A team of scientists recently discovered a new virus in a river in the small coastal town of Kamakura, Japan. Collected and then cultivated in the laboratory using an amoeba (a microorganism living in the soil) as a host, it was finally named furtovovirus by researchers, indicates IFL Science. The results of their scientific work are published in the Journal of Virology.
A so-called “giant” virus is characterized by its ability to carry out several tasks itself that smaller viruses must normally leave to the cell they infect (their hosts). Some also have genes that are normally found in complex cells rather than in viruses, for example those linked to the transformation of sugar into energy, the organization of DNA or the internal structure of the cell (cytoskeleton).
At around 200 nanometers in size, furtovovirus is among the smallest of the giant viruses, with some members of this group being up to ten times larger. Scientists don’t yet know exactly why giant viruses got so big or how they got such unusual genes.
Some think they gradually took over genes from the organisms they infected, while others believe they descended from more complex ancestors whose genomes shrank over time.
Better knowledge about viruses
The researchers discovered that the furtovovirus has a very large genome (around 560,000 base pairs) and that it reproduces in an unusual way, since it uses the nucleus of the cell it infects, but by damaging its membrane and making new viruses directly inside the nucleus, where the cell’s DNA is normally stored and used.
This behavior differs from that of two other types of giant viruses, medusaviruses, which replicate inside an intact nucleus, and ushikuviruses, which completely destroy the nucleus and then multiply elsewhere in the cell.
“Although these viruses belong to the same group, they use the cell nucleus in different wayssummarizes Masaharu Takemura, of the Tokyo University of Science. SIf we can understand how giant viruses and host cells interact and evolve together, we could gain new insights into the importance of viruses as living organisms.” In addition, this new information would make it possible to better understand current viruses, such as hantaviruses.
The fact that these three types of giant viruses all use the nucleus of the cell they attack poses a big question about the evolution of life, indicates the scientific media. Some experts have proposed the idea that the nucleus of host cells may have originally come from ancient viruses, a hypothesis that remains highly controversial. The majority of researchers believe instead that the nucleus appeared during the ancient association between two types of simple microorganisms, bacteria and archaea, without the intervention of viruses.
