Coated Vesicles in Absorptive Cells of Hydra

1967 ◽  
Vol 2 (4) ◽  
pp. 563-572
Author(s):  
D. B. SLAUTTERBACK
Keyword(s):  
Hexagonal Lattice ◽  
Coated Vesicles ◽  
Selective Absorption ◽  
Luminal Surface ◽  
Gastrovascular Cavity ◽  
Apical Cytoplasm ◽  
Absorptive Cells ◽  
Ordered Array

The apical cytoplasm of absorptive cells in hydra gastroderm contains numerous vesicles having a discoidal shape, an asymmetrical membrane and a peculiar coat firmly attached to the luminal surface of the membrane. The coat of these ‘discoidal coated vesicles’ consists of a highly ordered array of subunits made up of ‘pegs’ and globules. That these vesicles are involved in selective absorption and transport of materials from the gastrovascular cavity can be seen readily using ferritin as tracer. They are also involved in the uptake of particulate glycogen and the phagocytosis and possibly the subsequent digestion of complex food droplets. It may reasonably be supposed that the array of the coat subunits indicates a similar array of the molecular constituents of the membrane to which it is attached. In tangential sections of the membrane a compressed hexagonal lattice is seen which could fit the coat array.

Distribution of actively absorbed diffusible sugars in the jejunal epithelium of the rat

1980 ◽  
Vol 45 (1) ◽  
pp. 199-210
Author(s):  
I.T. Johnson ◽  
J.R. Bronk
Keyword(s):  
Electron Microscopy ◽  
Intestinal Absorption ◽  
Frozen Sections ◽  
Apical Cytoplasm ◽  
Absorptive Cells ◽  
Freeze Dried ◽  
Intracellular Mechanism ◽  
Specific Activities ◽  
Peripheral Cytoplasm

Electron-microscopy autoradiography, using freeze-dried frozen sections of unfixed tissue, was used to study the distribution of actively transported materials in the jejunal epithelium of the rat in vitro. After a few minutes incubation, the grain density over the organelle-packed interiors of the apical cytoplasm of the columnar absorptive cells was significantly greater than that over the structureless peripheral cytoplasm. This difference in the relative specific activities of the 2 subcellular compartments increased during accumulation of labelled galactose, and decreased as preloaded galactose was washed out of the epithelium. A similar compartmentation was observed in vascularly perfused intestines exposed to labelled galactose from either the mucosal or the serosal sides. These observations suggest the presence of an intracellular mechanism controlling the location and concentration of transported substrates during intestinal absorption.

scholarly journals Ferritin-Containing Bodies in Human Small Intestinal Epitheliuin

Blood ◽  
1963 ◽  
Vol 22 (4) ◽  
pp. 397-405 ◽  
Author(s):  
ROBERTA S. HARTMAN ◽  
MARCEL E. CONRAD ◽  
RICHARD E. HARTMAN ◽  
ROBERT J. T. JOY ◽  
WILLIAM H. CROSBY
Keyword(s):  
Golgi Apparatus ◽  
Inclusion Bodies ◽  
Iron Hydroxide ◽  
The Body ◽  
Ground Substance ◽  
Sharp Boundary ◽  
Apical Cytoplasm ◽  
Absorptive Cells ◽  
Small Intestinal ◽  
Cytoplasmic Ground Substance

Abstract Ferritin was identified in the absorptive cells of human jejunum from normal iron-replete subjects by the demonstration of the tetrad form of the iron hydroxide micelle of the ferritin molecule. In a few sections ferritin molecules were observed to be dispersed in the cytoplasm, but usually they were within inclusion bodies found in the apical cytoplasm. These ferritin-containing bodies were oval in profile and 0.5-1.5 µ long. They were not bounded by membrane but did have a moderately dense background substance which made a sharp boundary with the cytoplasmic ground substance. A few clues suggest that the body itself, but not necessarily its substance, is formed within the Golgi apparatus.

scholarly journals The Ingestion of Proteins and Colloidal Materials by Columnar Absorptive Cells of the Small Intestine in Suckling Rats and Mice

1959 ◽  
Vol 5 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Sam L. Clark
Keyword(s):  
Cell Membrane ◽  
Fluorescent Antibody ◽  
Apical Cell ◽  
Intestinal Lumen ◽  
Apical Cell Membrane ◽  
Suckling Rats ◽  
Apical Cytoplasm ◽  
Absorptive Cells ◽  
Rats And Mice ◽  
Colloidal Materials

