Kolesnik Olga V, Rozhko Tatiana V, Lapina Maria A, Solovyev Vladislav S, Sachkova Anna S, Kudryasheva Nadezhda S
Federal Research Center 'Krasnoyarsk Science Center SB RAS', Institute of Biophysics SB RAS, 660036 Krasnoyarsk, Russia.
Biophysics Department, Siberian Federal University, 660041 Krasnoyarsk, Russia.
Bioengineering (Basel). 2021 Nov 29;8(12):194. doi: 10.3390/bioengineering8120194.
Thorium is one of the most widespread radioactive elements in natural ecosystems, along with uranium, it is the most important source of nuclear energy. However, the effects of thorium on living organisms have not been thoroughly studied. Marine luminescent bacteria and their enzymes are optimal bioassays for studying low-dose thorium exposures. Luminescent bioassays provide a quantitative measure of toxicity and are characterized by high rates, sensitivity, and simplicity. It is known that the metabolic activity of bacteria is associated with the production of reactive oxygen species (ROS). We studied the effects of thorium-232 (10-10 M) on and bacterial enzymatic reactions; kinetics of bacterial bioluminescence and ROS content were investigated in both systems. Bioluminescence activation was revealed under low-dose exposures (<0.1 Gy) and discussed in terms of "radiation hormesis". The activation was accompanied by an intensification of the oxidation of a low-molecular reducer, NADH, during the enzymatic processes. Negative correlations were found between the intensity of bioluminescence and the content of ROS in bacteria and enzyme systems; an active role of ROS in the low-dose activation by thorium was discussed. The results contribute to radioecological potential of bioluminescence techniques adapted to study low-intensity radioactive exposures.
钍是自然生态系统中分布最广泛的放射性元素之一，与铀一样，它是核能的最重要来源。然而，钍对生物体的影响尚未得到充分研究。海洋发光细菌及其酶是研究低剂量钍暴露的最佳生物测定方法。发光生物测定法提供了毒性的定量测量，其特点是速度快、灵敏度高且操作简单。已知细菌的代谢活性与活性氧（ROS）的产生有关。我们研究了钍-232（10-10 M）对细菌和细菌酶促反应的影响；在这两个系统中研究了细菌生物发光和ROS含量的动力学。在低剂量暴露（<0.1 Gy）下发现了生物发光激活现象，并根据“辐射兴奋效应”进行了讨论。这种激活伴随着酶促过程中低分子还原剂NADH氧化的增强。在细菌和酶系统中发现生物发光强度与ROS含量之间存在负相关；讨论了ROS在钍低剂量激活中的积极作用。这些结果有助于发光技术在研究低强度放射性暴露方面的放射生态学潜力。
