Ultrastructural studies on the cell walls in Fusarium sulphureum

1979 ◽  
Vol 25 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Edward F. Schneider ◽  
Alan B. Wardrop
Keyword(s):  
Cell Walls ◽  
Outer Wall ◽  
Wall Layer ◽  
Additional Treatment ◽  
Degree Of Crystallinity ◽  
Thick Wall ◽  
Wall Material ◽  
Fungal Cell ◽  
Ultrastructural Studies ◽  
Fusarium Sulphureum

The cell walls of Fusarium sulphureum have a microfibrillar component that is randomly arranged. X-ray-diffraction diagrams of the microfibrils are consistent with a high degree of crystallinity and show that they are chitin. The chitin microfibrils of the peripheral walls envelop the hyphal apex and extend across the septae. During the first 8 h in culture, the conversion of conidial cells to chlamydospores is evidenced by a swelling of the cells and the original microfibrils remain randomly arranged. Within 24 h new wall material is deposited as the cells expand and the wall thickens. The new microfibrils are indistinguishable from those of the original conidial cells.After 3 days in culture, the chlamydospores are fully developed and have the characteristic thick wall which is a continuous layer of randomly arranged microfibrils. Chlamydospores maintained in a conversion medium for 8 days have microfibrils identical with those in 3-day-old cultures; thus a further change in the microfibril orientation did not occur during that period.Alkaline hydrolysis of the walls removes most of the electron-dense staining constituents from the inner wall layer and leaves the outer wall layer intact. This treatment also reveals some of the wall microfibrils. An additional treatment of the walls with HAc/H2O2 completely removes the wall components that react positively to heavy metal stains. The results are discussed in relation to the structure of other fungal cell walls.

Distribution of Autofluorescence and Esterase and Peroxidase Activities in the Epidermis of Wheat Roots

1979 ◽  
Vol 6 (2) ◽  
pp. 201 ◽  
Author(s):  
MM Smith ◽  
TP O'brien
Keyword(s):  
Cell Walls ◽  
Outer Wall ◽  
Wheat Root ◽  
Root Cell ◽  
Gaeumannomyces Graminis ◽  
Wall Material ◽  
Wheat Roots ◽  
Pig Liver Esterase ◽  
Auto Fluorescence ◽  
Root Cell Walls

In the wheat root, peroxidases and esterases specific for a-naphthyl esters of acetate, propionate and butyrate are concentrated in cell walls, particularly the outer wall of epidermal cells undergoing extension. In contrast esterases specific for β-naphthyl esters of propionate and butyrate were intra- cellular and concentrated in epidermal and outer root-cap cells of the wheat root. Both α-naphthyl and β-naphthyl esters of longer-chain fatty acids proved to be poor substrates. The esterases and peroxidases associated with the outer epidermal wall may well be involved in turnover of phenolic acids cross-linked to polysaccharides. In this regard, ferulic acid and diferulate were shown to be constituents of wheat-root cell walls. The distribution of these substances can also be inferred from autofluorescence. Treatment with a commercial pig-liver esterase was without effect on the auto- fluorescence of the root cell-walls. Culture filtrates from Gaeumannomyces graminis did remove significant amounts of autofluorescent wall material. These preparations contained α-naphthyl acetate esterase as well as many polysaccharide hydrolase activities.

Chemical and ultrastructural studies on the distribution of sporopolleninlike biopolymers in six genera of lichen phycobionts

1985 ◽  
Vol 63 (12) ◽  
pp. 2221-2230 ◽  
Author(s):  
Ueli Brunner ◽  
Rosmarie Honegger
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Resistant Cell ◽  
Wall Layer ◽  
Conclusive Evidence ◽  
The Other ◽  
Chemical Methods ◽  
Ultrastructural Studies ◽  
Cell Wall Polymer ◽  
Infrared Absorption Spectra

Cell walls of cultured lichen phycobionts of the genera Coccomyxa, Elliptochloris, Myrmecia, Pseudochlorella, Trebouxia, and Trentepohlia were investigated with cytological and chemical methods with regard to the presence or absence of trilaminar sheaths and (or) resistant biopolymers. Trilaminar cell wall layers occurred in Coccomyxa, Elliptochloris, Myrmecia, and (less distinctly) Pseudochlorella species. A biopolymer highly resistant to nonoxidative degradation by phosphoric acid occurred only in the isolated and vigorously extracted cell walls of Coccomyxa and Elliptochloris species. The walls of all the other phycobionts, including Myrmecia and Pseudochlorella, were totally degraded, showing that a trilaminar wall layer is not conclusive evidence for the presence of a resistant cell wall polymer. The infrared absorption spectra of the degradation-resistant cell wall polymer of Coccomyxa and Elliptochloris species were not fully identical with those of natural sporopollenins. When the widely used, but chemically less appropriate acetolysis method was applied to either entire cells or isolated but not fully extracted cell walls of Coccomyxa, Elliptochloris, Myrmecia, Pseudochlorella, Trebouxia, and Trentepohlia species, they all yielded acetolysis-resistant residues whose infrared spectra resembled natural sporopollenin.

