scholarly journals THE ENDOPLASMIC RETICULUM OF GASTRIC PARIETAL CELLS

1961 ◽  
Vol 11 (2) ◽  
pp. 333-347 ◽  
Author(s):  
Susumu Ito

An electron microscopic survey has been made of the gastric parietal or oxyntic cell of the human, cat, beaver, dog, hamster, rat, mouse, and bat, and of the corresponding cell type in two species of frog, two species of toad, and the horned lizard. A feature consistently found in the parietal cells of the mammals or their equivalent in the lower vertebrates is the agranular endoplasmic reticulum, which takes the form of branching and anastomosing small tubules approximately 200 to 500 A in diameter, sometimes expanded into flattened cisternae. In mammalian parietal cells this form of the endoplasmic reticulum is found only in limited amounts, but in the corresponding secretory cells of the amphibia and reptilia the tubular agranular reticulum is abundant. It is believed to comprise a more or less continuous system of channels, but owing to their tortuous course only short profiles are seen in thin sections. Immediately subjacent to the plasmalemma at the free surface, the cytoplasm is relatively free of organelles but is occasionally traversed by the agranular reticulum, which appears to be continuous at some points with the cell surface. The possible participation of the agranular endoplasmic reticulum in hydrochloric acid secretion is discussed.

1983 ◽  
Vol 31 (8) ◽  
pp. 987-999 ◽  
Author(s):  
J Roth

A method is described for the electron microscopic detection of lectin-binding sites in different cellular compartments and extracellular structures that uses thin sections from resin-embedded tissues. Various lectins (Ricinus communis lectin I and II, peanut lectin, Lotus tetragonolobus lectin, Ulex europeus lectin I, Lens culinaris lectin, Helix pomatia lectin, and soybean lectin) were bound to particles of colloidal gold and used for direct staining of thin sections or glycoprotein--gold complexes were prepared and applied in an indirect technique (concanavalin A and horseradish peroxidase--gold complex; wheat germ lectin and ovomucoid--gold complex). The details for preparation of such complexes from 14 nm gold particles are reported. The conditions of tissue processing that gave satisfactory staining results and good fine structure preservation were mild aldehyde fixation without osmification and low temperature embedding with the hydrophilic resin Lowicryl K4M. None of the so-called etching procedures was necessary prior to labeling of Lowicryl K4M thin sections. Examples of the use of this approach for detection of glycoconjugates in the rough endoplasmic reticulum, Golgi apparatus, and mucin of intestinal goblet cells as well as plasma membrane and various intracellular structures of absorptive intestinal and renal tubular cells are shown. A comparison is made with preembedding staining results on Concanavalin A-binding site localization in rat liver which shows that problems of penetration common in such a technique are circumvented by the postembedding approach described here. Concanavalin A-binding sites were not only consistently found in nuclear envelope, rough and smooth endoplasmic reticulum, plasma membranes, and collagen fibers, but also in mitochondria, glycogen, ribosomes, and nucleus. These data and those of a previous investigation (Roth J, Cytochem 31:547, 1983) prove the applicability of this cytochemical technique for postembedding localization of glycoconjugates by light and electron microscopy.


Parasitology ◽  
1957 ◽  
Vol 47 (1-2) ◽  
pp. 66-69 ◽  
Author(s):  
H. Meyer ◽  
I. De Andrade Mendonça

Toxoplasma ‘Nicolle et Manceaux’ has been examined in the electron microscope in thin sections of infected tissue cultures. The intracellular forms, single or in rosette formations, show that the parasite has no flagella, cilia or other organelles for locomotion. It is covered by a double membrane which is especially well denned at the two poles. A ring-like formation, often slightly protruding, can be seen at one end of the parasite, and in connexion with this, long, homogeneous, dark-stained inclusions of still unknown nature. At the opposite pole a distinct opening has been found.Mitochondria and strands of an endoplasmic reticulum are also present in the cytoplasm and a fine striation in the region of the periplast. No dividing forms have been observed. Near the nucleus, in the region of what may correspond to the centrosome and the Golgi apparatus, a few extremely fine granules and a spiral-like formation of fine striae or tubules have been observed.This work has been partly supported by the National Research Council of Brazil. The cost of reproduction of figures was defrayed by the Institute de Biofísica da Universidade do Brasil.


