Scientists have uncovered a unique group of virus-like entities in the human gut and mouth.
Scientists have uncovered a never-before-seen class of virus-like entities hiding in the human gut and mouth, and these “viroids” may influence the gene activity within the human microbiome, Science reported.
The researchers confirmed one host for these viroids, namely, a common bacterium found in the mouth called Streptococcus sanguinis. They’ve yet to confirm additional hosts, but they suspect at least a fraction are bacteria.
Viroids are tiny loops of RNA, a genetic cousin of DNA, and they’ve been found to infect primarily plants, such as potatoes. Viroids differ from larger, RNA-based viruses in several ways. First, they’re naked, lacking the protective shells that viruses use to hold their genetic material. Second, their RNA doesn’t contain instructions to build proteins; whereas viruses carry instructions for their outer shells and for certain enzymes they need to replicate, viroids co-opt these enzymes from their hosts.
Although viroids were once thought to infect only plants, recent studies suggest they may infect additional hosts, such as animals, fungi or bacteria. In the new study, researchers searched for possible viroids among the genes of microbes that reside in the human body.