Low-Energy Ion-Species-Dependent Induction of DNA Double-Strand Breaks: Ion Energy and Fluence Thresholds.

The goal of this study was to determine the critical ion-radiation conditions under which heavy ion beams can induce DNA double-strand breaks. Helium, nitrogen and argon-ion beams in the energy range of 20 eV to 2 keV were used to irradiate naked DNA plasmid pGFP to fluences of 1, 2 and 4 × 10 ions/cm. The topological forms of DNA were subsequently analyzed using gel electrophoresis.

Expression of OsSPY and 14-3-3 genes involved in plant height variations of ion-beam-induced KDML 105 rice mutants.

The culm length of two semidwarf rice mutants (PKOS1, HyKOS1) obtained from low-energy N-ion beam bombardments of dehusked Thai jasmine rice (Oryza sativa L. cv. KDML 105) seeds showed 25.

Molecular simulations of ultra-low-energy nitrogen ion bombardment of A-DNA in vacuum.

For investigating mechanisms involved in low-energy ion beam induced mutation, besides experiments using low-energy and low-fluence ions to bombard naked DNA, molecular simulations were carried out as an effort towards the insight in molecular interactions between ions and DNA. In the current study, Monte Carlo (MC) and molecular dynamics (MD) simulations were applied. The results of MC simulations provide some clues about the interaction energies and sites of preference of N-ion bombardment on an A-DNA short duplex strand.

Theoretical analysis on ratiometric fluorescent indicators caused biased estimates of intracellular free calcium concentrations.

Ratiometric fluorescent calcium indicator dyes have been widely used for the study of the role of Ca2+ in cell physiopathology. Although these ratiometric dyes offer several advantages over others, they suffer some drawbacks which cause serious errors in measurement of intracellular Ca2+ concentration, [Ca2+]i. The present study systematically analyzes theoretical reasons and technical sources of discrepancies occurring in the measurement of the characteristics of the agonists-induced cells [Ca2+]i.