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).

Fine structural observations on substances attributable to Ceratocystis ulmi in American elm and aspects of host cell disturbances

1978 ◽  
Vol 56 (20) ◽  
pp. 2550-2566 ◽  
Author(s):  
G. B. Ouellette
Keyword(s):  
Host Cell ◽  
Cell Walls ◽  
Parenchyma Cell ◽  
Dutch Elm Disease ◽  
Similar Material ◽  
Fungal Cell ◽  
Fibrillar Material ◽  
American Elm ◽  
Vessel Walls ◽  
Parenchyma Cell Walls

Plugging of certain vessels may occur in elm shortly after inoculation with the Dutch elm disease pathogen, Ceratocystis ulmi (Buism.) C. Moreau. Plugging components include fibrillar material of varying density and fungal cells traceable mostly to inoculated spores. Some material is similar to fungal cell contents, and indications of extrusion of the latter through ruptured or unruptured walls were obtained. Other material is also attributable to disintegrating fungal walls. Radioautographs obtained from samples treated with [6-3H]thymidine indicate significant labeling of fungal cell contents and of similar material, free.Similar fibrillar material, some labeled, is present within pit membranes, in adjacent parenchyma cell walls, and in periplasmic areas associated with retraction of the plasmalemma and with other cytoplasmic disturbances. Host vessel walls are also altered in the presence of some fibrillar material but apparently release only limited amounts of disintegration products into vessels.The possible implications of these observations are discussed in relation to current hypotheses on wilt diseases.

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.

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.

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.

scholarly journals SELECTIVE "STAINING" FOR ELECTRON MICROGRAPHY

1942 ◽  
Vol 76 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Stuart Mudd ◽  
Thomas F. Anderson
Keyword(s):  
Heavy Metals ◽  
Cell Walls ◽  
Differential Staining ◽  
Bacterial Cells ◽  
Selective Staining ◽  
Electron Micrography ◽  
Chemical Effects ◽  
Microchemical Analysis ◽  
Cell Components ◽  
Selective Chemical

The physical basis of contrast and image formation in electron micrography is considered in relation to the possibility of recording selective chemical effects on cell components. A technology of selective microchemical analysis, equivalent to differential staining, is suggested as practicable in electron micrography. Electron pictures of bacteria after exposure to salts of heavy metals have shown the bacterial inner protoplasm, but not the cell walls, to be selectively darkened; shrinkage, coagulation, or escape of protoplasm from the injured cells may result and be recorded in the electron micrographs. Recording of the action of germicidal agents on individual bacterial cells is indicated as one promising field of application of microchemical analysis with the aid of the electron microscope.

Biochemical contributions to the taxonomic status of the Endogonaceae

1979 ◽  
Vol 57 (3) ◽  
pp. 284-291 ◽  
Author(s):  
A. C. M. Weijman ◽  
H. L. C. Meuzelaar
Keyword(s):  
Cell Walls ◽  
Intact Cell ◽  
Taxonomic Status ◽  
Fungal Cell ◽  
Saprolegnia Ferax ◽  
Mucor Mucedo ◽  
Allomyces Arbuscula ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Curie Point Pyrolysis

The Endogonaceae are generally considered as zygomycete representatives, although zygospores have only been observed in the type genus Endogone. Consequently, the oomycetous or chytridiomycetous nature of some fungi classified in the Endogonaceae cannot be excluded. The presence or absence of chitin in cell walls can indicate the oomycetous or zygomycetous relationship. The occurrence of glucosamine was investigated by gas–liquid chromatographic analysis of intact cell hydrolyzates, a process requiring small quantities of material. The cells were also characterized by Curie-point pyrolysis mass spectrometry. These two techniques were applied to lyophilized spores or sporocarps of Endogone, Glomus, Glaziella, and Gigaspora. Mucor mucedo, Allomyces arbuscula, Pythium spinosum, and Saprolegnia ferax were included for comparison.In all endogonaceous isolates tested, a strong predominance of chitin was indicated, supporting their classification within the Zygomycetes.The phylogenetic significance of chitin and cellulose distribution in fungal cell walls is discussed.

