scholarly journals Morphologically distinct microtubule ends in the mitotic centrosome of Caenorhabditis elegans

2003 ◽  
Vol 163 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Eileen T. O'Toole ◽  
Kent L. McDonald ◽  
Jana Mäntler ◽  
J. Richard McIntosh ◽  
Anthony A. Hyman ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Dynamic Behavior ◽  
High Voltage ◽  
Electron Tomography ◽  
In Vitro Studies ◽  
Embryonic Cells ◽  
Nematode Caenorhabditis Elegans ◽  
Voltage Electron ◽  
High Voltage Electron

During mitosis, the connections of microtubules (MTs) to centrosomes and kinetochores are dynamic. From in vitro studies, it is known that the dynamic behavior of MTs is related to the structure of their ends, but we know little about the structure of MT ends in spindles. Here, we use high-voltage electron tomography to study the centrosome- and kinetochore-associated ends of spindle MTs in embryonic cells of the nematode, Caenorhabditis elegans. Centrosome-associated MT ends are either closed or open. Closed MT ends are more numerous and are uniformly distributed around the centrosome, but open ends are found preferentially on kinetochore-attached MTs. These results have structural implications for models of MT interactions with centrosomes.

High-Voltage Electron Tomography of the Centrosome in Caenorhabditis elegans

2002 ◽  
Vol 8 (S02) ◽  
pp. 880-881
Author(s):  
Eileen O'Toole ◽  
Kent McDonald ◽  
Anthony Hyman ◽  
Thomas M�ller-Reichert
Keyword(s):  
Caenorhabditis Elegans ◽  
High Voltage ◽  
Electron Tomography ◽  
Voltage Electron ◽  
High Voltage Electron

High-Voltage Electron Tomography of the Early C. elegans Mitotic Spindle

2003 ◽  
Vol 9 (S03) ◽  
pp. 384-385
Author(s):  
Eileen T. O'Toole ◽  
Kent L. McDonald ◽  
Jana Mäntler ◽  
J. Richard McIntosh ◽  
Anthony A. Hyman ◽  
...  
Keyword(s):  
High Voltage ◽  
Mitotic Spindle ◽  
Electron Tomography ◽  
C Elegans ◽  
Voltage Electron ◽  
High Voltage Electron

High Voltage Electron Microscopy of Cultured Muscle Cells

1976 ◽  
Vol 34 ◽  
pp. 76-77
Author(s):  
Jerry W. Shay
Keyword(s):  
High Voltage ◽  
Three Dimensional ◽  
Muscle Differentiation ◽  
Biological Research ◽  
Muscular Tissue ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron

It is known from earlier observations that the in vitro rat L6 muscle cell line exhibits many of the features characteristic of in vivo muscle differentiation. The appearance of multinucleated cells, the development of highly organized contractile proteins and the phenomenon of muscle contraction are all easily recognizable features unique to muscular tissue. The L6 myoblasts fuse in a rather homogeneous and synchronous fashion to form myotubes and offer an excellent in vitro system to study the general mechanisms of muscle differentiation.The availability of the high voltage electron microscope (H.V.E.M.) in recent years for biological research has brought about a new interest in the three dimensional organization of components within whole cells, and the present study on L6 cells was undertaken, using the Jeol-1000 facility, at the University of Colorado in Boulder.

Increasing Access to Tomographic Resources: Web-based Telemicroscopy and Database

2001 ◽  
Vol 7 (S2) ◽  
pp. 92-93
Author(s):  
M. E. Martone ◽  
S. Peltier ◽  
S. Lamont ◽  
A. Gupta ◽  
B. Ludaescher ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
High Voltage ◽  
Cell Biology ◽  
Electron Tomography ◽  
The United States ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Electron Microscopes

