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

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.

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.

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.

EMCAT: An automatic image-processing system for electron-microscopic tomography

1994 ◽  
Vol 52 ◽  
pp. 418-419
Author(s):  
Weiping Liu ◽  
John W. Sedat ◽  
David A. Agard
Keyword(s):  
Image Processing ◽  
Structural Information ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Processing System ◽  
Electron Microscopic ◽  
Data Set ◽  
Ordered Structures ◽  
Automatic Image Processing ◽  
Em Tomography

Any real world object is three-dimensional. The principle of tomography, which reconstructs the 3-D structure of an object from its 2-D projections of different view angles has found application in many disciplines. Electron Microscopic (EM) tomography on non-ordered structures (e.g., subcellular structures in biology and non-crystalline structures in material science) has been exercised sporadically in the last twenty years or so. As vital as is the 3-D structural information and with no existing alternative 3-D imaging technique to compete in its high resolution range, the technique to date remains the kingdom of a brave few. Its tedious tasks have been preventing it from being a routine tool. One keyword in promoting its popularity is automation: The data collection has been automated in our lab, which can routinely yield a data set of over 100 projections in the matter of a few hours. Now the image processing part is also automated. Such automations finish the job easier, faster and better.

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