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Genetic Material Cleans Microbe-Infested Water

Researchers have developed a genetic tool that can eradicate harmful microbes and viruses found in drinking water.

Duke University engineers demonstrated that short strands of genetic material could successfully target a matching portion of a gene in a common fungus found in water and make it stop working. If this new approach can be perfected, the researchers believe that it could serve as the basis for a device to help solve the problem of safe drinking water in Third World countries without water treatment facilities.

The relatively new technology, known as RNA interference (RNAi), makes use of short snippets of genetic material that match — like a lock and key — a corresponding segment of a gene in the target. When these snippets enter a cell and attach to the corresponding segment, they can inhibit or block the action of the target gene. This approach is increasingly being used as a tool in biomedical research, but has not previously been applied to environmental issues.

The research findings were presented during the annual meeting of the American Society of Microbiology in Boston on June 3, 2008.

The new approach might address shortcomings of current technologies used to treat drinking water in more developed nations like chlorine and ultraviolet light, which are expensive and often make the water taste and smell bad.

Although chlorine and ultraviolet methods have worked for decades, problems have begun to emerge when the treated water enters the distribution system, where they encounter pathogens. Water is often over-chlorinated at the plant so that it remains in high enough concentrations in the pipes to neutralize pathogens as a result. In addition, chlorine can react with other organic matter in the system, leading to potentially harmful by-products.

Ultraviolet light neutralizes pathogens at treatment facilities, but has no effect once the water is pumped out of the plant. In addition, many pathogens have develop resistance to the effects of chlorine and UV light, increasing the need for new newer treatment options are needed.

The first prototypes would likely involve a filter “seeded” with RNAi that would eliminate pathogens as the water passed through it. These filters would likely need to be replaced regularly, Gunsch said, adding that she believes it would theoretically be possible to create a living, or self-replicating system, which would not require replacement.

The researchers are currently conducting additional experiments targeting other regions of the fungus’ genome. They are now testing this approach to silence or block genes essential to the viability of the pathogen. Ultimately, they plan to test this strategy in water that contains a number of different pathogens at the same time, as well as trying to determine the optimal concentration needed in the water to be effective.