News Excerpt:
Scientists at Stanford University have reported an extremely simple and unusual form of an organism named “obelisks”, which may represent a whole new class of infectious agents.
About the “Obelisks”:
- The Stanford team discovered obelisks when analysing RNA from all the bacteria in the human gut.
- Further searches revealed obelisks were present in the human gut and oral bacteria from all seven continents.
- The newly discovered biological entity falls somewhere between viruses and viroids.
- Like viroids, the obelisks have a circular, single-stranded RNA genome and no protein coat, but their similarities end there.
- But, like viruses, their genomes contain genes that are predicted to code for proteins.
- The discovery of obelisk was made possible using data obtained using a powerful technique called next-generation sequencing (NGS).
- NGS allows researchers to parallelly determine genome sequences in bits and pieces from different organisms.
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Viruses:
- For nearly seven decades since their discovery in 1898, viruses were the only organisms at the boundary between the living and the non-living.
- Their obligate host dependence, parasitism, and small genome sizes collectively ensured they weren’t classified as ‘life’ per se.
- Viruses are microscopic organisms that can infect hosts, like humans, plants or animals.
- They consist of genetic material (either DNA or RNA) surrounded by a protein coat called capsid.
- They cause many diseases, including the common cold, flu, HIV/AIDS, COVID-19, etc.
- Viruses can be treated with antiviral medications, and vaccines can prevent many viral infections.
Viroids:
- In 1971, Theodor Diener, a plant pathologist, tried to isolate the pathogen that caused potato spindle tuber disease.
- Diener called these life forms ‘viroids’ since they resembled viruses.
- Deiner’s discovery added a new dimension to plant pathology, and, as a result, viruses were no longer the sole creatures at the edge of life.
- They consist solely of a short, single-stranded RNA molecule.
- Unlike viruses, viroids do not have a protein coat. They are much smaller than viruses and do not encode any proteins.
- There are no antiviral drugs or vaccines for viroid infections, so management typically involves controlling the spread of infected plants and using resistant plant varieties.
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Conclusion:
The discovery of obelisks raises questions about genome replication, spread, potential bacteria harm, evolution, and potential health impacts, with further research likely to provide answers.
