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