Electron microscopic study of oospore maturation and germination in an emasculate isolate of Saprolegnia ferax. 1. Gross changes

1980 ◽  
Vol 58 (2) ◽  
pp. 182-194 ◽  
Author(s):  
Gordon W. Beakes
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microscopic Study ◽  
Electron Microscopic ◽  
Saprolegnia Ferax ◽  
Transmission Electron ◽  
Cytological Changes ◽  
Thin Walled ◽  
Germ Tubes ◽  
Peripheral Cytoplasm

The main morphological and cytological changes which accompany oospore maturation and germination in an emasculate isolate of Saprolegnia ferax have been followed by light and transmission electron microscopy. Oospore development proved similar to that described in antheridiate species except for the absence of motile granules within the central ooplast vacuole. Germination followed within a few days of maturation although it did not occur synchronously within a single oogonium. The ending of dormancy is indicated by a thinning of the oospore wall and a decrease in cytoplasmic refractivity. A new germination wall is secreted around the protoplast and the contents of the central ooplast break down and are partially dispersed into the peripheral cytoplasm as it becomes transformed into a typical somatic vacuole. Oospores swell slightly before the emergence of between one and four germ tubes. These often grow extensively within the oogonium, occasionally infesting and possibly parasitizing neighbouring germlings, before rupturing either the thin-walled pits or basal septa. After emergence most germ tubes continue to grow vegetatively in a sparsely branched fashion, although a few develop terminal sporangia. Oospore germination in this isolate is compared with that described in other oomycete species.

The blister of porphyria cutanea tarda: A Scanning and Transmission Electron Microscopic study

1986 ◽  
Vol 44 ◽  
pp. 334-335
Author(s):  
Veronika Burmeister ◽  
R. Swaminathan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Basement Membrane ◽  
Middle Age ◽  
Porphyria Cutanea Tarda ◽  
Minor Trauma ◽  
Electron Microscopic ◽  
Transmission Electron Microscopic Study ◽  
Transmission Electron ◽  
Transmission Electron Microscopic

Porphyria cutanea tarda (PCT) is a disorder of porphyrin metabolism which occurs most often during middle age. The disease is characterized by excessive production of uroporphyrin which causes photosensitivity and skin eruptions on hands and arms, due to minor trauma and exposure to sunlight. The pathology of the blister is well known, being subepidermal with epidermodermal separation, it is not always absolutely clear, whether the basal lamina is attached to the epidermis or the dermis. The purpose of our investigation was to study the attachment of the basement membrane in the blister by comparing scanning with transmission electron microscopy.

Tracheal Transplantation: Cytological Changes Studied by Scanning and Transmission Electron Microscopy in the Rabbit

2001 ◽  
Vol 111 (4) ◽  
pp. 657-662 ◽  
Author(s):  
Carlos Zagalo ◽  
Nuno R. Grande ◽  
Jos?? Martins dos Santos ◽  
Emanuel Monteiro ◽  
Jos?? Brito ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Tracheal Transplantation ◽  
Cytological Changes

Light and electron microscopic investigations in the Dictyonemataceae (Basidiolichens)

1977 ◽  
Vol 55 (20) ◽  
pp. 2565-2573 ◽  
Author(s):  
Robert D. Slocum ◽  
Gary L. Floyd
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cellular Level ◽  
Fungal Symbiont ◽  
Electron Microscopic ◽  
Basidiomycetous Fungus ◽  
Transmission Electron ◽  
Fungal Symbiosis ◽  
Algal Host ◽  
Microscopic Investigations

The nature of the association between the basidiomycetous mycobiont and the blue-green phycobiont in two species of the tropical basidiolichen Dictyonema was investigated using Nomarski light optics and scanning and transmission electron microscopy. Although members of this family may exhibit either a homoiomerous or heteromerous type of thallus organization, the fungus–alga relationship at the cellular level is remarkably consistent. Scytonema filaments are intimately associated with appressorial hyphae of the mycobiont and with extensive intracellular hyphae, which appear to be unrelated to the basidiomycetous fungal symbiont. This is the first report of a lichen displaying an apparent dual fungal symbiosis with the algal host. Association with the intracellular fungus produces no discernible damage to the phycobiont and apparently does not interfere with the symbiosis involving the basidiomycetous fungus.

The influence of aluminium on iron oxides: XII. High-resolution transmission electron microscopic (HRTEM) study of aluminous goethites

Clay Minerals ◽  
1985 ◽  
Vol 20 (2) ◽  
pp. 255-262 ◽  
Author(s):  
S. Mann ◽  
R. M. Cornell ◽  
U. Schwertmann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Iron Oxides ◽  
Dissolution Kinetics ◽  
Electron Microscopic ◽  
Al Substitution ◽  
Transmission Electron ◽  
Transmission Electron Microscopic

Aluminium-substituted goethites are found in many soils and can also be synthesised readily in the laboratory. In recent years, synthetic substituted goethites have been examined by various techniques including XRD, IR, TEM and dissolution kinetics (Thiel, 1963; Jonas & Solymar, 1970; Fey & Dixon, 1981; Fysh & Fredericks, 1983; Schulze & Schwertmann, 1984; Schwertmann, 1984). Transmission electron microscopy (TEM) studies have shown that as Al substitution rises above 10%, the goethite needles become shorter and also thicker in the a direction. Furthermore, crystals which at zero substitution consist of domains parallel to the c axis become less domainic with increasing Al substitution (Schulze & Schwertmann, 1984).

