The ultrastructure of the double membrane-bound bodies and endoplasmic reticulum in serial sections of wheat spot mosaic-affected wheat plants

1990 ◽  
Vol 48 (3) ◽  
pp. 694-695
Author(s):  
M. H. Chen ◽  
C. Hiruki
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Membrane Structure ◽  
Mosaic Disease ◽  
Serial Sections ◽  
Thin Sections ◽  
Double Membrane ◽  
Southern Alberta ◽  
Membrane Bound ◽  
Scanning Em

Wheat spot mosaic disease was first discovered in southern Alberta, Canada, in 1956. A hitherto unidentified disease-causing agent, transmitted by the eriophyid mite, caused chlorosis, stunting and finally severe necrosis resulting in the death of the affected plants. Double membrane-bound bodies (DMBB), 0.1-0.2 μm in diameter were found to be associated with the disease.Young tissues of leaf and root from 4-wk-old infected wheat plants were fixed, dehydrated, and embedded in Spurr’s resin. Serial sections were collected on slot copper grids and stained. The thin sections were then examined with a Hitachi H-7000 TEM at 75 kV. The membrane structure of the DMBBs was studied by numbering them individually and tracing along the sections to see any physical connection with endoplasmic reticulum (ER) membranes. For high resolution scanning EM, a modification of Tanaka’s method was used. The specimens were examined with a Hitachi Model S-570 SEM in its high resolution mode at 20 kV.

An unusual cell surface modification: a double plasma membrane

1979 ◽  
Vol 39 (1) ◽  
pp. 355-372
Author(s):  
N.J. Lane ◽  
J.B. Harrison
Keyword(s):  
Plasma Membrane ◽  
Membrane Structure ◽  
Cell Layer ◽  
Peritrophic Membrane ◽  
Thin Sections ◽  
Double Membrane ◽  
Freeze Fracturing ◽  
Blood Sucking ◽  
Great Pressure ◽  
Insertion Sites

The occurrence of an unusual double plasma membrane structure is reported; it has been studied in conventional thin sections, after lanthanum-impregnation and with freeze-fracturing. This modification of the plasmalemma is found where the luminal cell membrane (I membrane) of gut microvilli in the haematophagous insect, Rhodnius prolixus, is surrounded by a second, outer membrane (O membrane), the 2 separated from one another by a highly regular I-O space of about 10 nm. Lanthanum impregnation reveals the presence of columns inclined at an angle, within this I-O space; as in the continuous junctions which link the lateral borders of these cells, these columns may maintain the very precise I-O distance. From the outer microvillar membranes radiate short spoke-like fibrils or sheets which encounter another more extensive system of myelin-like sheets. Freeze-fracturing reveals that the spoke-like sheets and the other ones which lie like a tube, around and parallel to the microvilli, contain linear ridges composed of particles, lying at random within layers of the myelin-like material which also extends into the lumen of the gut. The microvillar membanes, both O and I, fracture into faces containing rows of either PF particles or EF pits arranged as spiral ridges or grooves around the sides and across the tip of each microbillus. These could be the insertion sites of one or both of the I-O columns and spoke-like sheets while the sheets could represent a variant of peritrophic membrane. The double membrane may be a cellular device to increase the strength of the microvillar layer in these blood-sucking animals, since the cell layer must withstand great pressure owing to a sudden massive extension of the gut during a blood meal.

