- Recent studies show that viruses tend to study the host environment before choosing to attack.
- Scientists researched a phage that attacks only swarmer bacteria having flagella for locomotion. Flagella are made of protein.
- They found that the phage DNA has specific protein binding sites for the flagella of host bacteria thus helping in recognition and attack.
In recent days, viruses have been all over the global news for a lot of reasons. Primarily in 2019, due to the COVID-19 pandemic.
While the pandemic ushered in the birth of the “new normal”, it saw both thousands of people who sat witness to droning zoom calls, as well as a million more who said goodbye to their loved ones. All due to the work of a negative sense RNA virus.
Since April this year, news of the spread of the Monkeypox virus has also surfaced. After spreading in numerous countries in Europe, the Monkeypox virus has found its way into Asia by affecting people in China, Hong Kong, and Taiwan.
The disease was classified as an International cause of concern by the World Health Organisation(WHO) on 23rd July.
How do viruses cause disease?
Viruses are considered to be nonliving minute protein particles that infect humans virulently. When viruses enter the human body they can’t survive alone and thus take shelter inside the cells.
Furthermore, they take over the basic entities promoting immunity called macrophages. These macrophages act as “virus-producing factories” and help in the production of replicas or copies of the virus.
Finally, the infected cell bursts open to release the replicas which further infect more cells and the cycle continues.
What does the new study say?
Recently scientists have found something that makes this microscopic organism all the deadlier. New research has found that viruses can inspect and monitor the environment of the host’s body.
This analysis is then fruitful in deciding whether the virus would multiply or attack the host cells or even remain dormant to stay undetected by the immune system of the host.
This recent discovery about viruses makes the mechanism and functioning of the virus more advanced than we originally thought.
This research was analyzed via a bacteriophage. A bacteriophage is a parasitic virus that attacks bacteria and multiplies within them via methods such as lytic and lysogenic multiplication.
Researchers were trying to find out why a phage has a binding site for a protein despite not producing it. While trying to find an answer to this they discovered this quality of viruses learning from the host.
Scientists also claimed that this discovery could further reveal various unknown aspects of virus-host interaction which in turn could be helpful while developing a new generation of antiviral drugs and medicines.
Where it all started
The study that led to this baffling conclusion started when scientists were studying a phage that primarily infects caulobacterales: an order that consists of many types of gram-negative bacteria species.
The special characteristic of the caulobacter bacteria is the kind of cells produced based on the availability of food.
They noticed that with the availability of sufficient food the bacteria produced non-motile cells which lacked a flagellum, an organ that helps the bacteria move. Meaning these cells weren’t capable of locomotion. However, on a shortage of food, the cells developed flagella and as a result, the bacteria could move freely.
The phage only affected the swarmer bacteria which is flagella. Now the million dollar question was how was it able to differentiate between the different members of the caulobacterales. That is, how was it able to understand and detect the presence of flagella?
The answer to the million dollar question
The formation and growth of special outgrowths such as flagella in the bacteria are associated with CtrA protein.
So the CtrA protein decided whether the bacterial cell would divide to form stalkers (non-motile) or swarmers(capable of flagellar movement).
Scientists also found that there was a specific binding site in the phage DNA that was meant for the CtrA protein. Thus the CtrA levels in the caulobacter helped the page to choose the appropriate host which is the swarmer bacteria.
Also, the presence of the CtrA binding sites was not seen in just a few phage species but rather in numerous flagella-tropic phages.
These findings hence throw a lot of light onto the theory of how viruses study the host environment before deciding to attack.
