scholarly journals Differences in the Apparent Permeability of Spore Walls and Prothallial Cell Walls in Onoclea sensibilis

1980 ◽  
Vol 70 (4) ◽  
pp. 119 ◽  
Author(s):  
John H. Miller
Keyword(s):  
Cell Walls ◽  
Apparent Permeability ◽  
Onoclea Sensibilis ◽  
Spore Walls ◽  
Prothallial Cell

Ultrastructural localization of β-1,4-glucan-containing molecules in the cell walls of some fungi: a comparative study between spore and mycelium

1990 ◽  
Vol 36 (3) ◽  
pp. 149-158 ◽  
Author(s):  
Nicole Benhamou ◽  
Hélene Chamberland ◽  
Sylvain Noel ◽  
G. B. Ouellette
Keyword(s):  
Cell Walls ◽  
Trichoderma Viride ◽  
Ultrastructural Localization ◽  
Cell Wall Composition ◽  
Gold Complex ◽  
Important Criterion ◽  
Lytic Enzymes ◽  
Ophiostoma Ulmi ◽  
Cellulase Digestion ◽  
Spore Walls

An exoglucanase, purified from a cellulase produced by the fungus Trichoderma harzianum was complexed to colloidal gold and used for localizing β-1,4-glucan-containing molecules in the cell walls of some fungi. With the exception of Aspergillus niger, β-1,4-glucan-rich molecules were found to be associated with conidial walls of Trichoderma viride, Fusarium oxysporum f.sp. radicis-lycopersici, Verticillium albo-atrum, Penicillium thomii, and Ophiostoma ulmi. The abolition of wall labeling following previous cellulase digestion suggested that the compunds detected by the exoglucanase–gold complex were likely of cellulosic nature. Differences in cell wall composition between conidia and mycelium were reflected by the absence of β-1,4-glucan-containing molecules in the vegetative walls of most fungi tested. This raises the question as to what extent the chemical composition of spore walls should be considered as an important criterion in the taxonomy and phylogeny of fungi. The disappearance of these molecules upon conidial germination (with the exception of O. ulmi) suggests that lytic enzymes are produced to cause wall breakdown. The presence of molecules with β-1,4-linkages in conidia probably contribute to reinforcement of the wall architecture. Key words: fungi, spores, β-1,4-glucan, gold cytochemistry.

DIT101 (CSD2, CAL1), a cell cycle-regulated yeast gene required for synthesis of chitin in cell walls and chitosan in spore walls

Yeast ◽  
1992 ◽  
Vol 8 (12) ◽  
pp. 1089-1099 ◽  
Author(s):  
Manuela Pammer ◽  
Peter Briza ◽  
Adolf Ellinger ◽  
Tillman Schuster ◽  
Rolf Stucka ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Walls ◽  
Yeast Gene ◽  
Spore Walls ◽  
A Cell

scholarly journals The structure of plasmodesmata as revealed by plasmolysis, detergent extraction, and protease digestion.

1991 ◽  
Vol 112 (4) ◽  
pp. 739-747 ◽  
Author(s):  
L G Tilney ◽  
T J Cooke ◽  
P S Connelly ◽  
M S Tilney
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Walls ◽  
Plant Cells ◽  
Intercellular Bridges ◽  
Protease Digestion ◽  
Onoclea Sensibilis ◽  
Detergent Extraction ◽  
Triton X ◽  
Cut Surface

Plasmodesmata or intercellular bridges that connect plant cells are cylindrical channels approximately 40 nm in diameter. Running through the center of each is a dense rod, the desmotubule, that is connected to the endoplasmic reticulum of adjacent cells. Fern, Onoclea sensibilis, gametophytes were cut in half and the cut surfaces exposed to the detergent, Triton X 100, then fixed. Although the plasma membrane limiting the plasmodesma is solubilized partially or completely, the desmotubule remains intact. Alternatively, if the cut surface is exposed to papain, then fixed, the desmotubule disappears, but the plasma membrane limiting the plasmodesmata remains intact albeit swollen and irregular in profile. Gametophytes were plasmolyzed, and then fixed. As the cells retract from their cell walls they leave behind the plasmodesmata still inserted in the cell wall. They can break cleanly when the cell proper retracts or can pull away portions of the plasma membrane of the cell with them. Where the desmotubule remains intact, the plasmodesma retains its shape. These images and the results with detergents and proteases indicate that the desmotubule provides a cytoskeletal element for each plasmodesma, an element that not only stabilizes the whole structure, but also limits its size and porosity. It is likely to be composed in large part of protein. Suggestions are made as to why this structure has been selected for in evolution.

