scholarly journals Temperature-dependent nanomechanics and topography of bacteriophage T7

2018 ◽  
Author(s):  
Zsuzsanna Vörös ◽  
Gabriella Csík ◽  
Levente Herényi ◽  
Miklós Kellermayer
Keyword(s):  
Structural Changes ◽  
Mechanical Stability ◽  
Genetic Material ◽  
Heat Inactivation ◽  
Infectious Agents ◽  
Temperature Dependent ◽  
Thermally Induced ◽  
Partial Denaturation ◽  
Induced Changes ◽  
T7 Bacteriophage

AbstractViruses are nanoscale infectious agents which may be inactivated by heat treatment. Although heat inactivation is thought to be caused by the release of genetic material from the capsid, the thermally-induced structural changes in viruses are little known. Here we measured the heat-induced changes in the properties of T7 bacteriophage particles exposed to two-stage (65 °C and 80 °C) thermal effect by using AFM-based nanomechanical and topographical measurements. We found that exposure to 65 °C caused the release of genomic DNA due to the loss of the capsid tail which leads to a destabilization of the T7 particles. Further heating to 80 °C surprisingly led to an increase in mechanical stability due to partial denaturation of the capsomeric proteins kept within the global capsid arrangement.

scholarly journals Temperature-Dependent Nanomechanics and Topography of Bacteriophage T7

2018 ◽  
Vol 92 (20) ◽  
Author(s):  
Zsuzsanna Vörös ◽  
Gabriella Csík ◽  
Levente Herényi ◽  
Miklós Kellermayer
Keyword(s):  
Heat Treatment ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Mechanical Stability ◽  
Structural Constraints ◽  
Thermally Induced ◽  
Force Microscopy ◽  
Partial Denaturation ◽  
Induced Changes ◽  
T7 Phage

ABSTRACT Viruses are nanoscale infectious agents which may be inactivated by heat treatment. The global molecular mechanisms of virus inactivation and the thermally induced structural changes in viruses are not fully understood. In this study, we measured the heat-induced changes in the properties of T7 bacteriophage particles exposed to a two-stage (65°C and 80°C) thermal effect, by using atomic force microscopy (AFM)-based nanomechanical and topographical measurements. We found that exposure to 65°C led to the release of genomic DNA and to the loss of the capsid tail; hence, the T7 particles became destabilized. Further heating to 80°C surprisingly led to an increase in mechanical stability, due likely to partial denaturation of the capsomeric proteins kept within the global capsid arrangement. IMPORTANCE Even though the loss of DNA, caused by heat treatment, destabilizes the T7 phage, its capsid is remarkably able to withstand high temperatures with a more or less intact global topographical structure. Thus, partial denaturation within the global structural constraints of the viral capsid may have a stabilizing effect. Understanding the structural design of viruses may help in constructing artificial nanocapsules for the packaging and delivery of materials under harsh environmental conditions.

Thermally induced changes in reconstituted and membranous cytochrome c oxidase

1979 ◽  
Vol 57 (3) ◽  
pp. 238-249 ◽  
Author(s):  
A. S. Denes ◽  
N. Z. Stanacev
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Spin Label ◽  
Liquid Crystalline ◽  
Spectral Characteristics ◽  
Temperature Dependent ◽  
Scanning Calorimetry ◽  
Thermally Induced ◽  
Lipid Protein Interaction ◽  
Induced Changes

The Arrhenius plots of electron transport activity in cytochrome c oxidase reconstituted with well-defined phospholipids have been shown to display a change in slope at 20–25 °C regardless of the chemical nature of the incorporated lipid. In native membranous cytochrome c oxidase, the discontinuity in Arrhenius activity plot occurred at 16–18 °C. These temperature breaks were found to correlate with changes in spin-label mobilities but not with the bulk lipid transition observed by differential scanning calorimetry. Temperature-dependent reciprocal equilibrium between the immobilized and fluid pools is demonstrated. It is suggested that the changes in kinetic and spin-label spectral characteristics in cytochrome c oxidase membranes are related very likely to a lipid-protein interaction prompted by a thermally induced change in the physical state of the lipids that does not involve a gel to liquid crystalline transition.

Thermally induced changes in cluster-assembled carbon nanocluster films observed via photoelectron spectroscopy

2003 ◽  
Vol 212-213 ◽  
pp. 879-884 ◽  
Author(s):  
E. Magnano ◽  
C. Cepek ◽  
M. Sancrotti ◽  
F. Siviero ◽  
S. Vinati ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Thermally Induced ◽  
Induced Changes

Formation process of interface states at grain boundaries in sputtered polycrystalline Si films

1999 ◽  
Vol 14 (2) ◽  
pp. 371-376 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Jiro Sakata ◽  
Yasunori Taga
Keyword(s):  
Energy Levels ◽  
Columnar Structure ◽  
Systematic Investigation ◽  
Defect States ◽  
Electron Microscopic ◽  
Thermally Induced ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Si Films ◽  
Induced Changes

A systematic investigation has been made on surface defect states of crystallites in the crystallization process of sputtered amorphous silicon films by isothermal annealing. Transmission electron microscopic observations indicate a pronounced vertical columnar structure in the upper part of the films, where the crystallization is delayed. Admittance spectroscopy reveals that two newly generated energy levels with the crystallization are attributed to the crystallites in the lower and upper parts of the films in view of the anisotropic crystallization. These thermally induced changes can be well explained by Si–Si shearing modes at the interfaces of crystallites through the process of crystallization.

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