Cell wall structures of Epicoccum nigrum (Hyphomycetes)

1973 ◽  
Vol 51 (5) ◽  
pp. 1071-1073 ◽  
Author(s):  
J. A. Brushaber ◽  
R. H. Haskins
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Outer Layer ◽  
Secondary Wall ◽  
Outer Wall ◽  
Wall Layer ◽  
Wall Material ◽  
Primary Wall ◽  
Electron Dense Material ◽  
Wall Structures

Two structurally distinct types of secondary wall layers are present in older hyphae in addition to the primary wall. A coarsely fibrous outer wall layer often becomes quite massive and frequently fuses with the outer wall layers of adjacent cells in the formation of hyphal strands. The uneven deposition of this outer layer often produces large verrucosities. The inner secondary wall layer is relatively electron transparent and contains a reticulum of electron-dense lines. The interface of the inner secondary wall with the cytoplasm is often very irregular, and sections of the plasma membrane are frequently overlain by wall material. The outer secondary wall of conidia is composed of an electron-dense material different from that of the outer wall of hyphae. Cells in the multicellular conidia tend to be polyhedral in shape with either very thick primary walls or thin primary walls having a thick inner wall deposit.

Sporopollenin in the cell walls of Coccomyxa and Myrmecia phycobionts of various lichens: an ultrastructural and chemical investigation

1981 ◽  
Vol 59 (12) ◽  
pp. 2713-2734 ◽  
Author(s):  
Rosmarie Honegger ◽  
Ueli Brunner
Keyword(s):  
Mother Cell ◽  
Cell Walls ◽  
Freeze Fracture ◽  
Thick Layer ◽  
Outer Wall ◽  
Wall Layer ◽  
Middle Part ◽  
Wall Structure ◽  
Thin Sections ◽  
Ir Spectrophotometry

Symbiotic and cultivated Myrmecia phycobionts of Baeomyces rufus and Coccomyxa phycobionts of five different asco- and basidio-lichens were investigated with cytological and chemical methods. The cell wall structure of the free-living type species Coccomyxa dispar was compared with that of the lichen phycobionts.Three different wall layers were observed in all Coccomyxa and Myrmecia cells investigated. An innermost, variably thick layer is amorphous in structure and is built up mainly by Golgi-derived hemicelluloses. An outer wall layer, uniformly thick, appears electron dense in thin sections and exhibits short, probably cellulosic fibrils embedded in an amorphous matrix in freeze-fracture preparations. Beyond these two wall layers is an outermost trilaminar wall layer of uniform thickness in all species investigated. It contains sporopollenin in its electron-transparent, rigid middle part; proteinlike particles are embedded in an amorphous, carbohydrate-containing matrix on its electron-dense inner and outer surfaces. IR spectrophotometry of acetolysis-resistant material yielded data comparable with those of other sporopollenin-containing algal walls, although the Coccomyxa and Myrmecia sporopollenin did not dissolve in chromic acid. The trilaminar layer is not lysed during or after autospore formation. Persistent mother cell walls were detected in all lichen thalli investigated, as well as in the culture medium of isolated phycobionts. Persistent mother cell walls were also found in the gelatinous sheath of Coccomyxa dispar.This type of wall structure affords protection against fungal parasitism and may be a significant factor in the success of some lichens and some other symbiotic systems.

Ultrastructural study of promycelial development and basidiospore initiation in Ustilago maydis

1980 ◽  
Vol 58 (14) ◽  
pp. 1548-1561 ◽  
Author(s):  
Jane E. Ramberg ◽  
David J. McLaughlin
Keyword(s):  
Ultrastructural Study ◽  
Ustilago Maydis ◽  
Outer Wall ◽  
Wall Layer ◽  
Wall Material ◽  
Basidiomycetous Yeasts ◽  
Cytoplasmic Organelles ◽  
Spherical Vesicles