Proteins and colloidal materials, administered orally to suckling rats and mice, were ingested by columnar absorptive cells of the jejunum and ileum, but not of the duodenum. Bovine gamma globulin and ovalbumin were identified in the apical cytoplasm by staining with fluorescent antibody; trypan blue, Evans blue, saccharated iron oxide, and colloidal gold were detected intracellularly by their color, specific staining, and appearance in the electron microscope. Each substance was segregated in membrane-enclosed vacuoles, apparently part of a system of potentially interconnecting vacuoles and tubules in the apical cytoplasm which is continuous in places with the apical cell membrane. We postulate that ingestion of foreign materials was accomplished by pinocytosis, that is, by invagination of the apical cell membrane to form vacuoles containing material from the intestinal lumen. Approximately 18 days after birth columnar absorptive cells lost the ability to ingest proteins and colloids, and no longer contained large vacuoles and numerous tubules. At this age rats and mice lose the ability to absorb antibodies from the intestine in an immunologically intact form, and we conclude that cellular ingestion is part of the mechanism of absorption of intact proteins in suckling animals. Particulate fat apparently is absorbed in both newborn and adult animals by micropinocytosis. Thus adult animals may not have lost the capacity for pinocytosis, but rather have become selective as to what substances provoke it. Cortisone acetate, administered subcutaneously to rats 8 to 10 days old alters the columnar absorptive cells within 72 hours so that they resemble the cells in adult animals and no longer ingest proteins.

Intracellular transport and secretion of fibroin in the posterior silk gland of the silkworm Bombyx mori

1981 ◽  
Vol 50 (1) ◽  
pp. 19-44 ◽  
Author(s):  
S. Sasaki ◽  
E. Nakajima ◽  
Y. Fujii-Kuriyama ◽  
Y. Tashiro
Keyword(s):  
Intracellular Transport ◽  
Cytochalasin B ◽  
Silk Gland ◽  
Luminal Surface ◽  
Golgi Bodies ◽  
Apical Cytoplasm ◽  
Radial Microtubule System ◽  
Microfilament System ◽  
Silkworm Bombyx Mori ◽  
Posterior Silk Gland

Intracellular transport and secretion of fibroin in the posterior silk gland cells of the silkworm, Bombyx mori, were investigated in relation to the radial microtubule and circular microtubule-microfilament systems of the cells. The silk glands were pulse-labelled for 3 min with [3H]glycine in vitro and then chased in media containing excess cold glycine and in some cases antimitotic reagents (colchicine or vinblastine) or cytochalasin (B or D), and the flow of the label in the glands was investigated by radioautography. It was revealed that the label initially located over the rough endoplasmic reticulum subsequently moves to the Golgi bodies to be condensed there. The secretory granules of fibroin or fibroin globules thus formed are transported via the radial microtubule system to the apical cytoplasm to be secreted there under some regulation by the circular microtubule-microfilament system. In the presence of colchicine or vinblastine, the secretion of fibroin was suppressed an marked accumulation of fibroin globules in the Golgi regions was observed, while in the presence of cytochalasin B or D the secretion was accelerated and extensive invagination of the luminal surface, which was probably due to the serial exocytosis of fibroin globules, was observed. These results suggest that the radial microtubule system and the circular microtubule-microfilament system are responsible for intracellular transport of fibroin globules from Golgi bodies to the apical cytoplasm and secretion by exocytosis at the luminal surface, respectively.

Common features of coated vesicles from dissimilar tissues: composition and structure

1978 ◽  
Vol 30 (1) ◽  
pp. 87-97 ◽  
Author(s):  
J.W. Woods ◽  
M.P. Woodward ◽  
T.F. Roth
Keyword(s):  
Membrane Vesicle ◽  
Coated Vesicles ◽  
Sodium Dodecylsulphate ◽  
Exterior Surface ◽  
Porcine Brain ◽  
Molecular Weights ◽  
Composition And Structure ◽  
Structural Subunit ◽  
Ordered Array ◽  
Coat Material

Coated vesicles were purified and characterized from porcine brain and chicken oocyte. Electrophoresis on sodium dodecylsulphate (SDS) gels showed that coated vesicles from either source have three major proteins in common with apparent molecular weights of 180000, 120000, and 55000 Daltons. Negatively stained specimens from both sources appear to consist of a highly ordered array of short interconnected rods or ridges of material on the exterior surface of a membrane vesicle. Coated vesicles purified from porcine brain and chicken oocyte have mean external diameters of 75.0 and 85.0 nm, respectively. In coated vesicles of the appropriate orientation, portions of the coat material appear to be organized into hexagons and pentagons. Based on the observed variability of size and apparent structure, it is postulated that the basic structural subunits of coated vesicles are the short rods or ridges of material observed on the exterior membrane vesicle surface. It is suggested that multiples of the subunits can be assembled into many arrangements to yield coated vesicles of different sizes and coat structure. It is also proposed that the structural subunit is a complex of 3 proteins of molecular weight of 180000, 120000 and 55000 Daltons.

