Tentacular ultrastructure and feeding behaviour of Neopentadactyla mixta (Holothuroidea: Dendrochirota)

1983 ◽  
Vol 63 (2) ◽  
pp. 301-311 ◽  
Author(s):  
Timothy B. Smith
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Feeding Behaviour ◽  
Cell Types ◽  
Nerve Cells ◽  
Secretory Cells ◽  
Suspension Feeding ◽  
Adhesive Secretion

Suspension-feeding in the holothurian Neopentadactyla mixta (Östergren), 1898 is accomplished by an adhesive secretion synthesized in modified retractable discs of epithelial cells located on the terminal tentacular nodes. Besides secretory cells, each disc epithelium is composed of three other cell types: ciliated, granular and nerve cells. The fine structure and possible functions of the epithelium are described with reference to the behaviour of tentacles during feeding and the observations are compared with existing information on holothuroid feeding mechanisms.

scholarly journals CHANGES IN FINE STRUCTURE DURING SILK PROTEIN PRODUCTION IN THE AMPULLATE GLAND OF THE SPIDER ARANEUS SERICATUS

1969 ◽  
Vol 42 (1) ◽  
pp. 284-295 ◽  
Author(s):  
Allen L. Bell ◽  
David B. Peakall
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Protein Production ◽  
Distal Portion ◽  
Silk Gland ◽  
The Body ◽  
Single Type ◽  
Secretory Cells ◽  
The Web ◽  
Tunica Intima

The ampullate silk gland of the spider, Araneus sericatus, produces the silk fiber for the scaffolding of the web. The fine structure of the various parts of the gland is described. The distal portion of the duct consist of a tube of epithelial cells which appear to secrete a substance which forms the tunica intima of the duct wall. At the proximal end of the duct there is a region of secretory cells. The epithelium of the sac portion contains five morphologically distinct types of granules. The bulk of the synthesis of silk occurs in the tail of the gland, and in this region only a single type of secretory droplet is seen in the epithelium. Protein synthesis can be stimulated by the injection of 1 mg/kg acetylcholine into the body fluids. 10 min after injection, much of the protein stored in the cytoplasm of the epithelial cells has been secreted into the lumen. 20 min after stimulation, the ergastoplasmic sacs form large whorls in the cytoplasm. Protein, similar in electron-opacity to protein found in the lumen, begins to form in that portion of the cytoplasm which is enclosed by the whorls. The limiting membrane of these droplets is formed by ergastoplasmic membranes which lose their ribosomes. No Golgi material has been found in these cells. Protein appears to be manufactured in the cytoplasm of the tail cells in a form which is ready for secretion.

scholarly journals The Fine Structure of the Wheat Scutellum During Germination

1972 ◽  
Vol 25 (3) ◽  
pp. 469 ◽  
Author(s):  
JG Swift ◽  
TP O'brien
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Wall Material ◽  
Cytological Evidence ◽  
Starch Grains ◽  
Parenchyma Cells ◽  
Cytological Changes

The cytological changes that take place in the scutellar epithelium and parenchyma during the first 5 days of germination are described by light and electron microscopy. Within 6 hr small starch grains appear in the plastids of both cell types and the size and number of starch grains increase gradually as germination proceeds. Later in germination starch disappears again from the plastids in the epithelial cells, but large starch grains still remain in the parenchyma cells. The reserves of the protein bodies are hydrolysed and the residual vacuoles undergo extensive coales-cence. Modifications in the appearance of the wall material of the epithelial cells as these cells elongate are illustrated and possible functional bases for these changes are suggested. The cells of the scutellar epithelium show no cytological evidence for their known functions of diastase secretion and nutrient absorption.

scholarly journals FORMATION OF ARROWHEAD COMPLEXES WITH HEAVY MEROMYOSIN IN A VARIETY OF CELL TYPES

1969 ◽  
Vol 43 (2) ◽  
pp. 312-328 ◽  
Author(s):  
Harunori Ishikawa ◽  
Richard Bischoff ◽  
Howard Holtzer
Keyword(s):  
Epithelial Cells ◽  
Actin Filaments ◽  
Cell Types ◽  
Nerve Cells ◽  
Collagen Fibrils ◽  
Heavy Meromyosin ◽  
Thin Filaments ◽  
Cellular Components

