scholarly journals THE FINE STRUCTURAL ORGANISATION OF ROUS TUMOUR CELLS

1957 ◽  
Vol 3 (6) ◽  
pp. 851-858 ◽  
Author(s):  
M. A. Epstein
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Tumour Cells ◽  
Thin Sections ◽  
Outer Nuclear Membrane ◽  
Structural Organisation ◽  
Perinuclear Space

The fibroblast-like tumour cells of Rous sarcomata have been studied in thin sections with the electron microscope. A description is given of the fine structure of the cells which includes some features not hitherto recorded. The tightly packed piles of smooth cisternae usually found only in the centrosome region have been observed, in individual Rous cells, in two separate areas of cytoplasm at opposite poles of the nucleus. Continuity between the perinuclear space and the lumen of rough surfaced cisternae of the endoplasmic reticulum has frequently been found; a similar continuity between the cisternae and the exterior of the cell has also been seen. In some cases, the cell membrane has been shown to have an unbroken connection with the outer nuclear membrane through continuity with the limiting membranes of elements of the endoplasmic reticulum. These findings are discussed.

An Electron Microscope study of a Small Free-living Amoeba (Hartmanella astronyxis)

1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Layered Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Honeycomb Structure ◽  
Free Living ◽  
Free Living Amoeba

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.

scholarly journals Endoplasmic reticulum-to-Golgi transitions upon herpes virus infection

F1000Research ◽  
2018 ◽  
Vol 6 ◽  
pp. 1804 ◽  
Author(s):  
Peter Wild ◽  
Andres Kaech ◽  
Elisabeth M. Schraner ◽  
Ladina Walser ◽  
Mathias Ackermann
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Golgi Complex ◽  
Nuclear Membrane ◽  
Progeny Virus ◽  
Cytoplasmic Matrix ◽  
Outer Nuclear Membrane ◽  
Nuclear Membranes ◽  
Perinuclear Space ◽  
Hsv 1

Background: Herpesvirus capsids are assembled in the nucleus, translocated to the perinuclear space by budding, acquiring tegument and envelope, or released to the cytoplasm via impaired nuclear envelope. One model proposes that envelopment, “de-envelopment” and “re-envelopment” is essential for production of infectious virus. Glycoproteins gB/gH were reported to be essential for de-envelopment, by fusion of the “primary” envelope with the outer nuclear membrane. Yet, a high proportion of enveloped virions generated from genomes with deleted gB/gH were found in the cytoplasm and extracellular space, suggesting the existence of alternative exit routes.Methods: We investigated the relatedness between the nuclear envelope and membranes of the endoplasmic reticulum and Golgi complex, in cells infected with either herpes simplex virus 1 (HSV-1) or a Us3 deletion mutant thereof, or with bovine herpesvirus 1 (BoHV-1) by transmission and scanning electron microscopy, employing freezing technique protocols.Results:  The Golgi complex is a compact entity in a juxtanuclear position covered by a membrane on thecisface. Golgi membranes merge with membranes of the endoplasmic reticulum forming an entity with the perinuclear space. All compartments contained enveloped virions. After treatment with brefeldin A, HSV-1 virions aggregated in the perinuclear space and endoplasmic reticulum, while infectious progeny virus was still produced.Conclusions: The data suggest that virions derived by budding at nuclear membranes are intraluminally transported from the perinuclear space via Golgi -endoplasmic reticulum transitions into Golgi cisternae for packaging. Virions derived by budding at nuclear membranes are infective like Us3 deletion mutants, which  accumulate in the perinuclear space. Therefore, i) de-envelopment followed by re-envelopment is not essential for production of infective progeny virus, ii) the process taking place at the outer nuclear membrane is budding not fusion, and iii) naked capsids gain access to the cytoplasmic matrix via impaired nuclear envelope as reported earlier.

scholarly journals THE FINE STRUCTURE OF NEURONS

1955 ◽  
Vol 1 (1) ◽  
pp. 69-88 ◽  
Author(s):  
Sanford L. Palay ◽  
George E. Palade
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cerebellar Cortex ◽  
Dorsal Root Ganglia ◽  
Medulla Oblongata ◽  
Dorsal Root ◽  
Thin Sections ◽  
Lipid Inclusions ◽  
Nissl Substance

1. Thin sections of representative neurons from intramural, sympathetic and dorsal root ganglia, medulla oblongata, and cerebellar cortex were studied with the aid of the electron microscope. 2. The Nissl substance of these neurons consists of masses of endoplasmic reticulum showing various degrees of orientation; upon and between the cisternae, tubules, and vesicles of the reticulum lie clusters of punctate granules, 10 to 30 mµ in diameter. 3. A second system of membranes can be distinguished from the endoplasmic reticulum of the Nissl bodies by shallower and more tightly packed cisternae and by absence of granules. Intermediate forms between the two membranous systems have been found. 4. The cytoplasm between Nissl bodies contains numerous mitochondria, rounded lipid inclusions, and fine filaments.