scholarly journals ISOLATION OF THE PLASMA MEMBRANE OF THE LUMINAL SURFACE OF RAT BLADDER EPITHELIUM, AND THE OCCURRENCE OF A HEXAGONAL LATTICE OF SUBUNITS BOTH IN NEGATIVELY STAINED WHOLE MOUNTS AND IN SECTIONED MEMBRANES

1970 ◽  
Vol 45 (3) ◽  
pp. 542-553 ◽  
Author(s):  
R. M. Hicks ◽  
B. Ketterer
Keyword(s):  
Plasma Membrane ◽  
Membrane Structure ◽  
Mercuric Acetate ◽  
Hexagonal Lattice ◽  
Negative Contrast ◽  
Luminal Surface ◽  
Hexagonal Array ◽  
Bladder Epithelium ◽  
Luminal Membrane ◽  
Whole Mounts

A method of isolating the thick luminal membrane from homogenates of bladder epithelium is described, which entails pretreatment of the epithelium with fluorescein mercuric acetate and centrifugation of the homogenate on sucrose density gradients. A hexagonal array of hexamers is illustrated by negative contrast staining in whole mounts of the isolated thick membrane. Subunits are also shown in tangential sections of this thick membrane, in fixed, embedded bladder epithelium. The significance of the subunits is discussed in the context of membrane structure and permeability.

scholarly journals Distribution of immunoglobulin G receptors in the small intestine of the young rat.

1980 ◽  
Vol 85 (1) ◽  
pp. 18-32 ◽  
Author(s):  
R Rodewald
Keyword(s):  
Small Intestine ◽  
Immunoglobulin G ◽  
Specific Binding ◽  
Proximal Jejunum ◽  
Luminal Surface ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Absorptive Cells ◽  
Igg Receptors ◽  
Old Rats

Conjugates of horseradish peroxidase (HRP) and immunoglobulin G (IgG) were used to map the distribution of cell surface receptors that can bind IgG at 0 degrees C within the small intestine of 10-12-d-old rats. Luminal receptors are present only within the duodenum and proximal jejunum. In these locations, receptors are limited to absorptive cells that line the upper portion of individual villi. Near villus tips, receptors are relatively evenly distributed over the entire luminal plasmalemma. In the midregion of villi, receptors are unevenly distributed over the luminal surface. Receptors (a) specifically bind rat and rabbit IgG, (b) recognize the Fc portion of the immunoglobulins, and (c) bind at pH 6.0 but not pH 7.4. To determine whether IgG receptors are confined to the luminal portion of the plasmalemma, intact epithelial cells were isolated from the proximal intestine of 10-12-d-old rats and incubated with HRP conjugates at 0 degree C. The specific binding of rat IgG-HRP to cells at pH 6.0 indicates that IgG receptors, which are functionally similar to those found on the luminal surface, are also present over the entire abluminal surface of absorptive cells. These results are consistent with the transport of IgG to the abluminal plasma membrane in the form of IgG-receptor complexes on the surface of vesicles. Exposure of these complexes to the serosal plasma, which is presumably at pH 7.4, would cause release of IgG from the receptors. To assess possible inward movement of vesicles from the abluminal surface after discharge of IgG, intravenously injected HRP was used as a space-filling tracer in the serosal plasma. HRP could be visualized within the coated and tubular vesicles responsible for transport of IgG in the opposite direction. These vesicles may, therefore, provide a pathway whereby receptors shuttle between the luminal and abluminal surfaces of cells.

scholarly journals FUNCTIONS OF COATED VESICLES DURING PROTEIN ABSORPTION IN THE RAT VAS DEFERENS

1967 ◽  
Vol 35 (2) ◽  
pp. 357-376 ◽  
Author(s):  
Daniel S. Friend ◽  
Marilyn G. Farquhar
Keyword(s):  
Electron Microscopy ◽  
Golgi Complex ◽  
Vas Deferens ◽  
Hydrolytic Enzymes ◽  
Rat Vas Deferens ◽  
Coated Vesicles ◽  
Multivesicular Bodies ◽  
Dense Bodies ◽  
Apical Cytoplasm ◽  
Golgi Region