Heavy meromyosin (HMM) forms characteristic arrowhead complexes with actin filaments in situ. These complexes are readily visualized in sectioned muscle. Following HMM treatment similar complexes appear in sectioned fibroblasts, chondrogenic cells, nerve cells, and several types of epithelial cells. Thin filaments freshly isolated from chondrogenic cells also bind HMM and form arrowhead structures in negatively stained preparations. HMM-filament complexes are prominent in the cortex of a variety of normal metaphase and Colcemid-arrested metaphase cells. There is no detectable binding of HMM with other cellular components such as microtubules, 100-A filaments, tonofilaments, membranes, nuclei, or collagen fibrils. The significance of HMM-filament binding is discussed in view of the finding that arrowhead complexes form in types of cells not usually thought to contain actin filaments.

Fine Structure of Nerve Cells in the Brain of the House Fly, Musca Domestica (Diptera)

1971 ◽  
Vol 29 ◽  
pp. 274-275
Author(s):  
Venita F. Allison ◽  
Suraj P. Sharma ◽  
R. S. Sohal
Keyword(s):  
Fine Structure ◽  
Musca Domestica ◽  
Structural Characteristics ◽  
Cell Types ◽  
Small Population ◽  
House Fly ◽  
Nerve Cells ◽  
Type I ◽  
Structural Level ◽  
The Brain

Because of its comparative structural simplicity insect central nervous system has been frequently used for basic neurological studies. However, relatively little is known regarding the cytological organization of the different neuronal types, especially at the fine structural level. The precise localization and identification of particular cell types within the brain would be useful in correlating structural characteristics of neurons with their integrative functional role. The present study reports the fine structure of three different types of nerve cells within the anterior protocerebral region of the brain of the adult male house fly, Musca domestica.Type I Neuron (Figure 1): Examination of the anterior lateral region of the protocerebrum reveals a small population of uni-polar neurons further characterized by perikarya with a paucity of cytoplasm and proportionately large dense nuclei. The cytoplasm contains poorly developed endoplasmic reticulum, an abundance of ribosomes and a few ovoid to rounded mitochondria with shelf-like cristae. Small Golgi regions and dense inclusion bodies are seen in certain planes of section.

Fine Structure of the Ultimobranchial Gland in the Chick

1971 ◽  
Vol 29 ◽  
pp. 510-511
Author(s):  
A. S. Chan
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Electron Density ◽  
Osmium Tetroxide ◽  
Secretory Granules ◽  
Parenchymal Cell ◽  
Cell Types ◽  
Dark Cells ◽  
Ultimobranchial Gland

Although the ultimobranchial gland of the chick has been shown to contain large amounts of calcitonin relatively few reports have been published on its fine structure. In the present study, the ultrastructure of the chick ultimobranchial gland, with emphasis on the cells which appear to be the producers of the hormone, will be examined. Ultimobranchial glands were obtained from twenty 2-week-old chicks and fixed in glutaraldehyde followed by osmium tetroxide.The gland is composed of aggregate of cords and clusters of cells interspersed with variable numbers of cyst-like cavities. Two parenchymal cell types, namely, light and dark cells can be recognized (Figs. 1,2,3). Epithelial cells, varying from columnar to cuboidal, line the cavities of the cysts.Light cells form the majority of the cell types (Fig. 1). The cytoplasm is characterized by the presence of membrane-limited secretory granules, measuring from 100 to 350 mμ in diameter. The contents of the secretory granules vary in electron density from moderate to extreme (Figs. 1,2). Secretory granules are distributed randomly in the cytoplasm although some are lined near the cell membrane.

scholarly journals The Fine Structure of the Epithelial Cells of the Mouse Prostate

