Glowing green slime tracks gene swaps

Knowing how different types of bacteria exchange genes is vitally important to regulators trying to decide how safe genetically modified organisms are but, so far, the way genes are transferred naturally is poorly understood.

Research presented by scientists from the University of Manchester Institute of Science and Technology (UMIST) at a recent meeting of the Society for General Microbiology provides some of the missing information.

"We all know that bacteria have an incredible ability to exchange useful bits of DNA and genes between them, leading very quickly to critical problems like superbug antibiotic resistance in hospitals," said Dr Johanna Andrews from the Department of Chemical Engineering at UMIST. "But very few techniques have been developed to mimic the natural environment and the conditions in which these swaps actually happen and which means we know little about the true causes and mechanics of these transfers."

In the wild many bacteria stick together to produce clumps of cells when they grow, most often seen as a slime on rotting trees, around the plughole in a sink, or at the bottom of the refrigerator. The Manchester scientists have developed a new technique in which different bacteria that are found in natural communities are forced to form these slimes in specific areas on glass slides using electric fields.

"We produced slimes from two different strains of bacteria, one of which had been tagged with a classic reporter gene, GFP, the green fluorescent protein which comes from jellyfish," said Dr Andrews. "This enabled us to study the transfer of DNA from one bacterium to another in a natural type of environment."

The scientists believe that their work will contribute to the GM debate and eventually lead to safer techniques for producing GM crops and organisms, reducing the number of fertilisers and pesticides needed to grow our food.

Finding ways to reduce the spread of multiple antibiotic resistant bacteria would also cut down the number of hospital deaths from general infections.