The role of coated vesicles during the absorption of horseradish peroxidase was investigated in the epithelium of the rat vas deferens by electron microscopy and cytochemistry. Peroxidase was introduced into the vas lumen in vivo. Tissue was excised at selected intervals, fixed in formaldehyde-glutaraldehyde, sectioned without freezing, incubated in Karnovsky's medium, postfixed in OsO4, and processed for electron microscopy. Some controls and peroxidase-perfused specimens were incubated with TPP,1 GP, and CMP. Attention was focused on the Golgi complex, apical multivesicular bodies, and two populations of coated vesicles; large (> 1000 A) ones concentrated in the apical cytoplasm and small (<750 A) ones found primarily in the Golgi region. 10 min after peroxidase injection, the tracer is found adhering to the surface plasmalemma, concentrated in bristle-coated invaginations, and within large coated vesicles. After 20–45 min, it is present in large smooth vesicles, apical multivesicular bodies, and dense bodies. Peroxidase is not seen in small coated vesicles at any interval. Counts of small coated vesicles reveal that during peroxidase absorption they first increase in number in the Golgi region and later, in the apical cytoplasm. In both control and peroxidase-perfused specimens incubated with TPP, reaction product is seen in several Golgi cisternae and in small coated vesicles in the Golgi region. With GP, reaction product is seen in one to two Golgi cisternae, multivesicular bodies, dense bodies, and small coated vesicles present in the Golgi region or near multivesicular bodies. The results demonstrate that (a) this epithelium functions in the absorption of protein from the duct lumen, (b) large coated vesicles serve as heterophagosomes to transport absorbed protein to lysosomes, and (c) some small coated vesicles serve as primary lysosomes to transport hydrolytic enzymes from the Golgi complex to multivesicular bodies.

Structural analysis of the photosynthetic membrane from Ectothiorhodospira halochloris

1983 ◽  
Vol 41 ◽  
pp. 740-741
Author(s):  
H. Engelhardt ◽  
R. Guckenberger ◽  
W. Baumeister
Keyword(s):  
Lattice Structure ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Rhodopseudomonas Viridis ◽  
Photosynthetic Membranes ◽  
Ectothiorhodospira Halochloris ◽  
Main Components

Bacterial photosynthetic membranes contain, apart from lipids and electron transport components, reaction centre (RC) and light harvesting (LH) polypeptides as the main components. The RC-LH complexes in Rhodopseudomonas viridis membranes are known since quite seme time to form a hexagonal lattice structure in vivo; hence this membrane attracted the particular attention of electron microscopists. Contrary to previous claims in the literature we found, however, that 2-D periodically organized photosynthetic membranes are not a unique feature of Rhodopseudomonas viridis. At least five bacterial species, all bacteriophyll b - containing, possess membranes with the RC-LH complexes regularly arrayed. All these membranes appear to have a similar lattice structure and fine-morphology. The lattice spacings of the Ectothiorhodospira haloohloris, Ectothiorhodospira abdelmalekii and Rhodopseudomonas viridis membranes are close to 13 nm, those of Thiocapsa pfennigii and Rhodopseudomonas sulfoviridis are slightly smaller (∼12.5 nm).

Adenomatoid Tumor of the Testis, A Mesonephric Hamartoma

1971 ◽  
Vol 29 ◽  
pp. 318-319
Author(s):  
Raoul Fresco ◽  
Mary Chang-Lo
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Fibrous Tissue ◽  
Salient Feature ◽  
Luminal Surface ◽  
Adenomatoid Tumor ◽  
Ultrastructural Studies ◽  
Epithelial Origin ◽  
Brush Borders ◽  
Cell Processes

Confusion surrounds the nature of the “adenomatoid tumor” of the testis, as evidenced by the large number of synonyms which have been ascribed to it. Various authors have considered the tumor to be of endothelial, mesothelial or epithelial origin. There appears to be no controversy as to the stromal elements of the tumor, which consists mainly of smooth muscle and fibrous tissue. It is the irregular gland-like spaces which have given rise to the numerous theories as to its histogenesis, and even recent ultrastructural studies fail to agree on the origin of these structures.Electron microscopy of a typical intrascrotal adenomatoid tumor showed the gland-like spaces to be lined by epithelial cells (Fig. 1), rich in cytoplasmic tonofibrils and united to each other by numerous desmosomes (Fig. 2). The most salient feature of these epithelial cells was the presence on their luminal surface of numerous long and repeatedly branching microvillous structures of the type known as stereocilia (Fig. 3). These are extremely long slender cell processes which are as much as three to four times the length of those in brush borders.

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