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Y Clermont

Publications and source records attributed to Y Clermont.

At least 55 records · Page 3Linked to original sources
PubMed1988

Structure of the complex basement membrane underlying the epithelium of the vas deferens in the rat.

Underlying the epithelium of the vas deferens there is a complex basement membrane showing a thick lamina densa separated from the plasma membrane of epithelial cells by a lamina lucida. On the connective tissue side of the lamina densa, there are plaques composed of a material that is similar to that of the lamina densa but is more compact and has a greater electron density. This material also forms plaques at a short distance from the lamina densa, where it appears as irregular nodular masses. The plaques are bridged by striated anchoring fibrils (SAF) that are variable in structure. Some SAF are long (0.5-0.6 micron) and bilaterally symmetrical, with a central fusiform segment and, on each side, coarsely banded segments. While the fusiform segment presents 5 or 6 diffuse cross striations, the coarsely banded segments show distinct bands labeled B1-B4. Shorter SAF show a coarsely banded segment alone or a coarsely banded segment plus a fusiform segment. Some SAF also branch at the level of the fusiform segments, in which case they form star-shaped structures with three or more branches that have their extremities inserted into plaques. The plaques, as well as the lamina densa, are immunohistochemically reactive to type IV collagen, laminin, and heparan sulfate proteoglycan, whereas the SAF are not immunoreactive to these substances. SAF and plaques, considered as integral components of this basement membrane, form a series of arches or open tunnels traversed by collagen fibrils. It is thus apparent that these elements contribute to the attachment of the basement membrane and the overlying epithelium to the underlying dense connective tissue of the lamina propria.

Animals↗
PubMed1988

Contribution of the Golgi apparatus components to the formation of the acrosomic system and chromatoid body in rat spermatids.

The cytochemical distribution of two different acid phosphatases, nicotinamide adenine dinucleotide phosphatase (NADPase) and cytidine monophosphatase (CMPase), was analyzed within the Golgi apparatus, acrosomic system, and chromatoid body of early spermatids. Within the saccules composing the Golgi cortex, the phosphatases were localized in specific and nonoverlapping compartments: the cis-tubular network, or cis-element, and the first underlying saccule were unreactive for both enzymes, the following four to five saccules were reactive for NADPase, and the last three saccules were reactive for CMPase. Vesicles of various sizes and short membranous tubules, present near the edges of saccules and in the medulla of the Golgi apparatus, were NADPase- and/or CMPase-positive. The acrosomic system showed a weak but significant NADPase reactivity and a strong CMPase reactivity. The vesicles associated with the chromatoid body were reactive for NADPase and/or CMPase. The combined observations indicate that the two cytochemically distinct compartments of the Golgi cortex, the NADPase- and CMPase-positive saccules, independently contribute to the formation of the acrosomic system and the vesicular component of the chromatoid body.

Acrosome↗
PubMed1988

Isolation, structure and protein composition of the perforatorium of rat spermatozoa.

Heads of spermatozoa were sonically separated from tails and treated in 1 N NaOH until the perforatoria were partially detached from the nucleus. Their complete detachment was then assured by repeatedly passing the suspension through a 22-gauge needle. The perforatoria were then separated from nuclei on sucrose gradients and the purity of the fraction was verified by electron microscopy. The isolated perforatoria were denatured and used to raise antibodies or run on polycrylamide gels. Such gels revealed many polypeptide bands, six of which were most prominent (Mr approximately 13,000, 13,400, 16,000, 33,000, 35,000, and 43,000). Of these, the 16,000 Mr polypeptide was major. Anti-perforatorium serum reacted with the perforatoria of fixed spermatozoa, with a substance found between the plasmalemma and the outer acrosomal membrane of the acrosomal head cap and with the inner component of the ventral spur, but not with the postacrosomal dense lamina. This observation indicated that the perforatorium and dense lamina, although structurally continuous to form the perinuclear theca, are biochemically distinct. On Western blots, the anti-perforatorium serum reacted with the prominent polypeptides of the perforatorium and cross-reacted with some less prominent polypeptides of the fibrous sheath (FS) and outer dense fibers (ODF), most notably with a 16,000 Mr polypeptide found in both. Likewise anti-FS or anti-ODF serum cross-reacted with some major and minor polypeptides of the perforatorium, again most notably with a major 16,000 Mr polypeptide. The immunocross-reactions observed on Western blots were confirmed by immunocytochemical methods applied to spermatozoa. These results demonstrate that the perforatorium is composed of several polypeptides, is immunologically distinct from the postacrosomal dense lamina, may be immunologically similar to a substance found between the plasmalemma and outer acrosomal membrane and to a substance found on the inner aspect of the ventral spur, has antigenic determinants in common with the FS and ODF, and may share a 16,000 Mr polypeptide with these two cytoskeletal structures of the flagellum.

