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.

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 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.

Analysis of the Anterior Secretory Cells of Onchidohs Muricata (Nudibranchia)

1981 ◽  
Vol 39 ◽  
pp. 614-615
Author(s):  
Roy Skidmore
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Golgi Body ◽  
The Body ◽  
Secretory Cells ◽  
Secretory Vesicles ◽  
High Magnification ◽  
Large Numbers ◽  
Membrane Bound ◽  
Sole Of The Foot

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).

scholarly journals Natural Herbal Estrogen-Mimetics (Phytoestrogens) Promote the Differentiation of Fallopian Tube Epithelium into Multi-Ciliated Cells via Estrogen Receptor Beta

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 722
Author(s):  
Maobi Zhu ◽  
Sen Takeda ◽  
Tomohiko Iwano
Keyword(s):  
Estrogen Receptor ◽  
Cell Differentiation ◽  
Epithelial Cells ◽  
Fallopian Tube ◽  
Ciliated Cell ◽  
Estrogen Receptor Beta ◽  
Notch Pathway ◽  
Secretory Cells ◽  
Ciliated Cells ◽  
Receptor Beta

Phytoestrogens are herbal polyphenolic compounds that exert various estrogen-like effects in animals and can be taken in easily from a foodstuff in daily life. The fallopian tube lumen, where transportation of the oocyte occurs, is lined with secretory cells and multi-ciliated epithelial cells. Recently, we showed that estrogen induces multi-ciliogenesis in the porcine fallopian tube epithelial cells (FTECs) through the activation of the estrogen receptor beta (ERβ) pathway and simultaneous inhibition of the Notch pathway. Thus, ingested phytoestrogens may induce FTEC ciliogenesis and thereby affect the fecundity. To address this issue, we added isoflavones (genistein, daidzein, or glycitin) and coumestan (coumestrol) to primary culture FTECs under air–liquid interface conditions and assessed the effects of each compound. All phytoestrogens except glycitin induced multi-ciliated cell differentiation, which followed Notch signal downregulation. On the contrary, the differentiation of secretory cells decreased slightly. Furthermore, genistein and daidzein had a slight effect on the proportion of proliferating cells exhibited by Ki67 expression. Ciliated-cell differentiation is inhibited by the ERβ antagonist, PHTPP. Thus, this study suggests that phytoestrogens can improve the fallopian tube epithelial sheet homeostasis by facilitating the genesis of multi-ciliated cells and this effect depends on the ERβ-mediated pathway.

Understanding Semantic Web: a conceptual model

2015 ◽  
Vol 64 (1/2) ◽  
pp. 82-100 ◽  
Author(s):  
Michael Calaresu ◽  
Ali Shiri
Keyword(s):  
Semantic Web ◽  
Conceptual Model ◽  
The Body ◽  
Three Dimensional Model ◽  
Conceptual Approach ◽  
Web Based ◽  
Content Type ◽  
Software Applications ◽  
Web Architecture ◽  
The Web

Purpose – The purpose of this article is to explore and conceptualize the Semantic Web as a term that has been widely mentioned in the literature of library and information science. More specifically, its aim is to shed light on the evolution of the Web and to highlight a previously proposed means of attempting to improve automated manipulation of Web-based data in the context of a rapidly expanding base of both users and digital content. Design/methodology/approach – The conceptual analysis presented in this paper adopts a three-dimensional model for the discussion of Semantic Web. The first dimension focuses on Semantic Web’s basic nature, purpose and history, as well as the current state and limitations of modern search systems and related software agents. The second dimension focuses on critical knowledge structures such as taxonomies, thesauri and ontologies which are understood as fundamental elements in the creation of a Semantic Web architecture. In the third dimension, an alternative conceptual model is proposed, one, which unlike more commonly prevalent Semantic Web models, offers a greater emphasis on describing the proposed structure from an interpretive viewpoint, rather than a technical one. This paper adopts an interpretive, historical and conceptual approach to the notion of the Semantic Web by reviewing the literature and by analyzing the developments associated with the Web over the past three decades. It proposes a simplified conceptual model for easy understanding. Findings – The paper provides a conceptual model of the Semantic Web that encompasses four key strata, namely, the body of human users, the body of software applications facilitating creation and consumption of documents, the body of documents themselves and a proposed layer that would improve automated manipulation of Web-based data by the software applications. Research limitations/implications – This paper will facilitate a better conceptual understanding of the Semantic Web, and thereby contribute, in a small way, to the larger body of discourse surrounding it. The conceptual model will provide a reference point for education and research purposes. Originality/value – This paper provides an original analysis of both conceptual and technical aspects of Semantic Web. The proposed conceptual model provides a new perspective on this subject.

Epithelial cells and their importance in the body

1927 ◽  
Vol 23 (12) ◽  
pp. 1287-1287
Keyword(s):  
Epithelial Cells ◽  
The Body

With a number of new studies the author proves his earlier view that epithelial cells produce a hormone circulating in the blood and passing into milk during lactation. The switching off of this hormone when the epithelial cells are removed leads to a decrease of calcium in the blood and causes tetany.

