scholarly journals Ultrastructure and Differentiation in Chara Sp.I. Vegetative Cells

1967 ◽  
Vol 20 (3) ◽  
pp. 539 ◽  
Author(s):  
JD Pickett-Heaps
Keyword(s):  
Endoplasmic Reticulum ◽  
Cytoplasmic Streaming ◽  
Plant Cells ◽  
Membrane Systems ◽  
Close Apposition ◽  
Vegetative Cells ◽  
Cytoplasmic Inclusions ◽  
Golgi Bodies ◽  
And Function ◽  
Vacuolated Cells

The ultrastructure of young growing cells of Ohara is described. The cells showed many features typical of plant cells. The nuclei of larger cells invariably contained groups of close�packed, heavily staining microtubular elements. Typical wall microtubules were always found, and large internodal cells contained filaments possibly involved in cytoplasmic streaming. Vacuolation in young internodes apparently commenced by extensive dilation of elements of the endoplasmic reticulum. In other cells, close apposition of endoplasmic reticulum to cytoplasmic inclusions indicated possible secretion of material into the organelles had been occurring. Golgi bodies with intercisternal elements were often grouped together, sometimes with interconnected cisternae. Isolated reticulate membrane systems, similar to those found at the reticulate face of golgi bodies, were sometimes seen in vacuolated cells. The golgi bodies might have been involved in vacuolation; they were also seen in association with coated vesicles that appeared to be involved in wall deposition. A large number of different cytoplasmic inclusions were found, whose nature and function is obscure. These sometimes contained crystal.like bodies.

scholarly journals FINE STRUCTURE AND ORGANELLE ASSOCIATIONS IN BROWN ALGAE

1965 ◽  
Vol 26 (2) ◽  
pp. 523-537 ◽  
Author(s):  
G. Benjamin Bouck
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Nuclear Envelope ◽  
Brown Algae ◽  
Algal Cell ◽  
Plant Cells ◽  
Membrane Systems ◽  
Two Envelopes

The structural interrelationships among several membrane systems in the cells of brown algae have been examined by electron microscopy. In the brown algae the chloroplasts are surrounded by two envelopes, the outer of which in some cases is continuous with the nuclear envelope. The pyrenoid, when present, protrudes from the chloroplast, is also surrounded by the two chloroplast envelopes, and, in addition, is capped by a third dilated envelope or "pyrenoid sac." The regular apposition of the membranes around the pyrenoid contrasts with their looser appearance over the remainder of the chloroplast. The Golgi apparatus is closely associated with the nuclear envelope in all brown algae examined, but in the Fucales this association may extend to portions of the cytoplasmic endoplasmic reticulum as well. Evidence is presented for the derivation of vesicles, characteristic of those found in the formative region of the Golgi apparatus, from portions of the underlying nuclear envelope. The possibility that a structural channeling system for carbohydrate reserves and secretory precursors may be present in brown algae is considered. Other features of the brown algal cell, such as crystal-containing bodies, the variety of darkly staining vacuoles, centrioles, and mitochondria, are examined briefly, and compared with similar structures in other plant cells.

scholarly journals cis-Golgi proteins accumulate near the ER exit sites and act as the scaffold for Golgi regeneration after brefeldin A treatment in tobacco BY-2 cells

2012 ◽  
Vol 23 (16) ◽  
pp. 3203-3214 ◽  
Author(s):  
Yoko Ito ◽  
Tomohiro Uemura ◽  
Keiko Shoda ◽  
Masaru Fujimoto ◽  
Takashi Ueda ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Fluorescent Proteins ◽  
Plant Cells ◽  
Brefeldin A ◽  
Eukaryotic Cells ◽  
Er Exit Sites ◽  
Intermediate Compartment ◽  
Golgi Protein ◽  
And Function

