The ultrastructure of the R.S. zoospore of the Chytridiomycete Physoderma gerhardti

1978 ◽  
Vol 56 (12) ◽  
pp. 1387-1393 ◽  
Author(s):  
Robert J. Lowry ◽  
Frederick K. Sparrow
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Inclusion Bodies ◽  
Smooth Endoplasmic Reticulum ◽  
Lipid Body ◽  
Dense Material ◽  
Electron Dense Material ◽  
General Internal ◽  
Deep Groove ◽  
Posterior Flagellum

The fine structure of the zoospore of Physoderma gerhardti Schroeter is described. It possesses a single very large lipid body (sometimes accompanied by several smaller ones) situated laterally to the nuclear cap – nucleus complex and is associated with electron-dense material (the microbody) and the single large posteriorly located mitochondrion. The single posterior flagellum proximally terminates in a kinetosome just short of the posterior cone-shaped end of the nucleus. The kinetosome lies in a deep groove in the mitochondrion and is associated with this organelle by striated rootlets. The kinetosome terminates in electron-dense material from which an array of microtubules arises. These microtubules run along the sides of the cone-shaped nucleus and nuclear cap. There is an accessory centriole lying close to and more or less parallel with the kinetosome. The cytoplasm contains a small amount of smooth endoplasmic reticulum and several inclusion bodies in the anterior region and several small vacuoles in the posterior region of the cell. The general internal organization of the zoospore of Physoderma gerhardti more nearly resembles that of a blastocladiaceous fungus than of any chytrid thus far investigated.

The apical structure in Perophora annectens (tunicate) spermatozoa: fine structure, differentiation and possible role in fertilization

1984 ◽  
Vol 66 (1) ◽  
pp. 175-187
Author(s):  
M. Fukumoto
Keyword(s):  
Fine Structure ◽  
Golgi Apparatus ◽  
Dense Material ◽  
Electron Dense Material ◽  
Extracellular Materials ◽  
Small Blister

The apical structure in Perophora annectens spermatozoa is approximately 4 micron in length and it is helically coiled. Its major component is a striated structure, which may be analogous to a perforatorium. The plasmalemma enclosing the anterior quarter of the apical structure is covered by extracellular materials, the anterior ornaments. During spermiogenesis, the apical structure is first recognized as a small blister of the plasmalemma at the apex of the young spermatid. It develops into a conical protrusion and then into a finger-like process (approximately 1 micron in length). This process is transformed into an elongated process (approximately 4 micron in length) with electron-dense material in its core. Finally, the elongated process is helically coiled to form an apical structure in which electron-dense material forms dense striations. Vesicles (50-70 nm in diameter), presumably derived from the Golgi apparatus, have been recognized in the blisters of younger spermatids, and can be followed through to the finger-like process. In the finger-like process these vesicles are transformed into smaller vesicles (20-30 nm in diameter), which probably fuse with the anterior plasmalemma of the finger-like process. This suggests that chorion lysin(s) is associated with the anterior membrane enclosing the apical structure in these spermatozoa.

Origine et formation de différents types de vacuoles induites par la multiplication d'Alphavirus Sindbis dans divers systemes cellulaires

1979 ◽  
Vol 25 (12) ◽  
pp. 1452-1459 ◽  
Author(s):  
Yves Lombard ◽  
Philippe Poindron ◽  
Aimé Porte
Keyword(s):  
Endoplasmic Reticulum ◽  
Glial Cells ◽  
Chicken Embryo ◽  
Cytoplasmic Membrane ◽  
Dense Material ◽  
Newborn Mice ◽  
Electron Dense Material ◽  
Double Membrane ◽  
Single Membrane ◽  
Chicken Embryo Fibroblasts

Spherule-containing vacuoles and nucleocapsid-bearing vacuoles (cytopathic vacuoles types 1 and 2 respectively of Grimley et al. 1968) induced by Alphavirus Sindbis were studied in brains from newborn mice, chicken embryo fibroblasts, and two lines of tumoral glial cells from muridae. Endoplasmic reticulum (ER) elements and finely granular electron-dense material also seen in contact with nucleocapsids seemed to be involved in the formation of the classical single-membrane spherule-containing vacuoles. A second type of spherule-containing vacuoles were characterized by their double membrane and an amorphous electron-dense content and were probably derived from mitochondria. Nucleocapsid-bearing vacuoles were formed from modified ER elements and seemed to be linked to excessive synthesis of viral material. Such ER alterations were not observed in RG6 cells. In these cells, there were only spherule-containing vacuoles, while nucleocapsids were seen associated with the cytoplasmic membrane only.

