominantly for TMPase. The functional significance of the two populations of lysosomes is not understood at present.

scholarly journals Effects of secretory stimulation on the Golgi apparatus and GERL of rat parotid acinar cells.

1984 ◽  
Vol 32 (4) ◽  
pp. 403-412 ◽  
Author(s):  
A R Hand ◽  
C Oliver
Keyword(s):  
Golgi Apparatus ◽  
Functional Relationship ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Dynamic Nature ◽  
Parotid Acinar Cells ◽  
Golgi Region ◽  
Thiamine Pyrophosphatase ◽  
Rat Parotid

The structure and cytochemistry of the Golgi apparatus and GERL of rat parotid acinar cells was studied after in vivo secretory stimulation with isoproterenol. Discharge of mature secretory granules was complete within 1 hr after isoproterenol injection, but immature granules in the Golgi region or near the lumen were not released. At early times (1-5 hr) after isoproterenol, acid phosphatase (AcPase) activity was markedly increased in GERL and immature secretory granules compared to uninjected controls. GERL appeared increased in extent and numerous continuities with immature granules were observed. Reaccumulation of mature secretory granules was first evident at 5 hr, and was almost complete by 16 hr after isoproterenol. Thiamine pyrophosphatase (TPPase) activity, normally restricted to the trans Golgi saccules, was frequently present in immature granules during this time. Narrow cisternae resembling GERL, occasionally in continuity with immature granules, also contained TPPase reaction product. By 16-24 hr after stimulation, the activity and distribution of AcPase and TPPase were similar to control cells. These results demonstrate the dynamic nature of the Golgi apparatus and GERL in parotid acinar cells, and emphasize the close structural and functional relationship between these two structures.

scholarly journals Ultrastructural localization of nicotinamide adenine dinucleotide phosphatase (NADPase) activity to the intermediate saccules of the Golgi apparatus in rat incisor ameloblasts.

1980 ◽  
Vol 28 (1) ◽  
pp. 16-26 ◽  
Author(s):  
C E Smith
Keyword(s):  
Golgi Apparatus ◽  
Nicotinamide Adenine Dinucleotide ◽  
Secretory Granules ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Ultrastructural Localization ◽  
Nicotinamide Adenine ◽  
General Phenomenon ◽  
Rat Incisor ◽  
Selective Staining ◽  
Dense Bodies

Cytochemical evidence for the existence of a Golgi-associated phosphatase activity that hydrolyzes nicotinamide adenine dinucleotide phosphate (NADP) at acid pH in rat incisor ameloblasts was obtained by incubating sections from glutaraldehyde-fixed teeth in a medium containing NADP as substrate and lead ions as capture agent. Following incubation for 1 hr at 37 degrees C and pH 5.0, the Golgi saccules situated between those at the cis (immature) and trans (mature) faces of the ameloblast Golgi apparatus were marked by reaction product with the heaviest deposit in the middle saccule. Reaction product was otherwise seen in trace amounts only over some elements of the GERL system as well as a few lysosomal dense bodies and immature secretory granules. Control experiments established that the selective staining of intermediate Golgi saccules at pH 5.0 could only be duplicated by using substrates that resembled the complete NADP molecule, and not just the portion containing the adenosine 2'-monophosphate group. As well, no deposits of reaction product were seen within the Golgi saccules of ameloblasts incubated at pH 5.0 with nictoinamide adenine dinucleotide (NAD) as the substrate or that were incubated at pH 7.2 or pH 9.0 with NADP as the substrate. It was concluded that a specific, acid-NADPase activity is present in the intermediate Golgi saccules of secretory ameloblasts. Preliminary observations on other cells suggest that the localization of NADPase activity to Golgi saccules may constitute a general phenomenon.

scholarly journals AUTORADIOGRAPHIC STUDIES OF SYNTHESIS AND INTRACELLULAR MIGRATION OF GLYCOPROTEINS IN THE RAT ANTERIOR PITUITARY GLAND

1974 ◽  
Vol 62 (1) ◽  
pp. 185-197 ◽  
Author(s):  
Georges Pelletier
Keyword(s):  
Golgi Apparatus ◽  
Secretory Granules ◽  
In Vivo Studies ◽  
Time Intervals ◽  
Electron Microscope Autoradiography ◽  
The Matrix ◽  
Silver Grains ◽  
Gonadotrophic Cells

