Schematic representation of the effects of cell concentration on microbial resistance to CIR. Source: PLOS OneSchematic representation of the effects of cell concentration on microbial resistance to CIR. Source: PLOS One

The discovery of radiation-sensitive bacteria along with extremely radiation-resistant bacteria underneath a million-gallon radioactive waste tank that has been leaking for over 50 years puzzled researchers from the Uniformed Services University of the Health Sciences in Bethesda, Maryland. How can sensitive microbial populations survive under high levels of chronic ionizing radiation (CIR)?

Growth characteristics of bacteria were investigated under high-level continuous gamma-CIR radiation. Radiation-sensitive bacteria, Escherichi coli, were demonstrated to survive such environmental conditions when mixed with radiation-resistant bacteria, Deinococcus radiodurans.

The study suggests that Deinococcus bacteria, and some fungal species, express high concentrations of antioxidants and could be used as a natural radioprotective probiotic to protect microbes in the intestines of radio- and chemotherapy patients. The findings also suggest a new tool that could help protect military personnel and astronauts who experience gastrointestinal side effects from high levels of chronic ionizing radiation.

The protection of radiosensitive cell-types by radioresistant ones under high-level CIR can offer a new tool for bioremediation of radioactive sites and development of CIR-resistant microbiota as radioprotectors.

The research is published in PLOS One.

To contact the author of this article, email shimmelstein@globalspec.com