Showing papers on "Apical cytoplasm published in 1995"
TL;DR: The presence of both centrosomal and noncentrosomal gamma-tubulin in apical cytoplasm suggest multiple mechanisms by which microtubule nucleation might occur in epithelial cells.
Abstract: Microtubules oriented in the apicobasal axis of columnar epithelial cells are arranged with a uniform polarity with minus ends toward the apical surface, suggesting that these cytoskeletal filaments might serve as a substrate for polarized movement of membrane vesicles within the cell. It is not known whether hepatocytes, a cuboidal epithelium in which transcellular transport is a requisite step in normal apical membrane biogenesis, contain microtubules arranged with a similar polarity. In the present study, we explore the question of microtubule polarity and possible mechanisms for nucleation in the epithelial cell lines WIF-B (hepatocyte), Caco-2 (intestine), and Madin-Darby canine kidney (MDCK). Caco-2 microtubules in the apicobasal axis had uniform polarity with minus ends nearest the apical surface. After cold and nocodazole-induced depolymerization, microtubule regrowth initiated in the apical region in all three cell types. The apex of WIF-B and Caco-2 cells contained two pools of gamma-tubulin: one associated with centrosomes and the other delocalized under the apical membrane. Non-centrosomal gamma-tubulin was present in complexes that sedimented between 10S and 29S; both forms could bind microtubules. The presence of both centrosomal and noncentrosomal gamma-tubulin in apical cytoplasm suggest multiple mechanisms by which microtubule nucleation might occur in epithelial cells.
193 citations
TL;DR: Results suggest that VIP17/MAL is an important component in vesicular trafficking cycling between the Golgi complex and the apical plasma membrane.
109 citations
Journal Article•
TL;DR: Examination of the distribution and localization of the APC protein and alpha -catenin in the normal mouse intestine by light and immunoelectron microscopy suggests that a portion of theAPC protein localized in the lateral cytoplasm of intestinal epithelial cells functions in cooperation with catenins, whereas the APCs protein in microvilli and in the apical cytopLasm has other functions independent of catenin.
Abstract: Mutations in the APC gene are linked to the development of sporadic colorectal tumors as well as to familial adenomatous polyposis. Recently, the APC protein was reported to associated with catenins, proteins that bind to the cell adhesion molecule E-cadherin. In the present study, we examined the distribution and localization of the APC protein and alpha -catenin in the normal mouse intestine by light and immunoelectron microscopy using specific antibodies. The APC protein was found to be localized in microvilli and in the apical and lateral cytoplasm of the epithelial cells, whereas alpha-catenin was detected only in the lateral cytoplasm. Double-labeling immunoelectron microscopy showed colocalization of the APC protein with alpha-catenin in the lateral cytoplasm, especially along the lateral plasma membrane, although a certain portion of the APC protein in this region was distributed independently of alpha-catenin. These results suggest that a portion of the APC protein localized in the lateral cytoplasm of intestinal epithelial cells functions in cooperation with catenins, whereas the APC protein in microvilli and in the apical cytoplasm has other functions independent of catenins.
92 citations
TL;DR: It is suggested that a subset of mucous cells is the primary site for production of prostaglandins in the rat gastrointestinal tract, and that two forms of COX are expressed in distinct types of mucus cell.
Abstract: Prostaglandins are considered to play important roles in gastric mucosal protection. The rate-limiting enzyme involved in the biosynthesis of prostaglandins is cyclooxygenase (COX), also known as prostaglandin H synthase. Two forms of COX are known: a constitutively expressed form (COX-1) and a newly-characterized, inducible form (COX-2). In the present study, the immunocytochemical localization of COX-1 and COX-2 was examined in the rat gastrointestinal tract. A strong immunoreactivity for COX-1 was localized in the mucous neck cells of gastric gland. A weak reactivity for COX-1 was also found in the mucous cell types in the cardiac gland and pyloric gland of the stomach as well as in the Brunner's gland of duodenum. Ultrastructurally, the immunoreactivity was localized to the apical cytoplasm of these cells. On the other hand, immunoreactivity for COX-2 was distributed in the surface mucous cells in both the fundic and pyloric regions of stomach. These results suggest that a subset of mucous cells is the primary site for production of prostaglandins in the rat gastrointestinal tract, and that two forms of COX are expressed in distinct types of mucous cell.
