Electron microscopic localization of concanavalin A receptor sites in pollen surface material after fixation with glutaraldehyde-cetylpyridinium chloride.

1984 ◽  
Vol 32 (8) ◽  
pp. 869-871 ◽  
Author(s):  
M Grote ◽  
H G Fromme
Keyword(s):  
Concanavalin A ◽  
Cetylpyridinium Chloride ◽  
Pollen Grains ◽  
Dense Material ◽  
Con A ◽  
Electron Microscopic ◽  
Electron Dense Material ◽  
Receptor Sites ◽  
Pollen Surface ◽  
Ultrathin Sections

Pollen from birch trees (Betula pendula) was fixed in glutaraldehyde containing 0.5% cetylpyridinium chloride (CPC), incubated with concanavalin A (Con A)-ferritin, postfixed in osmium, dehydrated, and embedded in Epon. On ultrathin sections, ferritin particles were observed closely associated with the electron-dense material precipitated by CPC on the surface of the pollen grains. Controls for CPC, which were fixed in glutaraldehyde alone, showed no electron-dense material on the surface. In controls for Con A, which were incubated in Con A-ferritin in the presence of the inhibitory sugar (alpha-methyl-D-mannopyranoside), no ferritin particles were observed. The above-described procedure thus allows the localization of sugar residues in highly soluble pollen wall glycoproteins.

scholarly journals Ultrastructural localization of concanavalin A and wheat germ agglutinin binding sites in adult and embryonic mouse myocardium.

1982 ◽  
Vol 30 (3) ◽  
pp. 193-200 ◽  
Author(s):  
D Gros ◽  
B Bruce ◽  
C E Challice ◽  
J Schrevel
Keyword(s):  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Ultrastructural Localization ◽  
Embryonic Cells ◽  
Con A ◽  
Embryonic Mouse ◽  
Transverse Tubular System ◽  
Receptor Sites ◽  
Ultrathin Sections

The lectins, concanavalin A (Con A) and wheat germ agglutinin (WGA), have been used to localize with precision glycosyl residues in adult and embryonic mouse myocardium. They were detected by means of an affinity method using peroxidase and chitobiosylperoxidase, respectively, which then were revealed with 3,3'-diaminobenzidine and H2O2. Exhaustive controls have shown that the binding of Con A and WGA is reversible when experiments are performed with adult specimens (tissue blocks or ultrathin sections of glycol methacrylate-embedded material) or with isolated embryonic cells. Experiments carried out with tissue blocks from embryonic hearts have shown peroxidase binding. This finding is discussed on the basis of the presence of the endogenous lectin-like components in embryonic hearts. Results show that the surface of adult and embryonic myocardial cells specifically bind both Con A and WGA, thus indicating the presence of glycosyl residues similar to alpha-methyl-D-mannoside and N-acetyl-D-glucosamine. In adult heart the transverse tubular system was also labeled. The absence of Con A and WGA receptor sites in the gap junction regions was demonstrated by means of an electron microscope postembedding staining method.

Techniques to preserve soluble surface components in birch pollen wall: a scanning and transmission electron microscopic study.

1989 ◽  
Vol 37 (7) ◽  
pp. 981-987 ◽  
Author(s):  
M Grote
Keyword(s):  
Cetylpyridinium Chloride ◽  
Birch Pollen ◽  
Pollen Grain ◽  
Dense Material ◽  
Surface Coat ◽  
Electron Microscopic ◽  
Electron Dense Material ◽  
Transmission Electron ◽  
Cuprolinic Blue ◽  
Thin Electron

The exine of birch pollen was examined by scanning and transmission electron microscopy in the native state and after fixation in different aqueous fixatives: glutaraldehyde + OsO4; glutaraldehyde + cetylpyridinium chloride (CPC) + OsO4; glutaraldehyde + cuprolinic blue (CB); and periodate + lysine + paraformaldehyde (PLP). The native pollen exine showed a thin (3-5-nm) border of electron-dense material lining the tectum and electron-dense material within microchannels and bacula cavities. Fixation with the addition of CPC resulted in a voluminous surface coat surrounding the pollen grain, but empty microchannels and bacula cavities. After fixation with the addition of CB, there was a thin surface coat, whereas microchannels and bacula cavities were partially filled with electron-dense material. The other fixatives led to empty microchannels and bacula cavities. There was no surface coat on the pollen grain. However, after all fixation procedures, a thin electron-dense border of the tectum remained visible. Concerning the electron-dense material filling microchannels and bacula cavities in the native pollen grain, the results obtained in the present study suggest that it is either completely lost (after conventional and PLP fixation) or, after fixation with a precipitating additive, partially (CB) or completely (CPC) solubilized and precipitated on the surface of the pollen grain as a surface coat.

