The histology and histochemistry of the developing chorioallantoic membrane in the chick (Gallus domesticus)

1969 ◽  
Vol 47 (3) ◽  
pp. 323-331 ◽  
Author(s):  
B. A. Flumerfelt ◽  
M. A. Gibson
Keyword(s):  
Connective Tissue ◽  
Outer Layer ◽  
Surface Coating ◽  
Cell Layer ◽  
Secretory Granules ◽  
Lymphatic Vessels ◽  
Chorioallantoic Membrane ◽  
Rapid Decrease ◽  
Gallus Domesticus ◽  
Secretory Cells

The chorioallantoic membrane is composed of three layers. (1) An outer chorionic epithelium consisting of a thin outer layer of cells, an inner stratified cell layer, and a central blood sinus lined with flattened ectodermal cells. (2) A middle connective tissue which provides support and a pathway for the distribution of blood and lymphatic vessels. Numerous capillaries pass from this layer to the chorionic sinuses. (3) An inner allantoic epithelium composed of secretory cells. The components of all three layers increase in number and concentration during the first part of the incubation period. After day 17, however, there is a rapid decrease in the composition of each layer. The allantoic epithelium is rich in secretory granules. These granules include a sulfated mucopolysaccharide component. It is suggested that the liberation of this secretion provides a surface coating which protects the underlying tissues against the increasing toxicity of the allantoic contents.

A histological and histochemical study of the development of the amnioallantois in the chick, Gallus domesticus

1970 ◽  
Vol 48 (5) ◽  
pp. 1079-1086 ◽  
Author(s):  
T. P. Kenny ◽  
M. A. Gibson
Keyword(s):  
Connective Tissue ◽  
Incubation Period ◽  
Histochemical Study ◽  
Secretory Granules ◽  
Lymphatic Vessels ◽  
Muscle Layer ◽  
Peak Activity ◽  
Tissue Layer ◽  
Connective Tissue Layer ◽  
Period 2

The amnioallantoic membrane is composed of four layers. (1) An inner amnionic epithelium which is a stratified layer during most of the incubation period. This layer stains positively for glycogen, ribonucleic acid, and neutral and acidic lipids and appears to be most active during the 15 to 17 days of incubation period. (2) A muscle layer composed of dorsoventrally and anteroposteriorly directed bands. During the early incubation stages these bands are organized to form the muscle configurations known as "cross-figures." During the later incubation stages, the organization of these muscle layers is disrupted by invasions of connective tissue and fat. (3) A connective tissue layer which includes blood and lymphatic vessels. (4) An outer allantoic epithelium which is rich in secretory granules. These granules include a sulfated mucopolysaccharide component. The activity of the allantoic epithelium increases progressively during the incubation period and is at peak activity at the 17- to 19-day incubation stage. During the final stages of incubation all layers show signs of decreased activity and degeneration.

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).

Ultrastructural studies of the relationship between actin filaments and secretory granules

1990 ◽  
Vol 48 (3) ◽  
pp. 458-459
Author(s):  
Ellen Holm Nielsen
Keyword(s):  
Electron Microscopy ◽  
Colloidal Gold ◽  
Actin Filaments ◽  
Secretory Granules ◽  
Secretory Cells ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Granule Membrane ◽  
Ultrathin Sections ◽  
Lowicryl K4m

In secretory cells a dense and complex network of actin filaments is seen in the subplasmalemmal space attached to the cell membrane. During exocytosis this network is undergoing a rearrangement facilitating access of granules to plasma membrane in order that fusion of the membranes can take place. A filamentous network related to secretory granules has been reported, but its structural organization and composition have not been examined, although this network may be important for exocytosis.Samples of peritoneal mast cells were frozen at -70°C and thawed at 4°C in order to rupture the cells in such a gentle way that the granule membrane is still intact. Unruptured and ruptured cells were fixed in 2% paraformaldehyde and 0.075% glutaraldehyde, dehydrated in ethanol. For TEM (transmission electron microscopy) cells were embedded in Lowicryl K4M at -35°C and for SEM (scanning electron microscopy) they were placed on copper blocks, critical point dried and coated. For immunoelectron microscopy ultrathin sections were incubated with monoclonal anti-actin and colloidal gold labelled IgM. Ruptured cells were also placed on cover glasses, prefixed, and incubated with anti-actin and colloidal gold labelled IgM.

scholarly journals Anaphylactic Degranulation of Mast Cells: Focus on Compound Exocytosis

