Some advantages and uses of cryopreservation techniques for ultrastructural studies in mycology

1991 ◽  
Vol 49 ◽  
pp. 70-71
Author(s):  
Richard E. Edelmann ◽  
Kirk Czymmek ◽  
Karen L. Klomparens
Keyword(s):  
Electron Microscopy ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Chemical Fixation ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Freeze Etching ◽  
Cryopreservation Techniques ◽  
Cryo Scanning Electron Microscopy ◽  
Scanning Electron

To date, only limited use has been made of the advanced techniques of cryopreservation for mycological samples, with the exception of the unofficial “lab rat” Saccharomyces cerevisae. However, cyropreservation can offer some distinct advantages over conventional chemical fixation, as well as unique solutions for specific mycological problems. This presentation specifically deals with the utilization of cryo-scanning electron microscopy (cryo-SEM), freeze substitution for transmission electron microscopy (TEM), freeze fracture and freeze etching of mycological samples. Due to the distinctive morphological and biochemical nature of fungi, as compared to plant and animal samples, some significant adaptations to existing published protocols have had to be devised and are presented here.

Scanning electron microscopy of the septal pore cap of the basidiomycete Schizophyllum commune

1994 ◽  
Vol 40 (10) ◽  
pp. 879-883 ◽  
Author(s):  
Wally H. Müller ◽  
Adriaan C. van Aelst ◽  
Theo P. van der Krift ◽  
Teun Boekhout
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Schizophyllum Commune ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Transmission Electron ◽  
And Function ◽  
Tubular Endoplasmic Reticulum ◽  
Scanning Electron

As part of a comparative study of the structure and function of pore structures in heterobasidiomycetous yeasts, dikaryotic hyphae of Schizophyllum commune were subjected to chemical fixation, freeze fracturing, maceration, and freeze substitution, and were subsequently prepared for scanning electron microscopy. The interior of the hyphal cell was visualized and revealed the perforated septal pore cap or parenthesome, mitochondria, vacuoles, and tubular endoplasmic reticulum. The septal pore cap showed connections with tubular endoplasmic reticulum. This tubular endoplasmic reticulum covered the dolipore septal surface. The results presented here complement and extend the ultrastructural image of the septal pore cap obtained from transmission electron micrographs.Key words: septal pore cap, Schizophyllum commune, freeze fracture, maceration, scanning electron microscopy.

External morphology of Azotobacter vinelandii during cyst formation

1973 ◽  
Vol 19 (12) ◽  
pp. 1481-1485
Author(s):  
Gerald D. Cagle ◽  
R. M. Pfister ◽  
G. R. Vela ◽  
J. J. Porter
Keyword(s):  
Electron Microscopy ◽  
Central Body ◽  
Azotobacter Vinelandii ◽  
Cyst Formation ◽  
External Morphology ◽  
Cell Preparation ◽  
External Appearance ◽  
Transmission Electron ◽  
Freeze Etching ◽  
Scanning Electron

Conventional transmission electron microscopy (TEM), freeze-etching, and scanning electron microscopy (SEM) were used to study changes in the external morphology of Azotobacter vinelandii ATCC 12837 during cyst formation. The various methods of cell preparation used for SEM drastically affected the morphology of vegetative and early precystic forms, while little change was observed in the external appearance of late precysts and cysts. SEM preparations from which cyst exine was removed before observation appeared morphologically similar to frozen-etched cells which revealed the central body.

scholarly journals Scanning Electron Microscopic Study of Modified Chloroplasts in Senescing Broccoli Florets

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 99-103 ◽  
Author(s):  
Hirofumi Terai ◽  
Alley E. Watada ◽  
Charles A. Murphy ◽  
William P. Wergin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Structural changes in chloroplasts of broccoli (Brassica oleracea L., Italica group) florets during senescence were examined using light microscopy, scanning electron microscopy (SEM) with freeze-fracture technique, and transmission electron microscopy (TEM) to better understand the process of chloroplast degradation, particularly at the advanced stage of senescence. Light microscopy revealed that chloroplasts, which initially were intact and green, became obscure in shape, and their color faded during senescence. Small, colored particles appeared in cells as the florets approached the final stage of senescence and became full- to dark-yellow in color. Scanning electron microscopy showed that stroma thylakoids in the chloroplast initially were parallel to each other and grana thylakoids were tightly stacked. As senescence advanced, the grana thylakoids degenerated and formed globules. The globules became larger by aggregation as senescence progressed, and the large globules, called “thylakoid plexus,” formed numerous vesicles. The vesicles ultimately were expelled into the cytosol, and the light microscope revealed many colored particles in the senescent cells. These results indicate that the degradation of chloroplasts in broccoli florets progresses systematically, with the final product being colored particles, which are visible in yellow broccoli sepal cells.

Ultrastructural studies on conidiomata, conidiophores, and conidiogenous cells in six lichen-forming Ascomycetes

1984 ◽  
Vol 62 (10) ◽  
pp. 2081-2093 ◽  
Author(s):  
Rosmarie Honegger
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Transmission Electron Microscope ◽  
Developmental Studies ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Conidium Formation ◽  
Scanning Electron

The conidiomata, conidiophores, and conidia of six lichen-forming Ascomycetes were investigated using the scanning electron microscope, and conidium development in two of these species was studied by transmission electron microscopy. Phialidic (micro) conidium formation was observed in the mycobiont of Parmelia tiliacea, Physconia pulverulacea, and Cladonia furcata (Lecanorales), in Lobaria laetevirens (Peltigerales), and in Caloplaca aurantia (Teloschistales). Annellations, first described by Vobis on the basis of light and transmission electron microscope investigations, were also found in scanning electron microscope preparations of macroconidia bearing conidiogenous cells of Lecanactis abietina (Opegraphales). Ultrastructural and developmental studies on conidiophore structure and conidium formation may be of interest for taxonomic and evolutionary considerations in lichen-forming fungi.

