2023-11-28 09:00:00
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Scientists have crossed a new frontier in virology with an astonishing finding: Giant viruses buried in Harvard forest soilsdiscovered by experts from the University of Massachusetts and the Max Planck Institute for Medical Research.
These microbes, 350 giant viruses between 220 and 1200 nanometers in diameterexhibit morphological features never before seen in science: from star-shaped outer layers to tubular appendages that challenge our understanding of viral biology. Published in bioRXivthese discoveries represent a significant advance in our knowledge of viral diversity.
Video: The surprising shapes of viruses
THE ORIGIN OF GIANT VIRUSES
Giant viruses, known mainly for infecting single-celled organisms, open a debate in the scientific community about their possible interaction with animals or humans.
Noticeably larger than typical viruses, this type of virus has fascinated scientists with their size and enormous genomes. Unlike the COVID-19 virus, which measures between 100 and 160 nanometers, these giants surpass common measurements, becoming visible under electron microscopy, a technique that has revealed shapes so surprising that they have been nicknamed the “Christmas star”, the “Turtle” and the “Gorgon”.
a) “Mimi type”. b) «Supernova». c) «Haircut». d) «Turtle». e) «Plumber». f) “Christmas star”. g) «Flacón». h) «Gorgon». i) – k) large with cabbage structures.
These findings suggest immense genetic and structural diversity, challenging traditional perceptions and opening up an undiscovered world in environmental virology.
The origin of these giant viruses remains an enigma. Its presence is not only limited to forest soils, but also extends to diverse environments. like oceans and permafrost (As the Pithovirus sibericumwhich was resurrected after being frozen for 30,000 years).
Melting glaciers are releasing staggering amounts of bacteria unknown to science
All in all, we have known about this type of virus for decades. Take as an example the smallpox virus, whose size is comparable to that of a small bacteria. The evolution towards larger size in these viruses probably originated from their reduced dependence on the host cell they parasitize. These viruses carry their genetic information in the form of DNA. Curiously, the cells they infect keep their DNA machinery protected within the cell nucleus.
While other viruses have developed strategies to infiltrate this core, larger viruses have chosen a different tactic: Incorporate your own set of tools. Inside their encapsulated structure, technically known as a capsid, they house the essential proteins for reading DNA and transforming it into RNA. Once this is achieved, the virus proceeds to manipulate the host cell so that it converts said RNA into proteins. It is at this point where its stage as a cellular parasite begins, exploiting the cell’s resources for its own benefit.
The evolution towards larger size in viruses is not a recent phenomenon; It is linked to the need to integrate functions that cannot be usurped from the host cell. However, in the 2000s, a new group of viruses began to emerge, characterized by being even larger and, most notably, possess genomes of considerably larger dimensions.
Among these, Mimivirus was one of the first to be identified. This virus has a genome larger than that of some bacteria and a size comparable to that of a common bacterial cell. The term “mimi” in its name derives from “mimic” (to imitate, in English), due to its large size led to it being confused with a bacteria for years.
IMPLICATIONS AND FUTURE RESEARCH
This discovery not only enriches our understanding of viral biodiversity, but It also highlights the need for additional research to understand its role in human health and ecosystems..
The possibility that similar giant viruses exist in soils in other forests around the world, and the recognition that there are millions of viruses yet to be catalogued, underscore the importance of this new era of viral discovery. Environmental virology faces an exciting road ahead, full of mysteries to solve and answers to discover in the vast, unknown world of giant microbes.
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