Comparison of chronic low-dose effects of alpha- and beta-emitting radionuclides on marine bacteria

Abstract

Effects of Americium-241 (241Am), alpha-emitting radionuclide of high specific radioactivity, and tritium (3H), beta-emitting radionuclide, on luminous bacteria Photobacterium phosphoreum were compared. Bioluminescence intensity served as a marker of bacterial physiological activity. Three successive stages in the bioluminescence response to 241Am and 3H were found under conditions of lowdose irradiation: (1) absence of effects, (2) activation, and (3) inhibition. They were interpreted in terms of bacterial response to stressfactor as stress recognition, adaptive response/syndrome, and suppression of physiological function (i.e. radiation toxicity). Times of bioluminescence activation (TBA) and inhibition (TBI) were suggested as parameters to characterize hormesis and toxic stages in a course of chronic low-dose irradiation of the microorganisms. Values of TBA and TBI of 241Am were shorter than those of 3H, revealing higher impact of alpha-irradiation (as compared to beta-irradiation) under comparable radiation doses. Increases of peroxide concentration and NADH oxidation rates in 241Am aquatic solutions were demonstrated; these were not found in tritiated water. The results reveal a biological role of reactive oxygen species generated in water solutions as secondary products of the radioactive decay. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha- and beta-emitting radionuclides in aquatic solutions.

Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity

“…As follows from the previous section, luminous bacteria revealed complex responses to chronic effect of Am-241 and H-3 (Rozhko et al, 2007;Alexandrova et al, 2011;Selivanova et al, 2013Selivanova et al, , 2014Kudryasheva et al, 2014) (Figs. 1e3) in the range of radioactivities 1.0e6.7 kBq/L and 0.0002e200 MBq/L, respectively.…”

“…Effects of alpha-and beta-emitting radionuclides (Am-241, U-(235þ238), and H-3) on luminous marine bacteria Photobacterium phosphoreum were reported in a series of works (Rozhko et al, 2007(Rozhko et al, , 2008Alexandrova et al, 2010Alexandrova et al, , 2011Selivanova et al, 2013Selivanova et al, , 2014. The detailed investigation of the effects was conducted using tritium and Am-241 as examples.…”

Effects of radon on soil microbial community and their growth

“…Min et al showed that DNA damage in bacterial cells was positively correlated with the dose of gamma radiation [15]. On the contrast, a few scientific researches proposed that the low-dose of radiation gave the stimulatory effect, increasing function and resistance of the cellular organism [16,17]. However, to date, this phenomenon has been controversy [18].…”

Is bacterial luminescence response to low-dose radiation associated with mutagenicity?

“…Three successive stages in bioluminescence response to ionizing radiation were demonstrated: (1) absence of effect (stress recognition), (2) activation (adaptive response), and (3) inhibition (suppression of the physiological function or radiation toxicity). The effects of alpha and beta emitting radionuclides were compared in (Selivanova et al, 2014); different effects were explained with the differences in the Reactive Oxygen Species (ROS) concentration and the efficiency of biochemical redox processes (Alexandrova et al, 2011;Selivanova et al, 2013). Low-dose effects of gamma radiation on luminous bacteria were studied in (Kudryasheva et al, 2017).…”