Totally on their own, E. coli bacteria have shown that they can evolve to a point where they are resistant to antibiotic drugs. Now some of the nation’s top scientists are showing how E. coli bacteria can resist ionizing radiation. They are taking advantage of the bacteria’s built-in ability to evolve when they encounter hostilities in the environment.
“Evolution of extreme resistance to ionizing radiation via genetic adaptation of DNA repair” is the name of the study by a 12-member research team from the University of Wisconsin-Madison, the Lawrence Berkeley National Laboratory, Louisiana State University and A&M College. The findings of the study are published in the online journal eLife.
According to the University of Wisconsin, the scientists involved in the study “coaxed the model bacterium Escherichia coli to dramatically resist ionizing radiation and, in the process, reveal the genetic mechanisms that make the feat possible.”
The study found that E. coli could withstand doses radiation that would otherwise doom a microbe after only a handful of genetic mutations. Authors of the study said their findings provide understanding of how organisms can resist radiation damage to cells and repair damaged DNA.
“What our work shows is that the repair systems can adapt and those adaptations contribute a lot to radiation resistance, “ says Michael Cox, senior author of the report.
Earlier work by Cox, a biochemistry professor at the University of Wisconsin-Madison, and John R. Battista, Louisiana State University professor of biological science, found that E. coli could evolve to resist ionizing radiation after being exposed to highly radioactive isotope cobalt-60.
“We blasted the cultures until 99 percent of the bacteria were dead, “ Cox said. “Then we’d grow up the survivors and blast them again.” When it was over, the E. coli could resist ionizing radiation at four orders of magnitude.
By way of comparison, they make E. coli similar to Deinococcus radiodurans, a bacterium found in the desert and shown in the 1950s to be “remarkably resistant to radiation.” That bacterium can survive 1,000 times the radiation that would kill a human.
“Deinococcus evolved mainly to survive desiccation, not radiation, “ Cox said. He said Deinococcus can repair itself and start growing again very quickly.
The study means it might be possible in the future to use designer microbes to help clean radioactive waste sites or to use probiotics to help patients undergoing radiation therapy.© Food Safety News