92 citations
TL;DR: Results show that a conserved 170 kDa myosin heavy chain is present in a variety of monocot and dicot cells, consistent with the presence of multiple myosins in plants in general and pollen tubes in particular.
Abstract: A polyclonal antibody directed against a 170 kDa myosin heavy chain from lily pollen tubes was employed to (a) assess the cellular distribution of the polypeptide using immunofluorescence methods, and (b) ascertain if similar polypeptides are present in pollen tubes and somatic cells of other species. Fluorescence is associated with particles of various size as well as an amorphous component, and is concentrated in the apical cytoplasm of lily and tobacco pollen tubes. Apical fluorescence is more extensive in lily than in tobacco, which may be related to different streaming patterns and apical zonation seen at the ultrastructural level. In suspension cells of tobacco andArabidopsis, fluorescence is concentrated around the nuclei. Dual localizations indicate that anti-myosin fluorescence may be associated with the presence of actin. Little or no staining was seen in controls consisting of either pre-immune serum or mono-specific IgG that had been preadsorbed with the 170 kDa polypeptide. Immunoblots show that a 170 kDa immunoreactive polypeptide is present in pollen tubes of tobacco andTradescantia virginiana in addition to lily, and in suspension culture cells of tobacco andArabidopsis and extracts of wholeArabidopsis seedlings. Our results show that a conserved 170 kDa myosin heavy chain is present in a variety of monocot and dicot cells. They are also consistent with the presence of multiple myosins in plants in general and pollen tubes in particular.
89 citations
TL;DR: It is suggested that the apical cytoplasm of Caco-2 cells contains a population of MVB capable of receiving membrane proteins trafficking in from both apical and basolateral borders and then routing them to a variety of cell surface and intracellular destinations.
Abstract: By raising monoclonal antibodies to the apical surface of Caco-2 cells we have identified a membrane protein (p100) that internalizes and recycles constitutively between the apical plasma membrane and endosomes in the apical cytoplasm. By applying tracers bound to the transferrin receptor, which internalizes and recycles back to the basolateral border, we demonstrate that the apical endosomes containing p100 include a subset of multivesticular bodies (MVB), which are also accessible to proteins arriving from the basolateral endosome. Tracers bound to EGF receptors and alpha-2-macroglobulin, which internalize from the basolateral border and are degraded, probably in lysosomes, also pass through the p100-containing MVB. These studies therefore suggest that the apical cytoplasm of Caco-2 cells contains a population of MVB capable of receiving membrane proteins trafficking in from both apical and basolateral borders and then routing them to a variety of cell surface and intracellular destinations. The differential distribution of apical and basolateral tracers within the 50-nm-diameter tubules connected to these p100-positive apical MVB suggests that the destination of proteins trafficking from the MVB back to apical and basolateral surfaces is determined by the tubules to which they gain access.
84 citations
TL;DR: Observations indicate that apical stress fibers are attached to the plasma membrane by using principally the same molecular assembly as the focal adhesion associated with the basal stress fiber.
Abstract: Human fibroblasts stained with fluorescently labeled phalloidin revealed many stress fibers within the apical cytoplasm in addition to those located along the basal plasma membrane and associated with focal adhesions. The staining patterns of these apical stress fibers with fluorescent phalloidin, anti-alpha-actinin, and antimyosin were identical to those of the basal stress fibers, suggesting the same macromolecular organization for both types of stress fibers. There were two types of apical stress fibers that clearly interacted with the apical plasma membrane, those extending between the basal and the apical plasma membrane and those having both ends on the basal membrane forming arches whose top interacted with the apical plasma membrane. By electron microscopy, we observed that apical stress fibers were associated with the apical plasma membrane via electron-dense plaques reminiscent of the focal adhesion. Since several proteins have been specifically localized to the focal adhesion site, we examined whether they were also present at the apical stress fiber-membrane association site by using immunocytochemical methods and image reconstruction techniques. We found that vinculin, talin, paxillin, a fibronectin receptor protein, several integrin subunits including beta 1, fibronectin, and proteins with phosphorylated tyrosine were also components of the apical plaque. These observations indicate that apical stress fibers are attached to the plasma membrane by using principally the same molecular assembly as the focal adhesion associated with the basal stress fiber. We suggest that the complex molecular organization of the focal adhesion is not demanded by cell adhesion, but rather it is needed for anchoring stress fibers to the plasma membrane. Apical plaques did not stain with the anti-integrin alpha v subunit or anti-focal adhesion associated kinase (FAK), although these antibodies stained focal adhesions. These results suggest that the apical stress fiber-membrane contact has some important functions different from those of the focal adhesion.
