scholarly journals The endurance of flash-frozen biologics can be improved allowing high-resolution electron microscopy tomography on individual proteins

2021 ◽  
Author(s):  
Andrea Fera
Keyword(s):  
Electron Microscopy ◽  
Protein Interactions ◽  
Electron Beams ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Experimental Session ◽  
Protein Protein Interactions ◽  
Viral Origin ◽  
Cryo Electron Microscopy ◽  
Resolution Electron

Abstract Here surprising results are shown demonstrating a workflow possibly able to exploit the discreet nature of interactions between high-energy electron beams and matter. Isolated protein constructs have been imaged after an original temperature-curing in vacuum, introduced recently for flash-frozen rigid biopolymers, and here applied to flash-frozen oligomers of viral origin. These results, if confirmed, may extend to plastics and bio-oligomers the access to atomic coordinates in one experimental session, when imaged by electron microscopy. Which is the case when imaging semiconductors or other solid materials, provided that the samples are not damaged by the interaction with accelerated electron beams in vacuum. Therefore, potentially, this workflow introduces the possibility of achieving atomic resolution in only one experiment with data only about one individual protein, maybe out of thermodynamic equilibrium. Such data are vital to understand protein-protein interactions. Finally, this workflow offers the possibility, new to cryo-electron microscopy samples, to store a sample indefinitely under liquid nitrogen for imaging the same molecules in more than one experimental session.

Interaction Between Basal Stacking Faults and Prismatic Inversion Domain Boundaries in GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
Philomela Komninou ◽  
Joseph Kioseoglou ◽  
Eirini Sarigiannidou ◽  
George P. Dimitrakopulos ◽  
Thomas Kehagias ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Stacking Faults ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Low Energy ◽  
Inversion Domain ◽  
Resolution Electron ◽  
Domain Boundaries ◽  
Inversion Domain Boundaries

ABSTRACTThe interaction of growth intrinsic stacking faults with inversion domain boundaries in GaN epitaxial layers is studied by high resolution electron microscopy. It is observed that stacking faults may mediate a structural transformation of inversion domain boundaries, from the low energy types, known as IDB boundaries, to the high energy ones, known as Holt-type boundaries. Such interactions may be attributed to the different growth rates of adjacent domains of inverse polarity.

An investigation of grain boundaries in submicrometer-grained Al-Mg solid solution alloys using high-resolution electron microscopy

1996 ◽  
Vol 11 (8) ◽  
pp. 1880-1890 ◽  
Author(s):  
Zenji Horita ◽  
David J. Smith ◽  
Minoru Furukawa ◽  
Minoru Nemoto ◽  
Ruslan Z. Valiev ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
High Resolution ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Boundary Energy ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Structural Features ◽  
Resolution Electron

High-resolution electron microscopy was used to examine the structural features of grain boundaries in Al–1.5% Mg and Al–3% Mg solid solution alloys produced with submicrometer grain sizes using an intense plastic straining technique. The grain boundaries were mostly curved or wavy along their length, and some portions were corrugated with regular or irregular arrangements of facets and steps. During exposure to high-energy electrons, grain boundary migration occurred to reduce the number of facets and thus to reduce the total boundary energy. The observed features demonstrate conclusively that the grain boundaries in these submicrometer-grained materials are in a high-energy nonequilibrium configuration.

Dynamic behavior of biomaterials uncovered by cryo-electron microscopy.

2020 ◽  
Vol 23 ◽  
Author(s):  
Yimin Zhao ◽  
Yizhen Zhao ◽  
Bingquan Peng ◽  
Lei Zhang
Keyword(s):  
Electron Microscopy ◽  
Protein Interactions ◽  
Rapid Development ◽  
Conformational Space ◽  
Biological Macromolecules ◽  
Protein Protein Interactions ◽  
Static Structure ◽  
Cryo Electron Microscopy ◽  
Biological Complexes ◽  
Functional Mechanisms

: Structural biology develops rapidly as time goes on. Based only on static structure analysis of biomaterials is not enough to satisfy the studies of their functional mechanisms, with a huge obstacle for the dynamic process of biological complexes. The rapid development of cryo-electron microscopy(cryo-EM) technology makes that it is possible to observe the near-atomic resolution structures and dynamic nature of biological macromolecules, in the fields of dynamic characteristics of proteins, protein-protein interactions, molecular recognition, and structure-based design. In this review, we systematically elaborate the contribution of cryo-EM technology in the field of biomaterials such as ribosome motion, membrane protein structure and conformational space, dynamic transmission within the plasma membrane and clinical applications. We also put forwards a new standpoint in the development of cryo-EM technology.

Observations of grain boundary structure in submicrometer-grained Cu and Ni using high-resolution electron microscopy

1998 ◽  
Vol 13 (2) ◽  
pp. 446-450 ◽  
Author(s):  
Zenji Horita ◽  
David J. Smith ◽  
Minoru Nemoto ◽  
Ruslan Z. Valiev ◽  
Terence G. Langdon
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Nonequilibrium State ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Typical Feature ◽  
Boundary Structure ◽  
Grain Boundary Structure ◽  
Resolution Electron

Submicrometer-grained (SMG) structures were produced in Cu and Ni using an intense plastic straining technique, and the grain boundaries and their vicinities were observed by high-resolution electron microscopy. The grain boundaries exhibited zigzag configurations with irregular arrangements of facets and steps, and thus they were found to be in a high-energy nonequilibrium state. A similar conclusion was reached earlier for SMG Al–Mg solid solution alloys which have much lower melting points than Cu and Ni, suggesting that nonequilibrium grain boundaries are a typical feature of metals processed by intense plastic straining.

