scholarly journals Transmission electron microscopic observations of flagellum abnormalities in impala (Aepyceros melampus) sperm from the Kruger National Park

Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
D.J. Ackerman ◽  
A.J. Reinecke ◽  
H.J. Els
Keyword(s):  
Electron Microscopy ◽  
National Park ◽  
Kruger National Park ◽  
Electron Microscopic ◽  
Sperm Abnormalities ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Principal Piece ◽  
Adverse Influence ◽  
Aepyceros Melampus

Sperm must remain motile in order to reach and penetrate the ovum and defects in the ultrastructure of the tail can have an adverse influence on motility. Live spermatozoa were collected from the cauda epididymis of 64 impala rams in the Kruger National Park and studied by transmission electron microscopy to document sperm abnormalities. The following abnormalities of the flagellum were documented from micrographs: abnormal baseplate and neck attachments; neck vacuoles and displaced organelles; double or short flagella; bent flagella; principal-piece vacuoles; displaced axoneme and the Dag defect. The implications of these abnormalities for sperm motility are discussed.

scholarly journals Transmission electron microscopic observations of acrosome and head abnormalities in impala (Aepyceros melampus) sperm from the Kruger National Park

Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
D.J. Ackerman ◽  
A.J. Reinecke ◽  
H.J. Els
Keyword(s):  
Electron Microscopy ◽  
National Park ◽  
Chemical Compounds ◽  
Sperm Head ◽  
Kruger National Park ◽  
Electron Microscopic ◽  
Normal Sperm ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Aepyceros Melampus

Sperm morphological features play an important role in semen evaluation. Exposure to a variety of chemical compounds, especially environmental endocrine disrupters, elicit abnormalities in sperm of certain species. Baseline data on ultrastructure of normal sperm as well as abnormalities observed concomitantly, are required before causal links between such substances and abnormalities can be established. Live spermatozoa were collected from the cauda epididymis of 64 impala rams in the Kruger National Park and studied by transmission electron microscopy to document normal sperm features and abnormalities. The following abnormalities of the acrosome and sperm head were documented from micrographs: Loose acrosome in various stages of disintegration, lip forming of the acrosome; bizarre head, crater defect, poor condensation of the nucleus and the Dag defect. The observed abnormalities were very similar to those reported for other members of the Bovidae. Different forms of a hollow sphere, formed by the nucleus and covered by an abnormal acrosome have not previously been described for other species.

scholarly journals A transmission electron microscopic study of impala (Aepyceros melampus) sperm from the Kruger National Park

Koedoe ◽  
1996 ◽  
Vol 39 (2) ◽  
Author(s):  
D.J. Ackerman ◽  
A.J. Reinecke ◽  
H.J. Els
Keyword(s):  
National Park ◽  
Sperm Morphology ◽  
Kruger National Park ◽  
Electron Microscopic ◽  
Transmission Electron Microscopic Study ◽  
Normal Sperm ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
First Time ◽  
Aepyceros Melampus

Since knowledge of sperm morphology can play an important role in semen evaluation and fertilisation, baseline data are required. Live spermatozoa were collected from the cauda epididymis of 64 impala rams in the Kruger National Park and studied by trans- mission electron microscopy. The morphology of normal sperm was documented. The impala sperm shares characteristics with other members of the Bovidae. The occurrence of appendages on the cytoplasmic droplet of the flagellum of impala sperm is described for the first time. A total of 31 micrographs, showing typical features of impala sperm, in sections through various planes of the sperm, are presented.

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.

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).

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 .