47 citations
TL;DR: Significant decreases in carnosine level, consistent with the nickel sulfate exposure, were observed, however, there were no changes in olfactory function as measured by either absolute threshold or two-oder discrimination tasks.
39 citations
TL;DR: This study provides a description of the exact spatial relationships between the M cells and the cells harboured in these so‐called “pockets” of M cells in rabbit follicle‐associated epithelium.
Abstract: One of the major cell components of the rabbit follicle-associated epithelium is represented by the M cells. M cells are able to harbour variable amounts of immunocompetent cells inside peculiar invaginations of their basolateral cytoplasmic membrane, currently referred to as "pockets." This study provides a description of the exact spatial relationships between the M cells and the cells harboured in these so-called "pockets." Pieces of Peyer's patches, taken from the small intestine of an adult male rabbit, were treated as usual for conventional electron microscopy. Consecutive semithin and ultrathin sections were made through the entire thickness of the follicle-associated epithelium along planes parallel to the mucosal surface. Micrographs, taken from the ultrathin sections, were transposed into a software MacDraw Pro to obtain a computerized three-dimensional reconstruction. Three-dimensional reconstruction of the M cells showed that the "pockets" were not formed by mere invaginations of the cytoplasmic membrane, but that they resulted from the branching of the supranuclear portion of the M cell cytoplasm around the M cell-infiltrating lymphocytes. These intrusive cells could be found inside the "pockets" or lined up with one another, in vertical columns, bordering on the basal aspect of the M cells. The particular arrangement of the M cell apical cytoplasm created a labyrinth within the follicle-associated epithelium, which could be assumed as a real intraepithelial compartment expandable virtually throughout all the epithelium. The functional meaning of the intraepithelial compartment delimited by the M cells and its possible role is discussed.(ABSTRACT TRUNCATED AT 250 WORDS)
32 citations
TL;DR: A mature olfactory epithelium appears to be necessary to support the presence of this microvillar cell, suggesting that it is not crucial to the regeneration processes or recovery of Olfactory function, but perhaps plays some role, as yet undefined, in the unperturbed olfaction.
32 citations
TL;DR: Observations suggest that systemically-administered compounds causing site-specific lesions in the epithelium lining the DMM of the nasal cavity may do so by the in situ production of reactive epoxide metabolites which are then poorly capable of being detoxified.
Abstract: This study represents part an of ongoing effort to understand the mechanism underlying the distribution of the olfactory mucosal lesion resulting from the systemic administration of compounds such as 2,6-dichlorobenzonitrile (dichlobenil) and β,β'-iminodipropionitrile (IDPN). Immunohistochemistry was performed to localize the microsomal form of epoxide hydrolase (mEH) and glutathione S-transferase (GST) isozymes α, μ and π in the rodent olfactory mucosa. GST-π was found in abundance in the Bowman's glands of the mucosa lining the dorsal medial meatus (DMM) of the nasal cavity and in the nuclei of basal and sustentacular cells of the dorsal and lateral nasal cavity. Liver and olfactory mucosal levels of mEH are equivalent by Western blot analysis. mEH appeared to be localized in the apical cytoplasm of sustentacular cells in all regions of the olfactory mucosa except for the epithelium lining the DMM. These observations, coupled with the known profile of metabolites for dichlobenil, suggest that systemically-administered compounds causing site-specific lesions in the epithelium lining the DMM of the nasal cavity may do so by the in situ production of reactive epoxide metabolites which are then poorly capable of being detoxified. Thus, the distribution of metabolic enzymes, rather than the absolute level of an enzyme in a tissue, may dictate lesion distribution in the case of toxicants which are bioactivated in target tissues. Chem. Senses 20 : 385-392, 1995.
