Humic Substances Mitigate the Impact of Tritium on Luminous Marine Bacteria. Involvement of Reactive Oxygen Species.

Tatiana V Rozhko,Gennadii A Badun,Devard I Stom,Nadezhda S Kudryasheva,Olga V Kolesnik

doi:10.3390/ijms21186783

Abstract

The paper studies the combined effects of beta-emitting radionuclide tritium and Humic Substances (HS) on the marine unicellular microorganism—luminous bacteria—under conditions of low-dose radiation exposures (<0.04 Gy). Tritium was used as a component of tritiated water. Bacterial luminescence intensity was considered as a tested physiological parameter. The bioluminescence response of the marine bacteria to tritium corresponded to the “hormesis” model: it included stages of bioluminescence inhibition and activation, as well as the absence of the effect. HS were shown to decrease the inhibition and activation effects of tritium, similar to those of americium-241, alpha-emitting radionuclide, studied earlier. Correlations between the bioluminescence intensity and the content of Reactive Oxygen Species (ROS) were found in the radioactive bacterial suspensions. The results demonstrate an important role of HS in natural processes in the regions of low radioactive contamination: HS can mitigate radiotoxic effects and adaptive response of microorganisms to low-dose radioactive exposures. The involvement of ROS in these processes was demonstrated.

Highlights

Low-intensity radioactive contaminations create problems in the vast territories of the world.Low-intensity radiation is characterized by the concentration of radionuclides of alpha- and beta-type or/and dose rate of gamma rays which produce a “low-dose” impact on organisms
It should noted that ourframes previous revealed variations in time the dependence
We confirmed in this paper that a response of marine bacteria to the beta-emitting radionuclide tritium corresponds to a hormesis model: it includes stages of inhibition and activation

Summary

Introduction

Low-intensity radiation is characterized by the concentration of radionuclides of alpha- and beta-type or/and dose rate of gamma rays which produce a “low-dose” impact on organisms. According to [1], a tentative limit of low doses for high organisms is 0.1 Gy. In general, toxicology suggests that the low-dose border separates the low-dose effects from toxic effects: the latter means the suppression of physiological functions of organisms by radiation. Toxicology suggests that the low-dose border separates the low-dose effects from toxic effects: the latter means the suppression of physiological functions of organisms by radiation This limit can change under variation of the environmental conditions and the state of an organism [2,3]. The sensitivity of organisms to the low-dose radiation impact is not entirely clear yet; the variation of the sensitivity under natural conditions is a question of special interest

Methods

Results

Conclusion