Radiation blues

scientists from Switzerland and Ukraine have developed what they call a "biological equivalent of the Geiger counter". The team has engineered a plant that warns of dangerous levels of radiation. Right now, the only method to detect if plants have been exposed to radiation is to look for cell damage under a microscope. But this is time-consuming and labour-intensive. Further, damaged cells are often very easy to miss. The team, led by Barbara Hohn at the Friedrich Miescher Institute in Basel, Switzerland, has found a simpler way. They added a gene from the bacterium Escherichia coli ( E coli ) to thale cress, another bacterium ( Arabidopsis thaliana ). The E coli gene itself contained a foreign piece of dioxyribosenucleic acid ( dna ) that prevented it from producing a particular enzyme.

If plants were exposed to high-energy radiation, mutations would occur, some of which may 'knock' the foreign dna out of the bacterial gene. The two parts of the E coli gene could then join up, restoring its ability to produce the enzyme. Then, if the plant tissue is mixed with a stain that turns the enzyme blue, the mutated parts would be obvious as would be the fact that the plants have been affected by radiation.

Sure enough, when exposed to radiation and stained, parts of the plant turned blue. "If you irradiate plants with gamma rays for five to 10 minutes, the radiation will create a lot of breaks," says Olga Kovalchuk, a member of the team. The researchers say there is a clear relationship between the radiation dose and the plants' colour -- the more the radiation, the deeper will be the shade of blue ( Nature Biotechnology , Vol 16, No 2143).

Subscribe to Daily Newsletter :

SUPPORT US

We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.