Light and electron microscopic observations of sporangium formation in Albugo Candida (Peronosporales; Oomycetes)

1977 ◽  
Vol 55 (6) ◽  
pp. 730-739 ◽  
Author(s):  
Saeed R. Khan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscopic ◽  
Albugo Candida ◽  
Transmission Electron ◽  
Mode Of Development

The formation of sporangia in Albugo Candida was studied using light and scanning and transmission electron microscopy. Their mode of development is blastic and they are not formed by percurrent proliferation as previously suggested.

scholarly journals Correlating Fluorescence Microscopy with Electron Microscopy

2004 ◽  
Vol 12 (1) ◽  
pp. 3-7
Author(s):  
Stephen W. Carmichael ◽  
Jon Charlesworth
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fluorescence Microscopy ◽  
Fluorescent Probes ◽  
Cell Biology ◽  
Microscopic Image ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Electron Microscopic Image ◽  
Auto Fluorescence

The use of fluorescent probes is becoming more and more common in cell biology. It would be useful if we were able to correlate a fluorescent structure with an electron microscopic image. The ability to definitively identify a fluorescent organelle would be very valuable. Recently, Ying Ren, Michael Kruhlak, and David Bazett-Jones devised a clever technique to correlate a structure visualized in the light microscope, even a fluorescing cell, with transmission electron microscopy (TEM).Two keys to the technique of Ren et al are the use of grids (as used in the TEM) with widely spaced grid bars and the use of Quetol as the embedding resin. The grids allow for cells to be identified between the grid bars, and in turn the bars are used to keep the cell of interest in register throughout the processing for TEM. Quetol resin was used for embedding because of its low auto fluorescence and sectioning properties. The resin also becomes soft and can be cut and easily peeled from glass coverslips when heated to 70°C.

scholarly journals Applications of in situ electron microscopy in oxygen electrocatalysis

2022 ◽  
Author(s):  
Zhi-Peng Wu ◽  
Hui Zhang ◽  
Cailing Chen ◽  
Guanxing Li ◽  
Yu Han
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Degradation Mechanism ◽  
Structural Evolution ◽  
Reduction Reaction ◽  
Future Research ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
In Situ Electron Microscopy

Oxygen electrocatalysis involving the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) plays a vital role in cutting-edge energy conversion and storage technologies. In situ studies of the evolution of catalysts during oxygen electrocatalysis can provide important insights into their structure - activity relationships and stabilities under working conditions. Among the various in situ characterization tools available, in situ electron microscopy has the unique ability to perform structural and compositional analyzes with high spatial resolution. In this review, we present the latest developments in in situ and quasi-in situ electron microscopic techniques, including identical location electron microscopy, in situ liquid cell (scanning) transmission electron microscopy and in situ environmental transmission electron microscopy, and elaborate their applications in the ORR and OER. Our discussion centers on the degradation mechanism, structural evolution and structure - performance correlations of electrocatalysts. Finally, we summarize the earlier discussions and share our perspectives on the current challenges and future research directions of using in situ electron microscopy to explore oxygen electrocatalysis and related processes.

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 .

A Rapid Method for Electron Microscopic Examination of Biological Specimens

1971 ◽  
Vol 29 ◽  
pp. 486-487
Author(s):  
Glenn Stoner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Simple Procedure ◽  
Contact Point ◽  
Electron Microscopic Examination ◽  
Test Solution ◽  
Biological Applications ◽  
Electron Microscopic ◽  
Preparation Time ◽  
Transmission Electron

The purpose of this paper is to demonstrate the use of a method which reduces the sample preparation time for transmission electron microscopy studies to about one minute.The relatively simple procedure is as follows: When a sample is desired, place 1 mℓ test solution in a 2-5 mℓ container, add 0.1 mℓ of a solution of 0.3 mg/mℓ fibrinogen, immediately insert a 400 mesh E.M. grid held by forceps, withdraw immediately, blot (at the tweezer tip-grid contact point) with filter paper, blow dry with a lab drier, add one drop of stain (2% urinal acetate), blot and blow dry in the above manner. Then immediately insert in the pre-pump chamber of the E.M.The above process has been used by the author in a variety of biological applications, from studies of fibrin growth from fibrinogen to identification of unknown viruses. The accompaning figures for T4, bacteriophage are given simply to demonstrate the method.

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