Team led by MIT researcher finds new type of virus in the ocean

Postdoctoral researcher Kathryn Kauffman processed water samples in the lab to extract the viruses.Alison Takemura

For three months, an MIT researcher collected water samples off the Massachusetts coast, a biological detective looking for clues about the viruses that swarmed in each drop.

The work paid off with the discovery of a new family of viruses that appears to play an important role in killing marine bacteria and in the ocean ecosystem, according to MIT and the Albert Einstein College of Medicine in New York.

Related viruses may also live in the human gut, the scientists said in statements from the two institutions.

The research by Kathryn Kauffman, an MIT postdoctoral researcher; MIT professor Martin Polz; Einstein College professor Libusha Kelly; and nine others was published last week in the journal Nature.

Viruses are the main predators of bacteria, and about 10 million viruses are found in every milliliter of surface ocean water. Researchers incubated viruses from the ocean samples and analyzed them, finding 18 to be members of a new family, the institutions said.

The researchers said the newly discovered viruses had properties that caused them to be missed by previous studies. So they have been named “Autolykiviridae” after Autolykos, or Autolycus, who, according to Greek mythology, was difficult to catch.

“Bacteria are key components at the bottom of the ocean’s food chain, meaning that viruses — which can infect and kill bacteria — are also vital for understanding the ocean’s health and function,” Kelly said in an Einstein College statement.

She also noted that the new understanding of ocean viruses could lead to a better understanding of human biology.

“By expanding what’s known about the kinds of viruses that infect bacteria,” she says, “this study allows us to look at other ecosystems like the human gut, to detect previously unknown viruses and to learn how they might be influencing bacterial populations that are vital for health or that contribute to disease.”

The researchers say that the new group of viruses may be widespread. “We don’t think it’s ocean-specific,” Polz says.

For example, the viruses may even be prevalent in the human microbiome, the bacterial cells harbored within the gastrointestinal tract, and they may play a role in the Earth’s natural carbon cycle as it moves between land, atmosphere, and oceans.

Electron microscope images of marine bacteria infected with the newly discovered viruses. The bacterial cell walls are seen as long double lines. The viruses are the small round objects with dark centers.Courtesy of the researchers