5 January 2000
The Super Bug returns
by Kate Melville
Forget about the Millennium Bug (a dud except in the Science A Go Go forum), yes Virginia there is a real Super Bug!
Nuclear programs produce very nasty waste, that includes heavy metals, organic chemicals, and radioactive isotopes. Pollution eating bugs are not new (just think about how long dung beetles have been around) but when it comes to radiation most bugs turn up their toes very quickly. That's why it's so exciting to see a real Super bug that is resistant to radiation and can be engineered with the enzyme machinery to tackle both toxic metals and organics.
Now, scientists have exploited the hardy properties of the to create a Super Bug that can tackle all these contaminants at the same time. Unlike other pollution-eating bugs that quickly die as a result of radioactivity exposure at atomic dumps, the new bug is based on world's most radiation-resistant bacterium is resistant to radiation and can be engineered with the enzyme machinery to tackle both toxic metals and organics.
The bacterium - Deinococcus radiodurans - can clean organic waste present at radioactive sites. But many atomic waste sites also contain other toxins. So the researchers set about creating four different strains of D. radiodurans in which a set of foreign genes for converting toxic mercury into its less harmful elemental form were placed in the bacterium either on circles of DNA (plasmids) or integrated into the bacterial chromosome.
Each of the four strains was able to grow in the presence of radiation and ionic mercury, yet capable of detoxifying mercury. The researchers then developed a strain of the bacterium which detoxifies both mercury and toluene (a poisonous organic solvent) demonstrating that different sets of gene can be slotted into D. radiodurans to provide varied pollution-fighting attributes.
Now the challenge is to integrate other bioremediation functions into the bacterium, creating a new Super Bug capable of making a variety of other types of waste less hazardous.