Aids: Tubuloreticular Structures (Trs), Cylindrical Confronting Cisternae (Ccc), and Related Alterations

1999 ◽  
Vol 5 (S2) ◽  
pp. 1092-1093
Author(s):  
Gurdip S. Sidhu ◽  
Nicholas D. Cassai
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Matrix Material ◽  
Cell Types ◽  
Test Tube ◽  
Endoplasmic Reticulum Membrane ◽  
Annulate Lamellae ◽  
Electron Dense Material ◽  
Tubuloreticular Inclusions ◽  
Tubuloreticular Structures

TRS and CCC are endoplasmic reticulum membrane-derived structures seen in HIV-infected individuals in a variety of cell types. TRS (synonym: tubuloreticular inclusions) are 24-25 nm in diameter, branching tubules which are short or long and associated with the granular or smooth endoplasmic reticulum, the Golgi complex, the perinuclear cistern, and annulate lamellae (Fig. 1-3, 8). The tubules are noticeably more stretched out in Kaposi's sarcoma endothelial cells, presumably by an increase of matrix material within the reticulum sac (Fig. 3). TRS consist of membranous components, including polypeptides, but lack nucleic acid.CCC (test tube and ring-shaped forms; curvilinear membranes) are formed by a concentric stacking of two or three cisterns of endoplasmic reticulum resembling nuclear membrane in mitosis (Fig. 7), but with the interposition between the opposing membranes of a layer of electron-dense material that is resistant to lipid solvents (Fig. 4,5,8).

Ontogeny of lipid bodies in the endoplasmic reticulum of Fusarium sulphureum

1977 ◽  
Vol 23 (2) ◽  
pp. 190-196
Author(s):  
Edward F. Schneider ◽  
W. L. Seaman
Keyword(s):  
Endoplasmic Reticulum ◽  
Higher Plants ◽  
Broad Band ◽  
Lipid Body ◽  
Lipid Bodies ◽  
Unit Membrane ◽  
Electron Dense Material ◽  
Fusarium Sulphureum ◽  
Body Development ◽  
Adverse Environmental Conditions

The ontogeny of lipid bodies during the differentiation of conidial cells to chlamydospores in Fusarium sulphureum (F. sambucinum f. 6) is described. The lipid bodies are first seen as electron-transparent areas within dilated cisternae of the endoplasmic reticulum (ER). One or more such cisternae may be formed within a strand of ER. The intracisternal lipid bodies are bounded by a unit membrane derived from the double membrane of the ER. The dilated cisternae increase in size and remain electron-transparent; however, some electron-dense granular material is present in the lipid bodies. The limiting unit membrane is visible throughout development of the lipid body; however, in mature chlamydospores the membrane is obscured by a broad band of electron-dense material which may provide protection to the stored lipids during adverse environmental conditions. The system of lipid body development in F. sulphureum is discussed in relation to those described for higher plants.

