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Query: UNIPROT:Q9UIJ5 (
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58,342
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Uptake of H3-leucine into secretory product and its subsequent intracellular transport was analyzed by electron microscopic autoradiographic techniques in the rat submandibular gland acinar cells in vitro. The route and kinetic timetable of intracellular transport was established for the acinar cell secretory product by calculating the present of silver grains and relative grain density associated with the various organelles on a time sequence basis. Radioactivity was first associated with the rough
endoplasmic reticulum
; then the convex surface of the Golgi apparatus; the concave surface of the Golgi apparatus; and finetics of intracellular transport in the rat submandibular gland acinar cell with other established systems revealed only a difference in the exit of radioactivity from the concave surface of the Golgi apparatus.
Anat
Rec
1977 Mar
PMID:Electron microscopic autoradiographic analysis of the uptake and intracellular transport of H3-leucine by the rat submandibular gland acinar cells in tissue slices. 85 Dec 38
Earlier investigations of intestinal fat-absorption have stressed the importance of continued protein synthesis to provide membranes which are utilized for the intracellular transport of resynthesized lipid. The resulting membranes, when incorporated into the
endoplasmic reticulum
(ER) and Golgi complex, serve as vehicles for the movement of fat within the cell and for its release to the extracellular space. In the current study, attention was focused on the morphological changes in the ER and Golgi complex both during fat absorption and at successive time intervals after fat-absorption termination. Morphological interpretations were confirmed by morphometric analysis. This investigation supports the interpretation that during fat absorption, membrane synthesis by the rough
endoplasmic reticulum
(RER) is insufficient to accomodate membrane utilization and intraconversion, resulting in a decrease of both ER and Golgi complex components. However, following fat-absorption termination, and cell is able to replace previously depleted components of the ER and Golgi complex and regain the full membrane complement of the fasted state. Replenishment of cellular membranes is postulated as resulting from a continued synthesis of new membranes by the RER which eventually exceeds membrane utilized during lipid transport.
Anat
Rec
1977 May
PMID:Alterations in the endoplasmic reticulum and Golgi complex of intestinal epithelial cells during fat absorption and after termination of this process: a morphological and morphometric study. 86 34
The morphology of parafollicular (C) cells in the thyroid gland of the woodchuck, Marmota monax, was studied during the four seasons of the year. The spring C cells are characterized by a large Golgi zone, rough-surfaced
endoplasmic reticulum
, free ribosomes and relatively few dense granules. In the summer these cells appear to be larger and many are packed with dense granules. Fall cells exhibit morphological characteristics suggestive of intense synthetic activity, having rough-surfaced
endoplasmic reticulum
in whorls or parallel arrangement, a large Golgi apparatus and few, to many granules, some of which are larger than those seen in the spring and summer C cells. In the winter, most of the C cells are packed with granules. The Golgi zone, when observed, is small and the rough-surfaced
endoplasmic reticulum
is sparse. Many cell profiles exhibit apparent granule dissolution. These cyclic morphological findings are discussed along with previous studies of other hibernators and are correlated with the seasonal activities of the woodchuck.
Anat
Rec
1977 Nov
PMID:Seasonal variation in the morphology of thyroid parafollicular (C) cells in the woodchuck, Marmota monax: a light and electron microscopic study. 92 Sep 71
The differentiation of the mitral cell perikaryon in postnatal rat olfactory bulb was studied with the light and electron microscope. At birth the mitral cell was distinguishable and occupied a definitive position in the mitral cell layer. The cell contained a large oval nucleus surrounded by a thin rim of cytoplasm. Ribosomes, free and clustered, were scattered in the cell cytoplasm. Rough
endoplasmic reticulum
was relatively scarce. The Golgi complexes were made up of stacks of smooth-surfaced cisternae and associated vesicles. In certain cases the Golgi complexes projected into cellular processes. Mitochondria were present in all regions of the cytoplasm and contained well developed cristae. At the end of the first week, the mitral cell had developed significantly in size, and the cytoplasm contained well-developed rough
endoplasmic reticulum
. The Golgi complexes were made up of several stacks of smooth-surfaced cisternae with the association of vesicles and electron dense bodies. The apical dendrites of mitral cells at this period had increased significantly in length. Subsequently, during the second and third week, the rough
endoplasmic reticulum
and Golgi complexes became well developed. Associated with the Golgi complexes were electron dense lysosomal bodies. At three weeks and in older cells it was observed that dense lipofuschin granules increased significantly. It is suggested that the mitral cell matures and differentiates earlier than cells in the cerebral cortex.