Adhesion of Phytophthora palmivora zoospores: detection and ultrastructural visualization of concanavalin A-receptor sites appearing during encystment

1975 ◽  
Vol 19 (1) ◽  
pp. 11-20
Author(s):  
V.O. Sing ◽  
S. Bartnicki-Garcia
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Concanavalin A ◽  
Solid Surfaces ◽  
Trypsin Digestion ◽  
Phytophthora Palmivora ◽  
Con A ◽  
Binding Material ◽  
Ultraviolet Microscopy ◽  
Receptor Sites

The binding of concanavalin A (Con A) to the cell surface of zoospores and cysts of Phytophthora palmivora was studied by radiometry (125I-Con A), ultraviolet microscopy (fluorescein-Con A) and electron microscopy peroxidase-diaminobenzidine technique). Zoospores were found to secrete during the early stages of encystment a Con A-binding material susceptible to trypsin digestion. This glycoprotein is contained in the so-called peripheral vesicles and is probably responsible for the adhesion of the encysting zoospores to solid surfaces.

Bacteriophage ФX 174

1968 ◽  
Vol 26 ◽  
pp. 32-33
Author(s):  
M. E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Nutrient Medium ◽  
Structural Changes ◽  
Uranyl Acetate ◽  
Dense Material ◽  
Medium Ph ◽  
Electron Dense Material ◽  
Virus Particles ◽  
Ultrathin Sections

Cultures of Escherichia coli CIA (Bertani) growing logarithmically in nutrient medium were infected with 5 to 200 bacteriophage §X 174 per cell. At various times after infection the cultures were fixed for 1 hour in nutrient medium containing 5% formaldehyde pH 7, then pelleted and resuspended in 1% OSO4 in L-medium pH 7 for 1 hour; the material was pelleted again and resuspended in a mixture of 1% OsO4 and 1% uranyl-acetate in water; in this mixture the cells were fixed for 10 hours at 20° C; after fixation they were dehydrated in acetone and embedded in Vestopal W. In ultrathin sections the first structural changes became visible 15 minutes after infection when some of the cells seemed to swell and round up. In the cells small aggregates of electron dense material were observed in the chromosomal areas, and sometimes virus particles were also seen within the area of the cells’ chromosome.

The distribution of Concanavalin A receptor sites on the membrane of chromaffin granules

1975 ◽  
Vol 19 (1) ◽  
pp. 33-54
Author(s):  
P.A. Eagles ◽  
L.N. Johnson ◽  
C. Van Horn
Keyword(s):  
Concanavalin A ◽  
Plasma Membranes ◽  
Asymmetric Distribution ◽  
Chromaffin Granules ◽  
Intracellular Membrane ◽  
Chromaffin Granule ◽  
Binding Studies ◽  
Cell Cytoplasm ◽  
Con A ◽  
Receptor Sites

The distribution of concanavalin A (con A) receptor sites on the membranes of chromaffin granules has been investigated by binding studies using 125I-labelled con A and by electron-microscope studies using ferritin-labelled con A. In both experiments con A was observed to bind to chromaffin granule membranes but not to intact granules. The ferritin-con A particles bind to only one of the two possible surfaces of the chromaffin granule membranes. These results are in agreement with previous observations concerning the asymmetric distribution of saccharide residues on the surfaces of a number of different plasma membranes. They suggest that for the intracellular membrane of the chromaffin granule the saccharide sites, like those in plasma membranes, are not exposed to the cell cytoplasm. Further work is necessary to establish whether these sites are on the inner surface of the membrane or whether they are unmasked during the conversion of granules to membrane ghosts.

A light and electron microscopic study of microsporogenesis in Azolla microphylla

1985 ◽  
Vol 86 ◽  
pp. 53-58 ◽  
Author(s):  
Y. R. Herd ◽  
E. G. Cutter ◽  
I. Watanabe
Keyword(s):  
Dense Material ◽  
Electron Microscopic ◽  
Electron Dense Material ◽  
Azolla Microphylla ◽  
Dense Cytoplasm ◽  
Transmission Electron ◽  
Tapetal Cells ◽  
Electron Microscopes ◽  
Mother Cells ◽  
Membranous Material

SynopsisMicrosporogenesis in cultured material of Azolla microphylla was studied with the light and transmission electron microscopes. The first formed sporangium, a megasporangium, aborts and several microsporangia develop below. Initially, a single sporogenous cell is present, surrounded by a single layered tapetum and the microsporangial wall. Subsequently, several sporogenous cells are connected by plasmodesmata. The microspore mother cells are less densely cytoplasmic than the tapetal cells. Callose-like material is deposited around the microspore mother cells, but disappears before meiosis. The tetrads of microspores contain well defined organelles but less dense cytoplasm than the surrounding periplasmodium. Electron dense material deposited on the plasma membrane of the microspores eventually forms the endospore. The unornamented exospore develops by continued deposition of electron dense material. Degeneration of the periplasmodium gives rise to membranous material which appears to form a template for the massulae.

scholarly journals A temperature-sensitive NUP116 null mutant forms a nuclear envelope seal over the yeast nuclear pore complex thereby blocking nucleocytoplasmic traffic.