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ofir Klein ◽  
Ronit Sagi-Eisenberg
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Molecular Mechanisms ◽  
Secretory Granules ◽  
Cell Types ◽  
Secretory Cells ◽  
Regulated Exocytosis ◽  
Open Questions ◽  
Conflicting Evidence ◽  
Compound Exocytosis

Anaphylaxis is a notorious type 2 immune response which may result in a systemic response and lead to death. A precondition for the unfolding of the anaphylactic shock is the secretion of inflammatory mediators from mast cells in response to an allergen, mostly through activation of the cells via the IgE-dependent pathway. While mast cells are specialized secretory cells that can secrete through a variety of exocytic modes, the most predominant mode exerted by the mast cell during anaphylaxis is compound exocytosis—a specialized form of regulated exocytosis where secretory granules fuse to one another. Here, we review the modes of regulated exocytosis in the mast cell and focus on compound exocytosis. We review historical landmarks in the research of compound exocytosis in mast cells and the methods available for investigating compound exocytosis. We also review the molecular mechanisms reported to underlie compound exocytosis in mast cells and expand further with reviewing key findings from other cell types. Finally, we discuss the possible reasons for the mast cell to utilize compound exocytosis during anaphylaxis, the conflicting evidence in different mast cell models, and the open questions in the field which remain to be answered.

Barrier role of actin filaments in regulated mucin secretion from airway goblet cells

2005 ◽  
Vol 288 (1) ◽  
pp. C46-C56 ◽  
Author(s):  
Camille Ehre ◽  
Andrea H. Rossi ◽  
Lubna H. Abdullah ◽  
Kathleen De Pestel ◽  
Sandra Hill ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Actin Filaments ◽  
Fluorescent Protein ◽  
Secretory Granules ◽  
Yellow Fluorescent Protein ◽  
Goblet Cells ◽  
Actin Binding ◽  
Secretory Cells ◽  
Cortical Actin ◽  
Mucin Secretion

Airway goblet cells secrete mucin onto mucosal surfaces under the regulation of an apical, phospholipase C/Gq-coupled P2Y2receptor. We tested whether cortical actin filaments negatively regulate exocytosis in goblet cells by forming a barrier between secretory granules and plasma membrane docking sites as postulated for other secretory cells. Immunostaining of human lung tissues and SPOC1 cells (an epithelial, mucin-secreting cell line) revealed an apical distribution of β- and γ-actin in ciliated and goblet cells. In goblet cells, actin appeared as a prominent subplasmalemmal sheet lying between granules and the apical membrane, and it disappeared from SPOC1 cells activated by purinergic agonist. Disruption of actin filaments with latrunculin A stimulated SPOC1 cell mucin secretion under basal and agonist-activated conditions, whereas stabilization with jasplakinolide or overexpression of β- or γ-actin conjugated to yellow fluorescent protein (YFP) inhibited secretion. Myristoylated alanine-rich C kinase substrate, a PKC-activated actin-plasma membrane tethering protein, was phosphorylated after agonist stimulation, suggesting a translocation to the cytosol. Scinderin (or adseverin), a Ca2+-activated actin filament severing and capping protein was cloned from human airway and SPOC1 cells, and synthetic peptides corresponding to its actin-binding domains inhibited mucin secretion. We conclude that actin filaments negatively regulate mucin secretion basally in airway goblet cells and are dynamically remodeled in agonist-stimulated cells to promote exocytosis.

The cytoskeleton as a barrier to exocytosis in secretory cells

1988 ◽  
Vol 139 (1) ◽  
pp. 253-266 ◽  
Author(s):  
D. Aunis ◽  
M. F. Bader
Keyword(s):  
Chromaffin Cells ◽  
Binding Proteins ◽  
Secretory Granules ◽  
Actin Binding ◽  
Bacterial Toxin ◽  
Secretory Cells ◽  
Free Access ◽  
Actin Binding Proteins ◽  
Permeabilized Cells ◽  
Cytoskeletal Network