Anat
Rec
1977 Nov
PMID:Postnatal development of mitral cell perikaryon in the olfactory bulb of the rat. A light and ultrastructural study. 92 Sep 72
In an attempt to localize the site of remodelling of collagen in the periodontal ligament of the continuously erupting mouse incisor a radioautographic and stereologic investigation was undertaken. Grain distributions in radioautographs for light microscopy were studied at various time intervals after administration of [3H]-proline. The distribution of rough
endoplasmic reticulum
cisternae in fibroblasts and the incidence of collagen phagocytosis across the ligament were studied by means of stereologic methods at the electron microscopic level. No significant differences were found in half lives of [3H]-labelled substances among the various regions across the ligament. Rough
endoplasmic reticulum
cisternae within fibroblasts were distributed more or less uniformly throughout the entire width of the ligament. Analysis of the distribution of collagen phagocytosis, however, revealed that in the midregion of the ligament the amount of phagocytosed collagen was approximately four times as high as in the area adjacent to the tooth and about nine times as high as in the alveolar compartment. It is concluded that synthesis and turnover of total protein occurs throughout the periodontal ligament but that remodelling of collagen predominantly takes place in an intermediate area of the ligament.
Anat
Rec
1977 Nov
PMID:The site of remodeling of collagen in the periodontal ligament of the mouse incisor. 92 Sep 76
Near the end of spermiogensis, the late spermatids remain attached to the superficial layer of the seminiferous epithelium for an appreciable period of time (i.e., 3 to 4 days). Ths sickle-shaped heads of the spermatids are embedded in an apical process of Sertoli cell cytoplasm which is connected to the rest of the cell by a narrow stalk. In the concavity of the head several long (2-3 mum) and very narrow (50 nm) tubular projections of the spermatid's plasma membrane invaginate the Sertoli cell cytoplasm. These tubular processes terminate by a bulbous swelling which may measure up to 1 mum in diameter. Along the process the plasma membrane of the Sertoli cell is closely apposed to the spermatid's membrane, the intracellular space being only 6-8 nm wide. In the Sertoli cytoplasm immediately surrounding the tubular portion of the structure there is an accumulation of filamentous material, while next to the bulbous extremity there are, at a shrot distance, smooth surfaced cisternae of
endoplasmic reticulum
. The whole structure was referred to as a tubulobulbar complex. These complexes, of which there are up to 24 per spermatid, appear as these cells complete their migration toward the apex of the Sertoli cells. They disappear just before the release of the spermatids in the lumen of the seminiferous tubule as a result of the fragmentation of the spermatid's plasma membrane followed by a resorption of the Sertoli plasma membrane. Morphological evidence suggests that the Tubulobulbar complexes serve as anchoring devices that retain the spermatids at the surface of the seminiferous epithelium while their dissolution contributes in part to the process of spermiation. Similar tubulobulbar complexes were also formed by the plasma membranes of two adjacent Sertoli cells close to the Sertoli-Sertoli tight junctions near the tubular limiting membrane.
Anat
Rec
1976 Jul
PMID:Anchoring device between Sertoli cells and late spermatids in rat seminiferous tubules. 93 34
The incorporation of 3H-tryptophan into the inner enamel epithelium of newborn mouse incisor tooth organs has been studied in situ by light and electron microscopic autoradiography to determine the sites and kinetics of biosynthesis, migration, and secretion of precursor enamel protein during newborn mouse incisor tooth formation maxillary and mandibular incisor tooth amelogenesis was studied 5, 30, 60, 120, 240 minutes and 24 hours following the intraperitoneal injection of 3H-tryptophan. By 5 minutes, 40% of the total silver grains associated with the secretory ameloblasts were localized over the rough
endoplasmic reticulum
and 50% of the silver grains were localized over the Golgi apparatus. By 30 minutes, silver grains were observed predominately over condensing vacuoles and secretory granules within the forming Tomes' processes, and were also localized over the extracellular "granular" pre-enamel matrix. The enamel proteins were synthesized on membrane-bound polysomes, transferred within the cisternae of the rough
endoplasmic reticulum
and then accumulated in the inner saccules of the Golgi apparatus. The enamel proteins were than packaged in condensing vacuoles which subsequently became secretory granules which migrated to the lateral and apical secretory regions of the forming Tomes' processes. It was concluded from these in vivo studies that enamel protein were synthesized and subsequently secreted within 30 minutes. The initially secreted precursor enamel protein was localized over a material which demonstrated a granular or stippled ultrastructure. The labeled protein then was localized over the amorphous enamel matrix per se which contained the forming calcium hydroxyapatite crystals. We assumed, therefore, that there are two different ultrastructural forms of 3H-tryptophan containing extracellular enamel proteins and suggest that the granular or "stippled" form represents newly secreted precursor enamel protein.