Animals↗
PubMed1987

Tridimensional architecture of the Golgi apparatus and its components in mucous cells of Brunner's glands of the mouse.

The three-dimensional structure of the Golgi apparatus and its components has been analyzed in thin and thick sections of mucous cells of mouse Brunner's glands by using low- and high-voltage electron microscopes and a stereoscopic approach. In thick sections of glands impregnated with osmium or treated to detect nicotinamide adenine dinucleotide phosphatase (NADPase) or thiamine pyrophosphatase (TPPase) activity, the Golgi apparatus appeared, at low magnification, as a continuous network located in the supranuclear region. At higher magnifications and in thin sections of tissue postfixed with reduced osmium and stained with lead citrate or treated to demonstrate phosphatase activity, the following components were observed: on the cis-face of the Golgi stacks, an osmiophilic tubular network referred to as the cis-element; a cis-saccular-compartment composed of a distended porous saccule slightly reactive for NADPase and three or four underlying NADPase-positive, flattened, poorly fenestrated saccules; a trans-saccular-compartment consisting of four to six TPPase-positive saccules or sacculo-tubular elements, prosecretory granules, and "peeling off" trans-tubular networks. The saccules of the cis-compartment were often perforated by large pores in register. The cavities thus formed in the stacks were called wells and were pan-shaped with a mouth directed toward the cis-face of the stacks and a bottom closed by TPPase-positive saccules. The wells always contained 80-nm vesicles. The saccules of the trans-compartment were involved in the formation of secretory granules according to the following proposed sequence of transformation. The secretion product appeared initially as a granular material evenly distributed throughout a slightly distended, poorly fenestrated saccule. These saccules appeared to transform into fenestrated elements with irregular pores and with parts of them taking on the appearance of a tubular network; they were thus referred to as sacculotubular elements. The secretory material initially distributed throughout these elements accumulated in nodular dilatations randomly distributed along the tubular portions of the elements. The dilatations, considered as prosecretory granules, increased in size as they drained the secretory material from the rest of the sacculotubular elements. Such prosecretory granules, large and irregular in shape, "peeled off" from the stacks of saccules with residual saccular or tubular structures still attached to them, some of the latter forming trans-tubular networks. The prosecretory granules detached from such membranous residues, condensed, and finally transformed into spherical secretion granules.

Animals↗
PubMed1987

Tridimensional structure of the Golgi apparatus of nonciliated epithelial cells of the ductuli efferentes in rat: an electron microscope stereoscopic study.

The 3-dimensional structure of the Golgi apparatus has been analyzed in thin and thick sections of nonciliated epithelial cells of ductuli efferentes of rat by use of low- and high-voltage electron microscopes and a stereoscopic approach. In thick sections of tissue impregnated with osmium, the Golgi apparatus appeared at low magnification as a continuous network forming a corona at the apical pole of the nucleus. At higher magnification and in thin sections of tissue postfixed with reduced osmium and stained with lead citrate or treated to demonstrate phosphatase activity, the following structural features were observed. In the longitudinal axis of the Golgi network there were alternating compact and noncompact zones. The compact zones were composed of 6-8 flattened, poorly fenestrated saccules in close apposition to each other and forming stacks. The noncompact zones were composed of a number of highly fenestrated and slightly distended saccules, which were continuous with and bridged the saccules of the compact zones. In the cis-trans axis of the Golgi apparatus the following compartments were observed: (a) On the cis face there was a continuous osmiophilic tubular network referred to as the cis element; (b) a cis compartment composed of 3 or 4 NADPase-positive saccules perforated with pores in register forming wells that contained small vesicles; (c) a trans compartment composed of 1 or 2 TPPAse-positive elements underlying the NADPase ones, followed by 1 or 2 CMPase-positive elements that showed a flattened saccular part continuous with a network of anastomotic tubules. These tubular networks curved away from the overlying elements, giving these elements a 'peeling-off" configuration. These elements referred to as sacculotubular elements were discontinuous along the Golgi network. This compartment also included shriveled trans-tubular networks detached from the overlying sacculotubular elements and seemingly undergoing fragmentation into vesicles and tubules. The structural features of the elements of the trans compartment were indicative of continuous renewal.