Rapid determination of binding parameters of chitin binding domains using chitin-coated quartz crystal microbalance sensor chips

The Analyst ◽  
2018 ◽  
Vol 143 (21) ◽  
pp. 5255-5263 ◽  
Author(s):  
Stephan Vogt ◽  
Marco Kelkenberg ◽  
Tanja Nöll ◽  
Benedikt Steinhoff ◽  
Holger Schönherr ◽  
...  
Keyword(s):  
Cell Walls ◽  
Quartz Crystal ◽  
Fungal Infections ◽  
Rapid Determination ◽  
Binding Parameters ◽  
Fungal Cell ◽  
Binding Domains ◽  
Quartz Crystal Microbalance Sensor ◽  
Fungal Cell Walls

Chitin present in fungal cell walls has been considered as a diagnostic polymer for the detection of fungal infections.

scholarly journals Screening and Antifungal Activity of a β-Carboline Derivative against Cryptococcus neoformans and C. gattii

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kátia Santana Cruz ◽  
Emerson Silva Lima ◽  
Marcia de Jesus Amazonas da Silva ◽  
Erica Simplício de Souza ◽  
Andreia Montoia ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Cryptococcus Neoformans ◽  
Active Compound ◽  
Cell Walls ◽  
Human Fibroblasts ◽  
Lead Compound ◽  
Fungal Cell ◽  
Fungal Cell Walls

Background. Cryptococcosis is a fungal disease of bad prognosis due to its pathogenicity and the toxicity of the drugs used for its treatment. The aim of this study was to investigate the medicinal potential of carbazole and β-carboline alkaloids and derivatives against Cryptococcus neoformans and C. gattii. Methods. MICs were established in accordance with the recommendations of the Clinical and Laboratory Standards Institute for alkaloids and derivatives against C. neoformans and C. gattii genotypes VNI and VGI, respectively. A single active compound was further evaluated against C. neoformans genotypes VNII, VNIII, and VNIV, C. gattii genotypes VGI, VGIII, and VGIV, Candida albicans ATCC 36232, for cytotoxicity against the MRC-5 lineage of human fibroblasts and for effects on fungal cells (cell wall, ergosterol, and leakage of nucleic acids). Results. Screening of 11 compounds revealed 8-nitroharmane as a significant inhibitor (MIC 40 μg/mL) of several C. neoformans and C. gattii genotypes. It was not toxic to fibroblasts (IC50 > 50 µg/mL) nor did it alter fungal cell walls or the concentration of ergosterol in C. albicans or C. neoformans. It increased leakage of substances that absorb at 260 nm. Conclusions. The synthetic β-carboline 8-nitroharmane significantly inhibits pathogenic Cryptococcus species and is interesting as a lead compound towards new therapy for Cryptococcus infections.

scholarly journals Evaluation of Antifungal Activity and Mode of Action of New Coumarin Derivative, 7-Hydroxy-6-nitro-2H-1-benzopyran-2-one, againstAspergillusspp.

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Felipe Queiroga Sarmento Guerra ◽  
Rodrigo Santos Aquino de Araújo ◽  
Janiere Pereira de Sousa ◽  
Fillipe de Oliveira Pereira ◽  
Francisco J. B. Mendonça-Junior ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mode Of Action ◽  
Cell Walls ◽  
Coumarin Derivative ◽  
Antifungal Drugs ◽  
Azole Resistance ◽  
Subinhibitory Concentration ◽  
Fungal Cell ◽  
Mycelia Growth

Aspergillusspp. produce a wide variety of diseases. For the treatment of such infections, the azoles and Amphotericin B are used in various formulations. The treatment of fungal diseases is often ineffective, because of increases in azole resistance and their several associated adverse effects. To overcome these problems, natural products and their derivatives are interesting alternatives. The aim of this study was to examine the effects of coumarin derivative, 7-hydroxy-6-nitro-2H-1-benzopyran-2-one (Cou-NO2), both alone and with antifungal drugs. Its mode of action againstAspergillusspp. Cou-NO2was tested to evaluate its effects on mycelia growth and germination of fungal conidia ofAspergillusspp. We also investigated possible Cou-NO2action on cell walls (0.8 M sorbitol) and on Cou-NO2to ergosterol binding in the cell membrane. The study shows that Cou-NO2is capable of inhibiting both the mycelia growth and germination of conidia for the species tested, and that its action affects the structure of the fungal cell wall. At subinhibitory concentration, Cou-NO2enhanced thein vitroeffects of azoles. Moreover, in combination with azoles (voriconazole and itraconazole) Cou-NO2displays an additive effect. Thus, our study supports the use of coumarin derivative 7-hydroxy-6-nitro-2H-1-benzopyran-2-one as an antifungal agent againstAspergillusspecies.

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