There are plants that digest amphibians, algae that eat fish, or viruses that infect bacteria. But one of the relationships between predator and prey is one that is hardly known and that may be essential in the cycle of life: the organisms that eat viruses. Bachelorette, Although the term does not yet exist, a group of American researchers has discovered two groups of microorganisms that are neither animals, nor plants, nor fungi, but neither are bacteria, which are called ciliated protists. is, and those that feed on viruses. Although they are not the first virus-eating organisms, they have shown that viruses can thrive by feeding exclusively on viral material.
During the past three years, a group of researchers from the University of Nebraska in Lincoln (USA) has been investigating viruses from a different perspective than usual: not as pathogenic biological entities (there is no consensus that they are living beings, or not).), but as basic nutrients in the life cycle. After aquatic bacteria, viruses are the most abundant organisms on Earth. Being so numerous, it is common for filter-feeding organisms, which feed by filtering water, to ingest all kinds of organic matter, viruses included. But John DeLong, a scientist at American University, has gone on to show that there are actually at least two types of living beings that can only survive by eating viruses.
“As far as we know, this is the first time it has been shown [el consumo de virus] In these two species of protist.
John DeLong, Professor of Biology at the University of Nebraska at Lincoln, USA
“Several studies had already documented virus consumption,” recalls DeLonge in an email. “But, as far as we know, this is the first time it has been demonstrated in these two species,” he added. it refers Paramecium bursaria Even then Halteria sp., two aquatic ciliated protists. He was suspected of ingesting the virus, although it is not known whether he did so accidentally. What DeLong’s team has done is to look at it in the laboratory under controlled conditions. Thus, in small drops of water obtained from a pond near the university, they released large amounts of chlorovirus, a relatively large virus that infects the chlorophyll of algae in lakes and freshwater reservoirs across the planet.
In 24 hours, he carefully studied the drops of water. Results of experiments published in scientific journal PNAS, demonstrated that in the presence of both species, the amount of virus in the medium was reduced by up to 100-fold. Then they needed to know if they had ingested the virus. Using a staining technique (adding dye for contrast), they made many of them fluorescent and turned the protist’s vacuoles (which act like a stomach) bright green. they came to speculate that each Halteria sp. He was capable of ingesting between 10,000 and one million chloroviruses a day.
But you had to tell how badly viruses fared, with improvements in protists. Scientists observed that a population of paramecia It remained the same, they ate the virus, but it doesn’t seem to have benefited them. However, after 48 hours of exposure, they observed that a population of Halteria sp. increased while the amount of chlorovirus decreased drastically. In numbers, viral loads decreased 100-fold in just two days, while populations of protista, with nothing to eat except viruses, increased an average of 15-fold over the same period.
“We think that viruses with high levels of protein and phosphorus are probably very nutritious,” says DeLong. A study on the structure of viruses published a few years back also mentioned that they contain nucleic acids, lipids and amino acids. In the case of chloroviruses, in addition, they may have carbon that they steal from the chlorophyll of algae.
Ecologist Joshua Weitz co-authored this latest study on what’s in the virus. Weitz, who leads a group of researchers focused on the ecology of viruses at the Georgia Institute of Technology (USA), has also published several papers on the role of viral entities in the cycle of life, including his latest book Is. quantitative viral ecology (Not yet translated into Spanish). In an email, Weitz, not related to the study of chloroviruses and two protist species, argues that “viruses are potentially nutritious if swallowed by a microbe that digests them and is not infected by the virus.” ” In general, viruses are made of genetic material (DNA or RNA), which it protects. “Because viral genomes are relatively densely packed and because genetic material is rich in phosphorus, viruses have a relatively high phosphorus content compared to typical microbes and therefore may have a nutritional bonus for what their size “, Weitz details.
“viruses are potentially nutritious if swallowed by a microbe that digests them and is not infected by the virus”
Joshua Weitz, ecologist at the Georgia Institute of Technology in the United States
The fact that there are microorganisms that eat viruses has forced biologists to review what is known about their life cycle. It was known that the base contains virus keys. By infecting all kinds of living beings, they cause a process called viral shunting. At the stage where they are released from an infected cell (or single-celled organism), they rupture the cell, releasing organic matter and nutrients into the medium that would otherwise be lost. Now, as Weitz explains, “this research is an important step forward in advancing our understanding of the ways in which viral particles channel energy (and nutrients) both up and down microbial food webs.” That is, the role of viruses in the food chain of microorganisms.
But measuring the role of viruses as transmitters of energy and nutrients will not be easy. DeLong gives an example of this in a note from his university: “If you roughly estimate how many viruses there are, how many ciliates there are, and how much water there are, we get the movement of enormous amounts of energy (in the food) chain.” ).” DeLong estimates that a small pond could contain up to 10 trillion viruses a day, and said: “If this is happening on the scale that we think it could be, then it could be a major threat to the global carbon cycle.” Our approach must be completely changed.”
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