Hiding in plain sight: Researchers uncover the prevalence of ‘curiosity’ virus

A type of virus thought to be a ‘mere curiosity’ is plentiful in one common bacteria, and possibly others, a Monash University-led research team has found. 

The discovery improves understanding of how viruses work and could mean this particular virus is also common in other types of bacteria.

Published in Science Advances, the study looked at bacteriophages (phages), which are viruses that infect bacteria and come in many forms.

In particular, researchers investigated telomere phages, a type of phage that until now was considered a ‘curiosity’. Only their unique DNA replication mechanism had been studied.

Senior author and Monash Biomedicine Discovery Institute Bacterial Cell Biology Lab head Professor Trevor Lithgow said nothing was known about whether telomere phages were a benefit or burden to their host cells.

He said the study, which sequenced a Klebsiella bacteria strain associated with pneumonia, found telomere phages were prolific.

“This is astounding,” Professor Lithgow said of the finding. “For more than 20 years of intensive bacterial genomics, telomere phages had remained hidden in plain sight. We have missed an entire aspect of biology.

“Serendipitously, when we sequenced a clinical Klebsiella strain and identified a fourth telomere phage, our sequence analysis led to the realisation that telomere phages are not rare curiosities but highly prevalent throughout the thousands of lineages of Klebsiella, including strains collected from waterway environments.

“Our discovery of toxins that we call ‘telocins’ (for telomere-phage toxins) has a potential translation as a bacterial management strategy: ‘good’ bacteria carrying telomere phages will kill neighbouring ‘bad’ Klebsiella. An example of ‘bad’ bacteria would be antibiotic-resistant Klebsiella.”

First author Sally Byers, from the Lithgow Laboratory, said the work was significant due to the knowledge that would come from understanding a previously unknown element of bacterial biology.

“Our finding that telomere phages are so prevalent means that they are a selective force, one that we know little about,” she said.

“We now want to understand how the host secretes the toxin and also understand how the toxin wheedles its way into the unsuspecting bacterial neighbours.

“While all of our work has been done in Klebsiella, we predict that yet to be discovered telomere phages may be common in other species of bacteria too.”

Read the full paper published in Science Advances, titled Telomere bacteriophages are widespread and equip their bacterial hosts with potent inter-bacterial weapons

DOI: 10.1126/sciadv.adt1627

Photo credit: Telomere phages from Klebsiella, viewed by transmission electron microscopy. Photo credit: Dr Yan Li, Lithgow lab who acknowledges the Monash Ramaciotti Centre for Cryo-Electron Microscopy. The black scale bar is 200 nm long.    

About the Monash Biomedicine Discovery Institute
Committed to making the discoveries that will relieve the future burden of disease, the Monash Biomedicine Discovery Institute (BDI) at Monash University brings together more than 120 internationally-renowned research teams. Spanning seven discovery programs across Cancer, Cardiovascular Disease, Development and Stem Cells, Infection, Immunity, Metabolism, Diabetes and Obesity, and Neuroscience, Monash BDI is one of the largest biomedical research institutes in Australia. Our researchers are supported by world-class technology and infrastructure, and partner with industry, clinicians and researchers internationally to enhance lives through discovery.

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