First bacteria that eats viruses discovered

Any sort of organism has probably developed to consume some type of organic material. Different animals eat plants, meat, algae, insects and germs, but now scientists have found something new on the menu: viruses.

Since viruses are present everywhere, it is inevitable that creatures may unintentionally consume them, a study published in the journal Proceedings of the National Academy of Sciences said. John DeLong, a researcher at the University of Nebraska–Lincoln, sought to know whether any bacteria consumed viruses actively and whether such a diet could support both individual and community population development.

“They’re made up of really good stuff: nucleic acids, a lot of nitrogen and phosphorous,” said DeLong. “Everything should want to eat them. So many things will eat anything they can get ahold of. Surely something would have learned how to eat these really good raw materials.”

As per a New Atlas report, DeLong and his team took pond water samples, extracted several microorganisms, and then introduced a lot of chlorovirus, a freshwater resident that infects green algae, to test the theory. The scientists monitored the population sizes of the viruses and the other bacteria over the following few days to see whether the latter were consuming the former.

And indeed, a particular bacteria called Halteria, a ciliate, appeared to be chewing on the viruses. In just two days, Halteria populations grew by about 15 times in water samples where the ciliates lacked access to any other food source, but chlorovirus concentrations dropped by 100 times. In control samples, Halteria did not grow at all in the absence of the virus.

The team discovered that Halteria cells immediately started to glow after labelling chlorovirus DNA with fluorescent dye in follow-up experiments. This made it easier to verify that Halteria was indeed eating the virus.

These studies demonstrate that the recently formed term "virovory" can now coexist with herbivory, carnivory, and other forms of eating, with Halteria being recognised as the first known virovore. It is not the only one, of course, and the researchers intend to keep looking into it, as well as how it affects broader systems like the carbon cycle and food webs.