Ultrastructure of the conidia of Helminthosporium maydis

1973 ◽  
Vol 51 (10) ◽  
pp. 2006-2008 ◽  
Author(s):  
J. A. White ◽  
O. H. Calvert ◽  
M. F. Brown
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Electron Microscopic Examination ◽  
Cell Organelles ◽  
Electron Microscopic ◽  
Light Microscope Level ◽  
Melanin Pigmentation ◽  
Conidial Morphology ◽  
Distinct Cell ◽  
Septal Pores

Mature conidia of race O and of race T of Helminthosporium maydis were examined microscopically to characterize the general ultrastructure of the conidia and to determine if the two races could be differentiated on the basis of conidial morphology. At the light-microscope level, the two races could not be separated. Histochemical analyses showed that, in both races, the cell wall was composed of chitin with melanin pigmentation. Electron-microscopic examination of thin-sectioned conidia revealed the presence of two distinct cell walls. Cross-walls were found to have typical ascomycetous septal pores. The types of cell organelles found in mature conidia did not provide any indication of the pathogenic capability of the fungus. No consistent differences were found in the ultrastructure of the two races and it was concluded that race T could not be differentiated from race O on the basis of conidial morphology.

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.

scholarly journals Plasmodesmata-Related Structural and Functional Proteins: The Long Sought-After Secrets of a Cytoplasmic Channel in Plant Cell Walls

2019 ◽  
Vol 20 (12) ◽  
pp. 2946 ◽  
Author(s):  
Xiao Han ◽  
Li-Jun Huang ◽  
Dan Feng ◽  
Wenhan Jiang ◽  
Wenzhuo Miu ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plasma Membranes ◽  
Plant Cell Wall ◽  
Plant Cells ◽  
Protein Composition ◽  
Cell Contact ◽  
Plant Cell Walls ◽  
Cell Organelles

Plant cells are separated by cellulose cell walls that impede direct cell-to-cell contact. In order to facilitate intercellular communication, plant cells develop unique cell-wall-spanning structures termed plasmodesmata (PD). PD are membranous channels that link the cytoplasm, plasma membranes, and endoplasmic reticulum of adjacent cells to provide cytoplasmic and membrane continuity for molecular trafficking. PD play important roles for the development and physiology of all plants. The structure and function of PD in the plant cell walls are highly dynamic and tightly regulated. Despite their importance, plasmodesmata are among the few plant cell organelles that remain poorly understood. The molecular properties of PD seem largely elusive or speculative. In this review, we firstly describe the general PD structure and its protein composition. We then discuss the recent progress in identification and characterization of PD-associated plant cell-wall proteins that regulate PD function, with particular emphasis on callose metabolizing and binding proteins, and protein kinases targeted to and around PD.

Electron microscopic observations of infection threads in driselase treated nodules of Astragalus sinicus

1986 ◽  
Vol 32 (12) ◽  
pp. 947-952 ◽  
Author(s):  
Shiro Higashi ◽  
Kazuya Kushiyama ◽  
Mikiko Abe
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Root Nodules ◽  
Morphological Characteristics ◽  
Enzyme Treatment ◽  
Vascular Bundles ◽  
Electron Microscopic ◽  
Astragalus Sinicus ◽  
Infection Threads

The morphological characteristics of infection threads in the root nodules of Astragalus sinicus were examined by scanning and transmission electron microscopy. The infection threads, epidermal cell walls, and vascular bundles of the nodule were not altered when a nodule was treated with driselase (a plant cell wall degrading enzyme), although the cell walls of meristematic and bacteroid-including zones were completely decomposed by the enzyme treatment. Some infection threads were funnel shaped at the site of attachment of the infection thread to the host cell wall.

scholarly journals Six cases of daptomycin-non-susceptible Staphylococcus aureus bacteraemia in Singapore

2010 ◽  
Vol 59 (12) ◽  
pp. 1509-1513 ◽  
Author(s):  
Li-Yang Hsu ◽  
Micky Leong ◽  
Michelle Balm ◽  
Douglas S. Chan ◽  
Paul Huggan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Microscopic Examination ◽  
Salvage Therapy ◽  
Cell Walls ◽  
Susceptibility Testing ◽  
Electron Microscopic Examination ◽  
Therapeutic Failure ◽  
Vancomycin Therapy ◽  
Electron Microscopic ◽  
Initial Susceptibility

We report what we believe to be the first six cases of daptomycin-non-susceptible Staphylococcus aureus infections from Singapore. These strains were rapidly isolated after bacteraemic patients were switched to daptomycin following initial prolonged unsuccessful therapy with vancomycin, despite confirmation of daptomycin susceptibility just prior to initiating daptomycin therapy. The majority of post-vancomycin therapy strains exhibited marked thickening of their cell walls on electron microscopic examination. In patients with persistent S. aureus bacteraemia, therapeutic failure with daptomycin may occur if used as salvage therapy following vancomycin failure, notwithstanding initial susceptibility testing results.

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.

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.

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.

An ultrastructural morphometric analysis of platelet giant and fusion granules in control subjects and patients with neoplastic myeloproliferative disorders

1983 ◽  
Vol 41 ◽  
pp. 786-787
Author(s):  
Claire M. Payne ◽  
Lewis Glasser
Keyword(s):  
Human Platelet ◽  
Electron Microscopic Examination ◽  
Myeloproliferative Disorders ◽  
Qualitative Assessment ◽  
Structural Elements ◽  
Cell Organelles ◽  
Electron Microscopic ◽  
Platelet Factor ◽  
Normal Human ◽  
Myelomonocytic Leukemia

Electron microscopy has made a significant contribution to our understanding of the normal and defective human platelet. The normal human platelet is ultrastructurally complex and although only 2-4 microns in diameter, contains many cell organelles and structural elements shared with muscle cells and neurons. Platelet organelles include mitochondria, microfilaments, microtubules, α-granules (contain fibrinogen and platelet factor 4), dense bodies (contain serotonin, ADP, ATP and calcium), a dense tubular system and open canalicular system (Fig. 1). An ultrastructural description of giant granules were first reported in 1960 in Willebrand-Jürgens disease. Fusion granules (giant, irregularly-shaped granules) resulting from an apparent "fusion of normal-sized α-granules have since been reported to be characteristic of platelets obtained from patients with preleukemia and myelomonocytic leukemia.Electron microscopic examination of normal platelets in our laboratory revealed occasional granules which also appear fused and irregular in shape.A qualitative assessment of what constitutes an abnormal granule is therefore subjective. The purpose of this study was to establish morphometric criteria which can be used to define the pathological nature of giant and fusion-type platelet granules, and to determine if patients with neoplastic myeloproliferative disorders can be distinguished from patients with a variety of benign conditions for diagnostic purposes.

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