A Potentially Good Virus

...Figure out how it works. It might have a role in medical science

as a graduate student, rebecca hochstein

spent years walking the perilous backcountry of Yellowstone National Park, searching for hidden microbes. Eventually, she found a virus unlike any other.

Hochstein, then at Montana State University, found the organism in water she’d taken from a 176-degree Fahrenheit hot spring in the park. She reported the discovery in 2016 and worked with an international team of researchers to take a closer look at the specimen, now named the Acidianus tailed spindle virus.

The team shot X-rays at the virus to reveal the molecules making up its proteins. They also used a $7 million cryo-electron microscope to freeze the virus and pummel it with electrons, giving them an atomic-level picture.

What they saw surprised them. The virus is a shapeshifter: At one moment, it looks like a lemon, but in the next it can transform into a long cylinder.

Most viruses look like lemons, spheres or cylinders. Researchers know how the latter two shapes are made, but not how viruses build the lemon-like configuration.

Such knowledge could be important in using viruses as vessels for administering drugs, an emerging field of medicine. “The virus is like a container,” says Hochstein, now a researcher at the University of Minnesota. “You fill it with what you want.” And when it burrows inside a host cell—as viruses do to survive—it releases its medical filling instead of its own DNA.

The notion that Acidianus could deliver drugs intrigued the team. The hot and acidic conditions of its natural habitat might make the virus ideally suited to surviving, say, the hot and acidic human stomach.

Determining whether Acidianus might be clinically useful first requires knowing how it works. That’s where the atomic-level view comes in. According to the team’s detailed description, published in Proceedings of the

National Academy of Sciences in February, Acidianus is made of long, brick-like structures that look like ropes. Spirals of these ropes form the lemon-shaped container.

The researchers think pushing its DNA into a host makes the virus change shape, much like an actual lemon does when it is squeezed. Apparently, in the microscopic world of viruses, when life hands you lemons, make cylinders.

The hot and acidic conditions of its natural habitat might make the virus ideally suited to surviving the hot and acidic human stomach.

HOPE SPRINGS Hochstein, left, carried a stick when hiking Yellowstone National Park. “You can pound the ground ahead of you,” she said, “and then step gingerly.”