scholarly journals MICROTUBULE SURFACE LATTICE AND SUBUNIT STRUCTURE AND OBSERVATIONS ON REASSEMBLY

1974 ◽  
Vol 60 (1) ◽  
pp. 153-167 ◽  
Author(s):  
Harold P. Erickson
Keyword(s):  
Brain Tissue ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Reconstructed Image ◽  
Subunit Structure ◽  
Flat Sheet ◽  
Surface Lattice ◽  
Tissue Homogenates ◽  
Globular Particle

Neuronal microtubules have been reassembled from brain tissue homogenates and purified. In reassembly from purified preparations, one of the first structures formed was a flat sheet, consisting of up to 13 longitudinal filaments, which was identified as an incomplete microtubule wall. Electron micrographs of these flat sheets and intact microtubules were analyzed by optical diffraction, and the surface lattice on which the subunits are arranged was determined to be a 13 filament, 3-start helix. A similar, and probably identical, lattice was found for outer-doublet microtubules. Finally, a 2-D image of the structure and arrangement of the microtubule subunits was obtained by processing selected images with a computer filtering and averaging system. The 40 x 50 Å morphological subunit, which has previously been seen only as a globular particle and identified as the 55,000-dalton tubulin monomer, is seen in this higher resolution reconstructed image to be elongated, and split symmetrically by a longitudinal cleft into two lobes.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

The Structure of the Macromolecular Units on the Cell Walls of Bacillus Polymyxa

1967 ◽  
Vol 2 (4) ◽  
pp. 587-591
Author(s):  
J. T. FINCH ◽  
A. KLUG ◽  
M.V. NERMUT
Keyword(s):  
Cell Wall ◽  
Electron Micrographs ◽  
Electron Scattering ◽  
Cell Walls ◽  
Single Layer ◽  
Optical Diffraction ◽  
Square Lattice ◽  
Bacillus Polymyxa ◽  
Optical Filtering ◽  
Diffraction Patterns

Electron micrographs of negatively stained preparations of cell walls of Bacillus polymyxa have been investigated by optical diffraction and optical filtering techniques. Images of single layers of the cell wall, from which the ‘noise’ has been filtered optically, show hollow, square-shaped morphological units arranged on a square lattice of side 100 Å. Single-layer images showing the same pattern have been filtered from moiré patterns arising from two overlapping single layers. The morphological units are composed of four smaller subunits. The optical diffraction patterns from regions of two overlapping layers show extra reflexions which are attributed to multiple electron scattering.

Ribosome Crystals in Necrotizing Cells from the Posterior Necrotic Zone of the Developing Chick Limb

1972 ◽  
Vol 11 (2) ◽  
pp. 403-414
Author(s):  
N. K. MOTTET ◽  
S. P. HAMMAR
Keyword(s):  
Electron Micrographs ◽  
Protein Crystals ◽  
Embryonic Chick ◽  
3 Dimensional ◽  
Surface Lattice ◽  
Plane Group ◽  
High Doses ◽  
In Cells

Ribosome and ‘protein crystals" were observed in electron micrographs of degenerating cells from the posterior necrotic zone (PNZ) of developing chick limbs, stages 22 through 24. Ribosome crystals were made up of basic units of 4 ribosomes arranged in a square tetramer. They were monomorphic with the surface lattice being of the p4 plane group. The 1-ribosome-thick sheets of crystals were often seen stacked upon one another forming a 3-dimensional P422 configuration. The percentage of crystallized ribosomes within degenerating PNZ cells is nearly directly proportional to the degree of degeneration of the cell. Crystals identical to this have been observed in numerous types of embryonic chick cells subjected to hypothermia. The ‘protein crystals’ were composed of straight filamentous structures separated by a distance of 20-30 nm. They were always closely associated with the ribosome crystals. These crystals are similar to those seen in cells treated with high doses of vinblastine and vincristine. The pathogenesis of the ribosome and protein crystals occurring in degenerating PNZ cells is unknown. They are not associated in any way with hypothermia or vinblastine-vincristine treatment.

