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April 16, 2002

COLLEGE STATION – The reason tiny termites can take down a building has been found and that information, which upends a half-century-old belief, might lead to ways to stop their destruction.

"An enzyme in the digestive tract of the termite is what digests the wood," said Dr. Edgar Meyer, Texas Agricultural Experiment Station biochemist. "It has been the lore for 50 years that termites require a symbiotic bacteria in their gut to digest the cellulose, but that is not true in the higher termites, we now know."

The finding of the enzyme, Nasutitermes takasagoensis, is reported in the April edition of Biological Crystallography. Meyer did the research with Drs. Linda Guarino and Shahram Khademi, also with the Experiment Station, and researchers Hirofumi Watanabe and Gaku Tokuda, National Institute of Agrobiological Sciences in Tsukuba, Japan.

"This is the first finding in insects of the structure of an enzyme that degrades cellulose," Meyer said, noting that now a commercial company could use the information to find ways to "block the enzyme so that it can not digest the cellulose.

"If the digestion of cellulose is blocked, that would make the termite colony starve or at least not compete so hard (that damage is done to a building)," he said.

Subterranean termites, social insects that live in nests or colonies in the soil, are among the most destructive insects worldwide. In the United States, they cause more than $2 billion in damage each year – more property damage than that caused by fire and windstorm combined, according to Roger Gold, Texas Cooperative Extension urban entomology specialist.

But in nature, termites are useful, Meyer noted, so scientists have not wanted to devise a way to complete exterminate the insect.

"Termites do a useful service in our forests, consuming fallen trees and brush that build up there," Meyer noted, "so we must be careful in our solution."

He said, for example, a genetic method to block the cellulose digestion should not be done because that would impact the useful termites in forests. Instead, a topical chemical that is specific to the enzyme could be developed to prevent termites from infesting homes and buildings. Such a chemical presumably would be environmentally safer since it would block only the enzyme in the termite.

Meyer said the idea of proving how a termite digests wood, which is extremely tough, was first considered years ago and originally was in collaboration with an Australian researcher working on wood-eating cockroaches. Ultimately one of that researcher's students became a researcher in Japan, and through that connection and using scientific methods that have been developed since, the team was able to express the genetic material into protein and then crystallize it so that the enzyme's ability to digest cellulose could be viewed with special computer software, which Meyer and his group have pioneered over the past 30 years.

Meyer said the enzyme acts much like the well-known computer game character PacMan, with its mouth-like opening fitting around the cellulose as it is quickly digested.

He said that with more research, the enzyme technology eventually might be used on other insects, such as slugs and pill bugs, as well.

For more information, see http://www.tamu.edu/biograph/