Capture of nematodes by Arthrobotrys oligospora, an electron microscope study

1978 ◽  
Vol 56 (10) ◽  
pp. 1297-1307 ◽  
Author(s):  
Birgit Nordbring-Hertz ◽  
Margaretha Stålhammar-Carlemalm
Keyword(s):  
Electron Microscope ◽  
The Body ◽  
Fungal Culture ◽  
Arthrobotrys Oligospora ◽  
Thin Sections ◽  
Transmission Electron ◽  
Transmission Electron Microscope Micrographs ◽  
Nematode Cuticle ◽  
Nematode Penetration ◽  
Dense Vesicles

The capture of nematodes by Arthrobotrys oligospora consists of (1) firm adhesion of the nematode to the capture organ, (2) penetration of the nematode cuticle by a penetration hypha, and (3) digestion of the nematode. Penetration of the nematode cuticle by a penetration hypha originating from the trap took place within 1 h after addition of nematodes to a fungal culture and occurred at any point on the nematode surface. Vegetative hyphae were able to invade an immobilized nematode only through the body orifices (8–12 h after addition of nematodes to fungal cultures lacking traps). The presence of prey caused an increased secretion of adhesive from the trap. Scanning electron microscope micrographs show a captured nematode covered by a mucilaginous coat. In transmission electron microscope micrographs of thin sections, a distinct osmiophilic layer between trap and nematode is always present. Since penetration occurred at the point of deposit of these substances, it is suggested that the osmiophilic layer also has enzymatic activity. An osmiophilic layer was never seen around vegetative hyphae, indicating the lack of both adhesive and similar enzymes.The traps contained numerous membranous electron-dense vesicles (150–300 nm) not present in hyphae. Large osmiophilic inclusions (1–2 μm) were more common in traps at certain stages of development than in hyphae. The results indicate that the adhesive and the digestive enzymes originate from either or both of these organelles.

SEM Examination of a Used Diamond Knife

1971 ◽  
Vol 29 ◽  
pp. 452-453
Author(s):  
J. Temple Black
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
High Magnification ◽  
Metallic Materials ◽  
Wide Spread ◽  
Thin Sections ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scanning Electron ◽  
Diamond Knife

Since its introduction by Fernandez-Moran, the diamond knife has gained wide spread usage as a common material for cutting of thin sections of biological and metallic materials into thin films for examination in the transmission electron microscope. With the development of high voltage E.M. and scanning transmission E.M., microtomy applications will become increasingly important in the preparation of specimens. For those who can afford it, the diamond knife will thus continue to be an important tool to accomplish this effort until a cheaper but equally strong and sharp tool is found to replace the diamond, glass not withstanding.In Figs. 1 thru 3, a first attempt was made to examine the edge of a used (β=45°) diamond knife by means of the scanning electron microscope. Because diamond is conductive, first examination was tried without any coating of the diamond. However, the contamination at the edge caused severe charging during imaging. Next, a thin layer of carbon was deposited but charging was still extensive at high magnification - high voltage settings. Finally, the knife was given a light coating of gold-palladium which eliminated the charging and allowed high magnification micrographs to be made with reasonable resolution.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

Observations of thick and thin sections in a field-emission SEM

1994 ◽  
Vol 52 ◽  
pp. 1018-1019
Author(s):  
W. P. Wergin ◽  
S. Roy ◽  
E. F. Erbe ◽  
C. A. Murphy ◽  
C. D. Pooley
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Transmission Electron Microscope ◽  
Scanning Electron

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.

Images and Applications of Ion Explosion Spike Pits

1990 ◽  
Vol 48 (1) ◽  
pp. 584-585
Author(s):  
P. Fraundorf ◽  
J. Tentschert
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Bulk Material ◽  
Coulomb Repulsion ◽  
The Body ◽  
Atomic Scale ◽  
Early Solar System ◽  
Transmission Electron ◽  
Nuclear Particle ◽  
Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

PREPARATION, CHARACTERIZATION AND LUMINESCENCE PROPERTIES OF Eu DOPED CaAl2O4 NANOCONES

2013 ◽  
Vol 27 (19) ◽  
pp. 1341018 ◽  
Author(s):  
J. M. LIANG ◽  
L. L. HE ◽  
Z. Q. SHEN ◽  
D. L. ZHANG
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
The Body ◽  
Monoclinic Structure ◽  
Thermal Evaporation Method ◽  
Room Temperature Photoluminescence ◽  
Spectrum Measurement ◽  
Transmission Electron ◽  
First Time

Europium doped CaAl 2 O 4 nanocones have been grown first time by thermal evaporation method. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to analyze the morphology, size and crystal structure of the nanocones. The body of the nanocones are about 2–20 μm in length and their diameters are 200 nm to 1 μm at one end and tapers off to a ~ 40–200 nm at the tip end. The as-synthesized nanocones are single crystalline in monoclinic structure and grow along the [010] direction and the normal direction of (100) and (001). The room temperature photoluminescence (PL) and cathodoluminescence (CL) spectrum measurement reveals that CaAl 2 O 4: Eu 2+ nanocones emit light at about 440 nm.

