Microtubule structure studied by quick freezing: Cryo-electron microscopy and freeze fracture

1986 ◽  
Vol 141 (3) ◽  
pp. 361-373 ◽  
Author(s):  
Eva-Maria Mandelkow ◽  
Roberto Rapp ◽  
Eckhard Mandelkow
Keyword(s):  
Electron Microscopy ◽  
Freeze Fracture ◽  
Cryo Electron Microscopy ◽  
Quick Freezing ◽  
Microtubule Structure

Intercellular spaces in quick-frozen whole hearts of the frog and mouse

1986 ◽  
Vol 44 ◽  
pp. 262-263
Author(s):  
Sommer ◽  
N.R. Wallace ◽  
R. Nassar
Keyword(s):  
Electron Microscopy ◽  
Comparative Study ◽  
Freeze Fracture ◽  
High Fidelity ◽  
Ventricular Muscle ◽  
Intercellular Spaces ◽  
Cardiac Muscle Cells ◽  
Profound Influence ◽  
Quick Freezing

The geometry of cell apposition has a profound influence on certain electrophysiologic properties of aggregates of cardiac muscle cells, e.g. in bundles of frog versus mouse ventricular muscle. It should be assessed, ideally, in the absence of preparatory procedures that can be expected to change it. Since quick-freezing followed by freeze fracture eliminates all but freezing from the preparatory menue prior to electron microscopy, we have applied this technology to a comparative study of the geometry of intercellular spaces in frog and mouse hearts in an attempt to reproduce its in vivo state with high fidelity.

Controlled Multi-Stage Self-Assembly of Vesicles

1994 ◽  
Vol 372 ◽  
Author(s):  
Scotr A. Walker ◽  
S. Chiruvolu ◽  
J. A. Zasadzinski ◽  
F.-J. Schmitt ◽  
J. N. Israelachvlli
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Freeze Fracture ◽  
Site Specific ◽  
Cryo Electron Microscopy ◽  
Multi Stage ◽  
Unstressed State ◽  
Receptor Interactions ◽  
Freeze Fracture Electron Microscopy ◽  
Spherical Vesicles

AbstractThe association of lipid or surfactant molecules into spherical vesicles in solution constitutes a primary self-assembly process, although typical vesicles are not the equilibrium form of aggregation for most lipids. Such meta-stable vesicles can undergo a secondary self-assembly into higher order structures in a controlled and reversible manner by means of site-specific ligandreceptor coupling. Cryo-electron microscopy shows these structures to be composed of tethered vesicles in their original, unstressed state. In contrast, vesicles aggregated by non-specific forces are deformed. In this work, we show that equilibrium vesicles can also undergo a secondary selfassembly via ligand-receptor interactions, as evidenced by freeze-fracture electron microscopy. Such site-specific vesicle aggregation provides a practical mechanism for the production of stable, yet controllable, microstructured materials.

Freeze-Fracture Replication of Frozen Outer Segments of Rat Retinal Rods

1969 ◽  
Vol 27 ◽  
pp. 392-393
Author(s):  
Thomas S. Leeson ◽  
C. Roland Leeson
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Outer Segment ◽  
Freeze Fracture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Outer Segments ◽  
Retinal Rods ◽  
Temperature Electron ◽  
Freeze Etching

Numerous previous studies of outer segments of retinal receptors have demonstrated a complex internal structure of a series of transversely orientated membranous lamellae, discs, or saccules. In cones, these lamellae probably are invaginations of the covering plasma membrane. In rods, however, they appear to be isolated and separate discs although some authors report interconnections and some continuities with the surface near the base of the outer segment, i.e. toward the inner segment. In some species, variations have been reported, such as longitudinally orientated lamellae and lamellar whorls. In cross section, the discs or saccules show one or more incisures. The saccules probably contain photolabile pigment, with resulting potentials after dipole formation during bleaching of pigment. Continuity between the lamina of rod saccules and extracellular space may be necessary for the detection of dipoles, although such continuity usually is not found by electron microscopy. Particles on the membranes have been found by low angle X-ray diffraction, by low temperature electron microscopy and by freeze-etching techniques.

Cryomicroscopy of multiphase latices

1991 ◽  
Vol 49 ◽  
pp. 1060-1061
Author(s):  
O. L. Shaffer ◽  
M.S. El-Aasser ◽  
C. L. Zhao ◽  
M. A. Winnik ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Radiation Damage ◽  
Freeze Fracture ◽  
Particle Morphology ◽  
Second Stage ◽  
Transmission Electron ◽  
Important Approach ◽  
Carbon Coated ◽  
Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

New challenges to image processing posed by cryo-Electron microscopy of single particles

1991 ◽  
Vol 49 ◽  
pp. 422-423
Author(s):  
Joachim Frank
Keyword(s):  
Electron Microscopy ◽  
Phase Contrast ◽  
Particle Orientation ◽  
Single Particles ◽  
Contrast Transfer Function ◽  
Virtual Absence ◽  
Cryo Electron Microscopy ◽  
Spatial Frequencies ◽  
New Challenges ◽  
Particle Images

Compared with images of negatively stained single particle specimens, those obtained by cryo-electron microscopy have the following new features: (a) higher “signal” variability due to a higher variability of particle orientation; (b) reduced signal/noise ratio (S/N); (c) virtual absence of low-spatial-frequency information related to elastic scattering, due to the properties of the phase contrast transfer function (PCTF); and (d) reduced resolution due to the efforts of the microscopist to boost the PCTF at low spatial frequencies, in his attempt to obtain recognizable particle images.

Enhanced information from biological materials through technological improvements in cryo-electron microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 788-789
Author(s):  
Marc J.C. de Jong ◽  
Wim M. Busing ◽  
Max T. Otten
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Biological Materials ◽  
Electron Crystallography ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
The Many ◽  
Technological Improvements ◽  
Beam Damage

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.

Sign in / Sign up

Export Citation Format

Share Document