Cytoplasm and walls of developing promycelia and basidiospores of Ustilago maydis were examined. The promycelial wall was derived from an inner wall layer of the teliospore. Small vesicles and probable Golgi cistemae appeared to be associated with promycelial extension. Some promycelial septa contained small pores; spherical vesicles, formed centripetally in the electron-transparent lamella at the center of the septa, appeared to be involved in promycelial fragmentation. An inner layer of the basidial wall gave rise to the wall of the developing basidiospore, and a collar of torn outer wall material surrounded the spore base. Spores were formed on short sterigmata. No significant vacuolation occurred in the promycelium during initial basidiospore formation, a feature unique among phragmobasidiomycetes examined thus far. The distribution of cytoplasmic organelles in the promycelium is like that seen in vegetative structures of other fungi.The placement of Ustilaginales in the basidiomycetes is supported by the layered walls and small pores in the promycelium. Derivation of the basidiospore wall and the migration of the nucleus into the basidiospore before mitosis resembled aspects of budding in basidiomycetous yeasts.

Fine structure of the extracellular sheath and cell walls inOphiostoma novo-ulmigrowing on various substrates

1999 ◽  
Vol 45 (7) ◽  
pp. 582-597 ◽  
Author(s):  
G B Ouellette ◽  
H Chamberland ◽  
A Goulet ◽  
M Lachapelle ◽  
J -G Lafontaine
Keyword(s):  
Cell Walls ◽  
Surrounding Medium ◽  
Wall Layer ◽  
Dutch Elm Disease ◽  
Fungal Cell ◽  
Parallel Structures ◽  
Cell Components ◽  
Fungal Dna ◽  
Standard Fixation ◽  
Electron Lucent

The presence of microfilamentous-like structures of tubular appearance (MFS) in cell walls and extracellular sheath material (ES) in a number of isolates of Ophiostoma novo-ulmi Brasier grown on various substrates and following various treatments is reported. Standard fixation or high-pressure freezing methods were used, and cytochemical tests were carried out to detect fungal and host wall components and, in some cases, fungal DNA. In some cases, serial 0.2-μm-thick sections were examined at 120 kV and tilted to obtain stereoscopic images. Whether the fungal cell walls were thick and composed of an outer opaque and inner more electron-lucent layers, or thin and barely perceptible, MFS were observed to extend from the cell cytoplasm as parallel structures across the walls into the surrounding medium, including host cell components in infected elm tissues. MFS were associated (in samples from inoculated trees) with cleavage and desquamation of fungal walls. ES and MFS did not label for cellulose or chitin, but generally labelled slightly for β-(1-3)-glucan and mannose, and strongly for galactose. Only the lucent, inner fungal wall layer labelled for chitin and cellulose. DNA labelling was confined to nuclei and mitochondria in fungal cells from cultures on agar medium; in cells from cultures on millipore membranes, it was pronounced over imprecisely delimited cell regions. The possible ontogeny of MFS components and their importance are discussed. Key words: chitin, Dutch elm disease, fungal fimbriae, fungal walls, gold-complexed probes, microfilamentous structures (MFS).

Modes of cell-wall degradation of Sphagnum fuscum by Acremonium cf. curvulum and Oidiodendron maius

2001 ◽  
Vol 79 (1) ◽  
pp. 93-100 ◽  
Author(s):  
A Tsuneda ◽  
M N Thormann ◽  
R S Currah
Keyword(s):  
Cell Walls ◽  
Amorphous Matrix ◽  
Matrix Material ◽  
Outer Wall ◽  
Amorphous Layer ◽  
Wall Layer ◽  
Sphagnum Fuscum ◽  
The Matrix ◽  
Oidiodendron Maius ◽  
Wall Components

Electron microscopy of cryo-fractured hyaline leaf cells of Sphagnum fuscum Klinggr. revealed that their cell walls consist of three layers: a thick central layer flanked on either side by a thinner, amorphous layer. Acremonium cf. curvulum W. Gams and Oidiodendron maius Barron, both isolated from partly decomposed S. fuscum plants, were capable of degrading leaf cell walls of Sphagnum. Where hyphae of A. curvulum accumulated, the amorphous, outer wall layer of S. fuscum was first fragmented and then removed. The exposed central wall layer consisted of bundles of microfibrils embedded in an amorphous matrix material. After the matrix material and the inner surface wall layer were mostly removed, degradation of microfibrils occurred and localized voids were produced. Unlike A. cf. curvulum, O. maius degraded all wall components more or less simultaneously. In both fungi, active and autolysing hyphae frequently occurred in proximity on the Sphagnum leaves.Key words: hyphomycetes, peat, phenolics, cellulose, SEM.