TL;DR: NADPH-cytochrome P450 reductase was localized by ultrastructural immunocytochemistry in the cytoplasm of Clara cells, ciliated cells and type II pneumocytes of young female Wistar rats and MF1 mice.
TL;DR: The present findings indicate that M-cells similar to those in the gut-associated lymphoid tissue occur in the tonsil.
Abstract: The epithelium of the rabbit palatine tonsil was studied with vimentin immunohistochemistry, using cryosections and paraffin sections labelled with three monoclonal antibodies. Vimentin-positive epithelial cells were detected in crypt regions overlying lymphoid follicles but were absent from the surrounding stratified pharyngeal epithelium. The cells lay in close contact with intra-epithelial lymphocytes and their apical cytoplasm had a membranous shape. Since vimentin is a sensitive, specific marker for M-cells of the rabbit intestine, the present findings indicate that M-cells similar to those in the gut-associated lymphoid tissue occur in the tonsil.
TL;DR: In comparison with the adult enzyme, fetal aminopeptidase N has a more widespread subcellular distribution with substantial amounts present in apical endocytic compartments characteristic of the fetal enterocyte.
TL;DR: Ultrahistochemical evidence for quercitin-sensitive ATP enzyme activity, believed to represent Ca-ATPase activity, in the epidermal tissue underlying the exoskeleton of the marine crab, Callinectes sapidus, is presented for different stages of the moult cycle.
TL;DR: Structural differences in the epidermis of Diceratocephala boschmai Baer may be explained by functional differences between the syncytia.
Abstract: The epidermis of Diceratocephala boschmai Baer, 1952 (Temnocephalida : Platyhelminthes) was studied using silver-nitrate staining and electron microscopy. The epidermis consists of six syncytia separated by lateral membranes: the frontal, trunk, stalk, adhesive disc syncytia, and a pair of post-tentacular syncytia. Neighbouring syncytia differ in many characters including (1) the presence or absence of locomotory cilia, (2) the degree of the differentiation of the apical cytoplasm layer, (3) the presence or absence of bundles of cytoskeletal filaments, imaginations of basal membrane and other specialised cytoplasmatic structures, (4) the abundance of hemidesmosomes at the basal membrane, and (5) the abundance and nature of gland ducts penetrating the syncytium. These structural differences reflect functional differences between the syncytia. Thus, multisyncytial organisation of the epidermis may be explained by functional differences between the syncytia. Only between the frontal and trunk syncytia has no apparent ultrastructural difference been found.
TL;DR: A 7‐year‐old girl with a congenital apocrine hamartoma of the left cheek is described and it is thought this lesion may represent a form of organoid nevus with pure apocrine differentiation.
Abstract: Congenital apocrine hamartomas are rare tumors of the skin composed of mature apocrine glands in the papillary and reticular dermis. Several cases have been reported in the literature but few were of uniform clinical appearance. The term apocrine nevus has been used interchangeably with apocrine hamartoma in the literature, however, based on their distinctive morphologies we believe they are different entities. We describe a 7-year-old girl with a congenital apocrine hamartoma of the left cheek. A stained biopsy specimen from the lesion revealed large mature apocrine glands with decapitation secretion in the dermis. The presence of periodic acid-Schiff-positive, diastase-resistant granular material in the apical cytoplasm of some secretory cells helped differentiate these as apocrine glands. We think this lesion may represent a form of organoid nevus with pure apocrine differentiation.
TL;DR: These data show that the mRNA encoding an E2‐dependent oviduct‐specific protein is distributed in epithelial cells at perinuclear foci and at sites distant from the nucleus, which are also the sites of protein localization and protein synthesizing organelles, implying translation at unique cytoplasmic foci.
