GENTECH archive


GE Plants to clean up the environment?

CNN      Dec. 10/98
>From Correspondent Ann Kellan

ATHENS, Georgia -- Researchers at the University of Georgia say they've
found a way to restore mercury-contaminated habitats within several years,
a feat that could take Mother Nature thousands of years.

The researchers have genetically engineered plants that can transform toxic
mercury to a much weaker, virtually harmless, form known as elemental

Currently, millions of people worldwide are exposed to dangerously high
levels of mercury due to industrial waste.  Mercury poisoning can be found
almost anywhere, including places considered remote, like the Amazon River
basin in Brazil.

The mercury gets dumped in waste from industrial companies, then ingested
by fish. The toxic substance quickly moves its way up the food chain.

But the researchers say their mercury-eating plants could be grown in
mercury- polluted environments. The goal would be to rejuvenate the
environment and subsequently stop the contamination of the food chain.

"We're very excited," researcher Richard Meagher told CNN.  "It's taken
years... and now it works! It doesn't just work well, it works
spectacularly well."

The plants absorb mercury cavity fillings inside your mouth is a much less
harmful through their roots, then mercury than that found in release it in
a less-toxic form through industrial waste.

People who have silver mercury fillings are protected naturally from the
element's otherwise harmful effects by bacteria that grow inside their
stomachs. The bacteria digests the mercury, breaking it down into a less
toxic form.

The same type of bacteria grows in the soil at mercury-polluted sites. Once
the mercury is broken down, the less toxic form remains trapped in the
soil.  The researchers used genetic engineering to transfer the
mercury-eating trait from the bacteria's DNA into plants.

Their theory was that the altered plants would absorb the mercury through
their roots and release the less toxic form through their leaves.  After
isolating the mercury- eating genes, the researchers used a high-pressure
machine called a gene gun to "shoot" the genes into plant tissue.

"You have to transform a single cell that will divide to grow into a whole
tree so that every cell in that tree will be genetically engineered,"
explained UGA researcher Scott
Merkle. After the plant cells were given the mercury-eating DNA, the plants
were left to mature.

When they matured, the scientists took the seeds from the plants and
planted the seeds in mercury-contaminated solutions to see if they would
grow.  Some did.  Then the scientists measured whether the plants were
absorbing and changing the mercury in the soil.

"What these plants are capable of doing is changing the organic mercury all
the way to a much lesser toxicity and volatile form of mercury known as
elemental mercury," explained researcher Clayton Rugh.

The researchers say 12-year-old poplar trees that were genetically
engineered to eat mercury are living proof that the gene can survive for
years. The researchers also say the technique can be used on any plant.

Their project has been so successful that a private company, PhytoWork
Inc., has been set up to use the genetically engineered plants to help
clean up the environment.