Cell wall of Fusarium sulphureum. II. Chemical composition of the conidial and chlamydospore walls

1977 ◽  
Vol 23 (6) ◽  
pp. 763-769 ◽  
Author(s):  
E. F. Schneider ◽  
L. R. Barran ◽  
P. J. Wood ◽  
I. R. Siddiqui
Keyword(s):  
Cell Wall ◽  
Glucuronic Acid ◽  
Dry Weight ◽  
Outer Wall ◽  
Wall Layer ◽  
Dense Layer ◽  
Glucose Content ◽  
Fusarium Sulphureum ◽  
Spore Walls ◽  
Wall Components

Examination of the conidial and chlamydospore walls of Fusarium sulphureum by electron microscopy showed the presence of two distinct layers of differing electron densities. These include a relatively narrow outer electron-dense layer and a broader more transparent inner layer. Both chlamydospore cell wall layers were thicker than the conidial wall. The outer wall of the chlamydospore wall was 30% thicker while the inner cell wall layer was 250% thicker than the corresponding cell wall layers in the conidia. During conidial differentiation to form chlamydospores there was a considerable augmentation of all cell wall components which varied from 7 to 26-fold per cell. The augmentation of the major cell wall constituents (N-acetylglucoseamine (NAG), glucose, and protein) and the vast increase in the inner cell wall of the chlamydospore wall indicated that these newly synthesized constituents are predominently located in the inner cell wall layer.The major carbohydrate constituents on a dry weight basis in both the conidial and chlamydospore walls were glucose, glucuronic acid, and N-acetylglycosamine (NAG). However, the proportion of these and the other carbohydrate constituents were different for both spore walls. Thus, the conidial wall contained about 50% less NAG and glucuronic acid but twice the glucose content of the chlamydospore wall. Protein was a major component of both spore walls (21.6%, conidial wall; 28.5%, chlamydospore wall). Amino acid analysis indicated differences in the types of protein present in the two spore walls. The lipid content of both conidia and chlamydospore was low (1–2%).

scholarly journals DEMONSTRATION OF A FIBRILLAR COMPONENT IN THE CELL WALL OF THE YEAST SACCHAROMYCES CEREVISIAE AND ITS CHEMICAL NATURE

1974 ◽  
Vol 62 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Marie Kopecká ◽  
H. J. Phaff ◽  
G. H. Fleet
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Walls ◽  
Stationary Phases ◽  
Wall Layer ◽  
Wall Material ◽  
Detectable Effect ◽  
Complete Disappearance ◽  
Yeast Saccharomyces Cerevisiae ◽  
Wall Structures ◽  
Fibrillar Component

The ultrastructure of isolated cell walls of Saccharomyces cerevisiae from the log and stationary phases of growth was studied after treatment with the following enzymes: purified endo-ß-(1 → 3)-glucanase and endo-ß-(1 → 6)-glucanase produced by Bacillus circulans; purified exo-ß-glucanase and endo-ß-(1 → 3)-glucanase produced by Schizosaccharomyces versatilis; commercial Pronase. While exo-ß-glucanase from S. versatilis had no electron microscopically detectable effect on the walls, Pronase removed part of the external amorphous wall material disclosing an amorphous wall layer in which fibrils were indistinctly visible. Amorphous wall material was completely removed by the effect of either endo-ß-(1 → 3)- or endo-ß-(1 → 6)-glucanase of B. circulans or by a mixture of the two enzymes. As a result of these treatments a continuous fibrillar component appeared, composed of densely interwoven microfibrils resisting further action by both of the B. circulans enzymes. The fibrillar wall component was also demonstrated in untreated cell walls by electron microscopy after negative staining. Because of the complete disappearance of the fibrils following treatment with the S. versatilis endo-ß-(1 → 3)-glucanase it can be concluded that this fibrillar component is composed of ß-(1 → 3)-linked glucan. Bud scars were the only wall structures resistant to the effect of the latter enzyme.

Antifungal Proteins from Plant Latex

2020 ◽  
Vol 21 (5) ◽  
pp. 497-506
Author(s):  
Mayck Silva Barbosa ◽  
Bruna da Silva Souza ◽  
Ana Clara Silva Sales ◽  
Jhoana D’arc Lopes de Sousa ◽  
Francisca Dayane Soares da Silva ◽  
...  
Keyword(s):  
Cell Walls ◽  
Defense Mechanisms ◽  
Hydrolytic Enzymes ◽  
Fungal Species ◽  
Biologically Active ◽  
Protein Classification ◽  
Fungal Cell ◽  
Antifungal Proteins ◽  
Plant Latex

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants’ defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.

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