1989 ◽  
Vol 17 (4_part_2) ◽  
pp. 782-788 ◽  
Author(s):  
Stephen K. Durham ◽  
Abraham Brouwer

Recent results (3) indicate that 200 mg 3,4,3′,4′-tetrachlorobiphenyl induces hepatomegaly accompanied by significant decreases in serum and hepatic retinoid content and hepatocyte morphologic alterations of proliferated and vesiculated endoplasmic reticulum and megamitochondria with paracrystalline inclusions. There was also an associated change in the number, size, and distribution of lipid droplets in hepatocytes and fat-storing cells. Electron microscopic autoradiographic techniques were utilized to determine the cellular and subcellular distribution of 3H-3,4,3′,4′-tetrachlorobiphenyl (3H-TCB) in the adult rat liver and determine if there is any relationship between subcellular morphologic change and radiolabel localization. Adult female WAG/Rij rats received a single intraperitoneal injection of 200 mg TCB/kg containing 1.85 mCi of 3H-TCB and were sacrificed at 1, 3, 7, and 14 days following exposure. The vast majority of 3H-TCB-derived radioactivity was located in the hepatocyte at all time points examined, ranging from 79–86% of the total number of autoradiographic grains counted over the liver cells. Sequential order of radiolabel localization per liver cell type at 1, 3, and 7 days was hepatocyte > > > Kupffer cell > fat-storing cell > endothelial cell. At day 14, the sequential order of radiolabel localization per liver cell type was hepatocyte > > > fat-storing cell > Kupffer cell > endothelial cell, which indicates that there was some shift movement of label over time. The lipid droplet, mitochondria, and endoplasmic reticulum were the subcellular structures or organelles of hepatocytes having the highest number of 3H-TCB-derived grains at all time periods examined. The predominant morphological alterations induced following TCB intoxication were observed in these organelles. The results of this study suggests that there is an association between TCB localization and morphologic change induced in mitochondria and endoplasmic reticulum of hepatocytes following TCB exposure.


Neonatology ◽  
1979 ◽  
Vol 35 (5-6) ◽  
pp. 312-320 ◽  
Author(s):  
Y. Morikawa ◽  
S. Matsuo ◽  
Y. Eguchi ◽  
Y. Hashimoto

Author(s):  
M. R. Edwards ◽  
W. A. Samsonoff

Papillomas in catfishes have been described (1) but the presence of viruses in these tumors has not (2). This report is concerned with the study of a papilloma found on the lower lip of a brown bullhead (letalurus nebulosus) which had been frozen prior to arrival at our laboratory.Tumor tissues were thawed in 2.5% glutaraldehyde and postfixed in 1$ osmium tetroxide. Both fixatives were prepared in Millonig's buffer. Fixation, washing, dehydration, and Epon embedding were accomplished according to conventional electron microscopic techniques.Examination of thin sections revealed virus-like particles in epidermal cells which constituted the major part of the neoplasm (Fig. 1). No particles were found in the connective tissue surrounding the epidermal papillae. The cells containing particles were usually isolated from one another, had a spindle or fusiform shape, and exhibited many cytoplasmic extensions in random directions. Their nuclei were pleomorphic and displayed irregular nuclear envelopes with relatively large lacunae. Vesiculation of the cytoplasm was extensive, apparently caused by dilations of the endoplasmic reticulum.


Author(s):  
Gertraude Wittig

The fine structure of insect hemocytes has been the subject of very few investigations. In particular, the hemocytes of Lepidoptera have received almost no attention. The study presented here was carried out on the armyworm, Pseudaletia unipuncta. Hemocytes of the larva were fixed 2 to 4 days after molt to the sixth instar and studied in ultrathin sections.Microplasmatocytes (Fig. 1) were the most important phagocytes of army-worm hemolymph. They were relatively small, spherical cells with a small, round or lobed nucleus. Distensions of the perinuclear cisterna (p) were frequent and sometimes continuous with the rough endoplasmic reticulum (e). The latter formed greatly distended cisternae which almost filled the whole cytoplasm. The cisternae contained an amorphous material which appeared to be condensed in certain sacs (at e). Mitochondria (m) were rare, and they had tubular cristae. Up to four Golgi complexes (g) were identified in a microplasmatocyte section. Structured granules (sg) were specific for this cell type. Microfibrils (f) traversed the whole cytoplasm but were most frequent around the nucleus (N) and under the cell membrane.