Animals↗
PubMed1986

Tridimensional structure of the Golgi apparatus in type A ganglion cells of the rat.

The three-dimensional structure of the whole Golgi apparatus and of its components in type A ganglion cells was examined in thin and thick sections by low- and high-voltage electron microscopy. At low magnification, in 10-micron-thick sections of osmicated cells, the Golgi apparatus formed a broad, continuous perinuclear network. At higher magnification and in thinner sections of cells impregnated with uranyl acetate-lead-copper citrate or postfixed in K-ferrocyanide-reduced osmium, the Golgi apparatus appeared as a heterogeneous structure in which saccular regions characterized by stacks of saccules alternated with intersaccular regions made up of branching membranous tubules which bridged the saccules of adjacent stacks. The saccular regions consisted of the following superimposed elements: a cis-osmiophilic element made up of anastomosing tubules; two or three saccules negative for the phosphatases tested (i.e., nicotinamide adenine dinucleotide phosphatase = NADPase, thiamine pyrophosphatase = TPPase, and cytidine monophosphatase = CMPase); two saccules showing TPPase activity; and one to three trans-sacculotubular elements showing a "peeling-off" configuration, one of which showed CMPase activity. The saccules (phosphatase-negative) on the cis-side of the Golgi stacks showed, in addition to small circular pores, larger perforations in register. The cavities thus formed in the stacks of saccules, called "wells," always associated with small 80-nm vesicles, had a pan shape with the mouth directed toward the cis-face and the bottom closed by a TPPase-positive saccule. In face views of the saccules, the smallest of these perforations showed either a crescent shape, due to the presence of a bud on one side of the perforation, or a circular shape with a single small 80-nm vesicle in the center which was occasionally attached to the saccule by a filiform stalk. Such smaller cavities were considered as the precursors of the larger perforations and eventually of the wells. The small 80-nm vesicles seen in the small cavities or in the wells appeared to form in situ and possibly migrate toward the cisternae of endoplasmic reticulum seen proximal to the cis-face of the stack of saccules. Small 80-nm vesicles were also numerous in the intersaccular regions, along the lateral- and trans-aspects of the Golgi stacks, while larger, 150-to 300-nm vesicles, coated and uncoated, were seen only on the trans-face of the Golgi stacks in proximity to the trans-sacculotubular elements which appear to "peel off" from the Golgi stacks.

Animals↗
PubMed1986

Ultrastructural localization of concanavalin A-binding sites in the Golgi apparatus of various types of neurons in rat dorsal root ganglia: functional implications.

The localization of concanavalin A (con A) binding sites has been determined at the electron-microscopic level in the six types of neurons (A1, A2, A3, B1, B2, C) of rat dorsal root ganglia. In all ganglion cells, con A stained the plasma membrane, the nuclear envelope, the cisternae of the rough endoplasmic reticulum, and the matrix of some multivesicular bodies. In contrast, the con A reactivity of the Golgi apparatus varied according to cell type. In type B1 and B2 cells and possibly in type A3 cells, the lectin was exclusively located in three or four saccules on the cis side of the Golgi stacks, whereas the TPPase-positive saccules and the trans sacculotubular elements were unstained with con A. In type A1, A2, and C neurons, all Golgi saccules as well as the trans sacculotubular elements were stained with the lectin. These results suggest that different types of glycoproteins were produced in these two groups of neurons. In the type A1, A2, and C cells, the persistence of the lectin reactivity in the TTPase-positive saccules or sacculotubular elements on the trans side of the Golgi stacks suggests the presence of glycoproteins with oligosaccharide side chains rich in alpha-D-mannosyl residues in terminal positions. In contrast, the disappearance of the con A reactivity in equivalent elements of the Golgi stacks in type B1, B2, and A3 cells suggests the addition at this level of other sugar residues characteristic of complex oligosaccharide side chains. The majority of the vesicular elements associated with the Golgi apparatus, as well as lysosomes, were unstained with con A.

