| Autor: |
Rozhko TV; Department of Medical and Biological Physics, Krasnoyarsk State Medical Academy, 660022 Krasnoyarsk, Russia., Nemtseva EV; Biophysics Department, Siberian Federal University, 660041 Krasnoyarsk, Russia.; Institute of Biophysics SB RAS, FRC KSC SB RAS, 660036 Krasnoyarsk, Russia., Gardt MV; Biophysics Department, Siberian Federal University, 660041 Krasnoyarsk, Russia., Raikov AV; Biophysics Department, Siberian Federal University, 660041 Krasnoyarsk, Russia., Lisitsa AE; Biophysics Department, Siberian Federal University, 660041 Krasnoyarsk, Russia., Badun GA; Department of Chemistry, Moscow State University, 119991 Moscow, Russia., Kudryasheva NS; Biophysics Department, Siberian Federal University, 660041 Krasnoyarsk, Russia.; Institute of Biophysics SB RAS, FRC KSC SB RAS, 660036 Krasnoyarsk, Russia. |
| Abstrakt: |
The present study considers a possible role of enzymatic reactions in the adaptive response of cells to the beta-emitting radionuclide tritium under conditions of low-dose exposures. Effects of tritiated water (HTO) on the reactions of bacterial luciferase and NAD(P)H:FMN-oxidoreductase, as well as a coupled system of these two reactions, were studied at radioactivity concentrations ≤ 200 MBq/L. Additionally, one of the simplest enzymatic reactions, photobiochemical proton transfer in Coelenteramide-containing Fluorescent Protein (CLM-FP), was also investigated. We found that HTO increased the activity of NAD(P)H:FMN-oxidoreductase at the initial stage of its reaction (by up to 230%); however, a rise of luciferase activity was moderate (<20%). The CLM-FP samples did not show any increase in the rate of the photobiochemical proton transfer under the exposure to HTO. The responses of the enzyme systems were compared to the 'hormetic' response of luminous marine bacterial cells studied earlier. We conclude that (1) the oxidoreductase reaction contributes significantly to the activation of the coupled enzyme system and bacterial cells by tritium, and (2) an increase in the organization level of biological systems promotes the hormesis phenomenon. |