Preparing Better Samples for Cryo–Electron Microscopy: Biochemical Challenges Do not End with Isolation and Purification

2021 ◽  
Vol 90 (1) ◽  
Author(s):  
Robert M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Effective Control ◽  
Annual Review ◽  
Publication Date ◽  
Biological Macromolecules ◽  
Isolation And Purification ◽  
Cryo Electron Microscopy ◽  
Extreme Risk ◽  
Resolution Electron

The preparation of extremely thin samples, which are required for high-resolution electron microscopy, poses extreme risk of damaging biological macromolecules due to interactions with the air-water interface. Although the rapid increase in the number of published structures initially gave little indication that this was a problem, the search for methods that substantially mitigate this hazard is now intensifying. The two main approaches under investigation are ( a) immobilizating particles onto structure-friendly support films and ( b) reducing the length of time during which such interactions may occur. While there is little possibility of outrunning diffusion to the interface, intentional passivation of the interface may slow the process of adsorption and denaturation. In addition, growing attention is being given to gaining more effective control of the thickness of the sample prior to vitrification. Expected final online publication date for the Annual Review of Biochemistry, Volume 90 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Anti-Site Bonds and the Structure of Interfaces in SiC

1990 ◽  
Vol 183 ◽  
Author(s):  
P. Pirouz ◽  
J. Yang
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Compound Semiconductors ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Dangling Bonds ◽  
Resolution Electron ◽  
Elemental Semiconductors

AbstractHigh resolution electron microscopy has been used to study the structure of the 3C/6H interface, Σ,=3 {111}and Σ.=3 {112}grain boundaries in 3C-SiC. In SiC, as in other compound semiconductors, anti-site bonds occur in a variety of defects. These are high energy bonds comparable to that of dangling bonds. But, while dangling bonds at the grain boundaries may be eliminated by reconstruction just as in elemental semiconductors, it may not be possible to avoid anti-site bonds.These problems are discussed for the Σ=3 {112} grain boundary, where the structures proposed for Ge and Si are used as starting models for SiC.

High Resolution Electron Microscopy of Semiconductor Defects

1981 ◽  
Vol 39 ◽  
pp. 120-123 ◽  
Author(s):  
J.C.H. Spence
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
High Energy Resolution ◽  
Resolution Electron ◽  
The Individual

Any attempt to study the relationship between the electronic and atomic struc ture of isolated defects in semiconductors by high resolution electron microscopy must deal with the following difficulties: (i) The limited point reso lution of modern TEM instruments, which has fallen by about 1Å from 3.8Å to 2.8Å (with tilt) over the last decade. This is still not sufficient to resolve the individual atomic columns in any semiconductor. (ii) The fundamental difficulties in obtaining both high spatial resolution structural information and high energy resolution spectroscopic data from the same, isolated, defect. (iii) The considerable difficulties in extracting chemical, or atomic number information from electron scattering and imaging experiments with high spatial resolution. Among other problems, the separation of composition variation effects from those of thickness is an important problem. Some of our recent approaches to these problems are outlined below.

scholarly journals High-Resolution Electron Microscopy Studies of the Precipitation of Copper Under Neutron Irradiation in An Fe-1.3Wt%Cu Alloy

1998 ◽  
Vol 540 ◽  
Author(s):  
A. C. Nicol ◽  
M. L. Jenkins ◽  
M. A. Kirk
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Neutron Irradiation ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Model Alloy ◽  
Cu Alloy ◽  
Energy Cascades ◽  
Resolution Electron ◽  
Previous Assumption

AbstractWe have studied by electron microscopy the copper-rich precipitates in an Fe-1.3wt%Cu model alloy irradiated with neutrons to doses of 8.61 × 10−3dpa and 6.3×10−2 dpa at a temperature of-270°C. In the lower dose material a majority (ca. 60%) of the precipitates visible in high-resolution electron microscopy were twinned 9R precipitates of size ∼ 2−4 nm, whilst ca. 40 % were untwinned. In the higher dose material, a majority (ca. 75%) of visible precipitates were untwinned although many still seemed to have a 9R structure. The average angle α between the herring-bone fringes in the twin variants was measured as 1250, not the 1290 characteristic of precipitates in thermally-aged and electron-irradiated material immediately after the bcc-→9R martensitic transformation. We argue that these results imply that the bcc-→9R transformation of small (< 4 nm) precipitates under neutron irradiation takes place at the irradiation temperature of 270°C rather than after subsequent cooling. Preliminary measurements showed that precipitate sizes did not depend strongly on dose, with a mean diameter of 3.4 ± 0.7 nm for the lower dose material, and 3.0 ± 0.5 rim for the higher dose material. This result agrees with the previous assumption that the lack of coarsening in precipitates formed under neutron irradiation is a consequence of the partial dissolution of larger precipitates by high-energy cascades.

Microstructure of Nonpolar a-Plane GaN Grown on (1120) 4H-SiC Investigated by TEM.

2003 ◽  
Vol 798 ◽  
Author(s):  
D. N. Zakharov ◽  
Z. Liliental-Weber ◽  
B. Wagner ◽  
Z. J. Reitmeier ◽  
E. A. Preble ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stacking Faults ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Buffer Layers ◽  
Type I ◽  
Plan View ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Aln Buffer

ABSTRACTPlan-view and cross-section samples of (1120) (a-plane) GaN grown on 4H-SiC substrates with AlN buffer layers were studied by transmission electron microscopy. Samples reveal the presence of a high density of stacking faults formed on the basal plane of hexagonal GaN. These stacking faults, terminated in the growth plane by threading dislocations, nucleate at the AlN/4H-SiC interface and propagate to the GaN layer surface. High resolution electron microscopy shows that the majority of stacking faults are low-energy planar defects of the type I1and I2. High energy stacking faults (E) are not observed.

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