They are not viruses, as scientists often see them. They are initially ten times larger than a conventional virus. They are discovered in the most remote corners of the planet. They are in the Siberian permafrost and under the ice of the Antarctic. Giant viruses surprise science, confused by their very existence.
Michigan State University scientists shed light on these enigmatic giant microbes. They created a reliable model to identify some of the proteins they use to carry out the infection. The study was just published in Cell.
Giant viruses typically measure around 300 nanometers (sometimes even more). You are able to live thousands of years. The rhinovirus responsible for the common cold measures only 30 nanometers. "Giant viruses," says Kristin Parent, the study's main researcher, "are very complex. In Siberia, they retained the ability to infect frozen in permafrost even after 30,000 years."
The outer shells or capsids are very resistant in this virus class.
All of these species share a single mechanism to release their viral genome. It consists of a kind of seal in the form of a starfish. It is located on one of the corner points of the outer layer. This vertex was called the "star gate". During the infection, both the "starfish" and the "star gate" open synchronously to release the genetic material of the virus.
The results showed three environmental conditions that successfully induced the opening of the "star gate". A low pH, a high temperature and a high salt content. In addition, each of these conditions in itself caused a different stage of infection.
The parent and his group designed a model that can effectively and reliably mimic the various stages of infection to examine. "This new model," says the researcher, "will now enable scientists to reliably mimic the stages of infection."
The results led to various new findings. "We have discovered something interesting about the starfish" starfish ". It opens slowly while it adheres to the capsid instead of opening completely and immediately," explains Parent. The new strategy to release the giant virus genome represents a further paradigm shift in our understanding of virology. "
The researchers also examined the proteins released by the virus in the first stage. Proteins act as workers and cause a virus to infect and kidnap a cell's reproductive capacity. So it forces him to make copies of himself.
Giant viruses surprise science and it remains to be seen whether they can infect people like the corona virus. An aspect that is being discussed among virologists today.