scholarly journals Subcellular Localization of the TFF Peptides xP1 and xP4 in the Xenopus laevis Gastric/Esophageal Mucosa: Different Secretion Modes Reflecting Diverse Protective Functions

2020 ◽  
Vol 21 (3) ◽  
pp. 761 ◽  
Author(s):  
Heinz Schwarz ◽  
Werner Hoffmann

The TFF peptides xP1 and xP4 from Xenopus laevis are orthologs of TFF1 and TFF2, respectively. xP1 is secreted as a monomer from gastric surface mucous cells and is generally not associated with mucins, whereas xP4 is a typical secretory peptide from esophageal goblet cells, and gastric mucous neck and antral gland cells tightly associated as a lectin with the ortholog of mucin MUC6. Both TFF peptides have diverse protective functions, xP1 as a scavenger for reactive oxygen species preventing oxidative damage and xP4 as a constituent of the water-insoluble adherent inner mucus barrier. Here, we present localization studies using immunofluorescence and immunoelectron microscopy. xP1 is concentrated in dense cores of secretory granules of surface mucous cells, whereas xP4 mixes with MUC6 in esophageal goblet cells. Of note, we observe two different types of goblet cells, which differ in their xP4 synthesis, and this is even visible morphologically at the electron microscopic level. xP4-negative granules are recognized by their halo, which is probably the result of shrinkage during the processing of samples for electron microscopy. Probably, the tight lectin binding of xP4 and MUC6 creates a crosslinked mucous network forming a stabile granule matrix, which prevents shrinkage.

1984 ◽  
Vol 65 (1) ◽  
pp. 73-93
Author(s):  
M. Boloukhere

Silver staining at the electron microscopic level of the nucleolar organizers was carried out on Xenopus laevis oocytes at various stages of oogenesis. The results indicate that a positive reaction takes place exclusively in the dense fibrillar component of the extrachromosomal nucleoli. This constituent undergoes morphological changes of distribution and architecture, which have been correlated with modifications of the transcriptional activity of the nucleoli. When nucleolar activity is reduced, during previtellogenesis, this constituent appears as dense homogeneous spherules well-segregated from the granular component. In contrast, when nucleolar activity is high, during vitellogenesis, it forms an heterogeneous area with an ill-delimited outline: it is organized into a fibrillar core with emerging skein-like strings. It thus seems that this constituent remains silver-stained throughout oogenesis. These findings suggest that the method used would allow one to follow the evolution of the nucleolar organizer region (NOR) topography during oogenesis. Moreover, they point out facts that have relevance to the problem of the correlation between Ag stainability of NORs and nucleolar transcriptional activity.


The formation of mucus in goblet cells and its relation to the Golgi apparatus has been studied by various workers. Nassanow (1923) showed clearly that the mucin granules in the goblet cells of Triton originated in the Golgi apparatus, and so brought secretion in these cells into line with his theory of the bound secretion. More recently Clara (1926) has shown in the goblet cells of birds that the mucin first appears in the region next to the nucleus, between it and the gland lumen. Florey (1932, a, b ) has considered this more extensively in two recent papers, and for a number of mammals has shown that the mucin granules of goblet cells first form in the meshes of the Golgi network. In epithelial cells of the mouse vagina, undergoing conversion into mucous cells, he has found that the same process occurs. In a recent investigation of secretory formation in the salivary glands and pancreas it was found by the present author that in every cell type examined the young secretory granules first appeared in the basal region of the cell in relation to the mitochondria. Subsequent emigration occurred into the Golgi zone, where they underwent conversion into mature secretory granules. In the mucous cells of the salivary glands it was shown that these newly formed granules might be stained intravitam by Janus green or neutral red, and that in fixed preparations they stained selectively with acid fuchsin as described by Noll (1902), In the light of this work it appeared probable that while mucin formation might occur in the Golgi zone of the goblet cells as described by these authors, the origin of the granules might lie in the basal region of the cell.