The Golgi apparatus forms stacks of cisternae in many eukaryotic cells. However, little is known about how such a stacked structure is formed and maintained. To address this question, plant cells provide a system suitable for live-imaging approaches because individual Golgi stacks are well separated in the cytoplasm. We established tobacco BY-2 cell lines expressing multiple Golgi markers tagged by different fluorescent proteins and observed their responses to brefeldin A (BFA) treatment and BFA removal. BFA treatment disrupted cis, medial, and trans cisternae but caused distinct relocalization patterns depending on the proteins examined. Medial- and trans-Golgi proteins, as well as one cis-Golgi protein, were absorbed into the endoplasmic reticulum (ER), but two other cis-Golgi proteins formed small punctate structures. After BFA removal, these puncta coalesced first, and then the Golgi stacks regenerated from them in the cis-to-trans order. We suggest that these structures have a property similar to the ER-Golgi intermediate compartment and function as the scaffold of Golgi regeneration.

scholarly journals Endoplasmic Reticulum Export Sites and Golgi Bodies Behave as Single Mobile Secretory Units in Plant Cells

2004 ◽  
Vol 16 (7) ◽  
pp. 1753-1771 ◽  
Author(s):  
Luis L.P. daSilva ◽  
Erik L. Snapp ◽  
Jürgen Denecke ◽  
Jennifer Lippincott-Schwartz ◽  
Chris Hawes ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plant Cells ◽  
Golgi Bodies

Complex envelope system. Membrane systems of plant cells

1974 ◽  
Vol 268 (891) ◽  
pp. 119-128 ◽  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Smooth Endoplasmic Reticulum ◽  
Plant Cells ◽  
Membrane System ◽  
Cellulose Microfibrils ◽  
Membrane Systems ◽  
Complex Envelope ◽  
Pectic Substances ◽  
The Matrix

The membrane system is made up of the nuclear envelopes, rough and smooth endoplasmic reticulum, Golgi apparatus and plasmalemma. Interconnexions between the various parts of the system are shown and these probably represent a flow of membrane from the endoplasmic reticulum through the Golgi apparatus to the plasmalemma. Membrane fractions have been isolated from broken cells and their function in the synthesis of polysaccharides established. It has been shown that the matrix polysaccharides of the wall (pectic substances and hemicelluloses) are formed within the membranes and that the pattern of synthesis of these polymers changes during differentiation of the cells. Cellulose microfibrils are probably synthesized at the plasmalemma which is formed by incorporation of membrane bounded vesicles from the Golgi apparatus. Thus the assembly of the polymers takes place either when the membrane is within the cytoplasm or when it is incorporated as the plasmalemma of the cell.

scholarly journals Sperm aster in rabbit zygotes: its structure and function.

1976 ◽  
Vol 69 (3) ◽  
pp. 539-547 ◽  
Author(s):  
F J Longo
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Tritiated Thymidine ◽  
Structure And Function ◽  
Close Apposition ◽  
Male And Female ◽  
Autoradiographic Analysis ◽  
And Function ◽  
Dense Aggregation ◽  
Sperm Aster

Microscope observations of rabbit zygotes demonstrate that a sperm aster forms in association with the male pronucleus approximately 1 h postinsemination and consists of two regions. One, the centrosphere, contains a dense aggregation of cisternae of smooth endoplasmic reticulum and microtubules. The second consists of fascicles of microtubules which emanate from the centrosphere. Fertilized rabbit eggs were cultured in medium containing colcemid in order to determine its effects on various events of fertilization, such as movements of the male and female pronuclei and DNA synthesis. No evidence was obtained to indicate that a sperm aster is formed in colcemid-treated zygotes. In addition, migration and close apposition of the pronuclei do not take place. Breakdown of the pronuclear envelopes and condensation of the maternally and paternally derived chromosomes occur even though the pronuclei fail to migrate centrad. Autoradiographic analysis of the synthesis of DNA by both pronuclei demonstrates that their migration into close apposition to one another is not required for the incorporation of tritiated thymidine.

scholarly journals Maturation of the Na,K-ATPase in the Endoplasmic Reticulum in Health and Disease