1960 ◽  
Vol 7 (3) ◽  
pp. 511-513 ◽  
Author(s):  
David Brandes ◽  
Adolfo Portela
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Connective Tissue ◽  
Cell Membrane ◽  
Secretory Cells ◽  
Ventral Lobe ◽  
Cytoplasmic Matrix ◽  
Mouse Prostate

The fine structure of the epithelial cells of one component of the prostatic complex of the mouse—the ventral lobe—has been investigated by electron microscopy. This organ is composed of small tubules, lined by tall simple cuboidal epithelium, surrounded by smooth muscle and connective tissue. Electron micrographs of the epithelial cells of the ventral lobe show these to be limited by a cell membrane, which appears as a continuous dense line. The nucleus occupies the basal portion of the cell and the nuclear envelope consists of two membranes. The cytoplasmic matrix is of moderately low density. The endoplasmic reticulum consists of elongated, circular, and oval profiles representing the cavities of this system bounded by rough surfaced membranes. The Golgi apparatus appears localized in a region between the apical border and the nucleus, and is composed of the usual elements found in secretory cells (3, 9). At the base of the cells, a basement membrane is visible in close contact with the outer aspect of the cell membrane. A space of varying width, which seems to be occupied by connective tissue, separates the epithelial cells from the surrounding smooth muscle fibers and the blood vessels. Bodies with the appearance of portions of the cytoplasm, mitochondria, or profiles of the endoplasmic reticulum can be seen in the lumina of the acini and on the bases of these pictures and others of the apical region the mechanism of secretion by these cells is discussed. The fine structural organization of these cells is compared with that of another component of the mouse prostate—the coagulating gland.

The Fine Structure of Brunner’s Glands in the Rabbit

1967 ◽  
Vol 25 ◽  
pp. 64-65
Author(s):  
C. R. Leeson ◽  
T. S. Leeson
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Cell Types ◽  
Central Nucleus ◽  
Secretory Cells ◽  
Muscularis Mucosa ◽  
Apical Cytoplasm ◽  
Duodenal Glands ◽  
Distinct Cell ◽  
Hematoxylin And Eosin

In most species, the duodenal glands of Brunner are composed of secretory cells which are mucous in character. In the rabbit the glands appear unique in that they possess two morphologically distinct cell types, mucous and serous. The glands are composed of coiled tubules which occasionally branch. The tubules are arranged in aggregates within the submucosa and they extend through the muscularis mucosa to terminate in the bases of the intestinal glands. With the light microscope, the two cell types can be differentiated clearly. Most cells are mucous in type, possess basally situated nuclei, and exhibit an apical cytoplasm which appears foamy due to the presence of crowded, pale-staining, secretory granules (Figure 1). Serous cells are present in small aggregates at the blind endings of the tubules. In hematoxylin and eosin preparations they appear densely stained, and each cell is characterized by the presence of a central nucleus, basal basophilia and an apical cytoplasm which contains discrete secretory granules.

scholarly journals Prolactin Receptor (PRLR) Isoform Expression in the Murine Oviduct

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A771-A772
Author(s):  
Kelly C Radecki ◽  
Mary Y Lorenson ◽  
Ameae M Walker
Keyword(s):  
Epithelial Cells ◽  
Mrna Expression ◽  
Estrous Cycle ◽  
Expression Profiles ◽  
Cell Types ◽  
Serous Carcinoma ◽  
Secretory Cells ◽  
Ciliated Cells ◽  
Short Forms ◽  
Long Form