Chromaffin cells of the adrenal medulla synthesize, store and secrete catecholamines. These cells contain numerous electron-dense secretory granules which discharge their contents into the extracellular space by exocytosis. The subplasmalemmal area of the chromaffin cell is characterized by the presence of a highly organized cytoskeletal network. F-Actin seems to be exclusively localized in this area and together with specific actin-binding proteins forms a dense viscoelastic gel; fodrin, vinculin and caldesmon, three actin cross-linking proteins, and gelsolin, an actin-severing protein, are found in this subplasmalemmal region. Since fodrin-, caldesmon- and alpha-actinin-binding sites exist on secretory granule membranes, actin filaments can also link secretory granules. Chromaffin granules can be entrapped in this subplasmalemmal lattice and thus the cytoskeleton acts as a barrier preventing exocytosis. When cells are stimulated, molecular rearrangements of the subplasmalemmal cytoskeleton take place: F-actin depolymerizes and fodrin reorganizes into patches. In addition, introduction of monospecific antifodrin immunoglobulins into digitonin-permeabilized cells blocks exocytosis, demonstrating the crucial role of this actin-binding protein. In bacterial toxin-permeabilized chromaffin cells, experiments using actin-perturbing agents such as cytochalasin D and DNAase I suggest that exocytosis is in part controlled by the cytoskeleton. The intracellular signal governing the cytoskeletal reorganization (associated with exocytosis) is calcium. Calcium inhibits some and activates other actin-binding proteins and consequently causes dissolution of the subplasmalemmal cytoskeleton. This dissolution of cytoskeletal filaments should result in granule detachment and permit granules free access to exocytotic sites on the plasma membrane.

Experimental Data on the Function of the Interstitium of the Gonads: Experiments with Cockerels

1947 ◽  
Vol s3-88 (2) ◽  
pp. 135-150
Author(s):  
J. W. SLUITER ◽  
G. J. VAN OORDT
Keyword(s):  
Experimental Data ◽  
Connective Tissue ◽  
Leydig Cells ◽  
Cell Types ◽  
Sex Hormone ◽  
Secretory Cells ◽  
Secretory Function ◽  
Glandular Cells ◽  
Male Sex ◽  
Secondary Function

1. The relative volumes of the testes and their components of 31 cockerels, 2-200 days old, were calculated and compared with the size of their increasing head appendages (Text-figs. 1a-d, 2); in addition, the effect of gestyl-administration on testes of cockerels of this age was investigated. 2. Several types of interstitial testis-cells could be distinguished morphologically and physiologically (Text-figs. 3-6 and Pl. 1); these cell-types were studied with different techniques and counted separately. 3. The main types of the interstitial cells are: (a) Lipoid cells, totally packed with lipoid globules. These cells, which are considered by many authors as fully developed Leydig cells, are not directly connected with the production of the male sex hormone; perhaps they have a secondary function in this respect, as cholesterolderivatives are stored in these cells (Pl. 1, Text-fig. 3a). (b) Secretory cells, characterized by the absence of lipoid vacuoles and the presence of numerous granular and filamentous mitochondria. These secretory cells, which produce the male sex hormone, can be divided into secretory cells A (Text-fig. 6a) without, and secretory cells B with, one large vacuole (Text-figs. 6b, 6c, 6d). 4. A considerable and partly intercellular storage of lipoids may take place at any age in the intertubular connective tissue (Text-figs. 3-4 and Pl. 1). 5. The number of the lipoid cells depends on the nutritive conditions of the animal and the development of its testes (Text-fig. 7). 6. In older cockerels most of the glandular cells lose their secretory function and pass over into lipoid storing cells. 7. Therefore we agree with Benoit, when he denies the occurrence of a ‘secretion de luxe’, but we cannot accept the presence of a ‘parenchyme de luxe’ in the testes of older cockerels.

scholarly journals A novel function for Rab proteins during maturation of secretory granules

2021 ◽  
Author(s):  
Sarah D Neuman ◽  
Annika R Lee ◽  
Jane E Selegue ◽  
Amy T Cavanagh ◽  
Arash Bashirullah
Keyword(s):  
Salivary Glands ◽  
Secretory Granule ◽  
Secretory Granules ◽  
Secretory Cells ◽  
Rab Proteins ◽  
Dependent Manner ◽  
Rab Gtpases ◽  
Cargo Proteins ◽  
Granule Maturation ◽  
Granule Growth

Regulated exocytosis is an essential process whereby professional secretory cells synthesize and secrete specific cargo proteins in a stimulus-dependent manner. Cargo-containing secretory granules are synthesized in the trans-Golgi Network (TGN); after budding from the TGN, granules undergo many modifications, including a dramatic increase in size. These changes occur during a poorly understood process called secretory granule maturation. Here we leverage the professional secretory cells of the Drosophila larval salivary glands as a model system to characterize a novel and unexpected role for Rab GTPases during secretory granule maturation. We find that secretory granules in the larval salivary glands increase in size ~300-fold between biogenesis and release, and loss of Rab1 or Rab11 dramatically reduces granule size. Surprisingly, we find that Rab1 and Rab11 protein localize to secretory granule membranes. Rab11 associates with granule membranes throughout the maturation process, and Rab11 is required for recruitment of Rab1. In turn, Rab1 associates specifically with immature secretory granules and drives granule growth. In addition to their roles in granule growth, both Rab1 and Rab11 appear to have additional roles during exocytosis; Rab11 function is necessary for exocytosis, while the presence of Rab1 on immature granules may prevent precocious exocytosis. Overall, these results highlight a new and unexpected role for Rab GTPases in secretory granule maturation.