Abstract: Data from our laboratory have shown that an estrogen (E2)-dependent M(r) 90,000-92,000 protein and its mRNA are synthesized and expressed in abundant amounts at estrus from the fimbria and ampulla, not isthmus, oviduct of the sheep. Immunocytochemical studies have shown that the M(r) 90,000-92,000 protein is contained in apical secretory granules of oviduct epithelial cells. The objective of this study was to determine whether the mRNA for the E2-dependent oviduct protein was localized and compartmentalized in similar manner. Fimbria, ampulla, and isthmus oviducts obtained from estrous ewes were flash frozen in liquid nitrogen, cryosectioned, fixed in 4% paraformaldehyde, hybridized with digoxigenin (DIG)-labeled oviduct-specific riboprobes, incubated in anti-DIG antibodies conjugated with alkaline phosphatase, and developed in color substrate. Oviduct protein-specific transcripts were localized to basal perinuclear compartments and, surprisingly, at sites distant from the nucleus in the apical cytoplasm of epithelial cells in the fimbria and ampulla. No specific reaction product was observed in the underlying mucosa or smooth muscle layers. Oviduct protein mRNA was contained predominantly in the apical cytoplasm of epithelial cells at the free margins of mucosal folds and in the basal regions of cells located at the crypts of longitudinal folds. No reaction product was present when sections of the fimbria and ampulla oviduct of estrous ewes were incubated in sense riboprobe to the oviduct protein. In addition, when sections of the isthmus oviduct obtained from estrous ewes or fimbira and ampulla oviducts from long-term ovariectomized ewes were hybridized with antisense riboprobes no specific reaction product was detected. Electron microscopy of oviduct protein mRNA containing areas revealed the presence of secretory granules, rough endoplasmic reticulum (RER) and Golgi in the apical cytoplasm, and RER in the basal regions of epithelial cells. These data show that the mRNA encoding an E2-dependent oviduct-specific protein is distributed in epithelial cells at perinuclear foci and at sites distant from the nucleus, which are also the sites of protein localization and protein synthesizing organelles, implying translation at unique cytoplasmic foci.
TL;DR: The aim of this work is to establish presence oftublin, actin, vimentin, desmin, and cytokeratins in the sertoli cells of Gambusia affinis holbrooki and in their efferent duct epithelial cells which are possibly orginated from the Sertoli Cells.
Abstract: BACKGROUND There is little information about the distribution of cytoskeletal components in the testes of teleost fish. The aim of this paper was to know the distribution of some major cytoskeletal proteins (tubulin, actin, vimentin, desmin, and cytokeratins) in the Sertoli cells of Gambusia affinis holbrooki and in their efferent duct epithelial cells which are possibly originated from the Sertoli cells. METHODS Light and electron microscopic immunocytochemical studies and Western blotting analysis were performed in G. affinis testis. RESULTS Actin immunoreaction was observed in the Sertoli cells at all spermatogenic stages, although the intensity of this reaction varied from one stage to another. Sertoli cells that support spermatogonia or spermatocytes showed a weak immunoreaction which was uniformly distributed throughout the cytoplasm and somewhat more concentrated at the level of the inter-Sertoli specialized junctions. Immunoreaction to actin increased during the first stages of spermiogenesis and was mainly localized beneath the plasma membrane. This immunoreaction was more intense in the basal than in the apical cytoplasm of Sertoli cells. In a more advanced stage of spermiogenesis, actin immunoreaction become stronger in the apical cytoplasm where Sertoli cells displayed cytoplasmic projections around each spermatid. After sperm release, the apical Sertoli cell cytoplasm still showed an intense actin immunoreaction. Intense immunoreaction to actin was also observed in the epithelial cells lining the efferent ducts. Immunoreaction to tubulin was diffuse throughout the Sertoli cell cytoplasm. No immunoreaction to vimentin or desmin was observed in the Sertoli cells during the spermatogenic process. Immunoreaction to both vimentin and desmin was observed in the efferent duct cells. Desmin immunoreaction was also observed in the seminiferous tubule boundary cells, mainly in the sections showing germ cell cysts at the last stages of spermiogenesis and in the peritubular cells that surrounded the efferent duct epithelium. Immunoreaction to cytokeratins was found in the endothelium of testicular blood vessels but not in the Sertoli cells or in the efferent duct epithelium. CONCLUSIONS Immunoreaction pattern to cytoskeletal proteins in the Sertoli cells of G. affinis differs from that reported in mammalian Sertoli cells. These differences include the distribution of actin filaments and the absence of detectable vimentin immunoreaction in G. affinis Sertoli cells.