Fine structure of surface and sunken grooved pegs on the antenna of female Anopheles stephensi (Diptera: Culicidae)

1976 ◽  
Vol 54 (2) ◽  
pp. 235-244 ◽  
Author(s):  
K. S. Boo ◽  
S. B. McIver
Keyword(s):  
Fine Structure ◽  
Electron Density ◽  
Anopheles Stephensi ◽  
Olfactory Receptors ◽  
The Other ◽  
Dense Material ◽  
Extracellular Material ◽  
Electron Dense Material ◽  
Subtype B ◽  
Antenna Surface

The antenna of female Anopheles stephensi Liston bears three types of sensilla with grooved pegs: those sunken in pits and subtypes A and B of those located on the flagellar surface. The sunken peg sensilla are innervated by four or five neurons with branching dendrites. The dendrites are exposed to the exterior by means of longitudinal clefts at the bases of the grooves in the peg wall. Surrounding the dendrites and extending into the clefts is an extracellular material of medium electron density. Three sheath cells are associated with each sunken peg sensillum.Subtype-A surface peg sensilla are generally similar to the sunken peg sensilla, except that they are located on the antenna) surface and are innervated by two neurons with unbranched dendrites. Subtype-B surface peg sensilla have three or four neurons, the dendrites of which do not branch and are exposed less to the exterior than those in the other peg sensilla because the clefts in the peg wall are smaller and less frequent. Only trace amounts of electron-dense material occur in the clefts of the subtype-B surface peg sensilla.The sunken peg and both subtypes of the surface peg sensilla are probably olfactory receptors.

Fine structure of the thraustochytrid Ulkenia amoeboidea. II. The amoeboid stage and formation of zoospores

1982 ◽  
Vol 60 (7) ◽  
pp. 1103-1114 ◽  
Author(s):  
S. Raghu Kumar
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Fine Structure ◽  
Nuclear Division ◽  
Smooth Endoplasmic Reticulum ◽  
Dense Granule ◽  
Multivesicular Bodies ◽  
Golgi Bodies ◽  
Dense Bodies ◽  
Spindle Microtubules

In the thraustochytrid Ulkenia amoeboidea (Bahnweg & Sparrow) Gaertner the contents of the mature vegetative thallus escape from the cell wall in the form of a limax cell. The limax cell is covered by a layer of scales and possesses a nucleus, a paranuclear body, Golgi bodies, mitochondria, bands of smooth endoplasmic reticulum, vacuoles, multivesicular bodies, and cisternae with filamentous contents. The posterior end is filled with smooth endoplasmic reticulum and fusiform vesicles. The anterior end is organelle free and filled with cytoplasm with free ribosomes. Subspherical dense bodies, bounded by a single membrane, are present. The limax cell rounds up prior to mitosis and the Golgi bodies increase in number. During mitosis, the nuclear membrane breaks down totally. Chromosomes are not well defined. Spindle microtubules arise from the centriole and enter the nucleus. After nuclear division, the nuclear envelope is reformed. Cytokinesis is by cleavage into two cells, accompanied by formation of microtubules along the cleavage furrows. The zoospore possesses a nucleus, a paranuclear body, mitochondria, vesicles with presumptive mastigonemes and kinetosome rootlet microtubules and they are covered by a layer of scales. An electron-dense granule and two peripheral thickenings are present within the lumen of the kinetosome.

Fine structure of the spores of Minchinia chitonis (Lankester, 1885) Labbé, 1896 (Sporozoa: Haplosporida), a parasite of the chiton, Lepidochitona cinereus

Parasitology ◽  
1980 ◽  
Vol 81 (1) ◽  
pp. 169-176 ◽  
Author(s):  
S. J. Ball
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Morphological Study ◽  
Smooth Endoplasmic Reticulum ◽  
Spore Wall ◽  
Single Nucleus

SUMMARYA morphological study of the fine structure of the spores of Minchinia chitonis, a haplosporidian parasite of the chiton, Lepidochitona cinereus, is described. The spores contained a single nucleus, mitochondria, haplosporosomes, smooth endoplasmic reticulum, ribosomes and a large spherule (presumed Golgi apparatus). The spore wall was discontinuous at the spherule end, forming an opening covered by a lid which rested on a circumscribed flange. The flange of the spore wall and the lid were continuous in only one area which served as a hinge. The entire spore was encapsulated by epispore cytoplasm bounded by a strengthened membrane and extended to form 2 long projections, one at either end.