1978 ◽  
Vol 89 (3) ◽  
pp. 521-529 ◽  
Author(s):  
D. J. McComb ◽  
K. Kovacs

ABSTRACT Fifteen sparsely granulated prolactin-producing adenomas and 10 non-tumourous adenohypophyses, removed by surgical hypophysectomy, have been studied using morphometry at the electron microscopic level. Compared to non-tumourous prolactin cells, sparsely granulated adenomatous prolactin cells showed a significant decrease in diameter and volume density of secretory granules and an increased volume density of rough-surfaced endoplasmic reticulum and Golgi apparatus. The volume density of mitochondria remained unchanged. These results indicate that the cells of the adenoma are in a highly active functional state. It appears that the equilibrium between hormone synthesis, storage and release is altered in adenomatous prolactin cells.


1980 ◽  
Vol 28 (10) ◽  
pp. 1113-1118 ◽  
Author(s):  
T Tanaka ◽  
E W Gresik ◽  
A M Michelakis ◽  
T Barka

By using antibodies against highly purified submandibular gland renin, renin was localized immunocytochemically at the light and electron microscopic level in the submandibular glands and kidneys of adult male SWR/J and C57BL/6J mice. In accord with the data of Wilson et al. (Proc Natl Acad Sci USA 75:1185, 1977), renin was demonstrable only in the submandibular glands of SWR/J mice (high strain), where it was confined to the secretory granules of the granular convoluted tubules. In the kidneys of both strains, renin was confined to epithelioid cells of the juxtaglomerular apparatus. Electron microscopically immunostaining was restricted to the granules of the juxtaglomerular epitheliod cells. Morphometric analyses suggested that the kidney of the C57BL/6J mice contained more immunoreactive complexes per unit volume of cortex than SWR/J mice kidney. The data indicate that submandibular gland renin cross-reacts with kidney renin, but that genetic controls of these polypeptides in the two organs are independent.


1982 ◽  
Vol 30 (7) ◽  
pp. 682-690 ◽  
Author(s):  
I M Varndell ◽  
F J Tapia ◽  
J De Mey ◽  
R A Rush ◽  
S R Bloom ◽  
...  

Enkephalin-like immunoreactivity has been localized to electron-dense secretory granules of cat and piglet carotid bodies and adrenal medullae, horse adrenal medulla, and also to human adrenal medulla and pheochromocytomas using a gold-labeled antibody technique performed at the electron microscopic level. The same granules were also demonstrated to exhibit dopamine-beta-hydroxylase-like immunoreactivity, which suggests a granular colocalization of amines and peptides in catecholamine-storing cells.


1992 ◽  
Vol 40 (7) ◽  
pp. 919-930 ◽  
Author(s):  
A Ellinger ◽  
M Pavelka

Using lectin binding, we characterized subdomains of the rough endoplasmic reticulum (rER) in goblet cells of the rat colon. In this cell type, special rER regions can be differentiated on the basis of their content of low electron density and dilated cisternal spaces in conventional transmission electron microscopic preparations. The fine fibrillar content of these cisternal regions demonstrated high-affinity binding with lectins from wheat germ, Helix pomatia, Griffonia simplicifolia I-A4 and -B4, and Ricinus communis I, although not with the sialic acid-specific Limax flavus lectin and the fucose-binding Ulex europaeus I lectin. Sugar-inhibitory experiments indicated that glycoconjugates packed within these regions bound the lectins with higher affinity than molecules present in the Golgi apparatus and secretory granules. Furthermore, the lectin binding patterns of the rER subdomains differed from those of the Golgi apparatus and mucin granules: the terminal sugar residues sialic acid and fucose were demonstrable in the Golgi apparatus and mucin granules and were absent from the rER, while galactose-recognizing lectins bound intensely at these rER regions, weakly to Golgi elements, and were almost absent from mucin granules.


