JUL 13, 2021 9:48 AM PDT

Expanding Viral Populations May be More Adaptable Than We Knew

WRITTEN BY: Carmen Leitch

In nature, many kinds of growing populations, from bacterial colonies to humans, tend to physically expand. In pulled expansions, the individuals at the perimeter are pioneering the expansion. But in pushed expansions, the outward movement is driven from within. Researchers set out to learn more about how viral expansions occur in infected tissues, and whether they can transition from the pulled state to the pushed.

In this work, which was reported in Physical Review X, the sccientists found that as viruses expand, there was a transition; at first, the viral particles on the leading edge of the expansion pulled the expansion, but after a while the expansion was pushed ahead by viruses within the infected region.

So-called pushed waves of expansion can hold on to genetic diversity for longer periods than populations that are pulled, a phenomenon that was found to be true of viral expansions. Viral expansions may, therefore, be evolving more than was known. This work may help researchers predict this evolution in infected organisms.

"Pushed expansions are normally observed in populations that display cooperative behavior, like herds of animals. Yet, no cooperation among these viruses is known to occur," noted first study author Michael Hunter of the Cavendish Laboratory at Cambridge University.

The researchers used a bacteriophage called T7 that infects Escherichia coli cells to show that viral infections in tissues went from a pulled to pushed expansion. Even though viruses can't talk to one another, they can create pushed waves. This involves signaling among virus-infected cells.

"Our observations show that the transition from pulled to pushed expansions spontaneously arises from the feedback between virus and host dynamics, whereby the viral dispersal depends on the host density, which, in turn, is continuously modified by the virus as the expansion advances," added Hunter.

The researchers suggested that two mechanisms are involved in this process. One involves volume; physical obstacles can prevent viruses from diffusing through host tissues in a dense environment. Another is related to the time the virus needs to grow in the host cell; viruses may have to incubate for a period before they're able to diffuse.

"Our results point to the phage-bacteria system as a highly controllable platform to experimentally investigate the dynamics of expanding populations with density-dependent dispersal," noted senior study author Dr. Diana Fusco, also from the Cavendish Lab.

"Beyond phages, our findings show that viral expansions can retain genetic diversity much longer than previously thought, suggesting that viral populations expanding in an infected organism may be very adaptable to changes in the environment. This realization will help in building better models for viral growth and evolution in infected tissues and organisms."

Sources: AAAS/Eurekalert! via University of Cambridge, Physical Review X

About the Author
Bachelor's (BA/BS/Other)
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
OCT 24, 2022
Neuroscience
Frankenworld: Should We Be Afraid of Playing God or Failing To Love Our Monsters?
Frankenworld: Should We Be Afraid of Playing God or Failing To Love Our Monsters?
Lawyer Henry T. Greely analyzes the relevance of Mary Shelley's classic, "Frankenstein," in light of today's bioscience
NOV 25, 2022
Drug Discovery & Development
Antibiotics for Acne May Impair Bone Development in Teens
Antibiotics for Acne May Impair Bone Development in Teens
Long-term antibiotic use to treat adolescent acne disrupts the gut microbiome and impairs bone maturation. The correspon ...
DEC 07, 2022
Health & Medicine
Vague Plague: Historically Prevalent Diseases in Popular Culture
Vague Plague: Historically Prevalent Diseases in Popular Culture
Every so often, diseases that ravaged past populations pop up in movies or TV, and every now and again an archaeologist ...
DEC 12, 2022
Microbiology
Large Studies Reveal Specific Links Between Depression & Gut Microbes
Large Studies Reveal Specific Links Between Depression & Gut Microbes
Trillions of microbes live in our gastrointestinal tracts, and they exert a powerful influence on various aspects of hum ...
JAN 03, 2023
Clinical & Molecular DX
Antimicrobial Peptides: The Solution to Antimicrobial Resistance?
Antimicrobial Peptides: The Solution to Antimicrobial Resistance?
According to the World Health Organization, antimicrobial resistance is among the top ten global health threats facing h ...
JAN 09, 2023
Microbiology
Looking for custom media? We are here to help.
Looking for custom media? We are here to help.
Are you looking for custom media manufactured in a FDA compliant facility? Hardy Diagnostics is an employee owned compan ...
Loading Comments...