The Daily Californian Online

Chip Helps Researchers Pinpoint Cause of Coral Reef Death

By Alexandra Wilcox
Contributing Writer
Wednesday, February 4, 2009
Category: News > University > Research and Ideas

Elisabeth Tracey/Illustration

At a time when coral reefs are threatened by disease and environmental changes, a new technology developed at UC Berkeley is helping researchers pinpoint what is killing "the rainforests of the sea."

Researchers from UC Merced and Lawrence Berkeley National Laboratory were the first to use the Phylochip-a credit card-sized chip that detects disease-causing microbes by scanning for bacteria-for a study about coral reefs.

The study, which appeared in the International Society of Microbial Ecology Journal last month, sought to find the microbial cause of white-plague disease. The aggressive disease can kill up to two centimeters of coral per day, destroying a large colony within a week, said Shinichi Sunagawa, a UC Merced graduate student and lead author of the study.

Although the study did not find the exact pathogen responsible for the white-plague disease, the Phylochip gave researchers a more comprehensive picture of how microbes impact a coral community, said Gary Andersen, who leads a microbial ecology program at the lab and was an investigator in the study.

New versions of the chip can detect the DNA of 9,000 species, said Todd DeSantis, a software developer at the lab who helped develop the chip. Researchers soon hope to expand the catalog to 50,000 species for better isolation of the specific causes of disease.

"Then we start to ask how these disease bacteria invade the coral and what we can do to prevent that," he said.

The technology was originally developed after the Sept. 11 attacks to detect pathogens used for bioterrorism, such as anthrax, and has also been used to detect microbes in New Orleans flood waters after Hurricane Katrina.

Now more researchers are using the technology to advance reef studies by detecting organisms responsible for coral diseases more quickly.

"It's been really difficult to detect what the causal organisms of the disease are," Andersen said.

The National Institute of Health is also considering using the chip to catalog microbes in humans, DeSantis said.

Andersen said about 90 percent of the world's reefs have been destroyed from disease, pollution, or environmental changes.

Worldwide, the occurrence of disease in coral reefs is increasing in correlation with the warmer waters brought on by climate change, Sunagawa said.

He added that the destruction of coral reefs threatens tourism, as well as species that inhabit reefs and humans that rely on them.

"If we lose this biodiversity, that would mean a huge loss in biodiversity in itself, but also the potential for discovering new species," he said. "Unknown species and genes could always bear the potential for products we don't know yet."

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