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Viruses 'Overheard' Talking to One Another - Israeli scientists have been able to track down the "conversations" between viruses and the messages they leave for each other.
- Viruses sense chemical signals left behind by their forebears so they can decide whether to kill or just to infect their hosts.
The discovery marks the first time that any type of viral communication system has ever been found. - But researchers say that many other viruses could communicate with each other through their own molecular languages.
- If that is the case, scientists might have found a new way to disrupt viral attacks.
- Sorek’s team was looking for evidence that a bacterium called Bacillus subtilis might alert other bacteria to phages.
The researchers knew that bacteria speak to their brethren through secreting and sensing an array of chemicals. - This phenomenon, called quorum sensing, allows the bacteria to adjust behaviours according to the numbers of other bacteria around.
- For instance, bacteria use quorum sensing to decide whether to divide or when to launch an infection.
Instead, the team found, to its surprise, that a viral invader makes a chemical that influences the behaviour of other viruses. - Some phages can infect cells in two different ways. Usually, they hijack host cells and multiply until the hosts die.
- Sometimes, however, phages insert their own genetic material into a host’s genome, then lie dormant until a trigger causes them to reawaken and multiply later.
- Phages broadcast in different frequencies. They speak in different languages and they can hear only the language that they speak
Continue reading and see more illustrations
Prof. Rotem Sorek (pictured on the right) and his group in the Weizmann Institute’s Molecular Genetics Department have now discovered that during infection, viruses secrete small molecules into their environment that other viruses can pick up and “read.”
In this way, they can actually coordinate their attack, turning simple messages into a fairly sophisticated strategy.
Sources
http://www.jewishpress.com/news/breaking-news/viruses-overheard-talking-to-one-another/2017/01/18/
http://www.nature.com/news/do-you-speak-virus-phages-caught-sending-chemical-messages-1.21313
https://www.sciencedaily.com/releases/2017/01/170119163345.htm
http://www.nature.com/nature/journal/v541/n7638/full/nature21049.html
Images - Assorted viruses for illustration purposes - Not related to this particular news story.
Viruses may be stealthy invaders, but a study at the Weizmann Institute of Science in Israel reveals a new, chatty side of some: For the first time, viruses have been found communicating with one another.
This communication – short “posts” left for kin and descendants – helps the viruses reading them to decide how to proceed with the process of infection. The research was reported in Nature and may help in the search to discover what makes some viruses go dormant and others, not.
Many viruses face a choice after they have infected their hosts: to replicate quickly, killing the cell in the process, or to become dormant and lie in wait. HIV, herpes and a number of other human viruses behave this way and, in fact, even the viruses that attack bacteria – phages – face similar decisions when invading a cell.
What causes a virus to choose dormancy over immediate gratification?
Prof. Rotem Sorek (pictured on the right) and his group in the Weizmann Institute’s Molecular Genetics Department have now discovered that during infection, viruses secrete small molecules into their environment that other viruses can pick up and “read.” In this way, they can actually coordinate their attack, turning simple messages into a fairly sophisticated strategy.
Sorek says that he and his group discovered the communications between phages almost by accident. “We were looking for communication between bacteria infected by phages, but we realized that the small molecules we were finding had been sent by the phages themselves,” he says.
To find evidence for this communication, the team grew bacteria in culture and infected them with phages; they then filtered the bacteria and phages out of the culture, leaving only the smallest molecules that had been released to the medium.
When they grew more bacteria on the filtered medium, infecting them with the same phages, they were surprised to find that the new phages became dormant rather than killing the bacteria.
When they grew more bacteria on the filtered medium, infecting them with the same phages, they were surprised to find that the new phages became dormant rather than killing the bacteria.
Sorek and his group, led by research student Zohar Erez, with Staff Scientist Dr. Gil Amitai and Dr. Ida Levy of the Israel Institute for Biological Research, worked to isolate the communication molecule, eventually discovering that it is a small piece of protein called a peptide; they also worked to identify the gene encoding it and to unravel the way it functions.
They found that in the presence of high concentrations of this peptide, phages choose the dormancy strategy, so they named it arbitrium, the Latin word for decision.
They found that in the presence of high concentrations of this peptide, phages choose the dormancy strategy, so they named it arbitrium, the Latin word for decision.
“At the beginning of infection, it makes sense for the viruses to go the fast-replication, kill-the-host route,” explains Sorek, “but if they are too gung-ho, there won’t be any hosts left for future generations of viruses to infect. At some point, the viruses need to switch strategies and become dormant.
The molecule we discovered enables each generation of viruses to communicate with successive generations by adding to concentrations of the arbitrium molecule.
“Each virus can then ‘count’ how many previous viruses have succeeded in infecting host cells and thus decide which strategy is best at any point in time.”
The team found that the peptide binds a particular viral protein, which they identified as the genetic inhibitor of the dormancy life cycle.
This binding inactivates the inhibitor, shifting the balance into choosing dormancy.
Once they had identified this communication molecule in one phage, the researchers were able to find similar molecules in dozens of related phages – each phage encoding a slightly different communication molecule.
This binding inactivates the inhibitor, shifting the balance into choosing dormancy.
Once they had identified this communication molecule in one phage, the researchers were able to find similar molecules in dozens of related phages – each phage encoding a slightly different communication molecule.
“We deciphered a phage-specific communication code. It is as if each phage species broadcasts on a specific molecular ‘frequency’ that can be ‘read’ by phages of its own kind, but not by other phages,” says Sorek.
He points out that the communication-based dormancy strategy he and his group discovered was found in phages, but it may have broader implications.
He points out that the communication-based dormancy strategy he and his group discovered was found in phages, but it may have broader implications.
“We don’t really know how viruses that infect the human body decide to go dormant. It is possible that a similar strategy to that of the phages could be used by viruses that infect us.”
If the viruses that infect humans are found to communicate with one another in a similar manner, we might learn to intercept these messages and use them to our advantage.
If the viruses that infect humans are found to communicate with one another in a similar manner, we might learn to intercept these messages and use them to our advantage.
Prof. Rotem Sorek’s research is supported by the Abisch Frenkel Foundation for the Promotion of Life Sciences; the Leona M. and Harry B. Helmsley Charitable Trust; the Dana and Yossie Hollander Center for Structural Proteomics; the Dr. Dvora and Haim Teitelbaum Endowment Fund; and Martin Kushner Schnur, Mexico.
Sources
http://www.jewishpress.com/news/breaking-news/viruses-overheard-talking-to-one-another/2017/01/18/
http://www.nature.com/news/do-you-speak-virus-phages-caught-sending-chemical-messages-1.21313
https://www.sciencedaily.com/releases/2017/01/170119163345.htm
http://www.nature.com/nature/journal/v541/n7638/full/nature21049.html
Images - Assorted viruses for illustration purposes - Not related to this particular news story.
More articles on fascinating viruses
and other microbes on this blog
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