The fine structure and development of chlamydospores of Fusarium oxysporum

1972 ◽  
Vol 18 (7) ◽  
pp. 997-1002 ◽  
Author(s):  
I. L. Stevenson ◽  
S. A. W. E. Becker
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cell Surface ◽  
Outer Layer ◽  
Outer Wall ◽  
Wall Layer ◽  
Thin Sections ◽  
Hyphal Wall

Methods have been developed for the rapid, reproducible induction of high-density populations of F. oxysporum chlamydospores. On transferring washed pregerminated conidia to a simple two-salts medium, chlamydospore morphogenesis was evident by 12 h and masses of mature spores could be harvested at the end of 4 days. Electron-microscope studies of thin sections of mature chlamydospores reveal a thick triple-layered cell wall. The cytoplasm contains, in addition to large lipid deposits, a nucleus, mitochondria, and endoplasmic reticulum all typical of fungal cells. Chlamydospores of F. oxysporum exhibit two distinct types of cell surface in thin section. The outer wall layer of two of the isolates studied was smooth-surfaced while the outer layer of the two other isolates was distinctly fibrillose. Some evidence is presented suggesting that the fibrillose material arises through the partial breakdown of the original hyphal wall.

scholarly journals STUDIES ON THE FINE STRUCTURE OF THE MAMMALIAN TESTIS

1955 ◽  
Vol 1 (4) ◽  
pp. 287-300 ◽  
Author(s):  
Mario H. Burgos ◽  
Don W. Fawcett
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Golgi Complex ◽  
Nuclear Membrane ◽  
Posterior Margin ◽  
Frequent Occurrence ◽  
Thin Sections ◽  
Acrosomal Vesicle ◽  
Mammalian Testis

The differentiation of cat spermatids was studied in thin sections examined with the electron microscope. The Golgi complex of the spermatid consists of a central aggregation of minute vacuoles, partially surrounded by a lamellar arrangement of flattened vesicles. In the formation of the acrosome, one or more moderately dense homogeneous granules arise within vacuoles of the Golgi complex. The coalescence of these vacuoles and their contained granules gives rise to a single acrosomal granule within a sizable membrane-limited vacuole, termed the acrosomal vesicle. This adheres to the nuclear membrane and later becomes closely applied to the anterior two-thirds of the elongating nucleus to form a closed bilaminar head cap. The substance of the acrosomal granule occupies the narrow cleft between the membranous layers of the cap. The caudal sheath is comprised of many straight filaments extending backward from a ring which encircles the nucleus at the posterior margin of the head cap. Attention is directed to the frequent occurrence of pairs of spermatids joined by a protoplasmic bridge and the origin and possible significance of this relationship are discussed.

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.

A Pre-Golgi Copartment Connecting Golgi Cisterns to the Perinuclear Space in Bovine Herpesvirus 1 (Bhv-1) Infected Mdbk Cells. Evidence for an Intracisternal Pathway

2001 ◽  
Vol 7 (S2) ◽  
pp. 738-739
Author(s):  
P. Wild ◽  
E.M. Schraner ◽  
D. Cantieni ◽  
M. Engels ◽  
E. Loepfe ◽  
...  
Keyword(s):  
Nuclear Membrane ◽  
Nuclear Periphery ◽  
Uranyl Acetate ◽  
Bovine Herpesvirus 1 ◽  
Thin Sections ◽  
Outer Nuclear Membrane ◽  
Perinuclear Space ◽  
Mdbk Cells ◽  
Infected Cells ◽  
Herpesvirus 1

The nucleocapsid of herpesviruses is assembled within the nucleus and transported to the perinuclear space by budding through the inner nuclear membrane. The route from the perinuclear space to the plasma membrane for exocytotic release is assumed to involve loss of the acquired envelope by fusion with the outer nuclear membrane followed by wrapping of the nucleocapsid by Golgi membranes. Alternatively, virions are thought to leave the perinuclear space via vacuoles originating from the outer nuclear membrane. Non of these processes has been shown so far. We thus examined the nuclear periphery of MDBK cells infected with BHV-1 by cryobased electron microscopy. Infected cells were high-pressure frozen at 4, 5 and 6 hours of incubation, and freezesubstituted employing a protocol yielding high resolution of membranes.Thin sections stained with uranyl acetate and lead citrate showed 3 distinct stages of viral envelopment at any time of incubation.

