Fine structure of compound eyes of cicindela tranquebarica herbst (coleoptera: cicindelidae)

1978 ◽  
Vol 36 (2) ◽  
pp. 604-605
Author(s):  
Janice E. Kuster
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Cell Nucleus ◽  
The Other ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Basal Bodies ◽  
Protein Deposits ◽  
Corneal Lens

The fine structure of photopic eucone eyes of Cicindela tranquebarica adults was examined using cryofracture SEM, TEM, and freeze-etch techniques. A “subcorneal layer” can be distinguished between the corneal lens and crystalline cone. In surface view (Fig. 1) this layer consists of concave polygons (po). It has parabolic lamellae (lm) of endocuticle consisting of microfibrils (mf) having a chitin core with protein deposits along their lengths (Fig. 2). Two primary pigment cells (lp) are devoid of pigment granules, but are rich in rough endoplasmic reticulum (rer) and surround a crystalline thread (ct) (Fig. 3). Extensions of the crystalline thread form inter-retinular fibers (f) containing microtubules between retinula cells 1/2, 3/4, 5/6, and 7/1 (Figs. 4, 5).Distal to each retinula cell nucleus are two basal bodies (bb), one perpendicular to the other (Fig. 4). The proximal body extends two fibrillar feet which fuse to form a horizontally banded ciliary rootlet which extends the retinula length peripheral to the rhabdom.

The Fine Structure of Primordial Germ Cells of the Rat

1973 ◽  
Vol 31 ◽  
pp. 634-635
Author(s):  
E. M. Eddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Life History ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Germ Cells ◽  
Fibrous Material ◽  
Primordial Germ Cells ◽  
The Other ◽  
Large Size ◽  
History Of

Primordial germ cells are readily recognizable in embryos of the rat due to their large size, generally rounded shape and prominent nuclei with uniformly dispersed heterochromatin. They often have blunted pseudopodal processes at one end and small ruffles or trailing processes at the other, characteristics expected from their known ameboid activity- and migratory abilities. Also, the cytoplasm is rich in polyribosomes and contains a modest amount of rough endoplasmic reticulum and the mitochondria are frequently larger and less dense than those of adjacent somatic cells.In addition to these general characteristics, there are features unique to germ cells which allow them to be identified with certainty. These are: 1) small vesicles containing an irregular, dense core and 2) discrete accumulations of fibrous material known as nuage. Both of these features are present in other species and at other times in the life history of germ cells. The dense-cored vesicles have been noted in fetal and early postnatal mouse oogonia and oocytes, and in hamster and rabbit oocytes.

The fine structure of the leucocytes of the holothurian, Cucumaria miniata

1977 ◽  
Vol 55 (9) ◽  
pp. 1530-1544 ◽  
Author(s):  
A. R. Fontaine ◽  
Philip Lambert
Keyword(s):  
Stem Cells ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Acid Mucopolysaccharide ◽  
Rough Er

The fine structure of amoebocytes, lymphocytes, and morula cells is described and related to their functions. Three morphological phases (bladder, transitional, and filiform) of the amoebocyte are distinguished. Their surface protrusions and activities are based on microtubule and microfilament systems and the transitional-filiform phases are functionally involved in coelomocyte aggregation. The bladder phase is phagocytic; bladder formation and activities are also microfilament based. Morula cells contain spherules composed of acid mucopolysaccharide and protein. Dilated rough endoplasmic reticulum (ER) cisternae apparently synthesize spherule material which is added by accretion. Lymphocytes have little cytoplasm and relatively few organelles, except for abundant rough ER and free ribosomes. Lymphocytes are probably stem cells for amoebocytes and morulas. These cells are compared with the leucocytes of other echinoderms.

Freeze-Fracture Replication of Rough Endoplasmic Reticulum of Mouse Liver Cells

1972 ◽  
Vol 11 (2) ◽  
pp. 477-489
Author(s):  
A. S. BREATHNACH ◽  
C. STOLINSKI ◽  
M. GROSS
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Mouse Liver ◽  
Freeze Fracture ◽  
The Other ◽  
Fracture Face ◽  
Mitochondrial Membranes ◽  
En Face

Fresh, chemically unfixed, glycerinated specimens of mouse liver were examined by the technique of freeze-fracture replication without sublimation (i.e. they were not ‘etched’). Where extensive areas of fractured lamellar membranes of the rough endoplasmic reticulum are revealed en face, 2 types of fracture face are distinguishable. One of these fracture faces (A) is directed towards the cytoplasm, and the other (B) towards the cisternal cavity. A characteristic mosaic, or patchwork pattern of flat areas circumscribed by particles, is evident on both faces, and more clearly so on face B, due to a greater number of more prominent particles. Similar mosaic patterns are revealed on convex faces of the nuclear membrane, and on concave fracture faces of mitochondrial membranes, but are not evident on fracture faces of the plasma membrane. Uncertainty in establishing the exact plane of fracture of membranes in this material, since glycerol is virtually non-sublimable, makes it difficult to assess the significance of these mosaic patterns. The fact that ribosomes are not identifiable on either face of fractured endoplasmic reticulum membranes, gives no certain indication of the plane of fracture.