2021 ◽  
Author(s):  
Vitalii Kryvenko ◽  
Olga Vagin ◽  
Laura A. Dada ◽  
Jacob I. Sznajder ◽  
István Vadász
Keyword(s):  
Endoplasmic Reticulum ◽  
Intracellular Signaling ◽  
Loss Of Function ◽  
Α Subunit ◽  
Rate Limiting Step ◽  
Atpase Subunits ◽  
A Cell ◽  
Health And Disease ◽  
And Function ◽  
Rate Limiting

Abstract The Na,K-ATPase establishes the electrochemical gradient of cells by driving an active exchange of Na+ and K+ ions while consuming ATP. The minimal functional transporter consists of a catalytic α-subunit and a β-subunit with chaperon activity. The Na,K-ATPase also functions as a cell adhesion molecule and participates in various intracellular signaling pathways. The maturation and trafficking of the Na,K-ATPase include co- and post-translational processing of the enzyme in the endoplasmic reticulum (ER) and the Golgi apparatus and subsequent delivery to the plasma membrane (PM). The ER folding of the enzyme is considered as the rate-limiting step in the membrane delivery of the protein. It has been demonstrated that only assembled Na,K-ATPase α:β-complexes may exit the organelle, whereas unassembled, misfolded or unfolded subunits are retained in the ER and are subsequently degraded. Loss of function of the Na,K-ATPase has been associated with lung, heart, kidney and neurological disorders. Recently, it has been shown that ER dysfunction, in particular, alterations in the homeostasis of the organelle, as well as impaired ER-resident chaperone activity may impede folding of Na,K-ATPase subunits, thus decreasing the abundance and function of the enzyme at the PM. Here, we summarize our current understanding on maturation and subsequent processing of the Na,K-ATPase in the ER under physiological and pathophysiological conditions. Graphic Abstract

scholarly journals Myosin-dependent endoplasmic reticulum motility and F-actin organization in plant cells

2010 ◽  
Vol 107 (15) ◽  
pp. 6894-6899 ◽  
Author(s):  
H. Ueda ◽  
E. Yokota ◽  
N. Kutsuna ◽  
T. Shimada ◽  
K. Tamura ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plant Cells ◽  
Actin Organization

scholarly journals The Lamellar Systems of Cytoplasmic Membranes in Dividing Spermatogenic Cells of Drosophila virilis

1960 ◽  
Vol 7 (3) ◽  
pp. 433-441 ◽  
Author(s):  
Susumu Ito
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Light And Electron Microscopy ◽  
Primary Spermatocyte ◽  
Drosophila Virilis ◽  
Spermatogenic Cells ◽  
Membrane Systems ◽  
Cytoplasmic Membranes ◽  
Pas Reaction ◽  
Staining Methods

Spermatogenic cells of Drosophila virilis were studied by light and electron microscopy. The persistence of a "nuclear wall" during the meiotic divisions has been reported by a number of early cytologists, but this interpretation has been a subject of debate. Electron micrographs of dividing spermatocytes reveal the presence of multiple layers of paired membranes surrounding the nuclear region. These lamellar membrane systems are not typical of the nuclear envelope, but were interpreted as such by light microscopists. The membranes constituting a pair are separated by an interspace of ∼ 100 A and successive pairs are 200 to 400 A apart. These spacings are similar but not identical to those found in the lamellar systems of the Golgi complex. The cisternae of the endoplasmic reticulum in this material are devoid of attached ribonucleoprotein particles, are more precisely ordered than in vertebrate cells, and show a uniform, narrow intracisternal space of ∼ 100 A. The conspicuous asters appear to be made up of similar paired membranes radiating from the centriolar region. The primary spermatocyte has numerous dictyosomes and a well developed endoplasmic reticulum in cisternal form, but no typical Golgi complex or endoplasmic reticulum is found during the meiotic division stages of metaphase to telophase. Evidence is presented that these cytoplasmic organelles contribute to the formation of the extensive lamellar systems that appear during meiosis. The results of the Golgi silver staining methods and staining tests for phospholipids, basophilia, and the PAS reaction, indicate that the lamellar arrays of membranes present during meiosis are indistinguishable from the Golgi complex in their tinctorial properties.

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