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.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

Adhesion of the Boston ivy tendril

1977 ◽  
Vol 55 (8) ◽  
pp. 918-924 ◽  
Author(s):  
Anton G. Endress ◽  
William W. Thomson
Keyword(s):  
Cell Walls ◽  
Tactile Stimulation ◽  
Electron Microscopic Examination ◽  
Ruthenium Red ◽  
Contact Interface ◽  
Electron Microscopic ◽  
Colloidal Iron ◽  
Peripheral Cells ◽  
Adhesive Secretion ◽  
Stimulation Of

Tactile stimulation of Boston ivy tendrils results in the development of bilaterally symmetric discs which adhere to substrates in the vicinity of the tendrils. Our electron microscopic examination of the tendrils indicates that adhesive secretion occurs from the peripheral cells at the contact face of the discs. Cell walls in this region develop pockets which fill with adhesive and ultimately coalesce. In fully adherent discs, the adhesive occupies the region between the substrate and the cells as well as the intracellular regions between the peripheral cells. While a cuticle was present on immature discs, no cuticle-like material was observed at the contact interface of mature discs.Staining of the adhesive was enhanced by ruthenium red and potassium ferrocyanide treatments, and the adhesive bound both colloidal iron and thorium. These results indicated that the adhesive is possibly a mucopolysaccharide.

A comparison of the effects of several antifungal imidazole derivatives and polyenes on Candida albicans: an ultrastructural study by scanning electron microscopy

1982 ◽  
Vol 28 (10) ◽  
pp. 1119-1126 ◽  
Author(s):  
M. Bastide ◽  
S. Jouvert ◽  
J.-M. Bastide
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Candida Albicans ◽  
Cytoplasmic Membrane ◽  
Electron Microscopic Examination ◽  
Yeast Cells ◽  
Electron Microscopic ◽  
Imidazole Derivatives ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.

An electron-microscope study of the structure of Domiati cheese

1973 ◽  
Vol 40 (1) ◽  
pp. 113-117 ◽  
Author(s):  
M. H. Abd El-Salam ◽  
Safinaz El-Shibiny
Keyword(s):  
Electron Microscope ◽  
Internal Structure ◽  
Microscopic Examination ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Electron Microscopic Examination ◽  
Spherical Particles ◽  
Electron Microscopic ◽  
Ultrathin Sections ◽  
Large Spherical

SummaryA technique is described for preparing ultrathin sections from cheese for electron-microscopic examination. The internal structure of fresh Domiati cheese was found to be composed of a framework of large, spherical casein aggregates held by bridges and enclosing fat.After pickling, the casein aggregates were partly disintegrated into small spherical particles forming a loose structure.

scholarly journals Two Types of Bacteria Adherent to Bovine Respiratory Tract Ciliated Epithelium

1993 ◽  
Vol 30 (1) ◽  
pp. 12-19 ◽  
Author(s):  
A. T. Hastie ◽  
L. P. Evans ◽  
A. M. Allen
Keyword(s):  
Cell Wall ◽  
Microscopic Examination ◽  
Lectin Binding ◽  
Electron Microscopic Examination ◽  
Tracheal Epithelium ◽  
Ciliated Cells ◽  
Electron Microscopic ◽  
Department Of Agriculture ◽  
Immunogold Staining ◽  
Transmission Electron

Two hundred sixty tracheas were obtained from a Philadelphia abattoir under permit from the Department of Agriculture; the tracheas were excised from predominantly Holstein calves of both sexes that weighed approximately 250 kg. Tracheas were transported in normal saline to the laboratory at Thomas Jefferson University, Philadelphia, Pennsylvania. Evidence of bacteria adherent to the tracheal epithelium was found in specimens from 20/24 of these tracheas. The epithelium from each of five tracheas was placed in glutaraldehyde fixative for transmission electron microscopic examination. Epithelium from each of 12 other tracheas was placed in formaldehyde fixative for light microscopic examination. Microscopically, 13 of these 17 bovine tracheal epithelia were observed to contain bacteria located longitudinally parallel to and between cilia and microvilli of ciliated cells. Preparations of ciliary axonemes isolated from the epithelium of seven additional bovine tracheas also contained these bacteria in sections viewed by a transmission electron microscope. These bacteria had two different ultrastructural morphologies: filamentous with a trilaminar-structured cell wall and short with a thick, homogeneously stained cell wall beneath a regularly arrayed surface layer. The short bacillus had surface carbohydrates, including mannose, galactose, and N-acetylgalactosamine, identified by lectin binding. The filamentous bacillus was apparently externally deficient in these carbohydrates. Immunogold staining revealed that the filamentous bacillus was antigenically related to cilia-associated respiratory (CAR) bacillus, which has been identified in rabbit and rodent species. Significantly decreased numbers of cilia were obtained from tracheal epithelium heavily colonized by the filamentous bacilli, suggesting a pathologic change in ciliated cells.