QUALITATIVE ANALYSES OF VEGETATIVE CELL WALLS AND SPORE WALLS OF SOME REPRESENTATIVE SPECIES OF STREPTOMYCES

1966 ◽  
Vol 12 (5) ◽  
pp. 985-994 ◽  
Author(s):  
Peter J. DeJong ◽  
Elizabeth McCoy
Keyword(s):  
Cell Wall ◽  
Aspartic Acid ◽  
Vegetative Cell ◽  
Cell Walls ◽  
Teichoic Acid ◽  
Minor Component ◽  
Paper Electrophoresis ◽  
Diaminopimelic Acid ◽  
Streptomyces Species ◽  
Spore Walls

Vegetative cell walls and spore walls of seven Streptomyces species representing four types of spore morphology were qualitatively analysed for their components. Amino acid and carbohydrate components (glucose, glucosamine, muramic acid, diaminopimelic acid, glutamic acid, glycine, alanine, arginine, threonine, valine, leucine, and aspartic acid) in both types of walls were identical in all species. Aspartic acid was a major component in spore walls, but a minor component in vegetative cell walls. Although organic phosphate was present in both vegetative- and spore-wall hydrolysates, the other components of teichoic acid were not found nor was teichoic acid extracted from the isolated walls by cold trichloroacetic acid. A portion of the vegetative cell wall was rendered soluble with lysozyme and separated by paper electrophoresis into two fractions detected with ninhydrin. The lysozyme-resistant portion of the vegetative cell wall showed the same major and minor components as the spore walls, which are also lysozyme resistant.

Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

1973 ◽  
Vol 31 ◽  
pp. 468-469
Author(s):  
N.C. Lyon ◽  
W. C. Mueller
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Nitric Acid ◽  
Oxalic Acid ◽  
Light Microscopy ◽  
Epidermal Cell ◽  
Cell Walls ◽  
Plant Viruses ◽  
Plant Leaves ◽  
Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

An ultrastructural study of vegetative incompatibility in plants

1978 ◽  
Vol 36 (2) ◽  
pp. 436-437
Author(s):  
Randy Moore
Keyword(s):  
Ultrastructural Study ◽  
Cell Walls ◽  
Growth And Development ◽  
Solanum Pennellii ◽  
Initial Product ◽  
Basic Aspect ◽  
Tissue Interactions ◽  
Graft Interface ◽  
Antigen Antibody ◽  
Standard Fixation

Cell and tissue interactions are a basic aspect of eukaryotic growth and development. While cell-to-cell interactions involving recognition and incompatibility have been studied extensively in animals, there is no known antigen-antibody reaction in plants and the recognition mechanisms operating in plant grafts have been virtually neglected.An ultrastructural study of the Sedum telephoides/Solanum pennellii graft was undertaken to define possible mechanisms of plant graft incompatibility. Grafts were surgically dissected from greenhouse grown plants at various times over 1-4 weeks and prepared for EM employing variations in the standard fixation and embedding procedure. Stock and scion adhere within 6 days after grafting. Following progressive cell senescence in both Sedum and Solanum, the graft interface appears as a band of 8-11 crushed cells after 2 weeks (Fig. 1, I). Trapped between the buckled cell walls are densely staining cytoplasmic remnants and residual starch grains, an initial product of wound reactions in plants.

Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 52-53
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Plastic Strain ◽  
Cell Walls ◽  
Room Temperature ◽  
Mechanical Response ◽  
Biaxial Tension ◽  
Initial Deformation ◽  
Uniaxial Deformation ◽  
Biaxial Deformation ◽  
Stress States ◽  
Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

Cryosectioning plant roots prepared by high-pressure freezing

1987 ◽  
Vol 45 ◽  
pp. 662-663
Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold
Keyword(s):  
High Pressure ◽  
Cell Walls ◽  
Plant Tissues ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Vitreous State ◽  
Radial Depth ◽  
Irregular Topography ◽  
Considerable Depth ◽  
Conventional Freezing

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.

Characterization of machined polystyrene foam

1989 ◽  
Vol 47 ◽  
pp. 372-373
Author(s):  
C. W. Price ◽  
E. F. Lindsey ◽  
R. M. Franks ◽  
M. A. Lane
Keyword(s):  
Surface Finish ◽  
Cell Walls ◽  
Surface Structures ◽  
Efficient Technique ◽  
Low Density ◽  
Polystyrene Foam ◽  
Planar Surfaces ◽  
Machining Characteristics

Diamond-point turning is an efficient technique for machining low-density polystyrene foam, and the surface finish can be substantially improved by grinding. However, both diamond-point turning and grinding tend to tear and fracture cell walls and leave asperities formed by agglomerations of fragmented cell walls. Vibratoming is proving to be an excellent technique to form planar surfaces in polystyrene, and the machining characteristics of vibratoming and diamond-point turning are compared.Our work has demonstrated that proper evaluation of surface structures in low density polystyrene foam requires stereoscopic examinations; tilts of + and − 3 1/2 degrees were used for the stereo pairs. Coating does not seriously distort low-density polystyrene foam. Therefore, the specimens were gold-palladium coated and examined in a Hitachi S-800 FESEM at 5 kV.

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