Animals↗
PubMed1986

Evolution of the endoplasmic reticulum during spermiogenesis of the rooster: an electron microscopic study.

The endoplasmic reticulum (ER) of rooster's spermatids was analyzed during spermiogenesis, which was subdivided into eight distinct steps on the basis of changes observed with the electron microscope in the nucleus, acrosome-perforatorium system, manchette, and flagellum. In steps 1 and 2, spermatids' ER cisternae presented the following specializations: A loose network of tubular cisternae was distributed throughout the cytoplasm. Six to eight tight networks of anastomosed tubular cisternae parallel to each other were closely stacked to form a discoid body (1.5-2.5 microns in diameter and 0.5-0.8-micron thick) in which spheroidal vesicles (0.4 micron in diameter) were inserted. Close to and connected with this body, called the alveolar body, there was a stack of annulate lamellae. Large, flattened ER cisternae were seen singly or in piles of two or three running parallel to the nuclear surface. A collection of tubular ER cisternae faced plaques of thickened plasma membranes. These elements of the ER system appear continuous with each other. During steps 3-5 of spermiogenesis, no modification of the alveolar body-annulate lamellae complex was noted; the large flattened ER cisternae disappeared, however, and the broad network of tubular cisternae developed markedly. During steps 6 and 7, the latter network of tubular cisternae fragmented into vesicles that swelled to give a vacuolated appearance to the cytoplasm. The alveolar body-annulate lamellae complex remained visible until late step 7, when it disintegrated just before spermiation. Thus the system of ER cisternae underwent marked structural modifications during spermiogenesis.

Animals↗
PubMed1986

Cyclic endocytic activity and kinetics of lysosomes in Sertoli cells of the rat: a morphometric analysis.

Native ferritin was injected into the rete testis of rats, and seminiferous tubules infused with the tracer were collected 6 h later and prepared for electron microscopic analysis. As a result of internalization of the tracer by Sertoli cells, label was found within 12-66% of the secondary lysosomes, depending on the stage of the cycle of the seminiferous epithelium. The Zeiss MOP-3 instrument was used on selected electron microscope photographs to measure a number of morphometric parameters. Applying appropriate formulae and a computerized program, it was possible to determine the absolute numbers of labeled and unlabeled secondary lysosomes per Sertoli cell for each one of the 14 stages of the cycle. Knowing the duration of these stages, it was also possible to evaluate the turnover kinetics and life span of lysosomes for each stage of the cycle. The percentage of ferritin-labeled lysosomes, regarded as an index of the endocytic activity of Sertoli cells, remained low in stages II to VIII, increased abruptly during stage IX, stayed high during stages X to XIV, and decreased to a low level during stage I of the following cycle. Correspondingly, the turnover of secondary lysosomes was relatively slow and their life span relatively long during stages II through VIII, while the turnover of lysosomes was faster and their life span shorter during stages X through XIV-I of the cycle. During stage IX, there was a sharp drop in the number of lysosomes per Sertoli cell associated with a fast rate of disappearance and a remarkably short life span of less than 4 h for the lysosomes. These features, characteristic of stage IX, are explained by the rapid fusion of lysosomes with residual bodies, which are phagocytosed by Sertoli cells at this particular stage of the cycle. The accelerated endocytosis taking place during stages IX through XIV of the cycle may explain the reduction of the surface area of the adluminal plasma membrane of Sertoli cells as well as the reduction in volume of the tubular lumen observed during these stages. Thus, the demonstrated cyclic endocytic activity of Sertoli cells and several other cyclical events taking place within seminiferous tubules correlate well.

Animals↗
PubMed1986

Receptor-mediated endocytosis of transferrin by Sertoli cells of the rat.

