Scientists discover a new class of life that exists in the human intestine
Scientists studying bacteria living in the human intestine have discovered a completely new class of virus-like objects. No sequences or even structural similarities with other biological objects were found in them
This was reported by Science Alert.
Stanford University biologist Ivan Zheludev and his colleagues believe that they have found not viruses, but a completely new group of objects that can help bridge the ancient gap between the simplest genetic molecules and more complex viruses.
“Obelisks are a class of diverse RNAs that have colonized and gone unnoticed in human microbiomes and around the world,” the researchers said in their article.
Obelisk was named after the highly symmetrical rod-like structures formed by twisted sections of RNA. Their size is only 1000 characters (nucleotides). According to scholars, this brevity may explain why the obelisks were not found earlier.
However, the research has not yet been peer-reviewed.
Scientists have studied 5.4 million datasets of published genetic sequences and identified almost 30 thousand different obelisks. They appeared in about 10% of the human microbiomes the team studied.
In one dataset, obelisks were found in 50% of the patients’ oral cavity samples. Moreover, there are different types of obelisks in different parts of our bodies.
The scientists were also able to isolate one type of obelisk host cell, Streptococcus sanguinis, in the human microbiome. It is the most common microbe in the human mouth. The length of the obelisks of these bacteria was 1137 nucleotides.
“So far, we do not know the ‘owners’ of the other obelisks. It is reasonable to assume that at least some of it may be in the bacteria,” Zheludev and his colleagues write.
According to the scientists, all obelisks contain codes for a new class of proteins, which the researchers called aubins. And the “instructions” for creating these proteins take up about half of the obelisk’s genetic material. Since such proteins are present in all obelisks, they are probably responsible for their replication.