Journal Article•
TL;DR: The data presented here support the existence of such a regulatory process for suppressing apoptosis in intestinal cells under starvation and biochemical markers for apoptosis such as increased transglutaminase activity and DNA fragmentation are clearly discernible in normally fed animals.
Abstract: Morphology at light and electron microscopic levels, expression and activation of transglutaminase and DNA fragmentation at internucleosomal sites were used as markers to study the effect of starvation on the apoptosis of small intestinal epithelial cells. The cells entering apoptotic programme in well-fed animals undergo many morphological changes in apical cytoplasm involving alterations in actin cytoskeleton organisation which may cause a discharge of microvilli. Some free floating cells in the intestinal lumen show characteristics of apoptotic cell death, e.g. shrinkage of cell and peripheral condensation of chromatin, while mitochondria and lysosomes remain unchanged. Apoptotic bodies are also seen in scanning electron micrographs. During progressive starvation, epithelial cells do not enter the apoptotic cell death programme. Biochemical markers for apoptosis such as increased transglutaminase activity and DNA fragmentation are clearly discernible in normally fed animals. The percentage of cells labelled immunohistochemically by antibody against transglutaminase decreased during starvation while DNA fragmentation was absent. The exact mechanism for suppressing apoptosis in intestinal cells under starvation is not known. However, the data presented here support the existence of such a regulatory process.
TL;DR: Findings indicate that repeated perforating penetration of the lymphocytes induces cell cleavage, and microcinematographic observations demonstrate the alternate protrusion and withdrawal of processes of lymphocytes.
Abstract: In previous ultrastructural studies we have shown that at the tip of intestinal villi in guinea pigs, effete enterocytes are separated into two portions: a thin apical cytoplasm to be exfoliated into the lumen and a major basal portion to be ingested by lamina propria macrophages During this process, intraepithelially disposed, large granular lymphocytes interdigitate with enterocytes in a complex manner In the present study, the relation between the enterocytes and the lymphocytes in the villous epithelium of the guinea pig small intestine is described by use of transmission and scanning electron microscopy in an attempt to visualize the roles and activities of the lymphocytes more clearly The lymphocytes project numerous pointed processes into effete enterocytes, even piercing them Enterocytes are deeply indented or perforated, probably as a result of the encroaching lymphocyte processes Some enterocytes are separated into apical and basal portions by numerous large excavations in the cytoplasm These findings indicate that repeated perforating penetration of the lymphocytes induces cell cleavage Supporting this supposition, our microcinematographic observations demonstrate the alternate protrusion and withdrawal of processes of lymphocytes The processes advance with a pointed end, and subsequently, retract with a rounded end in a cycle of 8–18 seconds
TL;DR: The ultrastructure of collar cells described here is discussed in comparison to that of other Cnidarians and in connection with the problem of Polypodium's systematic position.
Abstract: The existence of collar cells lining the stomach gastrodermis in free-living Polypodium hydriforme and their ultrastructure are described. The collar cells are provided with a collar consisting of 9–10 microvilli which encircles a central flagellum and forms a flagellar pit. At the bottom of the pit around the basal part of the flagellum there is fine crystalline material which extends also in the spaces between the microvilli and keeps them straight. The flagellum has a typical axoneme (9+2), its basal body is located below the apical surface of the collar cell and continues into a striated rootlet. An accessory centriole is situated close to the upper part of the rootlet. The cell nucleus is located in the basal part of the cell. Prominent mitochondria with tubular cristae, Golgi cisternae and fragments of rough endoplasmic reticulum are situated mostly in the basal part of the cytoplasm. Discoidal vesicles are abundant in the apical cytoplasm. The collar cells are connected to each other by septate junctions and interdigitations. The ultrastructure of collar cells described here is discussed in comparison to that of other Cnidarians and in connection with the problem of Polypodium's systematic position.
TL;DR: The present study suggests that LF in the nucleolus plays an important role in activation of ribosomal biogenesis preceding the cell differentiation and proliferation in the mouse uterus.
