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Dispatch from Denver
Tales of the strange and unpredictable
By Kate Dalke

Although we tend to think of stress as a particularly human affliction, species from yeast to underground microbes must find ingenious ways to combat stress and adapt to their environment in order to survive.

At the annual meeting of the American Association for the Advancement of Science in Denver, Colorado, last weekend, scientists discussed how sometimes strange and unpredictable responses to the environment could be applied to real-world problems.

Susan L. Lindquist of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, has spent years studying how proteins fold themselves into shapes or patterns that are important to the way they work. When proteins misfold they cause diseases like Alzheimer's, Huntington's, and 'mad cow' disease.

But in yeast, misfolded proteins form long, thin fibers that help the organism adapt to harsh environments. These thin threads, it turns out, can be coated with gold or silver to make tiny electronic circuits.

Lindquist is now investigating how the yeast proteins can be used to make electronic circuits and other nano-scale devices. The threads are "really tough" and therefore ideal for electronics.

The toughness may explain why their counterparts in humans are so hard to get out of the brain during disease, says Lindquist, who presented her research at the meeting.

If yeast electronics sounds odd, what about microbes that eat and breath rocks? Some microbes that live on rocks eat the same rocks to obtain essential nutrients. For these creatures, the soil or natural environment may lack essential metals, so the microbes have developed unusual strategies for extracting metal from rock.

Streptomyces coelicolor colonies with aerial mycelium and spores.

Streptomyces coelicolor "literally bites into the surface of rocks" to extract iron, says Susan Brantley at Pennsylvania State University in University Park. The bacterium secretes a compound that makes pits in the rock and allows it to take up iron.

Understanding how these microbes survive extreme environments and extract metals could help scientists manipulate microbes to clean up dangerous chemicals or microbes.

Scientists at the University of California, Santa Barbara, looked no further than the ocean outside their laboratory for new ways to make silicon. It takes a lot of energy to manufacture the silicon used to make semiconductors and microchips found in CD's, computers and televisions.

So Dan Morse of Santa Barbara and his colleagues turned to ocean sponges. The organism makes glassy silica needles as part of its spine. The researchers used the sponge DNA to design synthetic molecules that resemble the silica proteins. The natural, low-energy manufacture of silicon by the sponge could lead to new methods of making semiconductors.

Human proteins are the key to a diagnostic test for ovarian cancer discussed at the meeting by Emanuel F. Petricoin of the US Food and Drug Administration. His team has developed technology for separating thousands of proteins in blood and identifying patterns associated with ovarian cancer.

In a test study, the researchers used the pattern to correctly identify 50 out of 50 women with ovarian cancer, and 63 of 66 women without malignancies. A handful of proteins (out of 800,000) in blood could be used to predict ovarian cancer in the early stages of disease. Clinical trials of the diagnostic test are now underway for approval by the FDA.

"Early cancer detection has been a holy grail," says Petricoin. There have been no good screening methods or good markers. Proteins, rather than DNA, are the best markers for diagnosing disease and toxicity because they're actually doing the work of the cell, he adds.

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Petricoin E.F. et al. Use of proteomic patterns in serum to identify ovarian cancer. Lancet 359, 572-577 (February 16, 2002).

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