Optical diffraction studies of myofibrillar structure

1971 ◽  
Vol 261 (837) ◽  
pp. 201-208 ◽  
Keyword(s):  
Electron Micrographs ◽  
Focal Length ◽  
Optical Diffraction ◽  
Myofibrillar Proteins ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
Optical Filtering ◽  
X Ray ◽  
The Subject ◽  
Diffraction Patterns

We have used the techniques of optical diffraction and optical filtering to study electron micrographs of myofibrils and of paracrystals of myofibrillar proteins. The optical diffraction patterns provide information about periodic structure in the micrographs, and sometimes may reveal periodicities not apparent to the eye. We compare the optical diffraction patterns with the X-ray diffraction patterns obtained from living muscle, and this comparison can assist our interpretation of both the X-ray diffraction patterns and the electron micrographs. The optical diffractometer we have used is essentially similar to those described by Taylor & Lipson (1964), and by Klug & DeRosier (1966). The apparatus incorporates several refinements to facilitate operation. The recombining lens has a focal length, f , of about 1 m, and is placed so that the recombined image is formed at 2 f and has the same size as the subject. The diffraction subjects are not usually the electron micrographs themselves but copies on film. The film is of more uniform optical thickness than the glass electron micrograph, and is less fragile. Moreover, a set of films of varying contrast can be made from one micrograph.

scholarly journals Optical diffraction of the Z lattice in canine cardiac muscle.

1977 ◽  
Vol 75 (3) ◽  
pp. 818-836 ◽  
Author(s):  
M A Goldstein ◽  
J P Schroeter ◽  
R L Sass
Keyword(s):  
Cardiac Muscle ◽  
Electron Micrographs ◽  
Cross Sections ◽  
Optical Diffraction ◽  
Square Lattice ◽  
Thin Sections ◽  
Diffraction Patterns ◽  
Nemaline Rods

Optical diffraction patterns from electron micrographs of both longitudinal and cross sections of normal and anomalous canine cardiac Z bands have been compared. The data indicate that anomalous cardiac Z bands resembling nemaline rods are structurally related to Z bands in showing a repeating lattice common to both. In thin sections transverse to the myofibril axis, both electron micrographs and optical diffraction patterns of the Z structure reveal a square lattice of 24 nm. This lattice is simple at the edge of each I band and centered in the interior of the Z band, where two distinct lattice forms have been observed. In longitudinal sections, oblique filaments visible in the electron micrographs correspond to a 38-nm axial periodicity in diffraction patterns of both Z band and Z rod. We conclude that the Z rods will be useful for further analysis and reconstruction of the Z lattice by optical diffraction techniques.

Characterization of μ, κ, and δ Opioid Binding in Amphibian Whole Brain Tissue Homogenates

2002 ◽  
Vol 301 (1) ◽  
pp. 364-370 ◽  
Author(s):  
Leslie C. Newman ◽  
Steven S. Sands ◽  
David R. Wallace ◽  
Craig W. Stevens
Keyword(s):  
Brain Tissue ◽  
Whole Brain ◽  
Opioid Binding ◽  
Tissue Homogenates

Analysis of optical diffraction patterns from electron micrographs of lattices

1975 ◽  
Vol 99 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Douglas H. Ohlendorf ◽  
Myra L. Collins ◽  
Leonard J. Banaszak
Keyword(s):  
Electron Micrographs ◽  
Optical Diffraction ◽  
Diffraction Patterns

scholarly journals An electron microscopic and optical diffraction analysis of the structure of Limulus telson muscle thick filaments.

1982 ◽  
Vol 92 (2) ◽  
pp. 443-451 ◽  
Author(s):  
R W Kensler ◽  
R J Levine
Keyword(s):  
Electron Microscopy ◽  
Diffraction Analysis ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Cross Bridges

Long, thick filaments (greater than 4.0 micrometer) rapidly and gently isolated from fresh, unstimulated Limulus muscle by an improved procedure have been examined by electron microscopy and optical diffraction. Images of negatively stained filaments appear highly periodic with a well-preserved myosin cross-bridge array. Optical diffraction patterns of the electron micrographs show a wealth of detail and are consistent with a myosin helical repeat of 43.8 nm, similar to that observed by x-ray diffraction. Analysis of the optical diffraction patterns, in conjunction with the appearance in electron micrographs of the filaments, supports a model for the filament in which the myosin cross-bridges are arranged on a four-stranded helix, with 12 cross-bridges per turn or each helix, thus giving an axial repeat every third level of cross-bridges (43.8 nm).

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