The terahertz dynamics of human cells of the U937 line and their chromatin has been investigated by high-resolution inelastic X-ray scattering. To highlight its dynamical features in situ, nuclear DNA has been stained by uranyl-acetate salt. The general behavior of the collective dynamics of the whole cell is quite similar to that of bulk water, with a nearly wavevector-independent branch located at about 5 meV and a propagating mode with a linear trend corresponding to a speed of sound of 2900 +/- 100 m/s. We provide the first experimental evidence for the existence of two branches also in the dispersion curves of chromatin. The high-energy mode displays an acoustic-like behavior with a sound velocity similar to unstained cells, but in this case the branch likely originates from the superposition of intramolecular DNA optic modes. A low-energy optic-like branch, distinctive of the chromatin moiety, is found at about 2.5 meV.
Titolo: | Terahertz Dynamics in Human Cells and Their Chromatin |
Autori: | |
Data di pubblicazione: | 2014 |
Rivista: | |
Abstract: | The terahertz dynamics of human cells of the U937 line and their chromatin has been investigated by high-resolution inelastic X-ray scattering. To highlight its dynamical features in situ, nuclear DNA has been stained by uranyl-acetate salt. The general behavior of the collective dynamics of the whole cell is quite similar to that of bulk water, with a nearly wavevector-independent branch located at about 5 meV and a propagating mode with a linear trend corresponding to a speed of sound of 2900 +/- 100 m/s. We provide the first experimental evidence for the existence of two branches also in the dispersion curves of chromatin. The high-energy mode displays an acoustic-like behavior with a sound velocity similar to unstained cells, but in this case the branch likely originates from the superposition of intramolecular DNA optic modes. A low-energy optic-like branch, distinctive of the chromatin moiety, is found at about 2.5 meV. |
Handle: | http://hdl.handle.net/11562/950363 |
Appare nelle tipologie: | 01.01 Articolo in Rivista |