Incredible Medusabirus Turns Its Amoeba Victims Into "Stone"


Tom Hale

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

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Perseus with the Head of Medusa, a bronze sculpture made by Benvenuto Cellini, located under Loggia dei Lanzi in Florence, Tuscany. Michael R Evans/Shutterstock

In the waters of a Japanese hot spring, scientists have discovered a new family of giant virus that sounds like the stuff of Greek myths.

The Medusavirus, just like its namesake, is able to turn its hosts into “stone.” After infecting its host, a type of amoeba, Acanthamoeba castellanii, the virus makes the organisms form a thick hardened shell, encasing it into a state of dormancy. The outer layer of this unique giant virus is also covered in hundreds of spikes with spherical heads used to protect its genetic material, not dissimilar from the snake-covered head of Medusa herself.


Writing in the Journal of Virology, researchers from the University of Tokyo argue that the unusual specimen belongs to a totally new taxonomic family of giant viruses: Medusaviridae. Giant viruses are a group of, well, large viruses. Some of them are bigger than typical bacteria, but their name also denotes their extremely large genomes that contain many unique genes not found in other living organisms.

Giant viruses were only truly discovered in the early-2000s. Before this, scientists simply thought they were bacteria. While they are still only just being understood by science, they are continually surprising researchers by blurring the boundaries between viral particles and cellular life.

"The more you begin to know about these giant viruses, you will be awed by their surprisingly vivid and complex life-like systems,” the researchers said in a statement. "And at the end, we end up having fundamental questions such as 'Are viruses alive?', and also a more challenging and provocative hypothesis such as 'Did these viruses evolved from cells?'"

Medusavirus, alongside the "family tree" of giant viruses and eukaryotes. Genki Yoshikawa et al/Journal of Virology

The Medusavirus is exceptionally strange, even for a giant virus. The researchers believe it could help shed some light onto how giant viruses became entangled with the evolutionary history of eukaryotic cells, the cells that make up fungi, plants, and animals. They discovered that a number of the Medusavirus’ genes were actually inside the genome of the host amoeba. This could suggest that gene transfer occurred between the two a long time ago and might have helped to shape their evolutionary paths.


“Of course, it is indeed very interesting if viruses actually affected the birth of eukaryotes," added the researchers.

“Viruses are thought to have played an important role in the evolution and development of life. With the discovery of this Medusavirus, we were able to observe new traces of how the giant viruses got involved in the evolution of ancient eukaryotes.” 

[H/T: Live Science]


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