19. Scanning and Transmission Electron Microscopy and Freeze-Etching Techniques used in Ultrastructural Studies of Hyphomycetes

1971 ◽  
pp. 292-300 ◽  
Author(s):  
G.T. Cole ◽  
H.C. Aldrich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Freeze Etching

Re-evaluation of merogony of a Cystoisospora ohioensis-like coccidian and its distinction from gametogony in the intestine of a naturally infected dog

Parasitology ◽  
2019 ◽  
Vol 146 (6) ◽  
pp. 740-745
Author(s):  
J. P. Dubey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Microscopy ◽  
Developmental Stages ◽  
Surface Epithelium ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Sexual Stages ◽  
Endogenous Stages ◽  
Study Development

AbstractFour species of Cystoisospora, C. canis, C. ohioensis, C. neorivolta and C. burrowsi are described from feces of dogs. Of these, the oocysts of C. canis are the largest and easily distinguished from the remaining three species. Oocysts of C. ohioensis, C. neorivolta and C. burrowsi are difficult to distinguish because of overlap in their sizes. However, based on endogenous developmental stages, C. ohioensis is distinct from C. neorivolta and C. burrowsi because its endogenous stages are confined to surface epithelium of intestine whereas endogenous stages of C. neorivolta and C. burrowsi are predominantly in the lamina propria. There are uncertainties regarding the endogenous stages of C. neorivolta and C. burrowsi and there is no way now to determine whether C. burrowsi and C. neorivolta are different parasites; therefore, these are referred as C. ohioensis-like organisms. Additionally, mode of division of asexual stages of coccidia of dogs is largely unknown and ultrastructural studies are lacking. In the present study, development of asexual and sexual stages of a C. ohioensis-like organism in a naturally infected dog is described by light microscopy and by transmission electron microscopy. Merozoites divided by endodyogeny/merogony. Meronts were crescent/merozoite-shaped and contained a maximum of eight nuclei. A distinctive feature of merozoites was the presence of many PAS-positive amylopectin granules that were absent or rare in immature microgamonts making it possible to distinguish them.

Morphometrical Ultrastructural Studies of the Rat's Hepatocytes Under Cooling

1997 ◽  
Vol 3 (S2) ◽  
pp. 245-246
Author(s):  
A.S. Kaprelyants ◽  
A.A. Kaprelyants ◽  
A.N. Reylan ◽  
R.K. Migunova
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscopic ◽  
Rat Hepatocyte ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Morphometric Methods

The aim of given investigation is to study the effect of cooling upon rat hepatocyte structure using transmission electron microscopic and computer morphometric methods. Ultrastructural and morphometrical characteristics of hepatocytes under liver cooling for various levels under in vivo and in vitro conditions were investigated. Vistar rats of 180-250 g were used in the experiment. Liver cooling (in vivo) was performed by means of original cryoapplicator with different probe temperature (1,2). Liver tissue for transmission electron microscopy was fixed in glutaraldehyde fixator on cocadylate buffer and OsO4. Dehydration was completed on acetone (3). Tissue embedding was done into the mixture of Epon/Araldite epoxy rasin. Ultrathin slices were contrasted by the method of Reinolds. Cell viewing and imaging were accomplished by electron microscope at accelerating power of 75kV.Morphometrical and stereometrical analysis was performed using the “Morpho-Tools” original computer system (c) 1994-1996 A.S. Kaprelyants, A.A. Kaprelyants, A.N. Reylan .

Ultrastructural studies on infection of sclerotia of Sclerotinia sclerotiorum by Talaromyces flavus

1989 ◽  
Vol 67 (7) ◽  
pp. 2199-2205 ◽  
Author(s):  
D. L. McLaren ◽  
H. C. Huang ◽  
S. R. Rimmer ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sclerotinia Sclerotiorum ◽  
Cell Walls ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Talaromyces Flavus

Talaromyces flavus is a destructive hyperparasite capable of infecting sclerotia of Sclerotinia sclerotiorum. Examinations of sclerotia by transmission electron microscopy at 3, 7, and 12 days after inoculation revealed that hyphae of T. flavus penetrated the rind cell walls directly. Etching of the cell walls at the penetration site was evident. This suggests that wall-lysing enzymes may be involved in the process of infection. Hyphae of T. flavus grew both intercellularly and intracellularly throughout the rind, cortical, and medullary tissues. Ramification of the hyperparasite in the sclerotium resulted in destruction and collapse of sclerotial tissues.