The Structure of Trichocysts in Paramecium Caudatum

1972 ◽  
Vol 11 (3) ◽  
pp. 899-929
Author(s):  
L. H. BANNISTER
Keyword(s):  
Amorphous Matrix ◽  
Boundary Surface ◽  
The Body ◽  
Single Type ◽  
Apical Region ◽  
Paramecium Caudatum ◽  
Lower Phase ◽  
Microscopic Appearance ◽  
Outer Sheath ◽  
Crystalline Matrix

The structure of undischarged and discharged trichocysts has been examined in Paramecium caudatum, and their light-microscopic appearance compared with their fine-structural organization. In living specimens undischarged trichocysts appear to be of a single type with a unimodal variation in length about a mean of 3.7 µm. When fixed for electron microscopy or compressed beneath a coverslip many of the trichocysts expand within the cell, giving rise to a variety of different forms of lower phase density. Ultrastructurally the undischarged trichocyst consists of at least 10 different components: these include a mesh-like sheath surrounding the body of the organelle; an inner and an outer sheath enclosing the tip, the inner sheath being made up of 4 spiralling envelopes with a square net substructure, and the outer sheath being formed of a dense amorphous matrix containing longitudinal microtubules and scattered fine filaments; a boundary surface to the outer sheath; a membranous trichocyst sac the apical region of which is surrounded by a cylinder of microtubules joined to each other with dense material; and lastly, the crystalline matrix of the trichocyst body and tip. This crystalline appearance is apparently related to the presence of a loosely interwoven complex of fine filaments which form a highly regular pattern of unit structures repeating at 16-nm intervals. In extended trichocysts the 60-nm banding pattern of the body is also composed of fine filaments arranged in a different, elongated manner in 2 distinct and alternating patterns which are taken to be 2 views of the same structure. Measurements indicate that when trichocysts extend they elongate by a factor of from 6 to 8. It is proposed that the crystalline pattern of the unextended trichocyst body transforms into the extended form by a simple rearrangement of the constituent filaments accompanied by their elongation. Possible models of the undischarged and discharged states of organization are suggested.

Poecilia (Pamphorichthys) akroa, a new poeciliid species (Cyprinodontiformes: Poeciliidae) from the Rio Tocantins basin, Brazil

Zootaxa ◽  
2018 ◽  
Vol 4461 (3) ◽  
pp. 438
Author(s):  
CARLOS AUGUSTO FIGUEIREDO ◽  
CRISTIANO R. MOREIRA
Keyword(s):  
New Species ◽  
Sensory System ◽  
Color Pattern ◽  
Distal Portion ◽  
The Body ◽  
Caudal Peduncle ◽  
Posterior Portion ◽  
Anterior Branch ◽  
Black Blotch ◽  
A New Species

A new species, Poecilia (Pamphorichthys) akroa, is described from the Rio Tocantins drainage, Brazil. The new species differs from the remaining species of the genus by the possession of 10 or 11 pectoral-fin rays, entire preopercular ramus and posterior portion of the supraorbital ramus of the cephalic sensory system enclosed in canals, a faint longitudinal band along the body, a single gonapophysis, a homogeneous reticulate color pattern on sides of body, urogenital region of females heavily pigmented, distalmost segments of the anterior branch (4a) of the fourth gonopodial ray fused into an elongated segment turned anteriorly, subdistal segments of anterior branch (5a) of fifth gonopodial ray simple, without anterior (ventral) projections, dorsal fin with pigmentation at its distal portion and with a basal black blotch, and chromatophores more concentrated on the posterior margin of the mid-ventral scale series of the caudal peduncle and ventrolateral margin of the adjacent scales forming a series of rhombi posterior to anal fin. 

Fine structure and development of schizonts, merozoites and macrogamonts of Eimeria acervulina in the goblet cells of the duodenal epithelium of experimentally infected birds

Parasitology ◽  
1975 ◽  
Vol 70 (2) ◽  
pp. 223-229 ◽  
Author(s):  
E. Michael
Keyword(s):  
Fine Structure ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Host Cell ◽  
Goblet Cells ◽  
Cellular Level ◽  
Site Specificity ◽  
Eimeria Acervulina ◽  
Duodenal Epithelium

The fine structure of trophozoites, schizonts, merozoites and macrogamonts of Eimeria acervulina found in goblet cells of the duodenal epithelium of chicks is described and compared with the corresponding stages formed in other epithelial cells. Complete schizogony, with the formation of mature merozoites, occurred freely in goblet cells. Developing macrogamonts (but no microgamonts) were rarely found in goblet cells. The stages observed were confined to the cytoplasm of the host cell above the Golgi apparatus and were usually seen between the mucous granules. The stages seen appeared normal, and contained similar structures to corresponding stages developing in other cells. The finding of developing stages of E. acervulina in goblet cells provides further evidence that site specificity of Eimeria at the cellular level is not as strict as previously thought.

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