Electron microscopic observations of Toxoplasma ‘Nicolle et Manceaux’ in thin sections of tissue cultures

Parasitology ◽  
1957 ◽  
Vol 47 (1-2) ◽  
pp. 66-69 ◽  
Author(s):  
H. Meyer ◽  
I. De Andrade Mendonça
Keyword(s):  
Endoplasmic Reticulum ◽  
Research Council ◽  
National Research Council ◽  
Cost Of Reproduction ◽  
Tissue Cultures ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Double Membrane ◽  
Opposite Pole ◽  
The Cost

Toxoplasma ‘Nicolle et Manceaux’ has been examined in the electron microscope in thin sections of infected tissue cultures. The intracellular forms, single or in rosette formations, show that the parasite has no flagella, cilia or other organelles for locomotion. It is covered by a double membrane which is especially well denned at the two poles. A ring-like formation, often slightly protruding, can be seen at one end of the parasite, and in connexion with this, long, homogeneous, dark-stained inclusions of still unknown nature. At the opposite pole a distinct opening has been found.Mitochondria and strands of an endoplasmic reticulum are also present in the cytoplasm and a fine striation in the region of the periplast. No dividing forms have been observed. Near the nucleus, in the region of what may correspond to the centrosome and the Golgi apparatus, a few extremely fine granules and a spiral-like formation of fine striae or tubules have been observed.This work has been partly supported by the National Research Council of Brazil. The cost of reproduction of figures was defrayed by the Institute de Biofísica da Universidade do Brasil.

Evidence for Golgi Origin of Melanosomes

1968 ◽  
Vol 26 ◽  
pp. 148-149
Author(s):  
Gerd G. Maul
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Golgi Complex ◽  
Serial Sections ◽  
Human Malignant Melanoma ◽  
Close Proximity ◽  
Membrane Bound ◽  
Tubular Endoplasmic Reticulum ◽  
Internal Architecture

Electron microscopy has provided evidence that the melanosome evolves as a membrane bound structure with a highly complex internal architecture. The premelanosomes are found in close proximity to the golgi apparatus. Therefore, it was generally agreed that the melanosomes originate from the golgi apparatus.Vesicles have been described to pinch off the cysternae of the golgi apparatus. The vesicles would then grow and acquire a dense material. This material is aggregating to form the characteristic helical strands onto which melanin is deposited. Cloned human malignant melanoma lines were used to reinvestigate the problem of melanosome formation. The reconstruction of serial sections revealed the arrangement of premelanosomes and melanosomes in relation to the golgi complex. This study demonstrated that premelanosomes and melanosomes are continuous with the golgi complex by a smooth-surfaced tubular endoplasmic reticulum (SER) (Fig. la-d). The continuity of membranes of the SER and the premelanosome is depicted in Fig. 2. In this early premelanosome the protein strands have not yet coiled up into a helix. Rough-surfaced endoplasmic reticulum (RER) was also observed to be continuous with the golgi apparatus and melanosomes. After melanogenesis has started (Fig. 3) small vesicles appear inside the premelanosomes.

scholarly journals Co-translational excision of alpha-glucose and alpha-mannose in nascent vesicular stomatitis virus G protein.

1984 ◽  
Vol 98 (6) ◽  
pp. 2245-2249 ◽  
Author(s):  
P H Atkinson ◽  
J T Lee
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
G Protein ◽  
Vesicular Stomatitis Virus ◽  
Rough Endoplasmic Reticulum ◽  
Hela Cells ◽  
Chain Elongation ◽  
Carbonyl Cyanide ◽  
Membrane Bound ◽  
Vesicular Stomatitis

Membrane bound polysomes were prepared from HeLa cells infected with vesicular stomatitis virus (VSV), after pulse labeling with [3H]mannose for various times from 15 to 90 min. Oligosaccharides on nascent chains were released from peptides by treatment with endoglycosidase H and sized by high resolution Biogel P4 chromatography. Processing on some nascent chains proceeded to the removal of all three types of alpha-linked glucose and one alpha-1,2-mannose from the Glc3Man9GlcNAc precursor showing that the enzymes responsible were not only active on nascent chains but were present in the rough endoplasmic reticulum (RER). Incubation of cells for various times in cycloheximide, where chain elongation had ceased, made no difference to the profile of oligosaccharides on the nascent chains, and trimming proceeded no further than Man8GlcNAc2Asn . Carbonyl cyanide m-chlorophenylhydrazone (CCCP), an energy inhibitor reportedly able to block the transfer of glycoproteins from the RER, increases the amount of Man8-oligosaccharides on the nascent chains and also the amount of Glc3Man9GlcNAc precursor. On completed G protein in the RER fraction from which membrane bound polysomes were prepared, processing occurred to Man6 - but not to Man5GlcNAc sized oligosaccharides in the CCCP-treated cells. By contrast, processing to Man5GlcNAc oligosaccharides was observed in unfractionated control cells.