Calcium and contractions of isolated smooth muscle cells from rat myometrium

1987 ◽  
Vol 65 (9) ◽  
pp. 1966-1975 ◽  
Author(s):  
M. Kyozuka ◽  
J. Crankshaw ◽  
I. Berezin ◽  
S. M. Collins ◽  
E. E. Daniel
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Electron Microscopic Examination ◽  
Muscle Cells ◽  
Isolated Cells ◽  
Electron Microscopic ◽  
Cell Shortening ◽  
Before And After ◽  
Intracellular Ca ◽  
Small Muscle

Smooth muscle cells were isolated from estrogenized rat myometrium by collagenase digestion. Electron microscopic examination and measurement of cell lengths by image-splitting micrometry were carried out after fixation with acrolein. Mean lengths of cells before and after isolation were 81.7 and 66.9 μm, respectively. Responses of cells were compared with contractions of isolated strips recorded isometrically. Effects of carbachol and KCl were examined in 2 mM Ca, 2 mM Ca + 4 mM EGTA, and 2 mM Ca + 10−8 M nitrendipine solution. Carbachol and KCl produced concentration-dependent shortening of isolated cells maximal at 30 s after addition. The concentrations of carbachol required to produce shortenings were about 100-fold less than those required to produce isometric contractions; but no major difference was observed in the concentration dependence of cell shortening and isometric contraction produced by potassium-induced depolarization. In 2 mM Ca solution, there was a phasic response, followed by a tonic response such that more than 50% of maximum cell shortening was maintained for 10 min. However, in 2 mM Ca + 4 mM EGTA or 10−8 M nitrendipine, the tonic contraction was abolished and cells rapidly relaxed after 30 s. If carbachol was added to cells after varying times in the EGTA-containing solution, the ability to initiate a contraction declined exponentially with a half-time of 160 s. Effects of depolarization by KCl were examined in 2 mM Ca plus nitrendipine and 2 mM Ca + 4 mM EGTA solution. Shortening occurred in 2 mM Ca solution by depolarization but not if nitrendipine was added. Though shortening was not observed in 2 mM Ca + 4 mM EGTA solution by KCl, subsequent addition of carbachol induced shortening. These results suggested that there was an intracellular Ca store site from which Ca was released by carbachol and which was not affected by depolarization in the absence of external Ca. No evidence was obtained that the contraction persists in Ca2+-free medium in isolated cells, which is in agreement with previous findings in small muscle strips in which only a similar transient response was obtained.

The novel structure of a microorganism of human gingival plaque

1974 ◽  
Vol 20 (10) ◽  
pp. 1307-1309 ◽  
Author(s):  
Nagi Halhoul ◽  
J. Ross Colvin
Keyword(s):  
Cell Wall ◽  
Microscopic Examination ◽  
Electron Microscopic Examination ◽  
Extracellular Polysaccharide ◽  
The Novel ◽  
Electron Microscopic ◽  
Individual Fiber ◽  
Novel Structure ◽  
Pass Through

Electron-microscopic examination of gingival plaque microflora showed a bacillus-like, microencapsulated, thick-walled organism with a previously unreported structure. This structure, which is not an example of fimbriae, flagellae, or attached extracellular polysaccharide, is a tuft of thin fibers about 0.3 μm long at only one end of the cell. The fibers begin in or near to the cell wall and pass through the microcapsule to the outside. The name lotussy is proposed for this new structure and the name lotuslifa for an individual fiber or filament.

scholarly journals Chloramphenicol-Related Changes in Mitochondrial Ultrastructure

1970 ◽  
Vol 7 (2) ◽  
pp. 501-521
Author(s):  
UNA SMITH ◽  
D. S. SMITH ◽  
ADEL. A. YUNIS
Keyword(s):  
Oxidative Phosphorylation ◽  
Insect Flight ◽  
Potent Inhibitor ◽  
Mitochondrial Protein ◽  
Electron Microscopic Examination ◽  
Excellent Correlation ◽  
Ideal Model ◽  
Electron Microscopic ◽  
Before And After ◽  
Ultrastructural Modification

An electron-microscopic examination of bone marrow mitochondria derived from 10 patients before and after chloramphenicol (CAP) therapy has shown that CAP induces an ultrastructural modification resulting in an increase in the density of the mitochondrial matrix. These changes resemble the condensed mitochondrial configurations which have previously been interpreted in terms of electron transfer and oxidative phosphorylation. However, in the concentrations employed in this study, CAP has no effect on mitochondrial respiration or on oxidative phosphorylation, but is a potent inhibitor of mitochondrial protein synthesis. Evidence relating this effect of the drug to its myelotoxicity has been supported by a comparative study demonstrating lack of effect of a drug such as tetracycline which is not known to be myelotoxic, and the excellent correlation between the extensiveness of mitochondrial changes in the marrow and the serum level of free CAP. The results were confirmed in a parallel study on insect flight muscle mitochondria, in which the metabolic state under which the drug is administered can be con trolled and where the regular disposition of the mitochondrial cristae provides an ideal model for the study of configurational changes.

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