- Jose Carlos Cueto
- BBC World News
When the first pandoravirus was described a few years ago, it was clear to scientists that they were looking at something new.
Pandoraviruses are part of the giant virus family and can be up to 10 times larger than a common virus, even measuring as much or more than other small bacteria.
In addition, they have many more genes. The influenza A virus, for example, has a genome made up of about eight genes. A pandoravirus, such as salinus, can harbor about 2,500.
Investigating giant viruses has discovered surprising things such as that they are often targeted by cannibal viruses, that is, viruses that parasitize other viruses.
And recently, a study found evidence that some pandoraviruses generate a membrane potential only possible through the Energy production.
This study led by the Mediterranean University Hospital Institute for Infections in France reconsiders the scientific dispute over whether pandoraviruses are a type of virus or whether we are facing a biological group yet to be categorized.
However, other experts remain skeptical of this possibility, reasoning that there is still a lot of research pending to think about another biological classification.
“The first giant viruses were described in 2003 and the first was called mimivirus. Since then, the so-called pandoraviruses have been discovered and their genomes studied,” David Lamb, a scientist at the University of Swansea in Wales, UK, tells BBC Mundo. .
They are characterized by their size, greater than 200 nanometers, when common viruses are defined as being smaller than 200.
Giant viruses are observable under the light of an optical microscope, while the others can only be seen with an electron microscope.
But it was not until 2013 when the term pandoravirus was coined, when one of the largest was discovered, the salinus, in the Tunquén wetland in Chile.
“It is called pandoravirus in reference to the ‘pandora’s box’, a mysterious box that is spoken of in Greek mythology. It was put like this because its genome encodes 80% of completely unknown proteins that make this type of virus like a box full of surprises. One of them, the recent discovery of energy metabolism, “explains Professor Bernard La Scola, from the Aix-Marseille University in France, to BBC Mundo.
Are they really viruses?
Pandoraviruses and giant viruses, according to the researchers of the recent study, have changed the definition of viruses in several ways.
For example, the first time it was described that viruses could also be infected by other viruses was through the analysis of these giant entities.
Now, with the discovery of an electrical gradient, this group of scientists suspect that pandoraviruses could also be capable of producing their own energy.
“Energy production is associated with the living worldcell phone, but certainly not with viruses that, by definition, are not considered living beings, since they parasitize an organism and exploit its energy metabolism in order to replicate, “says La Scola.
“The findings question the definition of viruses and could suggest that pandoraviruses are simply not viruses,” adds the expert.
“Structurally, pandoraviruses are still viruses because of the way they replicate. There is still a lot of research to know if it could be something else, but what is certain is that they are shedding more and more light on biology”, clarifies Lamb.
The study on the energy production of pandoraviruses is preliminary and has not yet been peer-reviewed.
Faced with the recent coronavirus pandemic, La Scola acknowledges that there is a growing trend to classify viruses based on whether they can infect humans or not.
“But the world of viruses is very big. Pathogens are only a proportion something more studied. Right now there is no type of data that suggests that they could be dangerous, “concludes the expert.
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