The incorporation of [3H]fucose in the somatotrophic and gonadotrophic cells of the rat adenohypophysis has been studied by electron microscope autoradiography to determine the site of synthesis of glycoproteins and to follow the migration of newly synthesized glycoproteins. The pituitaries were fixed 5 min, 20 min, 1 h, and 4 h after the in vivo injection of [3H]fucose and autoradiographs analyzed quantitatively. At 5 min after [3H]fucose administration, 80–90% of the silver grains were localized over the Golgi apparatus in both somatotrophs and gonadotrophs. By 20 min, the Golgi apparatus was still labeled and some radioactivity appeared over granules. At 1 h and 4 h, silver grains were found predominantly over secretory granules. The kinetic analysis showed that in both protein-secreting cells (somatotrophs) and glycoprotein-secreting cells (gonadotrophs), the glycoproteins have their synthesis completed in the Golgi apparatus and migrate subsequently to the secretory granules. It is concluded from these in vivo studies that glycoproteins which are not hormones are utilized for the formation of the matrix and/or of the membrane of the secretory granules. The incorporation of [3H]fucose in gonadectomy cells (hyperstimulated gonadotrophs) was also studied in vitro after pulse labeling of pituitary fragments in medium containing [3H]fucose. The incorporation of [3H]fucose was localized in both the rough endoplasmic reticulum (ER) and the Golgi apparatus. Later, the radioactivity over granules increased while that over the Golgi apparatus decreased. The concentration of silver grains over the dilated cisternae of the rough ER was not found to be modified at the longest time intervals studied.

Matrix-Mineral Relationships-A. Morphologist's Viewpoint

1979 ◽  
Vol 58 (2_suppl) ◽  
pp. 922-929 ◽  
Author(s):  
M.U. Nylen
Keyword(s):  
Organic Material ◽  
Crucial Role ◽  
Crystal Surface ◽  
Organic Matrix ◽  
The Other ◽  
Enamel Matrix ◽  
Initial Cell ◽  
Cell Product ◽  
Ultrastructural Morphology ◽  
The Matrix

The literature on the ultrastructural morphology of the enamel matrix and its relationship to the crystals is reviewed. Two morphological entities of the matrix are discussed: One is the so-called stippled material which may be the initial cell product; the other, variously described as fibrillar, lamellar, tubular or helical, is thought by many to play a crucial role in nucleation and orientation of the crystals. A number of observations, however, suggest that the latter structures form secondarily to the crystals and that in reality they represent organic material adsorbed to the crystal surface and maintained as independent structures upon removal of the mineral. The need for additional studies is stressed including systematic studies of interactions between constituents of the organic matrix and the apatite crystals.

scholarly journals INDUCTION OF ENDOMETRIAL PEROXIDASE SYNTHESIS AND SECRETION BY ESTROGEN AND ESTROGEN ANTAGONIST

1974 ◽  
Vol 62 (2) ◽  
pp. 449-459 ◽  
Author(s):  
Andrew Churg ◽  
Winston A. Anderson
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Peroxidase Activity ◽  
Secretory Granules ◽  
Combined Treatment ◽  
Initial Injection ◽  
Immature Rats ◽  
Glandular Cells ◽  
Endogenous Peroxidase ◽  
Estrogen Antagonist

Synthesis of peroxidase was induced in the uterine epithelium of immature rats by multiple doses over a 24–96-h period of either 17 ß-estradiol, the estrogen-antagonist Parke-Davis CI-628, or a combination of estradiol plus antagonist. Endogenous peroxidase activity first appeared in the cisternae of the rough endoplasmic reticulum of surface epithelial and glandular cells within 24–48 after the initial injection. Uterine peroxidase activity was also visible in the cisternae of the Golgi apparatus, in Golgi-derived secretory granules, and within the uterine and glandular lumen. Some cells of the epithelium produced little or no peroxidase, even after 96 h. Whereas the antagonist appeared to induce synthesis and secretion of peroxidase, neither the antagonist alone nor the combined treatment (estradiol plus antagonist) reproduced the estradiol-mediated growth in organ size and increased lumen diameter.

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