scholarly journals STUDIES ON THE BIOCHEMISTRY AND FINE STRUCTURE OF SILICA SHELL FORMATION IN DIATOMS

1965 ◽  
Vol 24 (1) ◽  
pp. 39-55 ◽  
Author(s):  
B. E. F. Reimann ◽  
Joyce C. Lewin ◽  
B. E. Volcani
Keyword(s):  
Cell Wall ◽  
Organic Material ◽  
Hydrofluoric Acid ◽  
Electron Microscope Study ◽  
Silica Shell ◽  
Ruthenium Red ◽  
Enzyme Treatment ◽  
Shell Formation ◽  
Mechanical Method ◽  
Ultrathin Sections

An electron microscope study on the cell wall of the diatom Cylindrotheca fusiformis was carried out using stereoscopic and sectioning techniques. Material prepared by an enzyme treatment or by a mechanical method showed that the wall consists of two major components: a silica shell and organic material. Vapor of hydrofluoric acid was employed to remove the silica and thereby reveal the arrangement of the organic material. An attempt was made to increase the contrast of the organic component by "staining." Uranylacetate not only increased the electron opacity of the organic material but also apparently decreased the electron opacity of the silica shell. In ultrathin sections of complete cells, the structure as revealed by stereoscopy could be confirmed and extended. Every part of the silica shell is tightly enclosed by organic material. In the valve region the silica enclosed in this way is located between other layers of organic material. The whole cell wall is surrounded by a mucilaginous substance which stains with ruthenium red.

An electron microscope study of initiation of infection by conidia of Harposporium oxycoracum, an endozoic nematophagous Hyphomycete

1983 ◽  
Vol 61 (3) ◽  
pp. 893-898 ◽  
Author(s):  
Masatoshi Saikawa ◽  
Junko Totsuka ◽  
Chiharu Morikawa
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Electron Microscope ◽  
Electron Microscope Study ◽  
Germ Tube ◽  
Ruthenium Red ◽  
Convex Side ◽  
En Bloc ◽  
Dense Mass ◽  
Ultrathin Sections

Infective conidia of an endozoic nematophagous hyphomycete, Harposporium oxycoracum Drechsler, were examined by means of electron microscopy. Each of the conidia is very narrow and has a sharply pointed distal and slightly swollen basal end. The swollen basal end was shown, in ultrathin sections stained with ruthenium red en bloc, to be an electron-dense mass of fibrils (ca. 2–3 μm in diameter). The fibrils, thought to be derived from the conidial cell wall, were densely aggregated and were surrounded by a network of more sparsely aggregated fibrils spreading from the fibrous mass of the conidial base. The spreading fibrils seemed to correspond to the mucous droplet observed under the light microscope. It was also found in the present study that the conidia of the fungus were swallowed by nematodes into their lower gut. On germination in the lower gut, a narrow germ tube 5–6 μm wide developed from the convex side of the conidium and produced a simple pore septum at the site of penetration to delimit the empty conidium.

An Electron Microscope Study of the Outer Layers of Barley Leaves Infected with Rhynchosporium secalis

1974 ◽  
Vol 1 (2) ◽  
pp. 313 ◽  
Author(s):  
CC Ryan ◽  
CJ Grivell
Keyword(s):  
Cell Wall ◽  
Outer Layer ◽  
Electron Microscope Study ◽  
Electron Microscopic Examination ◽  
Ruthenium Red ◽  
Electron Microscopic ◽  
Before And After ◽  
Barley Leaves ◽  
Epidermal Cell Wall ◽  
Wall Following

An electron microscopic examination was made of barley leaves before and after infection by R. secalis. Ruthenium red was used as an electron-opaque stain for pectic material. In uninfected leaves the adaxial surface consisted of wax, cuticle, pectic and inner and outer layer of the epidermal cell wall. Following penetration, infecting hyphae grew between the pectic layer and outer layer of the epidermal wall. The pectic and cuticular layers remained largely intact in leaf lesions until conidia were produced, whereas the cell wall was degraded and replaced by hyphae.

scholarly journals THE FINE STRUCTURE OF CHONDROCOCCUS COLUMNARIS

1967 ◽  
Vol 35 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Jack L. Pate ◽  
Erling J. Ordal
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Electron Microscope ◽  
Outer Membrane ◽  
Electron Microscope Study ◽  
Ruthenium Red ◽  
Gliding Motility ◽  
Dense Layer ◽  
Adhesive Properties

An electron microscope study of the myxobacterium Chondrococcus columnaris has revealed the following structures in the peripheral layers of the cells: (1) a plasma membrane, (2) a single dense layer (probably the mucopeptide component of the cell wall), (3) peripheral fibrils, (4) an outer membrane, and (5) a material coating the surfaces of the cells which could be stained with the dye ruthenium red.The ruthenium red-positive material is probably an acid mucopolysaccharide and may be involved in the adhesive properties of the cells. The outer membrane and plasma membrane both have the appearance of unit membranes: an electron-translucent layer sandwiched between two electron-opaque layers. The peripheral fibrils span the gap between the outer membrane and the mucopeptide layer, a distance of about 100 A, and run parallel to each other along the length of the cell. The fibrils appear to be continuous across the ends of the cells. The location of these fibrillar structures suggests that they may play a role in the gliding motility of these bacteria.