Ultrastructural changes in tissues of larval Elateridae (Coleoptera) infected with the fungus Metarrhizium anisopliae

1971 ◽  
Vol 17 (2) ◽  
pp. 281-289 ◽  
Author(s):  
R. Y. Zacharuk
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Fat Body ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
The Other ◽  
Host Cells ◽  
Ultrastructural Changes ◽  
Host Death ◽  
Host Tissues

The ultrastructural changes that occur in the cells of the hypodermis, fat body, Malpighian tubule, midgut, ventral abdominal ganglion, and muscle during mycoses in three species of elaterid larvae infected with Metarrhizium anisopliae are described. The fungus penetrated all the above tissues before host death in most of the larvae examined. In some infected larvae, however, particularly in the smaller individuals or species, only the hypodermal and fat tissues were penetrated before death. Changes in fine structure appear in all the tissues soon after the fungus enters the hemocoel, even when no fungal growths are present near the host cells. In general, there is initially an increase in the number of lysosomes and of endoplasmic reticulum and ribosomes, followed by a vesiculation of the endoplasmic reticulum and of the cristae of the mitochondria and a progressive vacuolation of the cytoplasm. In some tissues the mitochondria increase in number before vesiculation. Glycogen granules and lipid and oil inclusions disappear rapidly during mycosis. Clear, membrane-limited vacuoles become particularly abundant in the Malpighian tubules and the midgut, suggesting increased secretion of fluids into their lumens. At or soon after death, the lysosomes disappear and all the membranous structures of the cells are disrupted, and laminated or whorled bodies of thickened membranes become numerous. Disintegration of all tissues, including muscle and nerve, was extensive in some larvae that were still capable of some sluggish movement before fixation for the study. It is suggested that the fungus incites lysosome production by the host tissues along with the other initial changes observed, and that final disintegration of the host tissues is by a process of autohistolysis.

On the morphology and fine structure of the alimentary canal of Corophium volutator (Pallas) (Crustacea: Amphipoda)

1984 ◽  
Vol 306 (1126) ◽  
pp. 49-78 ◽  
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
B Cells ◽  
Rough Endoplasmic Reticulum ◽  
Digestive Enzymes ◽  
Dense Matrix ◽  
Corophium Volutator ◽  
Pyloric Region ◽  
Anterior Dorsal ◽  
Apical Complex

In the mud-dwelling amphipod, Corophium volutator the foregut is lined with cuticle and consists of an oesophagus and a stomach, with the latter divided into cardiac, pyloric and funnel regions. The midgut comprises an intestine that is enlarged considerably by three pairs of diverticula: the small anterior dorsal and posterior caeca and the massive ventral caeca. Anteriorly, the intestine encompasses the funnel region and the ventral caeca open into the floor of the stomach at the posterior end of the pyloric region. The hindgut is essentially a simple tube connnecting the intestine with the anus. Particles of food pass along the oesophagus and enter the stomach through a valve. Rows of setae, or folds of cuticle, divide the stomach longitudinally into food, circulation and filtration channels. Ingested particles with a diameter greater than 2 pm are confined to the food channel and supplied with fluids and enzymes from the circulation channels. The digestive enzymes are produced primarily by the ventral caeca and are supplied to the circulation channels through a valve at the entrance of each ventral caecum. Any fine particles and soluble materials extracted from the food channel in the cardiac region are transported into the filtration channels through the first filter of a two part system. Digestible material continues to be extracted in the pyloric region where the volume of the lumen of the food channel is reduced by the intrusion of the vertex of the ventral pyloric ridge. The basis of this ridge supports the second filter which produces a filtrate with particles less than 0.06 pm in diameter. Material retained on the filter membrane is returned to the food channel by brush-like setae facing the membrane. The final filtrate is transported to the ventral caeca. A valve at the entrance to each ventral caecum prevents contamination of the filtrate by material in the food channel. All indigestible food is passed sequentially along the funnel, intestine and, finally, the hindgut from which it is voided as a faecal pellet. Most digestion and absorption occur in the ventral caeca where the epithelium is differentiated into the R /F and B cells. The R /F cells have a much thicker and denser microvillous border than the B cells. Each R /F cell also has numerous mitochondria located mainly ventral to the nucleus in the mid-region. Rough and smooth endoplasmic reticula are sited primarily in the apical and basal regions of the cell, respectively. Furthermore, most of the rough endoplasmic reticulum is confined to cells in the distal region of the caecum which probably forms the main site for the production of digestive enzymes. The proximal region of the caecum contains numerous lipid droplets and is probably involved in the absorption, transport and storage of the products of digestion. Each B cell has a single large, fluid-filled vacuole, distal to which are mitochondria and numerous smaller vacuoles of varying size forming an ‘apical complex’. The nucleus is located proximal to the vacuole together with free ribosomes and rough endoplasmic reticulum. Material from the lumen of the caecum is taken by pinocy tosis into the ‘apical complex’. The large vacuole develops at the expense of the ‘apical complex’ and the microvillous border. The vacuole is eventually liberated into the lumen of the caecum and the cell disintegrates. These discharges may supply enzymes to other regions of the gut, or they could be waste products derived from intracellular digestion. The anterior dorsal caeca and most of the intestine contain cells with a normal complement of organelles. These cells probably make a minor contribution to the processes of digestion and absorption. However, the cells of the posterior caeca and those at the posterior end of the intestine have an extensive development of smooth endoplasmic reticulum. In some cells the mitochondria have a dense matrix and there are only a few free ribosomes and cisternae of rough endoplasmic reticulum. The fine structure of the epithelium in the posterior caeca is typical of tissue that transports fluids and ions. The hindgut has a microvillous border which abuts its cuticular lining. In addition, some cells have numerous mitochondria which are often associated with infolds of the basal cell membrane. The fine structure of this tissue is similar to the ‘ion pumps’ described in the gut of insects which serve to maintain the normal ionic concentration of the blood. The posterior region of the hindgut has no structural specializations.

