For the first time in the world … a living organism that feeds on viruses has been discovered!
According to a new study by scientists at the University of Nebraska-Lincoln in the US, a freshwater plankton species has become the first organism to thrive on a diet of viruses.
Viruses are often inadvertently eaten by a wide variety of organisms and may even be recorded as an addition to the diet of some marine protists. But to qualify as a true step in the food chain described as viruses, viruses must provide a significant amount of energy or nutrients.
Halteria is a common genus of parasites that fly by moving through the water with their hair-like cilia. Not only did lab samples of ciliates consume chloroviruses added to their environment, the giant virus fueled Halteria’s growth and increased its size.
The side effects of widespread consumption of chloroviruses in the wild can have a profound effect on the carbon cycle. Known for their ability to infect microscopic green algae, chloroviruses infect their hosts by releasing carbon and other nutrients into the environment, a process that can limit their consumption of large amounts of viruses.
“If you multiply the initial estimate of how many viruses are there and how much water is there, it all comes down to this huge amount of energy moving through the food chain,” says ecologist John DeLong of the University of Nebraska at Lincoln. If this happens on such a scale as we think, it should completely change the way we look at the global carbon cycle.”
The study spanned three years and was based on the idea that the sheer number of viruses and micro-organisms found in water could cause the former to be eaten last, though the scientists don’t have much previous research they could refer to. Reference.
And there are some useful things inside viruses if you’re craving food, including amino acids, nucleic acids, fats, nitrogen, and phosphorus.
The team collected pond water samples and added chlorine viruses to it to see if any species treated the viruses as food rather than a threat. This led them to Halteria and Paramecium, both of which thrived in water.
And while Paramecium feasted on viruses, their size and quantity remained almost unchanged. Halteria, on the other hand, ingests its food using the chlorine virus as a source of nutrients. And the number increased by about 15 times in two days, and the amount of the virus decreased by a hundred times.
Green fluorescent dye was used to label the DNA of chlorine viruses before it was introduced into two types of plankton. This confirmed that the viruses had been eaten: the vacuoles – the bacterial equivalent of stomachs – glowed green from the food.
Further analysis showed that the growth of Halteria compared to the decline in chloroviruses was consistent with relationships seen in other microscopic predator-prey relationships in the aquatic environment, giving the team more clues as to what was going on.
The study is published in PNAS.
Source: Science Alert