Ferrozine Assay for Simple and Cheap Iron Analysis of Silica-Coated Iron Oxide Nanoparticles

2018 ◽  
Author(s):  
Hattie Ring ◽  
Zhe Gao ◽  
Nathan D. Klein ◽  
Michael Garwood ◽  
John C. Bischof ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Hydrofluoric Acid ◽  
Inductively Coupled Plasma ◽  
Silica Shell ◽  
Oxide Nanoparticles ◽  
Inductively Coupled ◽  
Digestion Process ◽  
Plasma Methods ◽  
Iron Analysis

The Ferrozinen assay is applied as an accurate and rapid method to quantify the iron content of iron oxide nanoparticles (IONPs) and can be used in biological matrices. The addition of ascorbic aqcid accelerates the digestion process and can penetrate an IONP core within a mesoporous and solid silica shell. This new digestion protocol avoids the need for hydrofluoric acid to digest the surrounding silica shell and provides and accessible alternative to inductively coupled plasma methods. With the updated digestion protocol, the quantitative range of the Ferrozine assay is 1 - 14 ppm. <br>

Ferrozine Assay for Simple and Cheap Iron Analysis of Silica-Coated Iron Oxide Nanoparticles

2018 ◽  
Author(s):  
Hattie Ring ◽  
Zhe Gao ◽  
Nathan D. Klein ◽  
Michael Garwood ◽  
John C. Bischof ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Hydrofluoric Acid ◽  
Inductively Coupled Plasma ◽  
Silica Shell ◽  
Oxide Nanoparticles ◽  
Inductively Coupled ◽  
Digestion Process ◽  
Plasma Methods ◽  
Iron Analysis

The Ferrozinen assay is applied as an accurate and rapid method to quantify the iron content of iron oxide nanoparticles (IONPs) and can be used in biological matrices. The addition of ascorbic aqcid accelerates the digestion process and can penetrate an IONP core within a mesoporous and solid silica shell. This new digestion protocol avoids the need for hydrofluoric acid to digest the surrounding silica shell and provides and accessible alternative to inductively coupled plasma methods. With the updated digestion protocol, the quantitative range of the Ferrozine assay is 1 - 14 ppm. <br>

scholarly journals An Electron Microscope Study of Basophile Substances of Frozen-Dried Rat Liver

1958 ◽  
Vol 4 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Henry Finck
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Rat Liver ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Freeze Drying ◽  
Light And Electron Microscopy ◽  
Enzyme Treatment ◽  
Dense Granules ◽  
Homogeneous Matrix

Small pieces of liver from rats subjected to different dietary regimes were fixed by freeze-drying, and postfixed by in vacuo heating and denaturation with alcohol. Specimens were digested with ribo- or deoxyribonuclease, and stained with gallocyanin-chromalum, azure II, the Feulgen procedure or alcoholic platinic tetrabromide. Some specimens were reserved as controls of the effects of enzyme treatment. Stained and unstained specimens were embedded in methacrylate and examined by light and electron microscopy. Basophilic and Feulgen-positive substances, after contact with watery reagents, were found by electron microscopy to exist as small dense granules embedded in a less dense homogeneous matrix, forming the walls of submicroscopic vacuoles. These granules were absent after digestion with nucleodepolymerases. In specimens (unstained, or stained with platinic tetrabromide) which had not passed through water, the dense (basophile) substances in nuclei and cytoplasm were found to exist, not as granules, but as ill defined submicroscopic concentrates which blended imperceptibly into the homogeneous matrix of the vacuolar walls. Objections to the use of stains for improving contrast conditions in electron microscopy of tissues are discussed, and it is concluded that the reagents do not necessarily produce the observed increases in contrast by selectively stabilizing certain structures. The concept of microsomes as pre-existing distinct morphological entities in intact (unhomogenized) cells is thought to be inconsistent with the distribution of basophile substances in frozen-dried liver.

Silica Shell Formation in Synchronously Dividing Diatoms

1966 ◽  
pp. 169-188 ◽  
Author(s):  
Joyce C. Lewin ◽  
Bernhard E. Reimann ◽  
William F. Busby ◽  
Benjamin E. Volcani
Keyword(s):  
Silica Shell ◽  
Shell Formation

Electron microscopy of two nematode-destroying fungi, Meristacrum asterospermum and Zygnemomyces echinulatus (Meristacraceae, Entomophthorales)

1997 ◽  
Vol 75 (5) ◽  
pp. 762-768 ◽  
Author(s):  
Masatoshi Saikawa ◽  
Masami Oguchi ◽  
Rafael F. Castañeda Ruiz
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Key Words ◽  
Septal Wall ◽  
Apical Portion ◽  
Key Words Infection ◽  
Ultrathin Sections

Infection of nematodes by Meristacrum asterospermum and Zygnemomyces echinulatus was initiated by conidia adhering to the nematode's cuticle. Each conidium developed an infection peg to penetrate the nematode after adhesion. In M. asterospermum, an infection peg just under the penetration was found in ultrathin sections, in which the peg's cell wall was broken into several lobes that were covered entirely with an amorphous mass of electron-opaque substance. Septa formed in the apical portion of aerial conidiophore under conidiation. The septal wall was nonperforate and often contained electron-opaque inclusions. Vegetative hyphae of Z. echinulatus had typical bifurcate septa, but septa at both ends of the pedicel of conidia were often slightly deformed. Key words: infection of nematodes, Meristacrum asterospermum, septum, Zygnemomyces echinulatus.

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