As fears about human exposure to ionizing radiation continue to abound, one group of scientists has found evidence that humans could potentially become resistant to radiation and its damaging effects. The study, led by researchers out of the University of Wisconsin at Madison in collaboration with a number of other research organizations and universities, was recently published in elife, an online research journal.
The researchers, led by Michael Cox, a biochemist, worked with the bacteria Escherichia coli, more commonly known as E. coli, in their attempts to discover whether they could breed the bacteria to become more resistant to damage caused by ionizing radiation. In order to do so they irradiated E. coli until 99 percent of its microbes were dead. They then bred new E.coli from the remainders. They repeated this process 20 times and eventually produced a group of the bacteria that were four times more capable of repairing damage inflicted by ionizing radiation than the originals. Further analysis analyzed a total of 69 mutations that were believed to have assisted the E. coli in the improved ability to repair themselves following irradiation, several were determined to be involved in the process.
The study has implications for human application, said Cox, because the human body repairs DNA in similar ways to that of the bacteria. The researches have concluded that it is at least possible for DNA repair systems to adapt and potentially contribute to increased resistance to radiation, perhaps even in humans at some point.
The research appears to have been inspired by the observation of organisms found in nature that are known to be particularly resistant to the effects of ionizing radiation. One such organism is known as Deinococcus radiodurans, discovered in the 1950s and known for its ability to survive 1000 times the amount of exposure to radiation that would result in human death. It is capable of repairing damage from radiation and beginning the growth process again rapidly following exposure. Prior to this recent work, the ability of organisms to actively repair the genetic damage inflicted by ionizing radiation was unknown. It is now believed that this approach is likely working along with a “passive detoxification approach” and additional as of yet unknown processes as well. The researchers intend to continue analysis of the data they have assembled in order to attempt to discover some of these additional processes.
While this research is only in its very early stages with regard to application for humans, it is hoped that it may be the beginnings of what could ultimately be responsible for creating drugs that could benefit cancer patients who undergo radiation therapy as a part of their treatment. The researcher’s work may also have the potential to assist in the creation of technology that will one day be useful in the clean up of radioactive waste or disaster sites. The research into the ability of humans to become increasingly resistant to the harmful effect of ionizing radiation might also be useful in assisting astronauts and other future space travelers with their journeys into space where they are exposed to much higher levels of radiation than are normally found on Earth.
By Michele Wessel