Light and electron microscope studies on the conidium and germ tube of Sphaerotheca macularis

1970 ◽  
Vol 16 (5) ◽  
pp. 273-280 ◽  
Author(s):  
N. L. Mitchell ◽  
W. E. McKeen
Keyword(s):  
Endoplasmic Reticulum ◽  
Germ Tube ◽  
Vacuolar Membrane ◽  
Serial Sections ◽  
Dense Granules ◽  
Leading Position ◽  
Membrane Bound ◽  
Sphaerotheca Macularis ◽  
Glycogen Particles ◽  
Germ Tubes

Measurements made from electron micrographs of serial sections and from thoroughly plasmolyzed conidia indicate that more than 50% of the volume of the conidia of Sphaerotheca macularis consists of vacuoles in which most of the water in the conidia is stored. Electron-dense granules inside the vacuoles evidently include storage materials. Some developing vacuoles, particularly those of the germ tube, enclose membrane-bound bodies resembling lysosomes which later disappear as the vacuoles enlarge. Conspicuous multimembraned myelin-like bodies project inside the vacuolar cavity, their membranes being continuous with the vacuolar membrane. These bodies are believed to function in the synthesis of new cytoplasmic materials from the reserves in the vacuoles.The conidium, which may later produce up to four germ tubes, always retains a nucleus. The nucleus contains a peripheral granule which maintains a leading position on migrating nuclei and divides into two during the initial stages of nuclear division.Germ tubes respond positively to the stimulus of unilateral illumination and are produced on the illuminated sides of the conidia. Cytoplasmic changes which accompany germination include the increase in number and size of mitochondria, particularly in the germ tube. Their multiplication appears to be by fission. Endoplasmic reticulum is greatly increased and ribosomes are more abundant. Aggregated granules resembling glycogen particles also occur, these not being usually seen in resting conidia.

scholarly journals High-resolution calcium mapping of the endoplasmic reticulum-Golgi-exocytic membrane system. Electron energy loss imaging analysis of quick frozen-freeze dried PC12 cells.

1997 ◽  
Vol 8 (8) ◽  
pp. 1501-1512 ◽  
Author(s):  
R Pezzati ◽  
M Bossi ◽  
P Podini ◽  
J Meldolesi ◽  
F Grohovaz
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Energy Loss ◽  
Pc12 Cells ◽  
Electron Energy ◽  
Thin Sections ◽  
Cell Functions ◽  
Freeze Dried ◽  
Quick Freezing ◽  
Electron Energy Loss

The calcium pools segregated within the endoplasmic reticulum, Golgi complex, exocytic, and other organelles are believed to participate in the regulation of a variety of cell functions. Until now, however, the precise intracellular distribution of the element had not been established. Here, we report about the first high-resolution calcium mapping obtained in neurosecretory PC12 cells by the imaging mode of the electron energy loss spectroscopy technique. The preparation procedure used included quick freezing of cell monolayers, followed by freeze-drying, fixation with OSO4 vapors, resin embedding, and cutting of very thin sections. Conventional electron microscopy and high-resolution immunocytochemistry revealed a high degree of structural preservation, a condition in which inorganic elements are expected to maintain their native distribution. Within these cells, calcium signals of nucleus, cytosol, and most mitochondria remained below detection, whereas in other organelles specific patterns were identified. In the endoplasmic reticulum, the distribution was heterogeneous with strongly positive cisternae (more often the nuclear envelope and stacks of parallel elements that are frequent in quick frozen preparations) lying in the proximity of or even in direct continuity with other, apparently negative cisternae. The Golgi complexes were labeled strongly and uniformly in all cisternae and part of their vesicles, with no appreciable differences along the cis-trans axis. Weaker or negative signals were recorded from the trans-Golgi network elements and from scattered vesicles, whereas in contrast secretion granules were strongly positive for calcium. These results are discussed in relation to the existing knowledge about the mechanisms of calcium transport in the variations organelles, and about the processes and functions regulated by organelle lumenal calcium in eukaryotic cells.

