Correction of distance-dependent blurring in projection data for fully three-dimensional electron microscopic reconstruction

2010 ◽  
Author(s):  
Joanna Klukowska ◽  
Gabor T. Herman ◽  
Ivan G. Kazantsev
Keyword(s):  
Three Dimensional ◽  
Projection Data ◽  
Dimensional Electron ◽  
Electron Microscopic

A Relatively Inexpensive Microprocessor-Linked Digital Plamimeter for Electron Microscopic Morphometry

1981 ◽  
Vol 39 ◽  
pp. 266-269
Author(s):  
Lee D. Peachey
Keyword(s):  
Theoretical Basis ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Structural Data ◽  
Large Set ◽  
Dimensional Electron ◽  
Electron Microscopic ◽  
Morphometric Methods ◽  
Electron Microscopic Morphometry ◽  
Separate Step

Stereology provides a theoretical basis for powerful morphometric methods for the estimation of three-dimensional structural parameters from two-dimensional electron micrographs of cells and tissues. These methods assume at the start that one has a sufficiently large set of micrographs containing valid structural data. The task of obtaining from these micrographs the large quantity of data needed to get statistically valid results has been eased in two general ways. Sampling of data in the micrograph can be done rapidly by point and intersection counting methods. An alternate method, planimetry, obtains all the data in the micrograph, but in general is more time-consuming than point and intersection counting. Some of the relative inefficiency of planimetry is compensated when a digital planimeter is coupled with a computer. Areas and lengths can be computed simultaneously as fast as profiles are traced. Furthermore, rapid and numerically accurate compilation and statistical analysis of the data can be done automatically as the planimetry is done, not as a separate step after the data have been obtained.

Development of a Side Entry High Tilt Cryotransfer Stage for Tomographic Applications

1998 ◽  
Vol 4 (S2) ◽  
pp. 402-403
Author(s):  
B.L. Armbruster ◽  
R. Zolkowski ◽  
P.R. Swann
Keyword(s):  
Large Range ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Current Data ◽  
Projection Data ◽  
Data Sets ◽  
Electron Microscopic ◽  
Specimen Holder ◽  
Clamping Device ◽  
Minimal Area

Three-dimensional electron microscopic imaging, or electron tomography, involves the reconstruction of individual objects from projection data collected over a large range of specimen tilts. Practical limitations of tomography are set by the range of specimen tilt available to generate projection data. In terms of tilt range, current data sets typically cover a range of up to +/-700° of tilt.When used for applications requiring high tilt such as tomography, problems with specimen holder designs which use circular 3mm diameter grids include restricted field of view created by the standard mesh pattern of commercially available specimen grids. The standard square or hexagonally patterned support grids provide minimal area between grid bars to view a sample at high tilt. The width of the specimen clamping device and holder tip blade also limit the useable grid area to the center of the specimen when the holder is at high tilt positions.

scholarly journals Chromosome Fragments Possessing Only One Kinetochore Can Congress to the Spindle Equator

1997 ◽  
Vol 136 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Alexey Khodjakov ◽  
Richard W. Cole ◽  
Bruce F. McEwen ◽  
Karolyn F. Buttle ◽  
Conly L. Rieder
Keyword(s):  
Three Dimensional ◽  
Spindle Pole ◽  
The Other ◽  
Dimensional Electron ◽  
Laser Microsurgery ◽  
Electron Microscopic ◽  
Spindle Poles ◽  
Chromosome Congression ◽  
Chromosome Fragments ◽  
Multiple Domains

We used laser microsurgery to cut between the two sister kinetochores on bioriented prometaphase chromosomes to produce two chromosome fragments containing one kinetochore (CF1K). Each of these CF1Ks then always moved toward the spindle pole to which their kinetochores were attached before initiating the poleward and away-from-the-pole oscillatory motions characteristic of monooriented chromosomes. CF1Ks then either: (a) remained closely associated with this pole until anaphase (50%), (b) moved (i.e., congressed) to the spindle equator (38%), where they usually (13/19 cells) remained stably positioned throughout the ensuing anaphase, or (c) reoriented and moved to the other pole (12%). Behavior of congressing CF1Ks was indistinguishable from that of congressing chromosomes containing two sister kinetochores. Three-dimensional electron microscopic tomographic reconstructions of CF1Ks stably positioned on the spindle equator during anaphase revealed that the single kinetochore was highly stretched and/or fragmented and that numerous microtubules derived from the opposing spindle poles terminated in its structure. These observations reveal that a single kinetochore is capable of simultaneously supporting the function of two sister kinetochores during chromosome congression and imply that vertebrate kinetochores consist of multiple domains whose motility states can be regulated independently.

D-CAT: Density and Clustering Annotation Tool for three dimensional electron microscopic volumes

2012 ◽  
Vol 177 (2) ◽  
pp. 571-577 ◽  
Author(s):  
M.N. Lebbink ◽  
L.H.P. Hekking ◽  
W.J.C. Geerts ◽  
J.A. Post
Keyword(s):  
Three Dimensional ◽  
Annotation Tool ◽  
Dimensional Electron ◽  
Electron Microscopic

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

Structural Role of rRNAs on the Ribosomal Subunits from E. Coli by Scanning Transmission Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 424-425
Author(s):  
M. Boublik ◽  
N. Robakis ◽  
J.S. Wall
Keyword(s):  
Three Dimensional ◽  
Uranyl Acetate ◽  
Dimensional Structure ◽  
Electron Microscopic ◽  
Ribosomal Subunits ◽  
E Coli ◽  
Freeze Dried ◽  
16S Rna ◽  
Scanning Transmission ◽  
And Function

The three-dimensional structure and function of biological supramolecular complexes are, in general, determined and stabilized by conformation and interactions of their macromolecular components. In the case of ribosomes, it has been suggested that one of the functions of ribosomal RNAs is to act as a scaffold maintaining the shape of the ribosomal subunits. In order to investigate this question, we have conducted a comparative TEM and STEM study of the structure of the small 30S subunit of E. coli and its 16S RNA.The conventional electron microscopic imaging of nucleic acids is performed by spreading them in the presence of protein or detergent; the particles are contrasted by electron dense solution (uranyl acetate) or by shadowing with metal (tungsten). By using the STEM on freeze-dried specimens we have avoided the shearing forces of the spreading, and minimized both the collapse of rRNA due to air drying and the loss of resolution due to staining or shadowing. Figure 1, is a conventional (TEM) electron micrograph of 30S E. coli subunits contrasted with uranyl acetate.

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