The fine structure of Verson's glands in molting larvae of Calpodes ethlius (Hesperiidae, Lepidoptera)

1973 ◽  
Vol 51 (11) ◽  
pp. 1201-1210 ◽  
Author(s):  
Joan Lai-Fook
Keyword(s):  
Fine Structure ◽  
Secretory Cell ◽  
Duct Cell ◽  
Secretory Cells ◽  
Dense Granules ◽  
Cell Processes ◽  
Residual Bodies

The three cells which make up Verson's glands in Calpodes undergo drastic changes as they produce the cuticular linings and the secretions of the glands. The duct cell secretes only the typical cuticular duct. The saccule cell produces both the atypical cuticular saccule and dense granules which are discharged just before ecdysis. The secretory cell is much enlarged by vacuoles which remain separate until they too are discharged before ecdysis. Dense granules are also produced by the secretory cell. During deposition of the cuticular duct and saccule, their lumina arc packed with cell processes containing microtubules, which appear to arise from centrioles. Isolation and residual bodies appear in both the saccule and secretory cells even before discharge of their secretions.

Anatomy, ultrastructure, and functional morphology of the metathoracic tracheal defensive glands of the grasshopper Romalea guttata

1991 ◽  
Vol 69 (8) ◽  
pp. 2100-2108 ◽  
Author(s):  
Douglas W. Whitman ◽  
Johan P. J. Billen ◽  
David Alsop ◽  
Murray S. Blum
Keyword(s):  
Secretory Cell ◽  
Tactile Stimulation ◽  
Defensive Secretion ◽  
Smooth Endoplasmic Reticulum ◽  
Duct Cell ◽  
Secretory Cells ◽  
Glandular Tissue ◽  
Golgi Bodies ◽  
Romalea Guttata ◽  
Defensive Glands

In the lubber grasshopper Romalea guttata, the respiratory system produces, stores, and delivers a phenolic defensive secretion. The exudate is secreted by a glandular epithelium surrounding the metathoracic spiracular tracheal trunks. Embedded in the glandular tissue are multiple secretory units, each comprised of a basal secretory cell and an apical duct cell. Secretory cells have numerous mitochondria, a tubular, smooth endoplasmic reticulum, well-developed Golgi bodies, and a microvillilined vesicle thought to transfer secretion to the intracellular cuticular duct of a duct cell. Ducts empty into the metathoracic tracheal lumina where the exudate is stored behind the closed metathoracic spiracle. Tactile stimulation elicits secretion discharge, which begins when all spiracles except the metathoracic pair are closed and the abdomen is compressed. Increased hemostatic and pneumatic pressures drive air and secretion out of the spiracle with an audible hiss. Both metathoracic spiracles discharge simultaneously. The secretion erupts first as a dispersant spray, then as an adherent froth, and finally assumes the form of a slowly evaporating repellent droplet. Discharge force and number vary with eliciting stimuli, volume of stored secretion, and age, disturbance state, and temperature of the insect. Molting grasshoppers are unable to discharge because the stored exudate is lost with the shed cuticle. The advantages and limitations of a tracheal defensive system are discussed.

Novel exocrine glands in the hindleg tarsi of the ant Nothomyrmecia macrops

2000 ◽  
Vol 48 (6) ◽  
pp. 661 ◽  
Author(s):  
Johan Billen ◽  
Fuminori Ito ◽  
Christian Peeters
Keyword(s):  
Golgi Apparatus ◽  
Secretory Cell ◽  
Anterior Part ◽  
Duct Cell ◽  
Exocrine Gland ◽  
Secretory Cells ◽  
Exocrine Glands ◽  
The Third ◽  
Duct Cells

The third tarsomere of the hindlegs of both workers and queens of Nothomyrmecia macrops is almost entirely filled with a hitherto unknown exocrine gland (which does not occur in the closely related Myrmecia). Each of the approximately 30 secretory cells is connected to the outside via a duct cell. These open individually via large cuticular pores at the mesoventral side of the anterior part of the tarsomere. The diameter of the duct cells is narrow near the secretory cell, but gradually increases towards their opening site. The rounded secretory cells show a well developed Golgi apparatus and numerous clear vesicles. The function of this gland is not yet known, although its opening site may be indicative of the deposition of marking substances. At the mediodistal side of tarsomeres 2, 3 and 4 in the three pairs of legs, a glandular thickening of the epidermal epithelium occurs; this represents another novel exocrine structure in ants. This epithelial gland occurs in both Nothomyrmecia and Myrmecia.

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.