1993 ◽  
Vol 123 (2) ◽  
pp. 275-284 ◽  
Author(s):  
S R Wente ◽  
G Blobel
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Nuclear Periphery ◽  
Dense Material ◽  
Nuclear Pore ◽  
Temperature Sensitive ◽  
Electron Microscopic ◽  
Electron Dense Material ◽  
Cytoplasmic Face ◽  
Delta Cells

NUP116 encodes a 116-kD yeast nuclear pore complex (NPC) protein that is not essential but its deletion (nup116 delta) slows cell growth at 23 degrees C and is lethal at 37 degrees C (Wente, S. R., M. P. Rout, and G. Blobel. 1992. J. Cell Biol. 119:705-723). Electron microscopic analysis of nup116 delta cells shifted to growth at 37 degrees C revealed striking perturbations of the nuclear envelope: a double membrane seal that was continuous with the inner and outer nuclear membranes had formed over the cytoplasmic face of the NPCs. Electron-dense material was observed accumulating between the cytoplasmic face of these NPCs and the membrane seal, resulting in "herniations" of the nuclear envelope around individual NPCs. In situ hybridization with poly(dT) probes showed the accumulation of polyadenylated RNA in the nuclei of arrested nup116 delta cells, sometimes in the form of punctate patches at the nuclear periphery. This is consistent with the electron microscopically observed accumulation of electron-dense material within the nuclear envelope herniations. We propose that nup116 delta NPCs remain competent for export, but that the formation of the membrane seals over the NPCs blocks nucleocytoplasmic traffic.

scholarly journals THE PARASPORAL BODY OF BACILLUS LATEROSPORUS LAUBACH

1957 ◽  
Vol 3 (6) ◽  
pp. 1001-1010 ◽  
Author(s):  
Christopher L. Hannay
Keyword(s):  
Cross Sections ◽  
Vegetative Cell ◽  
Culture Medium ◽  
Lateral Position ◽  
The Body ◽  
Dense Material ◽  
Spore Coat ◽  
Thin Sections ◽  
Electron Dense Material ◽  
Ultrathin Sections

On sporulation the slender vegetative rods swell and form larger spindle-shaped cells in which the spores are formed. When the spores mature they lie in a lateral position cradled in canoe-shaped parasporal bodies which are highly basophilic and can be differentiated from the surrounding vegetative cell cytoplasm with dilute basic dyes. On completion of sporulation the vegetative cell protoplasm and the cell wall lyse, leaving the spore cradled in its parasporal body. This attachment continues indefinitely on the usual culture medium and even persists after the spores have germinated. In thin sections of sporing cells the bodies are differentiated from the cell protoplasm by differences in structure. Whereas the protoplasm has a granular appearance, in both longitudinal and cross-sections the parasporal body comprises electron-dense lamellae running parallel with the membranes of the spore coat and less electron-dense material in the interstices of the lamellae. The inner surface of the body is contiguous with that of the spore coat as if it were part of the spore, rather than a separate body attached to the spore. The staining reactions of the parasporal body are not consistent with those of any substance described in bacteria. With Giemsa the bodies stain like chromatin, but the Feulgen reaction indicates that they do not contain the requisite nucleic acid. With an aqueous solution of toluidine blue they stain metachromatically, but with an acidified solution the results are variable. Neisser's stain for polyphosphate is negative. The basophilic substance is removed from the body with some organic solvents. This basophilic substance has not been specifically identified with any material seen in ultrathin sections, but it is suggested that it might be the less electron-dense material in the interstices of the lamellar structure. In contrast to the spore coat of B. laterosporus, those of its two relatives B. brevis and B. circulans take up basic stain like the parasporal body. Thin spore sections of these species have shown that the walls are thicker than those surrounding the spores of B. laterosporus, and it is suggested that the outer stainable layer of brevis and circulans spores is an accessory coat which in laterosporus may have been deformed to give a parasporal body.

scholarly journals Pollen Germination Potential Influences by Carbohydrates and Proteins in Pollen Grains of Asian Pear

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 762A-762
Author(s):  
Wol-Soo Kim* ◽  
Sang-Hyun Lee
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Germination Rate ◽  
Pollen Viability ◽  
Pollen Grains ◽  
Tube Growth ◽  
Con A ◽  
Asian Pear ◽  
Pollen Surface

In order to investigate the cause of differences of mature pollen in Asian pear (Pyrus phyfolia) that are collected from various sources for the artificial pollination, various factors were measured as below: the composition of nonstructural carbohydrate in bud at 30 days after full bloom, the contents of crude protein in skin, cytosol and membrane, and the affinity for lectin (CON-A: Concanavalin, type III A) of glycoprotein in cytosol of pollen were measured. Contents of sucrose and glucose in buds influenced pollen germination rate and pollen tube growth, respectively. Therefore, soluble types of carbohydrates stored in bud were regarded as influencing on pollen germination rate and pollen tube growth. Pollen, which showed low activity, had low affinity on CON-A, lectin of glycoprotein, because it had fragile membrane, proteins in cells were denatured to pollen surface and certain enzymes concerned in pollen germination lost stability and activity. Pollens that showed high activity contained 92 kDa protein while others not. This was assumed as influencing on control of pollen viability.

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