Morphology and Ultrastructure of the Dufours and Venom Gland in the Ant Myrmecia-Gulosa (Fabr) (Hymenoptera, Formicidae)

1990 ◽  
Vol 38 (3) ◽  
pp. 305 ◽  
Author(s):  
J Billen
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Control Mechanism ◽  
Smooth Endoplasmic Reticulum ◽  
Apical Cell ◽  
Venom Gland ◽  
Apical Cell Membrane ◽  
Cuticular Layer

The morphology and fine structure of the two major sting glands in the primitive Australian bull ant, Myrmecra gulosa, are described. The cells of the glandular epithelium of the tubiform Dufour's gland are characterised by a well developed vesicular smooth endoplasmic reticulum, numerous lamellar inclusions, and microvillar differentiations of the apical cell membrane. The cells of the secretory filaments of the venom gland contain a very extensive granular endoplasmic reticulum and numerous Golgi vesicles. The highly proteinaceous secretion reaches the filament lumen through the intracellular end apparatus. Passage through the convoluted gland probably accompanies the modification or production of additional secretory components, as is suggested by the ultrastructural organisation of the convoluted gland cells. The large venom gland reservoir is lined with squamous epithelial cells and a thick cuticular layer, that protects the ant from self-toxication by the powerful venom. Each sting gland opens separately through the sting, and possesses its own muscular control mechanism that allows independent discharge of secretion.

Ultrastructural features of ovarian interstitial tissue in a wild mouse, Apodemus flavicollis, at various reproductive stages, with a note on its histochemistry at the onset of the breeding period

1983 ◽  
Vol 61 (7) ◽  
pp. 1560-1567 ◽  
Author(s):  
Margareta Eriksson ◽  
Erik Nyholm
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Smooth Endoplasmic Reticulum ◽  
Wild Mouse ◽  
Hydroxysteroid Dehydrogenase ◽  
Breeding Period ◽  
Interstitial Tissue ◽  
Apodemus Flavicollis ◽  
Electron Dense Material ◽  
Glucose 6 Phosphate Dehydrogenase

In Apodemus flavicollis caught at the onset of the breeding season, interstitial tissue of the ovaries showed weak to moderate 3β-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity. Interstitial cells were found to be actively secretory among females with open vaginas. The active cells were characterized by round nuclei and well-developed cytoplasmic organelles. The mitochondria were sometimes associated with smooth endoplasmic reticulum and had mainly tubular cristae. Lipid droplets were few and contained electron-dense material. A Golgi complex with associated vesicles was conspicuous, as were endo- or exo-cytotic vesicles. It is concluded that in A. flavicollis interstitial tissue is actively secretory in connection with ovulation or early pregnancy.

A preliminary study of the fine structure of the oökinete, oöcyst, and sporozoite formation of Leucocytozoon simondi Mathis and Leger

1968 ◽  
Vol 46 (3) ◽  
pp. 303-307 ◽  
Author(s):  
Sherwin S. Desser ◽  
K. A. Wright
Keyword(s):  
Energy Source ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Epithelial Cells ◽  
Cell Membrane ◽  
Light Microscope ◽  
Dense Material ◽  
Blue Staining ◽  
Preliminary Study

The major features of the cytology of oökinetes, oöcysts, and sporozoites of Leucocytozoon simondi Mathis and Leger as seen in KMnO4-fîxed midguts of Simulium rugglesi and examined in the electron microscope, are related to their appearance in Giemsa-stained light microscope preparations. Thus, blue-staining regions of oökinete and oöcyst and the posterior, darkly stained region of sporozoites correspond to regions of endoplasmic reticulum; light "vacuole-like" regions correspond to accumulations of dense material which were not membrane enclosed; and minute red-stained spots at the anterior tip of sporozoites correspond to paired organelles. The dense material of oökinetes which, in oöcysts, is segregated into developing sporozoites may function as an energy source for sporozoites. The structure and development of these stages is similar to that of Plasmodium spp. The oöcyst of L. simondi develops extracellularly, enclosed by the basal lamina of the midgut with most of its surface surrounded by the basal cell membrane of midgut epithelial cells. This location of the oöcyst may be important in determining the subsequent pattern of development of this species.

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