Fine Structure of Interdental Cells in the Mouse Cochlea

1970 ◽  
Vol 28 ◽  
pp. 140-141
Author(s):  
Roberta M. Bruck
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Young Adult ◽  
Uranyl Acetate ◽  
Ground Substance ◽  
Tectorial Membrane ◽  
Lead Citrate ◽  
Unusual Structure ◽  
Thin Sections ◽  
Collagenous Fibers

An unusual structure in the cochlea is the spiral limbus; this periosteal tissue consists of stellate fibroblasts and collagenous fibers embedded in a translucent ground substance. The collagenous fibers are arranged in vertical columns (the auditory teeth of Haschke). Between the auditory teeth are interdental furrows in which the interdental cells are situated. These epithelial cells supposedly secrete the tectorial membrane.The fine structure of interdental cells in the rat was reported by Iurato (1962). Since the mouse appears to be different, a description of the fine structure of mouse interdental cells' is presented. Young adult C57BL/6J mice were perfused intervascularly with 1% paraformaldehyde/ 1.25% glutaraldehyde in .1M phosphate buffer (pH7.2-7.4). Intact cochlea were decalcified in .1M EDTA by the method of Baird (1967), postosmicated, dehydrated, and embedded in Araldite. Thin sections stained with uranyl acetate and lead citrate were examined in a Phillips EM-200 electron microscope.

scholarly journals A Cellular Reaction to Antibody in Tissue Culture Studied with Electron Microscopy

1959 ◽  
Vol 5 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Harrison Latta
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Normal Serum ◽  
Butyl Methacrylate ◽  
Heart Cells ◽  
Plasma Clot ◽  
Outer Nuclear Membrane ◽  
Cell Components

The reaction of embryonic chick heart cells grown in tissue culture to specific guinea pig antiserum has been studied with electron microscopy. Heart fragments from chick embryos were cultured with a plasma clot. After being tested with antiserum or normal serum, they were fixed with buffered osmium tetroxide and embedded in butyl methacrylate before removal from the glass culture chamber. Thin cells found by phase microscopy to have reacted were sectioned in a plane parallel to the glass surface on which they had grown. The results confirm and extend observations made previously while the reactions were occurring. The plasma membrane, like that of the red cell, becomes disrupted or less resistant to trauma following the action of antiserum. The membranes of mitochondria and endoplasmic reticulum vesiculate and swell. Before nuclear shrinkage becomes prominent, the outer nuclear membrane separates over a large portion of the nuclear envelope and forms one or more large swollen blebs. Thus, the outer nuclear membrane shows a reactivity similar to endoplasmic reticulum. It is suggested that the various physical and chemical changes observed to follow the action of antibody and complement on fibroblasts may be explained by osmotic pressure differences between various cell components. Some basic similarities to the action of hemolytic agents on red cells are noted.

Mechanism regulating nuclear calcium signalingThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 403-422 ◽  
Author(s):  
Anant N. Malviya ◽  
Christian Klein
Keyword(s):  
Endoplasmic Reticulum ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Calcium Signaling ◽  
Nuclear Membrane ◽  
Protein Fragment ◽  
Outer Nuclear Membrane ◽  
Nuclear Calcium ◽  
A Cell ◽  
Epidermal Growth

Although the outer nuclear membrane is continuous with the endoplasmic reticulum, it is possible to isolate nuclei both intact and free from endoplasmic reticulum contaminants. The outer and the inner nuclear membranes can be purified free from cross-contamination. Evidence in support of autonomous regulation of nuclear calcium signaling relies upon the investigations with isolated nuclei. Mechanisms for generating calcium signaling in the nucleus have been identified. Two calcium transporting systems, an ATP-dependant nuclear Ca2+-ATPase and an IP4-mediated inositol 1,3,4,5-tetrakisphosphate receptor, are located on the outer nuclear membrane. Thus, ATP and IP4, depending on external free calcium concentrations, are responsible for filling the nuclear envelope calcium pool. The inositol 1,4,5-trisphosphate receptor is located on the inner nuclear membrane with its ligand binding domain facing toward the nucleoplasm. Likewise, the ryanodine receptor is located on the inner nuclear membrane and its ligand cADP-ribose is generated within the nucleus. A 120 kDa protein fragment of nuclear PLC-γ1 is stimulated in vivo by epidermal growth factor nuclear signaling coincident with the time course of nuclear membrane epidermal growth factor receptor activation. Stimulated 120 kDa protein fragment interacts with PIKE, a nuclear GTPase, and together they form a complex with PI[3]kinase serving as a module for nuclear PI[3]K stimulation. Thus, the nucleus has its own IP3 generating system.

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