Viruses learn how to manage the metabolism of their victims – Science

TASS, April 6th. Molecular biologists from the United States have discovered many viruses that can not only multiply inside the cells of algae, but also manipulate their metabolism. This erases another line between living organisms and non-living viruses, researchers write in the journal Nature Communications.

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“In the past, we thought that there was little in common between the genes of viruses and living cells. Now we have reached a point where we can name only a small number of unique genes that are found only in cells or in viruses. They turned out to be much more similar than we expected, “said Frank Eyward, one of the authors of the study, associate professor at the Virginia Polytechnic University (USA).

In recent years, biologists have discovered many viruses that are unusually large in size. As a rule, their particles are orders of magnitude larger than most other viruses, and the genome is almost equal in length and degree of complexity to the structure of DNA of living organisms on which they parasitize.

The most interesting feature of these viruses is that such giant viruses (NCLDV), as they are called by scientists, greatly blur the line between full-fledged living things and viruses.

The fact is that in the genome of the latter there are not only “instructions” on how to bypass the protection of cells and multiply inside them, but also genes that are associated with the production of various proteins that are not directly related to the multiplication of the virus. Scientists previously considered the latter feature to be characteristic exclusively of living beings, but not viruses.

Researchers led by Aylward have found another example of how the boundary between living organisms and viruses is blurring. They studied the genetic diversity of giant viruses that infect algae.

Conducting viruses

For this, scientists collected the genomes of all representatives of the NCLDV group that parasitize on algae, compared them among themselves and identified the most interesting sites that have no analogues in the genomes of other types of viruses.

The analysis showed that a significant proportion of the 500 viruses studied by Aylward and his colleagues had not only a classic set of genes that are needed for their reproduction, but also large segments of DNA designed to control the metabolism of algae. Moreover, in the genomes of some viruses, scientists have found almost complete chains of genes that are responsible for the breakdown of glucose or other important parts of the metabolism of living organisms.

Most interestingly, these DNA fragments got into the viruses by no means randomly. As the researchers found out, they have existed in the genome of viruses for many millions of years. During this time, they did not become worthless due to the accumulation of mutations. This, as Aylward explains, means that these genes play an important role in the survival and spread of giant viruses.

This fact, in turn, suggests that many representatives of the NCLDV are able to directly control the metabolism of their victims. The virus not only uses algae as a factory for the production of new copies of itself, but takes it under its complete control.

“When such a virus enters a cell, we can no longer consider it as an autonomous being. The fundamental aspects of its life change as a result of infection. In other words, although we cannot call viruses living things, they play an important role in the balance of nutrients and the work of all the world’s aquatic ecosystems, “concluded Eyluord.

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