Binding of 125I-transferrin (125I-Tf) to the plasma membrane of Sertoli cells and its endocytosis were analyzed by means of light- and electron-microscope quantitative radioautography. Five minutes after 125I-Tf was injected into the interstitial space of the testis, a strong labeling of the basal aspect of the seminiferous epithelium was observed in light-microscope radioautographs. Injection of the same dose of 125I-Tf plus a 200-fold excess of cold transferrin resulted in a marked diminution of the radioautographic reaction, indicating that the initial strong labeling with radiolabeled transferrin was specific. These results were consistent with the localization of immunoreactive fluorescence of transferrin receptor at the base of the seminiferous epithelium. In electron-microscope radioautographs of tubules collected at 5 min after injection, the membrane of Sertoli cells facing the basement membrane was well labeled with 125I-Tf. At 15 and 30 min, the plasma membrane was less intensely labeled, but the silver grains were then seen overlying multivesicular bodies with an electron-lucent matrix, identified as endosomes. This population of endosomes was always seen at a short distance from the basal membrane of Sertoli cells. At 90 min, no more labeling of the plasma membrane, endosomes, or any other cytoplasmic component was observed. Isolated seminiferous tubules and Sertoli cells labeled with 125I-Tf at 4 degrees C were rinsed and reincubated in a label-free medium at 37 degrees C for various periods of time from 5 to 90 min. A radioactive protein precipitated by trichloroacetic acid, presumably intact transferrin, was released from the tubules into the incubating medium; when measured, it was found to increase rapidly from 5 to 45 min and stabilize thereafter. These results suggest that transferrin was internalized by receptor-mediated endocytosis, reached endosomes, and then was released to the extratubular space. When native ferritin (NF), a tracer for fluid-phase endocytosis, was infused within the lumen of seminiferous tubules and 125I-Tf was simultaneously injected into the interstitial space, both markers rapidly reached different populations of endosomes. Endosomes labeled with NF, scattered throughout the cytoplasm, evolved with time into dense multivesicular bodies and secondary lysosomes, whereas radiolabeled transferrin reached only the endosomes located in the basal cytoplasm of Sertoli cells. The latter thus appeared to be principally involved in the uptake and recycling of transferrin.

Animals↗
PubMed1985

Fluid-phase and adsorptive endocytosis in ciliated epithelial cells of the rat ductuli efferentes.

Ciliated cells of the ductuli efferentes show at their apex a discrete endocytic apparatus composed of small vesicles connected to or subjacent to the apical plasma membrane, small apical membranous tubules, and pale multivesicular bodies. Deeper in the cytoplasm, there are acid phosphatase-positive denser, multivesicular bodies and secondary lysosomes showing an electron-dense cortex and a crystalline, paler stained core. Cationic ferritin and concanavalin A-ferritin used to demonstrate adsorptive endocytosis, when injected into the rete testis, rapidly reached the lumen of the ductuli efferentes. At 1 min after injection, these tracers were seen bound to the apical plasma membrane of ciliated cells and within small endocytic vesicles and by 5 min in narrow apical tubules. At 15 and 30 min after injection, the tracers appeared in pale multivesicular bodies while at 1 hr they were found within dense multivesicular bodies. At 2 hr and longer time intervals these tracers accumulated within secondary lysosomes. Native ferritin, concanavalin A-ferritin in the presence of alpha-methyl-D-mannoside, and horseradish peroxidase or albumin-colloidal gold complexes were used to analyze fluid-phase endocytosis. At various intervals following their injection into the rete testis, these tracers presented a distribution identical in all respects to that described for cationic ferritin and concanavalin A-ferritin. In the present work, none of the above tracers were transported to the abluminal aspect of the ciliated cells. These cells, like the nonciliated epithelial cells of the ductuli efferentes are thus involved in adsorptive as well as in fluid-phase endocytosis.

Adsorption↗
PubMed1985

Glycoprotein synthesis in the Golgi apparatus of spermatids during spermiogenesis of the rat.

