Bacteriophages Influence the Gut Flora
“The ecosystem in our gut is even more complex than one might imagine, a study clarifies: It is teeming not only with bacteria but also with the viruses that infect them. Through genetic analyses, researchers have identified thousands of new representatives of these so-called bacteriophages. The results now form the basis for a database on gut flora viruses, which is intended to serve the research into their role in human health.” The gut habitat is increasingly becoming the focus of scientific attention: The bacteria that colonize our digestive tract have proven to be key players in our health in recent years. The composition of this microbial community influences the immune system, metabolism, and many other aspects of health. The characteristics of a person’s gut flora are determined by various factors. However, one factor has remained relatively under-researched so far: the influence of pathogens of gut bacteria. For just as coronavirus and co. infect us, certain viruses also target microbes. They are called bacteriophages – “bacteria eaters.”
Tiny Creatures That Infect Dwarfs
Like all viruses, they are also “pirates of life”: They do not have their own metabolism but exploit the vitality of their host cells. Many bacteriophages possess leg-like structures through which they can attach to the surface of bacteria. They then inject the genetic material stored in a head part into the cells. This transforms the cells into virus factories that produce new particles until they collapse. The released bacteriophages then travel to new victims. In this way, they can strongly influence bacterial populations and also contribute to the development of genetic changes. There are even approaches to specifically use phages specialized in certain bacteria to combat infectious diseases.
It has long been known that even the harmless or “friendly” bacteria of the human gut are infected by certain phage species. “However, the extent of viral diversity in the human gut has remained largely unclear,” writes the research team led by the Wellcome Sanger Institute in Hinxton. Therefore, the scientists have now systematically explored viral biodiversity using metagenomics. This technique of comparative DNA analysis made it possible to search for viral pathogens in the genetic data of over 28,000 human gut flora samples and nearly 3,000 genomes of bacterial isolates.
Teeming
As the scientists report, they identified a total of around 140,000 viral species found in the human gut, more than half of which were completely unknown. Among them are also viruses that apparently have a special common evolutionary history. The scientists have now given this group the name “Gubaphages.” They have found that their representatives are the second most common viruses in the human gut, after the so-called crAssphages. It is now an open question what role the newly discovered Gubaphages play in the gut’s ecosystem.
“It’s fascinating to see how many unknown species live in our gut and to try to unravel the connection between them and human health,” says co-author Alexandre Almeida from the Wellcome Sanger Institute. “It is important to emphasize that not all of these viruses are necessarily problematic, but rather represent an integral part of the gut ecosystem. This is also evident from the fact that the samples primarily came from healthy individuals who do not exhibit specific diseases,” says the scientist.
The researchers have now also used the information on the over 140,000 bacteriophages as a basis for developing a new database for science: They present the publicly accessible “Gut Phage Database.” The included genomes can now help scientists research the significance of these “bacteria eaters” for the microbes within us and thus for our health. “An important aspect of our work was therefore to ensure that the reconstructed viral genomes are of the highest quality,” says lead author Camarillo-Guerrero from the Wellcome Sanger Institute. His colleague Trevor Lawley concludes: “The new catalog of viruses in the human gut comes at the right time to serve as guidance in future studies.”
Source: https://www.wissenschaft.de/gesundheit-medizin/tausende-virenarten-der-darmflora-entdeckt/
