Alison Buchan summarizes her research on viruses and microbes. | University of Tennessee, Knoxville
While scientists have been exploring bacteria for a century, and they are only in the beginning stages of exploring viruses’ types and capabilities, including how they might be used to help humans fight climate change, or even diseases.
Viruses, the non-living bits of genetic material, can infect all living things, from animals and plants to bacteria. Even though they are more abundant than bacteria, viruses are much smaller, and since they don’t replicate on their own, harder to study.
There are approximately 100 viruses for every bacterium found in a sample of seawater, and even that’s probably an underestimate, said Alison Buchan, a professor of microbiology that the University of Tennessee, and one of three scientists who study viruses and participated in a news briefing at the 2019 AAAS Annual Meeting in Washington, D.C. on Sunday.
Buchan studies a common type of marine bacteria and how the viruses that can infect it work. Viruses can infect bacteria and grow inside them, influencing the cell’s functioning and appearance without killing them, but they can also switch to a lethal phase that kills the bacteria and releases more viruses. They seem to switch to the lethal phase when the bacteria they occupy are under some sort of stress, Buchan said, but what exactly triggers the switch is something she is still studying.
“A lot of what we know of host-virus interactions is based on a very limited number of systems, so anything we learn about new ones will help,” Buchan said.
As bacteria grow in the oceans, they take up half of the excess atmospheric carbon generated by humans, and cause some of it to sink to the sea floor, effectively reducing global warming. Matthew Sullivan, a professor of microbiology at Ohio State University, who studies viral populations in the world’s oceans, said at first, he thought “viruses would break the carbon pump and keep carbon circulating.” But instead, his team found that “sticky virus material may clump and make it sink – they seem to help,” he said.
Researchers are already investigating how they can use viruses to increase bacterial uptake and storage of carbon. “There is already talk of engineering viruses at scale,” to help control climate change, Sullivan said. “It’s complicated, … but I think in next couple decades we will see some release of viruses to create the interaction you want.”
Joshua Weitz, a professor of biological science and director of the quantitative bioscience doctoral program at the Georgia Institute of Technology, studies the ecological role viruses play in the environment. “We’re increasingly seeing the relevance in shaping the climate feedback, but we need more models of viral microbes to understand their functioning,” and the long-term effects of humans tweaking those systems, he said.
That will be an important aspect as other researchers try to use engineered viruses to kill bacteria that can infect humans. Creating a therapeutic virus, called a phage, that can infect and eliminate one type of harmful bacteria has potential, Weitz said, especially as more bacteria evolve to become resistant to multiple drugs. But researchers could be “just introducing a new problem — resistance to phages,” he cautioned.
[Associated image: Kirsty Pargeter/Adobe Stock]