Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Oct 1;6(19):3911-4.
doi: 10.1021/acs.jpclett.5b01585. Epub 2015 Sep 17.

Electron Resonance Decay into a Biological Function: Decrease in Viability of E. coli Transformed by Plasmid DNA Irradiated with 0.5-18 eV Electrons

S Kouass Sahbani  1 , P Cloutier  1 , A D Bass  1 , D J Hunting  1 , L Sanche  1
Affiliations

Electron Resonance Decay into a Biological Function: Decrease in Viability of E. coli Transformed by Plasmid DNA Irradiated with 0.5-18 eV Electrons

S Kouass Sahbani et al. J Phys Chem Lett. .

Abstract

Transient negative ions (TNIs) are ubiquitous in electron-molecule scattering at low electron impact energies (0-20 eV) and are particularly effective in damaging large biomolecules. Because ionizing radiation generates mostly 0-20 eV electrons, TNIs are expected to play important roles in cell mutagenesis and death during radiotherapeutic cancer treatment, although this hypothesis has never been directly verified. Here, we measure the efficiency of transforming E. coli bacteria by inserting into the cells, pGEM-3ZfL(-) plasmid DNA that confers resistance to the antibiotic ampicillin. Before transformation, plasmids are irradiated with electrons of specific energies between 0.5 and 18 eV. The loss of transformation efficiency plotted as a function of irradiation energy reveals TNIs at 5.5 and 9.5 eV, corresponding to similar states observed in the yields of DNA double strand breaks. We show that TNIs are detectable in the electron-energy dependence of a biological process and can decrease cell viability.

Keywords: DNA; cell transformation efficiency; low-energy electrons; radiation damage; transient anions.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Variation of transformation efficiency of JM109 E. coli cells by pGEM 3Zf(−) plasmids, with incident electron fluence at 10 eV. The data is taken from ref . Each point is the average of three identical measurements. At each fluence, the error bars represent the standard deviation. The solid line is a fit to the data using the parametric model described in ref .
Figure 2
Figure 2
(a) Variation of transformation efficiency of JM109 E. coli cells by pGEM 3Zf(−) plasmids irradiated by 0.5 to 18 eV electrons at a fluence of 27 × 1013 electrons/cm2. The y axis is inverted. Effective yield functions for (b) single strand breaks (SSBs), (c) double strand breaks (DSBs) and (d) DNA cross-links, from ref .
See this image and copyright information in PMC

References

    1. Bethe HA. Theory of Disintegration of Nuclei by Neutrons. Phys Rev. 1935;47:747–759.
    1. Chin C, Grimm R, Julienne P, Tiesinga E. Feshbach Resonances in Ultracold Gases. Rev Mod Phys. 2010;82:1225–1286.
    1. Fernandez-Alonso F, Zare RN. Scattering Resonances in the Simplest Chemical Reaction. Annu Rev Phys Chem. 2002;53:67–99. - PubMed
    1. Miroshnichenko AE, Sergej Flach S, Kivshar YS. Fano Resonances in Nanoscale Structures. Rev Mod Phys. 2010;82:2257–2298.
    1. Schulz GJ. Resonances in Electron Impact on Atoms. Rev Mod Phys. 1973;45:378–422.
    2. Resonances in Electron Impact on Diatomic Molecules. Rev Mod Phys. 1973;45:423–86.

Publication types

LinkOut - more resources