1980 ◽  
Vol 58 (17) ◽  
pp. 1859-1871 ◽  
Author(s):  
René Rohr ◽  
Jean Dexheimer ◽  
Mariette Kieffer

The general organisation and functioning of the secretory cells of the glandular hairs of Hygrophila difformis show some analogies with previously studied glandular systems of the same type; they differ from the latter, however, in the complexity of organisation of the reticulum – plastid complex.In the undifferentiated cell the plastids have a simple rounded, slightly elongated form; they display no special relationship with the endoplasmic reticulum which, at this stage, is represented by irregularly enlarged cisternae containing a dense substance of fibrous appearance.During the secretory phase, on the contrary, the ultrastructures of the plastids and of the endoplasmic reticulum undergo considerable changes; the latter appears in the form of small tubes arranged parallel to each other and in close contact with the plastids. The plastids themselves take on shapes which, until now, have never been observed in this type of cell and which can only be shown clearly by a three-dimensional reconstruction. This technique, which involves making a series of thin sections, has been applied to secretory plastids for the first time. It gives a faithful picture of their original morphology and the various modes of association possible between the plastids of a given reticulum – plastid complex.


Author(s):  
N. Sugai ◽  
S. Ito

The histochemical localization of carbonic anhydrase in parietal cells has been described by a number of investigators and its presence in these cells at the ultrastructural level has been also reported. However the precise distribution of this enzyme is not clear and there are some questions regarding the validity of the histochemical reaction. In the present study, various modifications of the technique were explored and it was found that tissues fixed in buffered formaldehyde, glutaraldehyde with trinitrocresol or picric acid retained good reaction product localization of this enzyme. Cryostat sections of the fixed tissues were treated with solutions recommended by Hannson. Incubation times that were most favorable 5 to 10 min for light microscopy and 8 to 15 min for electron microscopy. For ultrastructural observations of thin sections, it was found to be important that the reacted tissue sections were post osmicated with 1% osmium tetroxide in 1. 5% potassium ferrocyanide or with aqueous 1% 0s04 for only 3 to 5 min.


1982 ◽  
Vol 92 (1) ◽  
pp. 92-107 ◽  
Author(s):  
D Louvard ◽  
H Reggio ◽  
G Warren

Rabbits were immunized with membrane fractions from either the Golgi complex or the rough endoplasmic reticulum (RER) by injection into the popliteal lymph nodes. The antisera were then tested by indirect immunofluorescence on tissue culture cells or frozen, thin sections of tissue. There were may unwanted antibodies to cell components other than the RER or the Golgi complex, and these were removed by suitable absorption steps. These steps were carried out until the pattern of fluorescent labeling was that expected for the Golgi complex or RER. Electron microscopic studies, using immunoperoxidase labeling of normal rat kidney (NRK) cells, showed that the anti-Golgi antibodies labeled the stacks of flattened cisternae that comprise the central feature of the Golgi complex, many of the smooth vesicles around the stacks, and a few coated vesicles. These antibodies were directed, almost entirely, against a single polypeptide with an apparent molecular weight of 135,000. The endoplasmic reticulum (ER) in NRK cells is an extensive, reticular network that pervades the entire cell cytoplasm and includes the nuclear membrane. The anit-RER antibodies labeled this structure alone at the light and electron microscopic levels. They were largely directed against four polypeptides with apparent molecular weights of 29,000, 58,000, 66,000, and 91,000. Some examples are presented, using immunofluorescence microscopy, where these antibodies have been used to study the Golgi complex and RER under a variety of physiological and experimental condition . For biochemical studies, these antibodies should prove useful in identifying the origin of isolated membranes, particularly those from organelles such as the Golgi complex, which tend to lose their characteristic morphology during isolation.


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