Chemical and enzymatic changes in the cell walls of Candida albicans and Saccharomyces cerevisiae by scanning electron microscopy

1980 ◽  
Vol 26 (8) ◽  
pp. 965-970 ◽  
Author(s):  
Yvonne Koch ◽  
K. H. Rademacher
Keyword(s):  
Electron Microscopy ◽  
Saccharomyces Cerevisiae ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Candida Albicans ◽  
Cell Walls ◽  
Wall Structure ◽  
Before And After ◽  
Enzymatic Changes ◽  
Scanning Electron

Candida albicans and Saccharomyces cerevisiae cells were examined by scanning electron microscopy before and after extraction of the mannans of the cell wall. The surfaces of control cells were smooth; after mannan extraction they were rough and showed erosions which were particularly striking within the area of the scars. Helicase digested irregular holes through the cell wall within 20 min; these increased in size during an additional 40 min of digestion. These holes were not localized in or on the bud scars, which remained intact even after the long digestion period. The results were used to construct a model for yeast cell wall structure.

High-Resolution Field Emission Scanning Electron Microscopy (FESEM) Imaging of Cellulose Microfibril Organization in Plant Primary Cell Walls

2017 ◽  
Vol 23 (5) ◽  
pp. 1048-1054 ◽  
Author(s):  
Yunzhen Zheng ◽  
Daniel J. Cosgrove ◽  
Gang Ning
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
High Resolution ◽  
Field Emission ◽  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Critical Point Drying ◽  
Sputter Coating ◽  
Scanning Electron

AbstractWe have used field emission scanning electron microscopy (FESEM) to study the high-resolution organization of cellulose microfibrils in onion epidermal cell walls. We frequently found that conventional “rule of thumb” conditions for imaging of biological samples did not yield high-resolution images of cellulose organization and often resulted in artifacts or distortions of cell wall structure. Here we detail our method of one-step fixation and dehydration with 100% ethanol, followed by critical point drying, ultrathin iridium (Ir) sputter coating (3 s), and FESEM imaging at a moderate accelerating voltage (10 kV) with an In-lens detector. We compare results obtained with our improved protocol with images obtained with samples processed by conventional aldehyde fixation, graded dehydration, sputter coating with Au, Au/Pd, or carbon, and low-voltage FESEM imaging. The results demonstrated that our protocol is simpler, causes little artifact, and is more suitable for high-resolution imaging of cell wall cellulose microfibrils whereas such imaging is very challenging by conventional methods.

The effect of aculeacin A and papulacandin B on morphology and cell wall ultrastructure in Candida albicans

1984 ◽  
Vol 30 (6) ◽  
pp. 857-863 ◽  
Author(s):  
J. J. Bozzola ◽  
R. J. Mehta ◽  
L. J. Nisbet ◽  
J. R. Valenta
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Candida Albicans ◽  
Cell Walls ◽  
Cell Necrosis ◽  
Wall Ultrastructure ◽  
Dividing Cells ◽  
Complete Cell ◽  
Aculeacin A ◽  
Scanning Electron

Transmission (TEM) and scanning electron microscopy (SEM) of Candida albicans cultures treated with the cell wall active antibiotics aculeacin A and papulacandin B (10 μg/mL) revealed highly distorted, wrinkled, and collapsed cells. Dividing cells failed to separate properly and aggregates of enlarged and elongated forms were often seen. TEM sections revealed thick and layered cell walls in the treated cultures and bud cross walls failed to segregate completely. Approximately 20% of the cells demonstrated complete cell necrosis accompanied with cytoplasmic deterioration, layered and distorted walls, and improperly formed buds and scars.

scholarly journals Macroscopic and Microscopic Characteristics of 2- and 4-Year-Old Schizostachyum brachycladum

2019 ◽  
pp. 62-69
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Wall ◽  
Vascular Bundle ◽  
Middle Lamella ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Transmission Electron ◽  
Scanning Electron

Anatomical of cell wall structure on Schizostachyum brachycladum examined. The harvested two-year-old and four-year-old bamboo culms segregated into the bottom, middle and top portions. The samples then undergo the Light Microscopy (LM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) to determine their structure such as a vascular bundle, parenchyma, and sclerenchyma. Results show the surface of bamboo was visualized by LM to decide on their structural figure. In this part, 2-year age indicated that higher numbers of vascular bundle and average of mean compared to the 4-year S. brachycladum. Followed by a specific study of cell wall structure using SEM with highlighted 4-year S. brachycladum had more complex of morphology structure compared to the 2-year-old. Later on, TEM illustrated to shows most depth anatomically structure of bamboo such as middle lamella, primary and secondary walls.

Intercellular pectic strands in parenchyma: studies of plant cell walls by scanning electron microscopy.