scholarly journals FACTORS INFLUENCING THE INTERMITTENT PASSAGE OF LOCKE'S SOLUTION INTO LIVING SKIN

1941 ◽  
Vol 73 (1) ◽  
pp. 85-108 ◽  
Author(s):  
Philip D. McMaster
Keyword(s):  
Connective Tissue ◽  
Blood Vessels ◽  
Atmospheric Pressure ◽  
Interstitial Fluid ◽  
Lymphatic Vessels ◽  
Intermittent Flow ◽  
Venous Obstruction ◽  
Factors Influencing ◽  
Interstitial Connective Tissue ◽  
Living Mouse

Minute amounts of Locke's or Tyrode's solution have been brought into contact with the interstitial connective tissue of the skin of the living mouse, at atmospheric pressure, in such a manner that the blood or lymphatic vessels are not entered directly. Under such circumstances these absorbable fluids enter the tissue spontaneously. Entrance is strikingly intermittent, not continuous, and so too when very slight pressures are brought to bear on the fluids (1). Hyperemia of the tissues, with accompanying dilatation of the blood vessels, increases the entrance of fluids at atmospheric pressure but it is still intermittent. By contrast, venous obstruction leads to intermittent backflow into the apparatus, but reflex hyperemia, following release of the obstruction, is attended by an increase of flow into the tissues in spite of the great reactive dilatation of vessels. The inflow is also intermittent. If the skin is deprived of circulation, fluid does not enter it at all at atmospheric pressure, though it moves in regularly and continuously if slight pressure is put upon it. Edema-forming fluids, described in the text, also enter in a continuous manner when forced into the skin of either living or dead animals. So too do serum and sperm oil. The findings indicate that the passage of interstitial fluid into the blood vessels may be intermittent under normal circumstances and its escape from them as well. The observed occurrence of intermittent flow in the blood vessels of several tissues (9, 15–25) will go far to account for the intermittent entrance of fluid into the skin.

Cell membrane-associated proteoglycans mediate extramedullar myeloid proliferation in granulomatous inflammatory reactions to schistosome eggs

1993 ◽  
Vol 104 (2) ◽  
pp. 477-484
Author(s):  
M. Alvarez-Silva ◽  
L.C. da Silva ◽  
R. Borojevic
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Connective Tissue ◽  
Endogenous Growth ◽  
Cell Lines ◽  
Cell Layer ◽  
Heparan Sulphate ◽  
Myeloid Cells ◽  
Myeloid Cell ◽  
Gm Csf

In chronic murine schistosomiasis, extramedullar myelopoiesis was observed, with proliferation of myeloid cells in liver parenchyma and in periovular granulomas. We have studied the question of whether cells obtained from granulomatous connective tissue may act as myelopoietic stroma, supporting long-term myeloid proliferation. Primary cell lines (GR) were obtained in vitro from periovular granulomas, induced in mouse livers by Schistosoma mansoni infection. These cells were characterized as myofibroblasts, and represent liver connective tissue cells involved in fibro-granulomatous reactions. They were able to sustain survival and proliferation of the multipotent myeloid cell lines FDC-P1 and DA-1 (dependent on interleukin-3 and/or granulocyte-macrophage colony stimulating factor, GM-CSF) without the addition of exogenous growth factors. This stimulation was dependent upon myeloid cell attachment to the GR cell layer; GR cell-conditioned medium had no activity. Primary murine skin fibroblasts could not sustain myelopoiesis. The endogenous growth-factor was identified as GM-CSF by neutralization assays with monoclonal antibodies. The stimulation of myelopoiesis occurred also when GR cells had been fixed with glutardialdehyde. The observed stimulatory activity was dependent upon heparan sulphate proteoglycans (HSPGs) associated with GR cell membranes. It could be dislodged from the cell layer with heparin or a high salt buffer. Our results indicate a molecular interaction between endogenous growth-factor and HSPGs; this interaction may be responsible for the stabilization and presentation of growth factors in myelopoietic stromas, mediating extramedullar proliferation of myeloid cells in periovular granulomas.

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