As many as 16 kinds of 'gigantic virus' are discovered from the soil of natural forest

Generally speaking, virus is considered to be a very small size, but in 2003 the researchers said "a huge virus that is as big as a bacterium and has more than 1000 genes" By the discovery, the definition of the conventional virus is about to be overturned. The American research team reports that such a huge virus was found "from nature's forest soil".

Hidden diversity of soil giant viruses | Nature Communications
https://www.nature.com/articles/s41467-018-07335-2

Scientists Have Found Rare Giant Viruses Lurking in The Soil of a US Forest
https://www.sciencealert.com/scientists-discovered-rare-giant-viruses-lurking-in-harvard-forest-soil-under-assassusetts

Rare and diverse giant viruses unexpectedly found in a forest soil ecosystem
https://phys.org/news/2018-11-rare-diverse-giant-viruses-unexpectedly.html

In the northeast 28 mile (approximately 45 km) of the University of Massachusetts Amherst, there have been research forests where artificially temperate environments were created in order to investigate "the environmental impact due to global warming" over the past 30 years I will. In the research forest where the heating cable for preventing freezing is embedded in the ground, the soil temperature is kept at 5 degrees higher than the normal natural environment, and research data when the soil temperature rises due to global warming It is said that it is producing.

Jeff Blanchard, a biologist at the University of Massachusetts Amherst, got soil and analyzed the microbial communities contained in the soil. "We were not trying to find a huge virus, as our goal was to separate the bacteria directly from the soil sample and try to investigate the changes brought to the microbial community by global warming," Blanchard I am talking.

However contrary to Mr. Blanchard's expectation, 16 kinds of "completely new big virus" were found from soil samples. In most giant virus studies, we take the process of culturing and collecting protozoa and amoeba hosting large viruses, but with this method we can only observe gigantic viruses gathering in specific hosts. In addition, if a huge virus is discovered from nature, it is only what is found in the aquatic environment, and the research team believes that this case, which was discovered from land forests, is very valuable.

Instead of observing the giant virus by the method of culturing the host, it is possible to observe a larger variety of gigantic viruses than before by collecting samples directly from the soil and separating large viruses. The research field that deals with genomic DNA directly recovered from environmental samples is called metagenomics and is gaining attention as a new method to elucidate the genes of viruses and bacteria that are difficult to cultivate.

Frederik Schulz, research team's bioinformatist, helped identify bacteria and giant viruses in this study. "This environmental sample is only scratching the surface of the soil, and if we gather a larger sample and analyze it, the number of discovered new giant viruses will be doubled, tripled, perhaps We may be up to 4 times as much as we can, "he told his expectations for the future.