Marine fungi from Seychelles. III. Aniptodera mangrovii sp.nov. from mangrove wood

1986 ◽  
Vol 64 (12) ◽  
pp. 2989-2992 ◽  
Author(s):  
Kevin D. Hyde ◽  
C. A. Farrant ◽  
E. B. Gareth Jones
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Light Microscope ◽  
Marine Fungi ◽  
Undescribed Species ◽  
Transmission Electron ◽  
Transmission Electron Microscope Micrographs ◽  
Mangrove Wood

Collections of higher marine fungi in Seychelles included an undescribed species of Aniptodera: A. mangrovii Hyde sp.nov. from driftwood and dead mangrove wood. This species differs from A. chesapeakensis in the size of the ascospores and in ascospore appendage morphology. Aniptodera mangrovii is described and illustrated by light microscope and scanning and transmission electron microscope micrographs.

scholarly journals Observations of Microcrystalline Plagioclase Spherulites With the Transmission Electron Microscope

1982 ◽  
Vol 5 (1) ◽  
pp. 63-70
Author(s):  
R. Mark Bailey ◽  
H. R. Wenk
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Fiber Diameter ◽  
Growth Direction ◽  
Fiber Axis ◽  
Constant Thickness ◽  
Fiber Morphology ◽  
Thin Sections ◽  
C Fibers ◽  
Transmission Electron

Two thin sections of macroscopic plagioclase spherulites of approximately 1 cm diameter found in a rhyolitic glass have been studied with the transmission electron microscope (TEM). Orientations of the thin sections were chosen to give views down and perpendicular to the major fiber axis. The crystalline fiber phase is high albite microtwinned on the (010) composition plane, elongated in the major growth direction, [001]. Fiber morphology is non-polygonal with an average fiber diameter of 2000 Å perpendicular to c*. Fibers are separated by a non-crystalline residuum layer of approximately constant thickness (300–500 Å). Microtwinning relationships, as well as selected area diffraction (SAD) patterns, reveal both crystallographic and non-crystallographic branching with the former unexpectedly dominant.

Ultrastructure of graniferous tracheary elements in the haustorium of Exocarpus bidwillii , a root hemi-parasite of the Santalaceae

1979 ◽  
Vol 204 (1156) ◽  
pp. 329-343 ◽  
Keyword(s):  
Xylem Sap ◽  
The Body ◽  
Fibrillar Structure ◽  
Tracheary Elements ◽  
Thin Sections ◽  
Successive Layer ◽  
Transmission Electron ◽  
Vessel Elements ◽  
Homogeneous Matrix ◽  
Dispersed Material

The xylem in the body of the haustorium of E. bidwillii has the shape of an inverted conical flask with the expanded portion being known as the vascular core. The tracheary elements of the vascular core are notable for the occurrence of numerous granules within their lumina and the presence of mostly imperforate walls. Elsewhere in the haustorium graniferous tracheary elements are absent and the cells are usually ordinary vessel elements. Thin sections for transmission electron microscopy, post-stained in potassium permanganate, show that the secondary wall thickenings of the graniferous tracheary elements consist of eccentric layers in which the microfibrils of each successive layer run alternately longitudinally and transversely. The granules of the tracheary elements average 2 μm in diameter and consist of a homogeneous matrix which shows a fine fibrillar structure on high resolution. The granules are naked and mostly remain as separate structures within the lumen of the cell, but occasionally they fuse into small groups or irregular masses. In some cells the granules become transformed into fibrillar material that disperses throughout the lumen. This dispersed material may accumulate in vessels of the interrupted zone proximal to the vascular core. Occasionally, the granules also change into compacted amorphous masses that adhere to the walls of the cell. Ultrastructural cytochemistry confirms that the granules are protein and not starch as was originally believed for the Santalaceae. The function of the vascular core and its graniferous tracheary elements is discussed and we suggest that it might help regulate the pressure and flow of xylem sap entering the parasite from the host. Graniferous tracheary elements in the Santalaceae and in root parasites of the Scrophulariaceae are compared and it is concluded that they represent examples of convergent evolution.

Fine Structural Studies on the Scolex of Hymenolepis diminuta (Cestoda)

1974 ◽  
Vol 32 ◽  
pp. 184-185
Author(s):  
R. D. Specian ◽  
V. F. Allison ◽  
J. E. Ubelaker
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Osmium Tetroxide ◽  
Neurosecretory Cells ◽  
The Body ◽  
Hymenolepis Diminuta ◽  
Structural Studies ◽  
Major Area ◽  
Laboratory Rats ◽  
Transmission Electron

Although the scolex is the major area of contact between a cestode and its host, most fine structural studies have concentrated on the rest of the body. Davey and Breckenridge postulated, from histochemical data, that neurosecretory cells were present in the scolex of Hymenolepis diminuta. Such cells have been suggested to function in affecting growth and maturation of the strobila. Since a previous study by Rothman failed to determine such cells, the present study was undertaken.Specimens were collected from previously infected laboratory rats, fixed in paraformaldehyde, post-fixed in osmium tetroxide and embedded in Maraglas. Sections were examined on the Hitachi HU11B-2 transmission electron microscope.

Thin-section photomicrography

1992 ◽  
Vol 50 (2) ◽  
pp. 970-971
Author(s):  
Jack Holm ◽  
Rachel Goss
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Light Microscopy ◽  
Transmission Electron Microscope ◽  
Fundamental Problem ◽  
Depth Of Field ◽  
Large Section ◽  
Thin Sections ◽  
Transmission Electron ◽  
Conventional Light Microscopy

A fundamental problem in conventional light microscopy has long been the lack of image quality brought about by the use of sections which are thicker than the depth of field (DOF) of the microscope. These sections are used because “paraffin & steel” microtomy techniques preclude sections thinner than a few microns. The transmission electron microscope, however, requires section thicknesses of less than a micron. This requirement has resulted in the development of “epoxy & glass” microtomy techniques, and the ability to cut sections as thin as a few hundred Ångstroms. These thin sections are not routinely used for light microscopy because of the difficulty of preparation, the need for large section areas, and because of photomicrographic problems. The first two reasons may inhibit the use of thin sections in some situations, but the photomicrographic problems are surmountable.There is some disagreement in the literature regarding the actual DOF in photomicrographic situations.

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