3D reconstruction of the Medusavirus particle

A 3D reconstruction of the Medusavirus particle showcases its thousands of external spikes, which protrude roughly 14 nanometres from the particle’s surface. Credit: G. Yoshikawa et al./J. Virol. (CC BY 4.0)

Virology

The giant Medusavirus turns defenceless cells to ‘stone’

Novel virus extracted from a hot spring bears thousands of unique spikes.

A microscopic behemoth that can turn amoebae into stone-like cysts is shaking up the virus family tree. Scientists have named it the Medusavirus.

A team of researchers led by Masaharu Takemura at Tokyo University of Science and Hiroyuki Ogata at Kyoto University in Japan isolated the giant virus from a sample of mud and dead leaves collected from a Japanese hot spring. The scientists then mixed the virus with hundreds of amoebae called Acanthamoeba castellanii.

The virus infected the amoebae and multiplied inside them, causing some to burst. Other amoebae developed a hard shell, prompting the researchers to name the virus after Medusa, the Greek mythological monster who turned onlookers to stone. On closer examination, the scientists determined that the virus’s genetic material is protected by 2,660 spherical-headed spikes.

The strange findings led the researchers to propose that the virus receive its own taxonomic family: Medusaviridae.