Freeze-Fracture Demonstration of a Suture in the Free Sporozoite of Plasmodium Berghei

1982 ◽  
Vol 40 ◽  
pp. 314-315
Author(s):  
Charles A.M. Meszoely ◽  
Eric F. Erbe ◽  
Russell L. Steere ◽  
Nancy D. Pacheco ◽  
Richard L. Beaudoin
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Plasmodium Berghei ◽  
Phosphate Buffer ◽  
Sodium Phosphate ◽  
Anopheles Stephensi ◽  
Freeze Fracture ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
Cell Components

The ANKA strain of Plasmodium berghei was maintained in Anopheles Stephensi mosquitoes. Free sporozoites were obtained from a homogenized suspension of mosquito thoraces and heads. They were separated from cell components on a discontinuous gradient, concentrated by centrifugation, fixed in 2% glutaraldehyde, and cryoprotected in a solution containing approximately 12.5% glycerol by volume, and 12.5% sucrose by weight in a 0.2 molar sodium phosphate buffer. The sporozoite preparation was freeze-etched for 1 minute in a modified Denton DFE-2 freeze-etch module. The replicas were photographed in stereo (10 tilt between micrograph pairs) with a JEM-100B transmission electron microscope equipped with a 60° top entry goniometer stage.

Ultrastructure of ascus and ascospore appendages of the mangrove fungus Halosarpheia ratnagiriensis (Halosphaeriales, Ascomycota)

2001 ◽  
Vol 79 (11) ◽  
pp. 1307-1317 ◽  
Author(s):  
T A Baker ◽  
E BG Jones ◽  
S T Moss
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Freeze Fracture ◽  
Transmission Electron ◽  
Mucilaginous Material

Halosarpheia Kohlm. et E. Kohlm is a genus of eighteen species, all of which have septate ascospores with unfurling polar appendages. Asci and ascospores of Halosarpheia ratnagiriensis Patil et Borse were examined at the scanning (including freeze-fracture) and transmission electron microscope levels. The ascus wall has two well-defined layers and the apical apparatus comprises a refractive, electron-dense, lens-shaped disk embedded within a less electron-dense thickening. The ascospore wall comprises an episporium and a bipartite mesosporium, and the appendages are formed by extrusion of mucilaginous material through an episporial pore field. Ascospore appendage ontogeny is compared with other genera with unfurling polar appendages: Cataractispora, Diluviocola, Tunicatispora, Tirispora, and Halosarpheia aquadulcis Hsieh, H.S. Chang et E.B.G. Jones and Halosarpheia heteroguttulata S.W. Wong, K.D. Hyde et E.B.G. Jones.Key Words: ascospore appendage ontogeny, marine ascomycetes, unfurling polar appendages, ultrastructure.

Electron Beam-Induced Radiation Damage: The Bubbling Response in Amorphous Dried Sodium Phosphate Buffer

2010 ◽  
Vol 16 (3) ◽  
pp. 346-357 ◽  
Author(s):  
William H. Massover
Keyword(s):  
Phosphate Buffer ◽  
Sodium Phosphate ◽  
Amorphous Layer ◽  
Gas Content ◽  
High Dose ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
Spherical Bubbles ◽  
Long Lifetime ◽  
Nucleation Growth

AbstractIrradiation of an amorphous layer of dried sodium phosphate buffer (pH = 7.0) by transmission electron microscopy (100–120 kV) causes rapid formation of numerous small spherical bubbles [10–100 Å (= 1–10 nm)] containing an unknown gas. Bubbling is detected even with the first low-dose exposure. In a thin layer (ca. 100–150 Å), bubbling typically goes through nucleation, growth, possible fusion, and end-state, after which further changes are not apparent; co-irradiated adjacent areas having a slightly smaller thickness never develop bubbles. In moderately thicker regions (ca. over 200 Å), there is no end-state. Instead, a complex sequence of microstructural changes is elicited during continued intermittent high-dose irradiation: nucleation, growth, early simple fusions, a second round of extensive multiple fusions, general reduction of matrix thickness (producing flattening and expansion of larger bubbles, occasional bubble fission, and formation of very large irregularly-shaped bubbles by a third round of compound fusion events), and slow shrinkage of all bubbles. The ongoing lighter appearance of bubble lumens, maintenance of their rounded shape, and extensive changes in size and form indicate that gas content continues throughout their surprisingly long lifetime; the thin dense boundary layer surrounding all bubbles is proposed to be the main mechanism for their long lifetime.

scholarly journals Down the Resolution Road: Freeze-Fracture Revisited?

1995 ◽  
Vol 3 (1) ◽  
pp. 3-4
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Electron Microscope ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Transmission Electron Microscope ◽  
Freeze Fracture ◽  
Plant Viruses ◽  
Transmission Electron ◽  
Scalpel Blade

It must have seemed rather fantastic back in the fifties, when Russell Steere froze chunks of plant viruses (tobacco mosaic virus, tobacco nngspot virus, and squash mosaic virus) in drops of water, planed them freehand with a scalpel blade, made a replica of the surface, and examined the replica in a transmission electron microscope. But that was the birth of freeze-fracture and freeze-etch methodology that yielded enormous amounts of information about the morphology of membranes.

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

1974 ◽  
Vol 32 ◽  
pp. 214-215
Author(s):  
R. A. Waugh ◽  
J. R. Sommer
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Transmission Electron

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.

Surface Structure of the Spores of Glugea Weissenbergi

1969 ◽  
Vol 27 ◽  
pp. 238-239
Author(s):  
Sanford H. Vernick ◽  
Anastasios Tousimis ◽  
Victor Sprague
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Transmission Electron Microscope ◽  
Mature Spore ◽  
Spore Surface ◽  
Sectioned Material ◽  
Transmission Electron ◽  
Surface Detail

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.

A New High Resolution Transmission Electron Microscope with Second-Zone Objective Lens

1969 ◽  
Vol 27 ◽  
pp. 176-177 ◽  
Author(s):  
H. Tochigi ◽  
H. Uchida ◽  
S. Shirai ◽  
K. Akashi ◽  
D. J. Evins ◽  
...  
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Objective Lens ◽  
High Excitation ◽  
Transmission Electron ◽  
New Instrument

A New High Excitation Objective Lens (Second-Zone Objective Lens) was discussed at Twenty-Sixth Annual EMSA Meeting. A new commercially available Transmission Electron Microscope incorporating this new lens has been completed.Major advantages of the new instrument allow an extremely small beam to be produced on the specimen plane which minimizes specimen beam damages, reduces contamination and drift.

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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