Ultrastructure of the Parotid Gland of the Nine-Banded Armadillo

1977 ◽  
Vol 35 ◽  
pp. 640-641
Author(s):  
J. R. Ruby
Keyword(s):  
Endoplasmic Reticulum ◽  
Parotid Gland ◽  
Periodic Acid ◽  
Acinar Cells ◽  
Duct System ◽  
Parotid Glands ◽  
Dasypus Novemcinctus ◽  
Anterior Portion ◽  
Periodic Acid Schiff ◽  
Thin Sections

Parotid glands were obtained from five adult (four male and one female) armadillos (Dasypus novemcinctus) which were perfusion-fixed. The glands were located in a position similar to that of most mammals. They extended interiorly to the anterior portion of the submandibular gland.In the light microscope, it was noted that the acini were relatively small and stained strongly positive with the periodic acid-Schiff (PAS) and alcian blue techniques, confirming the earlier results of Shackleford (1). Based on these qualities and other structural criteria, these cells have been classified as seromucous (2). The duct system was well developed. There were numerous intercalated ducts and intralobular striated ducts. The striated duct cells contained large amounts of PAS-positive substance.Thin sections revealed that the acinar cells were pyramidal in shape and contained a basally placed, slightly flattened nucleus (Fig. 1). The rough endoplasmic reticulum was also at the base of the cell.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

Probing the ultrastructure of the mitotic and meiotic spindle in eggs: An expeditious approach based on semi-thin (0.25 μm) serial sections

1983 ◽  
Vol 41 ◽  
pp. 552-555
Author(s):  
Conly L. Rieder ◽  
S. Bowser ◽  
R. Nowogrodzki ◽  
K. Ross ◽  
G. Sluder
Keyword(s):  
Small Sample Size ◽  
Small Sample ◽  
Meiotic Spindle ◽  
Serial Sections ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Cell Cycles ◽  
Ultrastructural Studies

Eggs have long been a favorite material for studying the mechanism of karyokinesis in-vivo and in-vitro. They can be obtained in great numbers and, when fertilized, divide synchronously over many cell cycles. However, they are not considered to be a practical system for ultrastructural studies on the mitotic apparatus (MA) for several reasons, the most obvious of which is that sectioning them is a formidable task: over 1000 ultra-thin sections need to be cut from a single 80-100 μm diameter egg and of these sections only a small percentage will contain the area or structure of interest. Thus it is difficult and time consuming to obtain reliable ultrastructural data concerning the MA of eggs; and when it is obtained it is necessarily based on a small sample size.We have recently developed a procedure which will facilitate many studies concerned with the ultrastructure of the MA in eggs. It is based on the availability of biological HVEM's and on the observation that 0.25 μm thick serial sections can be screened at high resolution for content (after mounting on slot grids and staining with uranyl and lead) by phase contrast light microscopy (LM; Figs 1-2).

Membrane-bound vesicles associated with the microvilli in the midgut of the freshwater microcrustacean, Daphnia magna

1983 ◽  
Vol 41 ◽  
pp. 480-481
Author(s):  
Patricia L. Jansma
Keyword(s):  
Daphnia Magna ◽  
Intestinal Epithelial Cells ◽  
Uranyl Acetate ◽  
Intestinal Epithelial ◽  
Chlamydomonas Reinhardii ◽  
Thin Sections ◽  
Saturated Water ◽  
Cacodylate Buffer ◽  
Membrane Bound ◽  
Ethanol Series

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.

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