Abstract The most common and most deadly form of “ovarian”cancer is High-Grade Serous Carcinoma (HGSC), now appreciated to arise from epithelial cells of the fallopian tube/oviduct. The serum analyte with the greatest specificity and sensitivity that correlates with the presence or absence of HGSC is prolactin (PRL). However, unknown is whether elevated PRL initiates disease or is the result of disease, although once cancer is present,it is clear that PRL promotes disease. In order to examine the potential for disease initiation in normal animals, it was first important to determine which cells in the mouse oviduct respond to PRL. In many cell types, the long form of the Prlr mediates increased survival, proliferation and migration, whereas the short forms have the opposite effect. After establishing equivalent efficiencies of primers for the long form (LF) and 3 short forms (SF1-3) of the murine Prlr and the endogenous control gene, Gapdh, the mRNA expression profiles of these forms of the receptor were followed by RT-qPCR as a function of stage of the estrous cycle (proestrus, estrus, metestrus, diestrus - determined by vaginal cytology) and region of the oviduct (isthmus, ampulla and fimbria). Expression of SF1 was not detected. SF2 was essentially consistently expressed throughout the oviduct and at all stages of the estrous cycle. By contrast, the ratio of LF to SF3 varied by region of the tube, with more SF3 towards the fimbria and more LF towards the isthmus. The epithelium of the oviduct is primarily composed of multi-ciliated cells and secretory cells, with more ciliated cells towards the fimbria and more secretory cells towards the isthmus. The RT-qPCR results therefore suggested the possibility that a greater proportion of LF Prlr was present on secretory cells and a greater proportion of SF3 Prlr on ciliated cells. Using antibodies raised against intracellular peptide regions specificto the LF (aa 309-325) and SF3 (aa 281-296), both receptor isoforms were localized by immunofluorescence to apical regions of both epithelial cell types,but the presence of receptors on cilia (clearly demonstrated by 3Dreconstruction and rotation) complicated analysis of relative fluorescence by microscopy. Only the LF Prlr signals via Stat5 and so it was anticipated thatStat5 activation could serve as a substitute marker of the relative presence ofLF Prlr. Following in vivo intraperitoneal injection of PRL (5μg/g, 30 min),activated Stat5 was localized to epithelial cells at the base of, and in between, mucosal folds, thereby suggesting a further regionality to receptor distribution. For the fimbrial region only, which is where HGSC is thought to arise, expression of both the LF and SF3 Prlr changed as a function of the stage of the estrous cycle, with highest mRNA expression at diestrus/proestrus. Ongoing work includes flow cytometry of epithelial subpopulations and spatialanalysis of gene expression.

Fine Structure of the Malpighian Tubules of the Mosquito, Culex pipiens

1971 ◽  
Vol 29 ◽  
pp. 402-403
Author(s):  
Brendan Clifford
Keyword(s):  
Fine Structure ◽  
Culex Pipiens ◽  
Stellate Cell ◽  
Malpighian Tubule ◽  
Cell Types ◽  
Instar Larva ◽  
Malpighian Tubules ◽  
Calliphora Erythrocephala ◽  
Distinct Cell ◽  
Basal Plasma

An ultrastructural investigation of the Malpighian tubules of the fourth instar larva of Culex pipiens was undertaken as part of a continuing study of the fine structure of transport epithelia.Each of the five Malpighian tubules was found to be morphologically identical and regionally undifferentiated. Two distinct cell types, the primary and stellate, were found intermingled along the length of each tubule. The ultrastructure of the stellate cell was previously described in the Malpighian tubule of the blowfly, Calliphora erythrocephala by Berridge and Oschman.The basal plasma membrane of the primary cell is extremely irregular, giving rise to a complex interconnecting network of basal channels. The compartments of cytoplasm entrapped within this system of basal infoldings contain mitochondria, free ribosomes, and small amounts of rough endoplasmic reticulum. The mitochondria are distinctive in that the cristae run parallel to the long axis of the organelle.

Effect of Calcium on the Growth and Differentiation of Cultured Rat Esophageal Epithelial Cells

1982 ◽  
Vol 40 ◽  
pp. 132-133
Author(s):  
W.T. Gunning ◽  
M.R. Marino ◽  
M.S. Babcock ◽  
G.D. Stoner
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Replication Rate ◽  
Enzymatic Dissociation ◽  
Growth Assay ◽  
Epidermal Growth ◽  
Fetal Bovine ◽  
Esophageal Epithelial Cells ◽  
Cellular Replication

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.

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