Fine structure of the regressing interdigital membranes during the formation of the digits of the chick embryo leg bud

Development ◽  
1983 ◽  
Vol 78 (1) ◽  
pp. 195-209
Author(s):  
J. M. Hurle ◽  
M. A. Fernandez-Teran
Keyword(s):  
Extracellular Matrix ◽  
Fine Structure ◽  
Chick Embryo ◽  
Basal Lamina ◽  
Ultrastructural Study ◽  
Active Role ◽  
Epithelial Tissue ◽  
Complex Process ◽  
Cell Processes ◽  
Collagenous Material

There is recent evidence showing that in addition to the well-known mesenchymal necrotic mechanism involved in the disappearance of the interdigital membranes, the ectodermal tissue may also play an active role in the formation of the free digits of most vertebrates. Ultrastructural study of the regressing interdigital membrane of the chick leg revealed significant changes at the epitheliomesenchymal interface. Disruptions of the ectodermal basal lamina and an intense deposition of collagenous material were the most conspicuous changes observed in the extracellular matrix. In addition the basal ectodermal cells showed prominent cell processes projected into the mesenchymal core of the membrane, and mesenchymal macrophages appeared to migrate through the epithelial tissue to be detached into the amniotic sac. It is concluded from our results that the elimination of the interdigital membranes is a complex process requiring the interaction of all the tissue components of the membrane.

Sensitivity of mammary secretory cell turnover to protein restriction and re-alimentation during early lactation

1997 ◽  
Vol 1997 ◽  
pp. 130-130
Author(s):  
M.G. Goodwill ◽  
N.S. Jessop ◽  
J.D. Oldham
Keyword(s):  
Cell Proliferation ◽  
Mammary Gland ◽  
Milk Production ◽  
Secretory Cell ◽  
Protein Restriction ◽  
Secretory Cells ◽  
Early Lactation ◽  
Cell Turnover ◽  
Lactational Performance

Milk production depends on both the number and activity of secretory cells within the mammary gland. Our earlier work showed the sensitivity of lactational performance to changes in diet during lactation (Goodwill et al, 1996). This study investigated the influence of protein undernutrition and re-alimentation on secretory cell proliferation and death in the mammary gland of rats during early lactation.

Describing the lactation curve of dairy animals

1999 ◽  
Vol 1999 ◽  
pp. 197-197 ◽  
Author(s):  
G. E. Pollott
Keyword(s):  
Secretory Cell ◽  
Empirical Models ◽  
Secretory Cells ◽  
Cell Numbers ◽  
Biological Meaning ◽  
Lactation Curve ◽  
Dairy Animals ◽  
The Difference ◽  
Daily Milk Yield ◽  
Daily Milk

Most functions used to describe the lactation curve of dairy animals are empirical in approach and result in parameters with little or no biological meaning. A new model for describing lactation based on the biology of the pregnant and lactating animal is proposed and compared to several empirical models (Wood, 1967; Grossman and Koops, 1988; Morant and Gnanasakthy, 1989).Lactation is thought of as the balance between an increase in secretory cell numbers (NSCP) and their later decline (NSCD). The difference between them is the number of active secretory cells, each of which secretes milk at a particular rate (S kg/cell/day). Thus daily milk yield (MY) = (NSCP – NSCD) x S.

scholarly journals The Fine Structure of Some Blood Vessels of the Earthworm, Eisenia foetida

1960 ◽  
Vol 7 (4) ◽  
pp. 717-724 ◽  
Author(s):  
Kiyoshi Hama
Keyword(s):  
Fine Structure ◽  
Basement Membrane ◽  
Body Wall ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Eisenia Foetida ◽  
Longitudinal Muscle Layer ◽  
Cell Processes ◽  
Body Wall Musculature ◽  
Blood Pigment

The fine structure of the main dorsal and ventral circulatory trunks and of the subneural vessels and capillaries of the ventral nerve cord of the earthworm, Eisenia foetida, has been studied with the electron microscope. All of these vessels are lined internally by a continuous extracellular basement membrane varying in thickness (0.03 to 1 µ) with the vessel involved. The dorsal, ventral, and subneural vessels display inside this membrane scattered flattened macrophagic or leucocytic cells called amebocytes. These lie against the inner lining of the basement membrane, covering only a small fraction of its surface. They have long, attenuated branching cell processes. All of these vessels are lined with a continuous layer of unfenestrated endothelial cells displaying myofilaments and hence qualifying for the designation of "myoendothelial cells." The degree of muscular specialization varies over a spectrum, however, ranging from a delicate endowment of thin myofilaments in the capillary myoendothelial cells to highly specialized myoendothelial cells in the main pulsating dorsal blood trunk, which serves as the worm's "heart" or propulsive "aorta." The myoendothelial cells most specialized for contraction display well organized sarcoplasmic reticulum and myofibrils with thick and thin myofilaments resembling those of the earthworm body wall musculature. In the ventral circulatory trunk, circular and longitudinal myofilaments are found in each myoendothelial cell. In the dorsal trunk, the lining myoendothelial cells contain longitudinal myofilaments. Outside these cells are circular muscle cells. The lateral parts of the dorsal vessels have an additional outer longitudinal muscle layer. The blood plasma inside all of the vessels shows scattered particles representing the circulating earthworm blood pigment, erythrocruorin.