scholarly journals Ultrastructure of rhesus monkey renomedullary interstitial cells

1979 ◽  
Vol 13 (2) ◽  
pp. 75-80 ◽  
Author(s):  
David J. Lewis ◽  
David E. Prentice
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rhesus Monkey ◽  
Rough Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Stellate Cells ◽  
Interstitial Cells ◽  
Prominent Feature

Summary The fine structure of rhesus monkey renomedullary interstitial cells was studied by electron microscopy. These stellate cells contained variable numbers of lipid droplets, moderate numbers of mitochondria, moderate amounts of rough endoplasmic reticulum, and prominent Golgi zones. In rare instances, apparent release of lipid droplets into the interstitium was observed. The most prominent feature of the interstitial cells was large nuclear pseudoinclusions which were observed in a high proportion of the animals examined.

The fine structure of the developing macrogamete of Eimeria maxima

Parasitology ◽  
1979 ◽  
Vol 79 (2) ◽  
pp. 259-265 ◽  
Author(s):  
R. M. Pittilo ◽  
S. J. Ball
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Parasitophorous Vacuole ◽  
The Other ◽  
Granular Endoplasmic Reticulum ◽  
Type I ◽  
Type Ii ◽  
Eimeria Maxima ◽  
Lipid Inclusions

SUMMARYThe fine structure of the developing macrogamete of Eimeria maxima was studied from chicks killed at intervals from 138 to 147 h after inoculation. The macrogamete developed within a parasitophorous vacuole. Lying within this vacuole and extending for some distance around the periphery of the macrogamete were intravacuolar tubules, grouped in certain areas, and in some cases they were seen to make direct connexions with the cytoplasm of the parasite. During development, electron-pale vesicles were pinched off externally from the surface of the macrogamete. There appeared to be 2 forms of wall-forming bodies of the Type I during development, one form being less osmiophilic than the other. Other organelles present, such as wall-forming bodies of Type II, granular endoplasmic reticulum, mitochondria, canaliculi, lipid inclusions and intravacuolar folds, were similar in structure to those of other Eimeria species.

scholarly journals UNE FORME MICROTUBULAIRE ET PARACRISTALLINE DE RETICULUM ENDOPLASMIQUE DANS LES PHOTOCYTES DES ANNELIDES POLYNOINÆ

1966 ◽  
Vol 31 (1) ◽  
pp. 135-158 ◽  
Author(s):  
J. M. Bassot
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Nuclear Envelope ◽  
Contact Surface ◽  
Special Kind ◽  
The Other ◽  
Cytoplasmic Organelle ◽  
Specialized Form

Luminous cells of polynoid worm elytra have been examined by methods of electron microscopy, with special attention focused on the fine structure of photogenic grains. These cells send apical prolongations into the mid-part of the elytra. The plasma membrane is very sinuous, and a special kind of desmosome links two portions of the same membrane. In addition to all the organelles which can be found in nonluminescent epithelial cells of the elytra, numerous photogenic grains are contained in their cytoplasm. These grains are composed of undulating microtubules measuring 200 A in diameter; their disposition in the grain is highly regular, and the grains appear as paracrystals. At the borders of the grains, the walls of the microtubules are often in continuity with those of the endoplasmic reticulum and with the external membrane of the nuclear envelope. Because of this fact, the microtubules of the grains may be considered a cytoplasmic organelle, representing a specialized form of the endoplasmic reticulum. The microtubules permit the repartition, inside and outside their walls, of two different products, one being forty-three times more abundant than the other; thus, the contact surface, in comparison to the volume, is greatly increased. The induction of the luminous reaction by change in the permeability of the microtubule walls, allowing contact between the two substances, is suggested as a working hypothesis. There is an evolution of the grains along the axis of the photocytes. The grains are often surrounded by progressively increasing amounts of glycogen. Their paracrystalline disposition is altered at the apex of the luminous cells.

