APR 02, 2015 09:04 AM PDT

Microbes Scared to Death by Virus Presence

WRITTEN BY: Judy O'Rourke
The microbes could surrender to the harmless virus, but instead freeze in place, dormant, waiting for their potential predator to go away, according to a recent study in mBio.

Researchers found that Sulfolobus islandicus can go dormant, ceasing to grow and reproduce, to protect themselves from infection by Sulfolobus spindle-shaped virus 9 (SSV9). The dormant microbes are able to recover if the virus goes away within 24 to 48 hours-otherwise they die.

"The microbe is hedging its bet," says Rachel Whitaker, PhD, associate professor of microbiology, who led the research at the Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign. "If they go dormant, they might die, but we think this must be better than getting infected and passing it on."

Sulfolobus is a species of archaea (a domain of single-celled organisms distinct from bacteria) found in acidic hot springs all over the world, where free viruses are not as common as in other environments. These microbes will go dormant in the presence of just a few viruses, whether active or inactive. While inactivated virus particles cannot infect a host, Whitaker's lab found they could still cause dormancy, and ultimately, death in Sulfolobus.

"People thought these inactivated viruses were just an accident, that they were just mispackaged," Whitaker said. "Now we know they are being sensed by the host so they are having an effect. People are starting to think that it is adaptive for the virus to produce inactivated virus particles."

Sulfolobus have an adaptive immune system found in archaea and bacteria that allows the microbe to encode a specific piece of DNA that matches the viral DNA, causing it to target the viral DNA and degrade it thus preventing the virus from propagating, or reproducing. Cultures with immunity to SSV9 recover from dormancy and grow normally once the virus is removed from the culture. Microbes without this immunity are susceptible to infection and eventually kill their neighbors by maintaining viral particles in the environment.

The researchers do not know exactly what is going on while the microbes are dormant, only that the microbes look drastically different in that state. More research is needed to better understand these new interactions between microbes and viruses. Incorporating these findings into models will show the true ecological impact of viruses in the microbial world, Whitaker says.

"We really don't understand the way that viruses affect microbes," Whitaker says. "There is a lot to learn. These communities are usually modeled where a virus will either kill the microbe or the microbe is resistant. But actually there are all these other subtleties going on, like dormancy, that are having a bigger impact than we understand."

Dormant microbes are found everywhere, in water, soil, and even the human gut, says Maria Bautista, a graduate student in Whitaker's lab, who led the research.

"Many microbes go dormant when they face environmental stress such as a change in pH or temperature," Bautista says. "Maybe virus-induced dormancy is something that doesn't just happen in Sulfolobus; it may be a widespread response to viruses in other environments. We don't know."

The paper, "Virus-Induced Dormancy in Archaeon Sulfolobus islandicus," is available online in mBio, an open-access journal published by the American Society for Microbiology.

[Source: Institute for Genomic Biology, University of Illinois at Urbana-Champaign]
About the Author
  • Judy O'Rourke worked as a newspaper reporter before becoming chief editor of Clinical Lab Products magazine. As a freelance writer today, she is interested in finding the story behind the latest developments in medicine and science, and in learning what lies ahead.
You May Also Like
JUL 17, 2018
Microbiology
JUL 17, 2018
Understanding how Microbes Will Accelerate Climate Change
As permafrost starts to thaw out, it's exposing untold numbers of new bacteria, which can spew out methane....
AUG 06, 2018
Immunology
AUG 06, 2018
Maternal Dengue Immunity Protects Against Infant Zika Infection
Maternal Dengue immunity produces CD8+ T cells that protect against fetal Zika infection preventing zika-related malformations....
AUG 13, 2018
Genetics & Genomics
AUG 13, 2018
A Kind of Forensics to ID the Source of Bacterial Outbreaks
Scientists at Mayo Clinic have developed a way to use whole genome sequencing to locate the source of deadly bacterial pathogens....
OCT 01, 2018
Microbiology
OCT 01, 2018
A Virus That can Help Ensure Water is Clean
It's estimated that 780 million people worldwide don't have access to clean drinking water....
OCT 10, 2018
Microbiology
OCT 10, 2018
It's Time for Your Annual Flu Shot
After last year's flu season killed around 80,000 people, the CDC is trying to get the word out about the flu vaccine....
OCT 13, 2018
Microbiology
OCT 13, 2018
Gut Bacteria Connected to Heart Transplant Success - or Failure
The more they look, the more connections researchers find between our microbiome and our health....
Loading Comments...