Ultrastructural Studies of Isolated Polytene Chromosomes by Scanning Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 196-197
Author(s):  
Michael B. Payne
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Polytene Chromosomes ◽  
Mitotic Chromosomes ◽  
Characteristic Appearance ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Balbiani Rings ◽  
Chromatin Fibers ◽  
Scanning Electron

Scanning and transmission electron microscopy studies of mitotic chromosomes have demonstrated that these chromosomes are composed of single intricately coiled and folded chromatin fibers 200-300 A in diameter (1). Transmission electron microscopy studies (2) have shown similar fibers in dipteran polytene chromosomes. It has been proposed that these fibers are extended in the less densely appearing interband regions and become more tightly coiled or folded at specific sites to produce the densely appearing banded regions (3). With the scanning electron microscope it is now possible to observe the characteristic appearance of the chromatin fibers in the band and interband regions of isolated intact polytene chromosomes. Furthermore, the morphology of the nucleolus and Balbiani rings can be observed as specialized structures in the chromosome.

Advantages of Low Temperature SEM for Bacterial Studies

1995 ◽  
Vol 53 ◽  
pp. 1070-1071
Author(s):  
Stéphane Roy ◽  
Isabelle Babic ◽  
Alley E. Watada ◽  
William P. Wergin
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Field Emission ◽  
Taxonomic Identification ◽  
Chemical Fixation ◽  
Cold Stage ◽  
Transmission Electron ◽  
Critical Point Drying ◽  
Scanning Electron ◽  
Spinach Leaves

The application of transmission electron microscopy (TEM) has greatly increased our understanding of structure-function relationships in bacteriology. However, to achieve further advancements investigators are seeking preparation procedures that would avoid the artifacts associated with conventional chemical fixation, dehydration and critical point drying or embedding. In our laboratory a field emission scanning electron microscope (SEM) was recently equipped with a cold stage. This combination of techniques, referred to as low temperature (LT) SEM, allowed us to examine frozen, fully hydrated biological specimens. The present investigation images bacteria that were cryofixed for LTSEM observations and then freeze-substituted for TEM observations. In addition an attempt was made to culture the samples that had been cryofixed and observed with LTSEM so that taxonomic identification and further microscopic observations could be made.Bacteria used in this study were isolated from spinach leaves (variety New Jersey). LTSEM observations of cryofixed samples were performed on a Hitachi S-4100 field emission SEM equipped with an Oxford CT-1500HF Cryotrans System.

Ultrastructural studies on egg envelopes surrounding the miracidia of Mediogonimus jourdanei Mas-Coma et Rocamora, 1978 (Digenea, Microphalloidea, Prosthogonimidae)

2010 ◽  
Vol 55 (3) ◽  
Author(s):  
Zdzisław Świderski ◽  
Abdoulaye Bakhoum ◽  
Daniel Młocicki ◽  
Jordi Miquel
Keyword(s):  
Electron Microscopy ◽  
Lipid Droplets ◽  
Freeze Substitution ◽  
High Pressure Freezing ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Egg Envelopes ◽  
Egg Shell ◽  
Means Of Transmission ◽  
Inner Envelope

AbstractThe intrauterine, mature and fully embryonated eggs of the prosthogonimid trematode Mediogonimus jourdanei Mas-Coma et Rocamora, 1978 were examined by means of transmission electron microscopy (TEM), using high pressure freezing, freeze substitution and infiltration with resin techniques. Each embryonated egg is composed of a miracidium surrounded by three envelopes: (1) the egg shell, (2) the outer and (3) inner envelopes. Egg envelopes play an important role in the protection, metabolism, storage of nutritive reserves and the general biology of the M. jourdanei egg. The inner envelope is characterised by large, flattened nuclei, and its syncytial cytoplasm contains a heavy accumulation of glycogen, lipid droplets, mitochondria and large vesicles. These traits indicate that this layer has the features of a metabolically-active syncytial layer with an energy storage capability. In the infective eggs observed before the hatching of the miracidium, areas of so-called “focal cytoplasmic degradation” were frequently observed, which may be involved in the autolytic process of all components of this envelopes.

Frozen-Hydrated Lung Preparation for Low Temperature Scanning Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 372-373 ◽  
Author(s):  
Gregory Hook ◽  
Jacob Bastacky ◽  
Thomas Hayes ◽  
Robert Conhaim ◽  
Norman Staub
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Freeze Fracture ◽  
The Other ◽  
Chemical Fixation ◽  
Preservation Method ◽  
Temperature Scanning ◽  
Lung Preparation ◽  
Scanning Electron

Conventional lung preparatory methods for electron microscopy utilizing chemical fixation, dehydration, embedding and/or drying have been critical for understanding alveolar structure. However, these procedures cause the removal of all fluids, alteration of dimensions, and distortion of sp. tial relationships and therefore limit the information that can be obtained. Freeze fracture replica techniques, on the other hand, have provided information on frozen hydrated alveolar structures, but replica procedures require removal of all tissue and cannot preserve the convoluted topography of entire inflated alveoli. Described here is an alternative lung preservation method for use in freeze-fracture, low temperature scanning electron microscopy (SEM) which preserves alveoli in the frozen-hydrated state and permits direct observation of entire inflated alveoli.

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