Abstract: Lactoferrin (LF) is known as an estrogen-inducible protein in the murine uterus. This study, employing immunoelectron microscopy with the pre-embedding methods, was carried out to elucidate temporal LF induction, the process of the induction and intracellular localization after 17βestradiol (E2) stimulation in the enodometrial epithelium of ovariectomized adult mice. By single i. p. injection of E2 (20μg/kg b. w.), LF was rapidly induced, even after 1 hr, and was exclusively localized in the nucleoli of surface and glandular epithelium. At 7 hr after E2 injection, strong immunostaining was recognized in the amorphous cytoplasm and in nucleoli, especially in the dense fibrillar component of the epithelium. From 13 hr to 23 hr after E2 administration, strong reaction was observed in the secretory pathway, i. e., cisternae of endoplasmic reticulum and the Golgi apparatus, and in vesicles and vacuoles in the apical cytoplasm, in addition to the nucleolar staining. LF-immunoreaction was also detected in the nucleoli and cytoplasm of stromal and muscle cells; it was demonstrated in the epithelium at the earliest period, subsequently in the stromal cells (7 hr), and finally in the muscle cells (13 hr). After three days of consecutive E2 stimulation, many secretory granules in the apical cytoplasm and apical cell membrane showed intense LF immunoreaction. The present study suggests that LF in the nucleolus plays an important role in activation of ribosomal biogenesis preceding the cell differentiation and proliferation in the mouse uterus.
TL;DR: The most intense staining of secretory cells was observed with PNA after pre‐treatment with neuraminidase, which indicates that the terminal trisaccharide sequence sialic acid‐ (α2→3, 6) galactosyl (β1→3) N‐acetylgalactosamine is the most frequent oligosaccharides present in glycoproteins secreted by horse gustatory glands.
Abstract: In the present work, gustatory glands (von Ebner's glands) of the horse tongue were examined by means of five peroxidase-conjugated lectins (PNA, DBA, SBA, UEA I, WGA), with and without prior sialidase digestion, in order to investigate the presence and distribution of carbohydrate residues in secretory cells and duct cells. The most intense staining of secretory cells was observed with PNA after pre-treatment with neuraminidase. This indicates that the terminal trisaccharide sequence sialic acid- (alpha 2-->3, 6) galactosyl (beta 1-->3) N-acetylgalactosamine is the most frequent oligosaccharide chain present in glycoproteins secreted by horse gustatory glands. Secretory cells also contained oligosaccharides with terminal alpha-N-acetylgalactosamine and N-acetylglucosamine, whereas fucose was found in only a few glandular cells. The apical cytoplasm of duct lining cells reacted with all the lectins except WGA.
TL;DR: In the endothelial cells lining the rat splenic blood vessels, neutral carbohydrates were studied by means of combined periodic acid-thiocarbohydrazide-silver protein (PA-TCH-SP) and alpha-amylase digestion methods and cytochemical variations of neutral carbohydrates with the arteriolar and venous vessels of the rat spleen were discussed with special reference to varying cytophysiological functions.
Abstract: In the endothelial cells lining the rat splenic blood vessels, neutral carbohydrates were studied by means of combined periodic acid-thiocarbohydrazide-silver protein (PA-TCH-SP) and alpha-amylase digestion methods. In the endothelial cells lining the central and follicular arteries of the spleen, the neutral glycoconjugate-containing surface coat of the luminal plasma membrane and related pinocytotic invaginations and vesicles in the apical cytoplasm were strikingly distinguished, as compared with those in the cells lining the splenic sinuses. In contrast, cytoplasmic glycogen particles in the sinus endothelial cells were apparently larger in amount than those in the arteriolar endothelial cells. Such cytochemical variations of neutral carbohydrates with the arteriolar and venous vessels of the rat spleen were discussed with special reference to varying cytophysiological functions of the endothelial cells with the different segments of the splenic blood vessels.
Journal Article•
TL;DR: The presence of a special cell located in the ependymal wall at the level of the paraventricular nucleus is described, pointing out the possibility that those special cells may also be implicated in a ventricle-blood vessel communication.