Alpha(S1)-casein is required for the efficient transport of beta- and kappa-casein from the endoplasmic reticulum to the Golgi apparatus of mammary epithelial cells

1999 ◽  
Vol 112 (19) ◽  
pp. 3399-3412 ◽  
Author(s):  
E. Chanat ◽  
P. Martin ◽  
M. Ollivier-Bousquet
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Mammary Epithelial Cells ◽  
Whey Proteins ◽  
Mammary Epithelial ◽  
The Other ◽  
Soluble Form ◽  
Beta Casein

In lactating mammary epithelial cells, interaction between caseins is believed to occur after their transport out of the endoplasmic reticulum. We show here that, in alpha(S1)-casein-deficient goats, the rate of transport of the other caseins to the Golgi apparatus is highly reduced whereas secretion of whey proteins is not significantly affected. This leads to accumulation of immature caseins in distended rough endoplasmic reticulum cisternae. Casein micelles, nevertheless, were still observed in secretory vesicles. In contrast, no accumulation was found in mammary epithelial cells which lack beta-casein. In mammary epithelial cells secreting an intermediate amount of alpha(S1)-casein, less casein accumulated in the rough endoplasmic reticulum, and the transport of alpha(S1)-casein to the Golgi occurred with kinetics similar to that of control cells. In prolactin-treated mouse mammary epithelial HC11 cells, which do not express alpha(S)-caseins, endoplasmic reticulum accumulation of beta-casein was also observed. The amount of several endoplasmic reticulum-resident proteins increased in conjunction with casein accumulation. Finally, the permeabilization of rough endoplasmic reticulum vesicles allowed the recovery of the accumulated caseins in soluble form. We conclude that optimal export of the caseins out of the endoplasmic reticulum is dependent upon alpha(S1)-casein. Our data suggest that alpha(S1)-casein interacts with the other caseins in the rough endoplasmic reticulum and that the formation of this complex is required for their efficient export to the Golgi.

Fine Structure of the Cytoplasm in Salivary Glands of Simulium

1967 ◽  
Vol 2 (1) ◽  
pp. 137-144
Author(s):  
H. C. MACGREGOR ◽  
J. B. MACKIE
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Nuclear Envelope ◽  
Salivary Glands ◽  
Rough Endoplasmic Reticulum ◽  
Salivary Secretion ◽  
Septate Junction ◽  
Cell Junctions ◽  
Salivary Gland Cell ◽  
Apical Cytoplasm

The salivary glands of 3rd or 4th instar larvae of Simulium niditifrons are about 5 mm long and up to 400 µ wide. They have a capacious lumen which is normally filled with secretion. The apical (luminal) plasmalemma of the gland cells is thrown into numerous microvilli. The basal plasmalemma is usually straight but is infolded in places. The infoldings may be complex near to cell junctions. There is a thick, uniform basement membrane. Contact surfaces of adjacent cells often interdigitate. A septate junction extends inwards from the lumen for one-quarter the depth of the cells. Rough endoplasmic reticulum is distributed evenly throughout the cytoplasm. Many Golgi complexes with dark membrane-bounded granules are scattered throughout the cytoplasm. Solitary granules, often more than I µ in diameter, lie in the apical cytoplasm, especially near the apical border of the cell. These granules resemble the larger Golgi granules and the contents of the lumen. Solitary granules consisting of 2 components have been seen in various stages of passage through the cell membrane. The 2 components are present in roughly constant proportions and can be identified in the larger Golgi granules and in the secretion in the lumen. The nucleus is spherical. The nuclear envelope is smooth in the larger cells of a gland but may be folded in the smaller cells. There are 80-100 pores/µ2 of nuclear envelope. Each pore appears to have a small granule at its centre. Microtubules, about 180 Å thick, are numerous in the apical cytoplasm, particularly near the luminal border. Tubules which lie deep in the cytoplasm are flanked by a clear area 100-200 Å wide. The fine structure of a salivary gland cell of Simulium appears to indicate that the major components of the salivary secretion are synthesized in association with the ribosomes on the rough endoplasmic reticulum, concentrated in the Golgi regions, formed into secretion granules, and passed out of the cell into the lumen of the gland by reverse phagocytosis.

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