Anat
Rec
1976 Jul
PMID:The biosynthesis and secretion of precursor enamel protein by ameloblasts as visualized by autoradiography after tryptophan administration. 93 36
Chick primordial germ cells (PGCs) which separated from the "germinal crescent" entoderm in the period from stages 4 to 8 circulated mostly through the developing blood vessels from stage 10 onward and finally migrated into the gonad. The PGCs making their appearance up to this stage were generally spherical in profile, about 14 mum in diameter. Some of the PGCs in contrast, did not enter the blood vessels but remained in the tissue (mesenchyme) of the embryo proper (tissue PGCs) and possessed pseudopodial processes, suggesting their migration by means of amoeboid movements. The circulating PGCs emerged from blood vessels in the vicinity of developing gonads by three days (gonadal PGCs). The principal mechanism responsible for the subsequent migration of gonadal PGCs is assumed to be amoeboid movements as in the case of tissue PGCs. Notable amounts of PAS-positive glycogen were demonstrated in the cytoplasm of PGCs in all stages obsreved. They also contained yolk and lipids intracytoplasmically, the former dissipating in relatively early stages of development. Electron microscopic observation revealed the electron-opaque, "fragmented nucleolus" in the large nucleus (8 mum in diameter), which represented another prominent feature of chick PGCs. PGCs contained a well-developed Golgi complex and
endoplasmic reticulum
.
Anat
Rec
1976 Jun
PMID:The origin, migration and morphology of the primordial germ cells in the chick embryo. 94 7
By use of lanthanum tracer and freeze-fracture procedures it was found that granulosa-lutein cells of the pregnant mouse and rat ovaries are connected by gap junctions and septate-like zones of contact. Lutein cell gap junctions enlarge and become partially internalized by the end of the first week of gestation. Expansion of the gap junction domain appears to be due initially to intercalation of particles along borders of small gap junctions devoid of smaller non-junctional particles. The number of gap junction lined processes appearing at the cell border increases concomitantly with hypertrophy of the lutein cell during the second week of pregnancy. Strands of particulate or grooved membrane emanate from the margin of larger gap junctions undergoing interiorization. Most large gap junctions are intimately associated with elements of the smooth
endoplasmic reticulum
. Spherical gap junctional profiles assume a deeper location in the lutein cell and may form concentric arrays by term while true surface gap junctions appear to fragment in the post-partum corpus luteum. The modifications observed are interpreted with respect to biogenesis of the gap junction and the hormonal control of lutein cell function.
Anat
Rec
1975 Feb
PMID:Structural modifications of lutein cell gap junctions during pregnancy in the rat and the mouse. 109 Feb 3
Ultrastructural investigation of liver from ten radiothyroidectomized adult male albino rats, made hyperthyroid by administration of desiccated thyroid for eight to ten weeks, revealed changes in hepatic organelles, but no differences between centrilobular, midzonal and periportal hepatocytes of a single lobule. The mitochondria were enlarged with an increase in matrix density, but no increase in number of mitochondria or alterations in membranes or cristae was observed. The smooth
endoplasmic reticulum
appeared slightly increased and dilated in treated rats, while stacked cisternae of the rough
endoplasmic reticulum
were seldom seen. Large vacuoles, which often contained follicular material and frequently opened into the spaces of Disse, were observed at the periphery of hepatocytes. The vacuoles may arise from invaginations of the cell membrane along these spaces to increase the surface area and to act as channels for liver metabolites. Moreover, in hyperthyroid rats hepatic glycogen was uniformly depleted. Whether these changes were a primary effect of thyroid hormone or secondary to metabolic alterations is unclear.
Anat
Rec
1975 Jan
PMID:Alterations in the fine structure of hepatocytes in hyperthyroid rats. 110 64
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