During steps 1-7 of spermiogenesis the Golgi apparatus contributes to the formation of the acrosomic system which develops at the surface of the nucleus. Later, in step 8, the Golgi apparatus detaches from the acrosome and remains suspended in the elongated cytoplasm until it degenerates during step 16. Using 3H-fucose as a tracer and the radioautographic technique, we observed that the Golgi apparatus incorporates the tracer and delivers the labeled glycoproteins to the developing acrosomic system during steps 1-7 of spermiogenesis, to multivesicular bodies during steps 1-9, and to the remaining cytoplasm and plasma membrane during steps 1-15. Throughout these steps of spermiogenesis the Golgi apparatus does not show major changes in structure; it is composed of a cortex made up of connected stacks of saccules and a medulla showing a loose aggregate of vesicular profiles. Glycoprotein synthesis in this Golgi apparatus, before and after it contributes lysosomal glycoproteins to the growing acrosomic system, was quantitatively assessed in electron microscope EM radioautographs of tissue sections from animals sacrificed at 1, 4, 8, and 24 h of 3H-fucose injection. The incorporation of the labeled sugar was found to remain quantitatively similar during steps 1-15 of spermiogenesis, and therefore, no shift in glycoprotein synthesis took place following separation of the Golgi apparatus from the acrosomic system. Throughout these steps, fucose molecules are first incorporated in the cortex of the organelle and subsequently transported to the medulla, where they temporarily accumulate before being delivered, depending on the step of spermiogenesis, to the acrosomic system, to the multivesicular bodies, and also, presumably, to the plasma membrane.

Animals↗
PubMed1984

Tridimensional architecture of the Golgi apparatus in the atrial muscle cell of the rat.

The tridimensional structure of the Golgi apparatus of atrial muscle cells has been studied in thin and thick sections with low- and high-voltage electron microscopes. Cardiac tissue was inpregnated with osmium, stained to demonstrate phosphate activity (i.e., nicotinamide adenine dinucleotide phosphatase or NADPase; thiamine pyrophosphatase or TPPase; cytidine monophosphatase or CMPase) or postfixed and stained with potassium ferrocyanide-reduced osmium. At low power, in thick (3-10 micron) sections, the cisosmiophilic element and the NADPase- and the TPPase-positive saccules each appeared as a continuous irregular ribbon that formed, at the two poles of the nucleus, two conical masses connected to each other by beltlike bands encircling the nucleus. At higher magnifications, the continuous Golgi apparatus showed saccular regions along its length connected by short intersaccular tubular regions. In the saccular regions, the following five superimposed elements formed a stack: (1) the cis-osmiophilic network of anastomosed tubules; (2) a chromophobic, dilated saccule perforated with numerous pores; (3) a thin NADPase-positive saccule showing few pores; (4) a thin TPPase-positive saccule perforated with numerous minute pores; and (5) a CMPase-positive transelement that showed saccular and tubular regions and was often partly separated from the overlying saccule. In the intersaccular tubular regions, membranous tubules connected and bridged saccules of two adjacent saccular regions. Secretory granules usually appeared in this region as dilations of the tubules connected to all elements of the Golgi stack except the cis-osmiophilic element.

Animals↗
PubMed1984

Endocytosis in epithelial cells lining the rete testis of the rat.

The endocytic activity of the low cuboidal cells lining the rete testis was analyzed by electron microscopy following injection of various tracers into the lumen of these anastomotic channels. At 1 and 5 minutes after injection, cationic ferritin (CF) and concanavalin A-ferritin (Con A) were seen bound to the apical plasma membrane and to the membrane of subjacent vesicles or invaginations connected to this apical membrane. At 30 and 60 minutes, these tracers were found in intracytoplasmic vesicles and in vesicles connected to the lateral or basal plasma membrane as well as in the lateral intercellular space and in the lamina lucida of basal lamina. At 30 minutes, CF and Con A also appeared in the matrix of pale multivesicular bodies while at 1 hour dense multivesicular bodies were labeled. At 2 hours and later time intervals, the tracers accumulated in dense granules identified as lysosomes. Native ferritin (NF), concanavalin A-ferritin in presence of alpha-methyl-D-mannoside, and horseradish peroxidase or albumin bound to colloidal gold were all to be incorporated by the lysosomal system of these epithelial cells, as just described for CF and Con A, but these various tracers were not bound to the apical plasma membrane or to the membrane of cytoplasmic vesicles, nor were they found in the intercellular spaces or the lamina lucida at the base of the cells. Thus, the epithelial cells of the rete testis do not appear to be only involved in the uptake of substances from the lumen and their disposal by the lysosomal system, but also appear to contribute to the transport of certain macromolecules from the lumen to the laterobasal surfaces of the cells. These cells may thus play a role in determining the composition of the rete testis fluid.