The absorptive surfaces of Nectonema sp. (Nematomorpha: Nectonematoidea) from Pandalus montagui: histology, ultrastructure, and absorptive capabilities of the body wall and intestine

1988 ◽  
Vol 66 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Barbara Skaling ◽  
B. M. MacKinnon
Keyword(s):  
Body Wall ◽  
The Body ◽  
Secretory Cells ◽  
Intestinal Cells ◽  
Dense Granules ◽  
Blind Ending ◽  
Carrier Mediated Transport ◽  
Passamaquoddy Bay ◽  
Juvenile Stages

The histology, ultrastructure, and absorptive capabilities of the body wall and intestine of the juvenile stages of Nectonema sp. (Nematomorpha: Nectonematoidea) that parasitize the shrimp Pandalus montagui in Passamaquoddy Bay, New Brunswick, were examined using histological, histochemical, ultrastructural, and in vitro labeling techniques. The body wall consists of a multilayered cuticle that rests on, and is produced by, a thin cellular hypodermis. The intestinal tract consists of a minute mouth, a cuticularized oesophagus, and a blind-ending intestine consisting of a lumen surrounded at different places by two, three, or four elongated cells. These cells consists of a maximum of two "absorptive" cells with microvillar luminal surfaces, and a maximum of two "secretory" cells, which contain numerous electron-dense granules. Acid and alkaline phosphatases and nonspecific esterases were detected in the outer layers of the body wall (cuticle and hypodermis) and in the intestinal cells. Such enzymes appear to be related to absorption of nutrient substances. Autoradiography experiments using [3H]leucine showed that following incubation in [3H]leucine-labeled seawater, leucine was concentrated in the hypodermis and the intestinal cells. Similar results were obtained when worms were incubated first in [3H]leucine-labeled seawater and then chased in nonlabeled L-leucine. Uptake of [3H]leucine was inhibited by L-leucine when worms were incubated in a seawater solution of [3H]leucine and excess L-leucine. In vitro absorption of [3H]leucine provides evidence that a carrier-mediated transport system operates across both the cuticle and the intestine of Nectonema sp.

scholarly journals Knockdown of p180 Eliminates the Terminal Differentiation of a Secretory Cell Line

2009 ◽  
Vol 20 (2) ◽  
pp. 732-744 ◽  
Author(s):  
Payam Benyamini ◽  
Paul Webster ◽  
David I. Meyer
Keyword(s):  
Cell Line ◽  
Mammalian Cells ◽  
Secretory Cell ◽  
Terminal Differentiation ◽  
Secretory Cells ◽  
Rnai Technology ◽  
Apo E ◽  
Secretory Phenotype ◽  
Rough Er ◽  
Necessary And Sufficient

We have previously reported that the expression in yeast of an integral membrane protein (p180) of the endoplasmic reticulum (ER), isolated for its ability to mediate ribosome binding, is capable of inducing new membrane biogenesis and an increase in secretory capacity. To demonstrate that p180 is necessary and sufficient for terminal differentiation and acquisition of a secretory phenotype in mammalian cells, we studied the differentiation of a secretory cell line where p180 levels had been significantly reduced using RNAi technology and by transiently expressing p180 in nonsecretory cells. A human monocytic (THP-1) cell line, that can acquire macrophage-like properties, failed to proliferate rough ER when p180 levels were lowered. The Golgi compartment and the secretion of apolipoprotein E (Apo E) were dramatically affected in cells expressing reduced p180 levels. On the other hand, expression of p180 in a human embryonic kidney nonsecretory cell line (HEK293) showed a significant increase in proliferation of rough ER membranes and Golgi complexes. The results obtained from knockdown and overexpression experiments demonstrate that p180 is both necessary and sufficient to induce a secretory phenotype in mammalian cells. These findings support a central role for p180 in the terminal differentiation of secretory cells and tissues.

scholarly journals Histological and histochemical aspects of the penial glands of Girardia biapertura Sluys, 1997 (Platyhelminthes, Tricladida, Paludicola)

2002 ◽  
Vol 62 (3) ◽  
pp. 547-555 ◽  
Author(s):  
S. T. SOUZA ◽  
A. M. LEAL-ZANCHET
Keyword(s):  
Secretory Cell ◽  
Ejaculatory Duct ◽  
Distal Portion ◽  
Proximal Region ◽  
Secretory Cells ◽  
Type I ◽  
Type Ii ◽  
Cell Type ◽  
Median Region

Girardia biapertura was described with sperm ducts penetrating the penis bulb, subsequently opening separately at the tip of the penis papilla and receiving the abundant secretion of penial glands. In the present work, the penial glands of this species have been histologically and histochemically analysed, and four types of secretory cells are distinguished. The openings of the penial glands into the intrabulbar and intrapapillar sperm ducts, designated here as intrapenial ducts, allow for the distinction between three histologically differentiated regions. The most proximal region possibly corresponds to the bulbar cavity of other freshwater triclads whereas the median and distal portions correspond to the ejaculatory duct. The proximal region of the intrapenial ducts receives mainly the openings of a secretory cell type (type I) that produces a proteinaceous secretion. A second type of secretory cell (type II) that secretes neutral mucopolyssacharides opens into the median region of the intrapenial ducts. The distal portion of the ducts receives two types of secretory cells (types III and IV) which secret glycoprotein and glycosaminoglycans, respectively. Types III and IV open also directly into the male atrium through the epithelium of the penis papilla. A comparison with the results presented here and those of other authors for species of Girardia is provided and the importance of the study of the penial glands for taxonomic characterisation of freshwater triclads is emphasised.

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