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.

scholarly journals Adherence of Giardia lambliaTrophozoites to Int-407 Human Intestinal Cells

2001 ◽  
Vol 8 (2) ◽  
pp. 258-265 ◽  
Author(s):  
M. Céu Sousa ◽  
C. A. Gonçalves ◽  
V. A. Bairos ◽  
J. Poiares-da-Silva
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ventral Surface ◽  
Host Cells ◽  
Intestinal Cells ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Vitro Model

ABSTRACT Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonization of the small intestine and is considered a prerequisite for parasite-induced enterocyte dysfunction and clinical disease. In this work, coincubation of Giardiawith Int-407 cells, was used as an in vitro model to study the role of cytoskeleton and surface lectins involved in the attachment of the parasite. This interaction was also studied by scanning and transmission electron microscopy. Adherence was dependent on temperature and was maximal at 37°C. It was reduced by 2.5 mM colchicine (57%), mebendazole (10 μg/ml) (59%), 100 mM glucose (26%), 100 mM mannose (22%), 40 mM mannose-6-phosphate (18%), and concanavalin A (100 μg/ml) (21%). No significant modification was observed when Giardia was pretreated with cytochalasins B and D and with EDTA. Giardia attachment was also diminished by preincubating Int-407 cells with cytochalasin B and D (5 μg/ml) (16%) and by glutaraldehyde fixation of intestinal cells and ofG. lamblia trophozoites (72 and 100%, respectively). Ultrastructural studies showed that Giardia attaches to the Int-407 monolayer predominantly by its ventral surface. Int-407 cells contact trophozoites with elongated microvilli, and both trophozoite imprints and interactions of Giardia flagella with intestinal cells were also observed. Transmission electron microscopy showed that Giardia lateral crest and ventrolateral flange were important structures in the adherence process. Our results suggest a combination of mechanical and hydrodynamic forces in trophozoite attachment; surface lectins also seem to mediate binding and may be involved in specific recognition of host cells.

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.

Use of Transmission Electron Microscopy in Diagnosis of Acute Leukemias: A Prospective Study of Fifty Cases.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4509-4509
Author(s):  
Tathagata Chatterjee ◽  
Manoranjan Mahapatra ◽  
Hara P. Pati ◽  
Inusha Panigrahi ◽  
Rajat Kumar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bone Marrow Aspiration ◽  
Acute Leukemias ◽  
Ultrastructural Cytochemistry ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Large Round ◽  
Hypercellular Marrow ◽  
A Prospective Study

Abstract Ultrastructural studies have contributed substantially to the understanding of the cellular morphology of the acute leukemias. We present here 50 cases (aged 3-55 years, M: F-32: 18) of acute leukemias, which were studied for morphology, conventional cyto chemistry, immunophenotyping, and transmission electron microscopy (TEM) including ultrastructural cytochemistry using myeloperoxidase (MPO) and platelet peroxidase activity. TEM morphology using ultrastructural cytochemistry of MPO helped diagnose three cases of acute myeloid leukemia with minimal myeloid differentiation (AML M0). The blasts showed large round nuclei, 1–2 nucleoli, chromatin with peripheral condensation and abundant mitochondria. Of total of 5 cases of acute promyelocytic leukemias (APML), all had strong Sudan Black, MPO, dual esterase positivity; one case was non-specific esterase positive and sensitive to fluoride. On TEM, this unusual case was identified to be microgranular variant of APML. TEM morphology and ultrastructural cytochemistry using platelet peroxidase helped diagnose 3 cases of AML M7 (acute megakaryocytic leukemia), 2 cases of acute biphenotypic leukemias and also in differentiating one case of acute proerythroblastic leukemia (AML M6b) from 3 cases of AML M6a or acute erythroleukemia. Thus, TEM is helpful in differentiating further the subgroups of AML-M5 and AML-M6, in identifying the microgranular variant of APML, and in confirming the diagnosis of AML-M0 and biphenotypic leukemia. Also, in cases with very hypercellular marrow and with associated myelofibrosis, where the bone marrow aspiration gives low cell count, TEM and ultrastructural cytochemistry are a valuable aid to arriving at a accurate diagnosis. Characteristics of acute leukemia cases (n=50) FAB Subtype Morphology, Conventional Cytochemistry and Immunophenotyping Transmission Electron Microscopy (?) = doubt in diagnosis AML-M0 3 (?) 3 AML-M1and M2 11 11 AML-M3 4, 1(?) 5: Hypergranular-4, hypogranular-1 AML-M4 5 5 AML-M5 5 5a-4, 5b-1 AML-M6 4 6a-3 (erythroleukemia), 6b-1 AML-M7 3 3 Biphenotypic 2 (?) 2 ALL-L1 8 8 ALL-L2 4 4

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