Abstract: The present paper describes the presence of a special cell located in the ependymal wall at the level of the paraventricular nucleus. At this level, ultrastructural obsewation of these ependymal cells, unlike most other mammalian species, shows the presence of nucleoluslike bodies in their cytoplasm and occasionally basal processes. These processes appear perpendicular to the ependymal surface and end in contact with the basal membrane of hypothalamic capillaries. Mitochondria, endoplasmic reticulum and numerous filaments are present in the basal processes. Nucleolus-like bodies or nematosomes consist of round or ovoid unbound masses of granular appearing material of variable density located in the apical cytoplasm of the cells. Some of their ultrastructural characteristics are similar to other ependymal specialized cells which are classically termed tanycytes. These findings point out the possibility that those special cells may also be implicated in a ventricleblood vessel communication.
Journal Article•
TL;DR: The results indicate that the V-type proton pump is important both for intracellular and for urinary acidification.
Abstract: The effects of bafilomycin, an inhibitor of the vacuolar-type (V-type) proton pump, on nephron ultrastructure and acidification were analyzed in isolated perfused kidneys from rats with acute metabolic acidosis. Acidic intracellular compartments were labelled with the weak base DAMP, that was subsequently visualized immunocytochemically. The distribution of the proton pump was studied by immunocytochemistry. Bafilomycin inhibited urinary acidification and caused pronounced ultrastructural changes in proximal tubule cells and B-type intercalated cells (B-IC cells). Immunoreactivity for DAMP showed that bafilomycin also inhibits intracellular acidification. The distribution of the proton pump was essentially unchanged by bafilomycin in A-IC cells. In B-IC cells, immunoreactivity accumulated over studded membrane material in the apical cytoplasm. The results indicate that the V-type proton pump is important both for intracellular and for urinary acidification.
01 Jan 1995
TL;DR: The calmodulin immunoreactive substance existed in maturegonads of female and male amphioxus and the immuno-positive reaction was localized in thenucleus of spermatids and egg cell respectively.
Abstract: distribution of calmodulin in amphioxus was studied by immunohistochemical technique. The calmodulin immunoreactive substance existed in maturegonads of female and male amphioxus. The immuno-positive reaction was localized in thenucleus of spermatids (testis) and egg cell (ovary) respectively. Strong immuno-positive reactions were also found in apical cytoplasm of epithelial cells of amphioxus. The possible roles of calmodulin in amphioxus was discussed.
Journal Article•
TL;DR: Gastric mucosa ultrastructure was studied in 32 children and adolescents with chronic superficial active and inactive gastritis and Helicobacter pylori was found most frequently free in mucous layer without direct contact with the mucosa.
Abstract: Gastric mucosa ultrastructure was studied in 32 children and adolescents with chronic superficial active and inactive gastritis. Helicobacter pylori was found most frequently free in mucous layer without direct contact with the mucosa. But in 7 children (21.9%), it occurred quite close to superficial epithelial cells and influenced their outlook. In two cases, it was registered in intracytoplasmic channels of intact parietal cells. Another two children with massive helicobacterial infection showed superficial epithelial cells with big mucus vacuoles and sequestration of apical cytoplasm.
TL;DR: In vivo, the phospholipids may be diffusely distributed throughout the apical cytoplasm and released into the taste pores, and may thus act as a surfactant to promote the solubility of sapid materials, which facilitates their adsorption to the membranes of microvilli of taste bud cells.
Abstract: Circumvallate papillae of adult dd-mice were fixed in a mixture of tannic acid, glutaraldehyde, and paraformaldehyde, postosmicated, embedded in Epon, and observed under an electron microscope. An accumulation of globular electron-dense bodies (70-500 nm in diameter) was found in the apical cytoplasm of the three types of slender taste bud cells, and among the microvilli in the taste pores. High-resolution micrographs of these bodies revealed a lamellar structure with a period of 5 nm, which is characteristic of phospholipids. It is likely that tannic acid in the fixative reacts with the choline base of phospholipids to form an insoluble complex of lamellar bodies. In vivo, the phospholipids may be diffusely distributed throughout the apical cytoplasm and released into the taste pores, and may thus act as a surfactant to promote the solubility of sapid materials, which facilitates their adsorption to the membranes of microvilli of taste bud cells.