MOSCOW, March 23. /TASS/. Scientists have wrapped up research on the effects of low-level doses on luminescent bacteria and found out that they can be applied to track the toxicity of surrounding areas contaminated by radioactive pollutants, the press office of Siberian Federal University (SFU) said. The results of the study have been published in the Journal of Environmental Radioactivity.

"Luminescent bacteria is a very convenient object for investigating the effect of radiation on cellular levels. Our results show great potential for using this bacteria to estimate the toxicity of areas contaminated by radioactive pollution," commented Nadezhda Kudryashova, SFU professor and research assistant at RAS’ Institute of Biophysics.

The studies on gamma radiation are of particular importance because of the fact that it is quite hard to build a reliable protection from gamma radiation which consists of waves, in contrast to alpha and beta radiations which are the beams of particles. For instance, to effectively screen alpha-particles, an ordinary sheet of paper is enough. But to stop gamma-rays, a thick of heavy metal or concrete is needed. According to the researchers, the studies of the impact of low-level doses on luminescent bacteria was especially exciting because the effect of low doses has not been widely studied so far.

To find out how low-intensity gamma-radiation affects bacteria and what is different in this effect as opposed to the action from alpha-and beta-rays, scientists performed an experiment. They applied Photobacterium phosphoreum placed in the experimental capsule and irradiated it with the radioactive cesium-137 from the Yenisey river bed near the village Atamanovo in the Krasnoyarsk Region.

Those scientists discovered that in contrast to alpha and beta radiation, in low amounts gamma radiation has no positive impact with the most pronounced effect being the suppression of luminescence and consequently the bacterial activity. The other peculiarity is that upon low-intensive gamma-irradiation, it is the duration of exposure that matters, not the dose size. Moreover, the researchers noticed that the gamma rays did not damage the bacteria’s vital genes, although the danger of radiation is often associated with changes on a genetic level.

Luminescence bacteria from the genus, Photobacterium, produce proteins which shine in the dark. The bacteria live in the sea and at night the whiteness of the sea water’s bluish light arising from the bacterial activity can be seen. By tracking the changes in the intensity of the luminescence one can judge how the surroundings influence the bacteria. As a consequence, the luminescent organisms are successfully used to estimate the toxicity of chemical pollutions for up to several dozen years.