1998 ◽  
Vol 107 (6) ◽  
pp. 525-529 ◽  
Author(s):  
Kiminori Sato ◽  
Minoru Hirano

The present study was conducted to determine age-related changes in the human laryngeal glands by means of excised human adult larynges. Scanning and transmission electron microscopic observations were made. The results obtained are summarized as follows. 1) Granular endoplasmic reticulum and Golgi apparatus were sparse in the cytoplasm of serous and mucous cells. 2) Secretory granules in serous cells had decreased in number. 3) Secretory granules were less electron-dense compared to those in younger adult specimens, but were electron-lucent. 4) Mucigen droplets in mucous cells were not as numerous as those in younger adults. 5) Discharge of secretory granules and mucigen droplets had decreased. 6) Age-related morphologic changes in the laryngeal glands influenced not only the amount but also the quality of secretions. 7) The above changes lessened lubrication of the vocal folds, thus causing aging of the voice to some extent. 8) Local immunity and mucociliary transport were also affected. 9) Age-related changes in the laryngeal glands partially altered laryngeal function.


1987 ◽  
Vol 35 (11) ◽  
pp. 1285-1298 ◽  
Author(s):  
Y C Kao ◽  
L M Lichtenberger

Mammalian gastric mucosa is unusually hydrophobic or nonwettable, which may be an essential biophysical characteristic of the gastric mucosal barrier. Since this property may be attributable to an adsorbed layer of surface-active phospholipids (SAPL), we investigated the distribution of SAPL in rat oxyntic mucosa. Ferric hematoxylin (FH) and iodoplatinate (IP), selective histochemical stains for phospholipids (as confirmed by spot tests), were used to detect SAPL in frozen sections and aldehyde-fixed tissue, respectively. Using FH staining in conjunction with extraction procedures that either solvate or preserve SAPL, we determined that positive reactivity was the greatest in the apical third of the oxyntic mucosa between the glandular neck region and the surface. IP reactivity appeared to parallel the FH staining pattern. Mucous cells, especially the surface epithelial cells, were heavily stained. Electron microscopic examination revealed that these cells contain inclusion bodies associated with various subcellular organelles, e.g., nuclear envelope, endoplasmic reticulum, Golgi apparatus and its vesicles, and mucous secretory granules. Vesicles and myelin figures, which resembled those found in lung surfactant, were observed extracellularly in close association with the surface mucous cells. Our findings suggest that mucous cells are actively involved in synthesis and storage of SAPL, which may be an essential component of the stomach's protective hydrophobic lining.


1978 ◽  
Vol 26 (10) ◽  
pp. 855-861 ◽  
Author(s):  
E Gresik ◽  
A Michelakis ◽  
T Barka ◽  
T Ross

Renin was localized in the submandibular gland of the adult mouse at light and electron microscopic levels by the unlabeled antibody enzyme method of Sternberger. At the light microscopic level, renin was confined to the granular convoluted tubule (GCT) segment of the gland with considerable variation among GCT cells in intensity of staining. Some GCT cells failed to stain for renin. The pattern of staining was the same in the gland of male and female mice, but in the glands of females GCT segments were smaller and less numerous. At the electron microscopic level, staining for renin was also confined to the GCT cells, and was localized exclusively to the secretory granules. The intensity of staining of the secretory granules within a given GCT cell varied; some cells contained only minimally reactive or negative secretory granules. All other organelles within the GCT cell, except condensing vacuoles, failed to stain.


Author(s):  
N. W. Thomas

The secretion of mucus has been most intensively studied in goblet cells and mucous salivary gland cells from mammals, particularly laboratory rodents. It was therefore thought desirable to characterize mucous cells from the gut of Ciona intestinalis (L.), in which mucus has an important role in food capture, the formation of a food chain, the protection of the gut lining from physical and chemical abrasion and the formation of faeces. The alimentary canal of Ciona is composed of five regions: (I) a perforated pharynx, (II) a short tapering oesophagus, (III) an ovoid ridged stomach, (IV) an intestine and (V) a rectum. Previous authors (Roule, 1884; Yonge, 1925; Van Weel, 1940; Millar, 1953; Fouque, 1954) have described the preponderance of mucus-secreting cells which occur in the oesophagus, intestine and rectum. It is these three regions that have now been studied in more detail, with the use of histochemical and electron-microscopic techniques.


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