1975 ◽  
Vol 23 (1) ◽  
pp. 95 ◽  
Author(s):  
SGM Carr ◽  
DJ Carr
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Chemical Composition ◽  
Light Microscope ◽  
Cell Walls ◽  
Plant Cell Walls ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Scanning Electron

Rows of pectic strands, each 0.3-0.4�m in diameter, are shown to connect palisade mesophyll cells in regular ladder-like configurations ('pectic scala'). These structures are illustrated in some species of eucalypts, but probably occur in other kinds of plants. Less regular wall filaments can be observed in the intercellular spaces between other types of cells. They are particularly numerous in the parenchyma of species of ferns. These filaments and the pectic scala are readily observable by scanning electron microscopy, but can also be seen in conventional preparations for the light microscope. The structure, formation, chemical composition and possible function of these and other kinds of cell wall protuberances, described in the literature, are discussed.

Some small-sized Cosmarium (Conjugatophyceae, Desmidiales) from sphagnum bogs of Moscow Region

2013 ◽  
Vol 47 ◽  
pp. 13-20
Author(s):  
O. V. Anissimova
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Moscow Region ◽  
Biological Station ◽  
Sphagnum Bogs ◽  
Different Seasons ◽  
Scanning Electron

Algae samples were collected during different seasons from 1997 to 2011 in two swamps located at Zvenigorod Biological Station in Moscow Region. There were found 25 Cosmarium species and varieties, 9 taxa of them being new to the region. Descriptions of the taxa were specified by observation of cell wall ornamentation with light and scanning electron microscopy. Original descriptions, photos and drawings of algae are presented.

scholarly journals Redox Mechanism of Azathioprine and Its Interaction with DNA

2021 ◽  
Vol 22 (13) ◽  
pp. 6805
Author(s):  
Mihaela-Cristina Bunea ◽  
Victor-Constantin Diculescu ◽  
Monica Enculescu ◽  
Horia Iovu ◽  
Teodor Adrian Enache
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Structural Changes ◽  
Differential Pulse ◽  
Immunosuppressive Drug ◽  
Redox Mechanism ◽  
Before And After ◽  
Dna Film ◽  
Scanning Electron

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

Vergleich verschiedener Immun-Dekorationsmethoden für die Rasterelektronenmikroskopie am Beispiel eines Protein-Antigens auf der Oberfläche der Hefe Candida albicans/ A Comparison of Decoration Techniques for the Demonstration of Immunocomplexes by Scanning Electron Microscopy: Labeling of a Protein Antigen on the Surface of the Yeast Candida albicans

1985 ◽  
Vol 40 (7-8) ◽  
pp. 539-550 ◽  
Author(s):  
Margarete Borg
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Candida Albicans ◽  
Protein A ◽  
Peritoneal Macrophages ◽  
Polystyrene Latex ◽  
Target Antigen ◽  
Protein Antigens ◽  
Critical Point Drying ◽  
Scanning Electron

Abstract The labeling of immunocomplexes for scanning electron microscopy (SEM) is a fairly new technique, and the various procedures, that have been proposed, have not yet been compared. Such comparative evaluation was performed with Candida protease as a target antigen. This secretory enzyme of the opportunistic yeast Candida albicans can be localized on the surface of fungal blastopores and mycelia, both after growth in proteinaceous medium and upon infection of murine peritoneal macrophages. The presence of the protease antigen was confirmed by immunofluorescence and by immunoperoxidase-light microscopy. The decoration of protease - anti protease complexes for SEM was attempted with colloids derived from the immunoperoxidase reaction, by the immunogold technique, and by antibodies linked to beads of synthetic polymers (polystyrene, polymethacrylate, polyacrolein). In addition, inactivated Staphylococcus aureus was used, which binds to antibodies through its protein-A. The high resolution by SEM of surface structures was matched only by the colloid based decoration techniques. All conjugates with beads suffered from inconsistent binding, which did not correspond with the distribution of the surface antigen. The comparatively best result with beads was obtained with polystyrene (Latex). Colloid based techniques in addition allow for critical point drying, which cannot be applied to synthetic beads in the usual manner.

Actinomycetes in discolored wood of living silver maple

1981 ◽  
Vol 59 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Robert A. Blanchette ◽  
John B. Sutherland ◽  
Don L. Crawford
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Carbon Source ◽  
Cell Walls ◽  
Hydroxybenzoic Acid ◽  
Liquid Media ◽  
Streptomyces Strain ◽  
Culture Techniques ◽  
Silver Maple ◽  
Scanning Electron

The greenish-brown margin of discolored wood in three living silver maple trees, Acer saccharinum L., was examined by scanning electron microscopy and microbiological culture techniques. Micrographs of xylem vessels revealed filamentous structures; some of them appeared to be actinomycetous hyphae. Actinomycetes identified as Streptomyces parvullus Waksman & Gregory, S. sparsogenes Owen, Dietz & Camiener, and a third Streptomyces strain were isolated repeatedly from discolored wood of each tree. These isolates grew in liquid media in the presence of 0.1% (w/v) concentrations of several phenols. Although other phenols included in the test were not substantially degraded, p-hydroxybenzoic acid was utilized as a carbon source by S. parvullus. All three actinomycetes inhibited growth of selected wood-inhabiting fungi when paired on malt agar. When inoculated on sterilized sapwood and discolored wood from silver maple, the actinomycetes colonized vessel walls and occlusions, but were not observed to decay cell walls.

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

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