The application of electron tomography to cell biology has led to important insights into the 3D fine structure of subcellular processes and organelles. Tomography has been particularly useful for studying relatively large, multi-component structures such as the Golgi apparatus, mitochondria and synaptic complexes. When combined with very powerful high voltage electron microscopes, tomography has also provided high resolution quantitative views of extended structures such as neuronal dendrites in very thick sections (4 μm) at electron microscopic resolution. The utility of tomography is twofold: first, it provides 3D examination of subcellular structure without the need for serial section analysis; second, because the computed slices through the tomographic volumes can be much thinner than is possible to produce by physical sectioning, it reveals structural detail in the range of 5-30 nm that tends to be obscured in conventional thin sections. Tomographic analysis has forced re-assessment of long-standing views of organelles such as mitochondria and the Golgi apparatus and as the technique advances, additional insights are likely forthcoming.Electron tomography is an expensive technique, both in terms of the instruments used and the computational resources required. The three major high voltage electron microscope resources in the United States, San Diego, Boulder and Albany, all are actively engaged in tomographic research and offer this important technology to the scientific community at large.

scholarly journals High-Voltage Electron Tomography of Spindle Pole Bodies and Early Mitotic Spindles in the YeastSaccharomyces cerevisiae

1999 ◽  
Vol 10 (6) ◽  
pp. 2017-2031 ◽  
Author(s):  
Eileen T. O’Toole ◽  
Mark Winey ◽  
J. Richard McIntosh
Keyword(s):  
High Voltage ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Spindle Pole ◽  
Dimensional Structure ◽  
Microtubule Organizing Center ◽  
Median Length ◽  
Intact Cells ◽  
Voltage Electron ◽  
High Voltage Electron

The spindle pole body (SPB) is the major microtubule-organizing center of budding yeast and is the functional equivalent of the centrosome in higher eukaryotic cells. We used fast-frozen, freeze-substituted cells in conjunction with high-voltage electron tomography to study the fine structure of the SPB and the events of early spindle formation. Individual structures were imaged at 5–10 nm resolution in three dimensions, significantly better than can be achieved by serial section electron microscopy. The SPB is organized in distinct but coupled layers, two of which show ordered two-dimensional packing. The SPB central plaque is anchored in the nuclear envelope with hook-like structures. The minus ends of nuclear microtubules (MTs) are capped and are tethered to the SPB inner plaque, whereas the majority of MT plus ends show a distinct flaring. Unbudded cells containing a single SPB retain 16 MTs, enough to attach to each of the expected 16 chromosomes. Their median length is ∼150 nm. MTs growing from duplicated but not separated SPBs have a median length of ∼130 nm and interdigitate over the bridge that connects the SPBs. As a bipolar spindle is formed, the median MT length increases to ∼300 nm and then decreases to ∼30 nm in late anaphase. Three-dimensional models confirm that there is no conventional metaphase and that anaphase A occurs. These studies complement and extend what is known about the three-dimensional structure of the yeast mitotic spindle and further our understanding of the organization of the SPB in intact cells.

High Voltage Electron Microscopy of Ion-Milled Dental Enamel

1974 ◽  
Vol 32 ◽  
pp. 60-61
Author(s):  
L. D. Ackerman ◽  
S. H. Y. Wei
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Third Molar ◽  
Polarized Light ◽  
Dental Enamel ◽  
Longitudinal Section ◽  
Ion Milling ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron

Mature human dental enamel has presented investigators with several difficulties in ultramicrotomy of specimens for electron microscopy due to its high degree of mineralization. This study explores the possibility of combining ion-milling and high voltage electron microscopy as a means of circumventing the problems of ultramicrotomy.A longitudinal section of an extracted human third molar was ground to a thickness of about 30 um and polarized light micrographs were taken. The specimen was attached to a single hole grid and thinned by argon-ion bombardment at 15° incidence while rotating at 15 rpm. The beam current in each of two guns was 50 μA with an accelerating voltage of 4 kV. A 20 nm carbon coating was evaporated onto the specimen to prevent an electron charge from building up during electron microscopy.

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