Electron Microscopy in Tumor Diagnosis in 2001

2001 ◽  
Vol 7 (S2) ◽  
pp. 590-591
Author(s):  
J. Shelburne ◽  
D. Howell
Keyword(s):  
Electron Microscopy ◽  
Cell Biology ◽  
Tumor Diagnosis ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
S 100 ◽  
Molecular Information ◽  
Diagnostic Work ◽  
The Right

Immunohistochemistry (IH) has revolutionized tumor diagnosis in recent years. The antigenic/molecular information now available is extraordinarily helpful not only in clinical diagnostic work, but also in improving our understanding of the cell biology of neoplasia. As a result, there is now less need for diagnostic conventional transmission electron microscopic (CTEM) studies on neoplasms. For example, lymphomas and leukemias are now largely defined by IH and related techniques such as flow cytometry, not CTEM. A postive S-100 stain in the right setting usually obviates the need to search for melanosomes.However, CTEM is still a useful tool for surgical pathologists. One important advantage CTEM has over IH is that - like gross observations and the classic H&E section - CTEM can detect features not suspected in advance. This property of CTEM makes it particularly valuable in studying complex and unusual patients/tumors.

scholarly journals A scanning electron microscopic study of impala (Aepyceros melampus) sperm from the Kruger National Park

Koedoe ◽  
1996 ◽  
Vol 39 (2) ◽  
Author(s):  
D.J. Ackerman ◽  
A.J. Reinecke ◽  
H.J. Els
Keyword(s):  
National Park ◽  
Morphological Characteristics ◽  
Kruger National Park ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic Study ◽  
New Findings ◽  
Scanning Electron Microscopic ◽  
The Mean ◽  
Scanning Electron ◽  
Aepyceros Melampus

Since knowledge of sperm morphological characteristics can play an important role in semen evaluation and fertilisation, baseline data on sperm ultrastructure are required. Live spermatozoa were collected from the cauda epididymis from 64 impala rams in the Kruger National Park and 5082 spermatozoa from 40 of these impala were studied by scanning electron microscopy. The mean length of impala sperm was 59.23 @ 2.7 um. The morphology of normal sperm as well as the occurrence of abnormalities were documented. The morphology of impala sperm were compared with those of other mammals. New findings on appendages of the cytoplasmic droplet are described and interpreted.

Quantitative Field-Emission Transmission Electron Microscopic Study of Domain Boundaries in Cerium Doped A-Sialon Materials

2001 ◽  
Vol 7 (S2) ◽  
pp. 248-249
Author(s):  
F. Xu ◽  
Y. Bando ◽  
C. Wang ◽  
M. Mitomo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Domain Boundary ◽  
Earth Metal ◽  
Partial Replacement ◽  
Electron Microscopic ◽  
Transmission Electron Microscopic Study ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Transmission Electron Microscopic

α-sialon is the isostructural derivative based on the a-silicon nitride (α-Si3N4) structure by partial replacement of Si by Al and N by O. The structure is considered to be stabilized by the incorporation into the large interstices (r=0.146nm) of a metal like Li, Mg, Ca and most small rareearths. Large rare-earth metal ions have been considered not to be able to enter the interstices in α-sialon structure until several recent successes in accommodating large cerium ions (r=0.103nm). This gives rise to questions of the location and distribution of these large cerium ions within the asialon structure. It has been found that α-sialon grains formed in Ce-Si-Al-O-N system are usually rich in a new structural defect which has been considered to be initiated specifically by the presence of cerium in the lattice. This new intergrown defect is identified as domain boundary in our present study by transmission electron microscopy (TEM).

scholarly journals Transmission electron microscopy enables the reconstruction of the catenane and ring forms of CS2 hydrolase

2014 ◽  
Vol 50 (71) ◽  
pp. 10281-10283 ◽  
Author(s):  
Joseph Che-Yen Wang ◽  
Adam Zlotnick ◽  
Jasmin Mecinović
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Direct Evidence ◽  
Protein Assemblies ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Microscopic Studies ◽  
Good Agreement

Transmission electron microscopic studies on CS2 hydrolase provide direct evidence for the existence of the hexadecameric catenane and octameric ring topologies. Reconstructions of both protein assemblies are in good agreement with crystallographic analyses.

Sign in / Sign up

Export Citation Format

Share Document