Albumins↗
PubMed1984

Presence of an osmiophilic feltwork distinct from the Golgi apparatus in spinal ganglion cells of the rat.

Rat dorsal root ganglia were osmicated for 48 h at 42 degrees C in a 2% unbuffered aqueous solution of osmium tetroxide. In addition to the osmiophilic cis-element of the Golgi apparatus, the osmium stained a cytoplasmic structure which, although present in the perikaryon of all ganglionic neurons, was well developed in type B1 cells. In photographic stereopairs of 1-2 microns thick sections examined with the electron microscope at 100 kV, these osmiophilic elements appeared as long, wavy thread-like elements with fusiform enlargements. Their average diameter was smaller than that of the thinner cisternae of the smooth endoplasmic reticulum. Occasionally branched, these osmiophilic structures were oriented in all directions of space. When examined in 1.5-7 microns thick sections with a high voltage electron microscope, they formed an osmiophilic feltwork which extended from the juxtanuclear to the subplasmalemmal regions of the perikaryon. It was not connected with the osmiophilic cis-element of the Golgi apparatus. In sections of glutaraldehyde-fixed tissues impregnated with the double impregnation technique or postfixed with reduced osmium, the osmiophilic tubules were clearly distinguished from microtubules, cisternae of endoplasmic reticulum or endocytic structures.

Animals↗
PubMed1984

Glycoprotein synthesis in Sertoli cells during the cycle of the seminiferous epithelium of adult rats: a radioautographic study.

Glycoprotein synthesis in Sertoli cells was investigated in rats sacrificed at various intervals (10, 30 min; 1, 4, 8, 24 h) after a single intratesticular injection of [3H] fucose. Thin sections of glutaraldehyde-fixed testes were radioautographed and the relative concentration of the label over the various cytoplasmic components of the Sertoli cells was analyzed quantitatively from electron microscopic photographs. The analysis was performed at the various stages of the cycle of the seminiferous epithelium grouped as follows: I-IV, V-VII, VIII-XI, XII-XIV. The incorporation of [3H] fucose into glycoproteins took place initially in the Golgi apparatus of the cells and the labeled glycoproteins later migrated to the lysosomes and plasma membrane. The corrected grain counts over the various cytoplasmic components of the Sertoli cell at various intervals after [3H] fucose injection, indicated that the synthesis of glycoproteins detected by radioautography after [3H] fucose injection was constant during the cycle of the seminiferous epithelium. Furthermore, the rate of transfer of the labeled glycoproteins from the Golgi apparatus to the lysosomes and plasma membrane was also noncyclic.

Animals↗
PubMed1983

Two anatomical pathways for the renewal of surface glycoproteins in chloride cells of fish gills.

The cytoplasm of chloride cells found in the epithelium lining the gills of guppies (Lebistes reticulatus) contains, in addition to the Golgi apparatus and cisternae of endoplasmic reticulum, two distinct membranous components, the vesiculotubular and the tubular systems. While the latter is connected to the laterobasal plasma membrane, the former, made up of small vesicles and short membranous tubules, is seen mainly between the Golgi apparatus and the apical cavity which invaginates the apex of the cell. The role of these two systems in the transport of glycoproteins from the Golgi apparatus to the cell surface was investigated in fishes maintained in fresh and salt water, injected with 3H-fucose, and sacrificed at various intervals thereafter (10 and 30 min; 2.5, 8, 15.5, 24, and 48 hours). The distribution of the label was analyzed by quantitative radioautography in sections examined with the light and electron microscopes. The light microscopic data suggested that the label incorporated in the supranuclear region, where the Golgi apparatus is located, migrated toward the apical and the laterobasal regions of the chloride cells. The relative concentration of the tracer over the various components of the cytoplasm of these cells was calculated from data collected on electron microscope radioautographs at various intervals after 3H-fucose injection. The curves obtained supported the view that glycoproteins synthesized in the Golgi apparatus were transported to the apical surface via the vesiculotubular system, and to the laterobasal membrane via the tubular system.

Animals↗