Scientists from Tel Aviv University are cracking the secret of communication between bacteria and hope to use it to breed them in their own kind
By Michal Ben Yaakov
In the war that has been going on for about a century between us and the bacteria, the moves are quite rapid: we invest years and millions and develop a new and excellent antibiotic drug, and they, in response, rummage through their databases, stimulate or develop suitable genes, become resistant and run to share with the guys. This is how the problem of infections from resistant bacteria became one of our most difficult health problems. But a new study from Tel Aviv University may help the drug developers to deliver a decisive blow to the bacteria.
The key is the "cannibalistic" behavior of the bacteria in their colonies - a behavior that helps the colonies deal with stressful situations. "Our research outlines a new way to fight bacteria," says Professor Eshel Ben-Yaakov from the School of Physics and Astronomy at Tel Aviv University. "If we expose the entire colony to the chemicals that the bacteria secrete to make their neighbors kill each other, they will do the job for us. This is a promising strategy, because it is unlikely that bacteria will develop resistance to the substance they themselves produce."
Cannibalism among bacteria, Ben-Yaakov explains, is a fascinating cooperative behavior that the colony engages in stressful situations, such as a lack of food, intense heat or harmful chemicals. In response to the plague, the colony reduces the number of the population using a sophisticated mechanism, which dissolves a bacterium in its neighbor and causes it to attack it with a deadly chemical weapon. "Like a multicellular creature that reduces the number of cells in its body during starvation," says Ben-Yaakov. "The bacteria in the colony maintain a subtle chemical dialogue between them that guarantees that some of the cells will be killed to ensure the continued existence of the colony."
The study on how this dialogue works, which was published this month in the "Notes of the National Academy of Sciences", was conducted in collaboration with Prof. Harry Sweeney's group from the University of Texas and especially with the Israeli Dr. Avraham Baer, who is there for post-doctoral training. Ben Yaakov believes that the discoveries open the door to an effective fight against bacterial infections, including bacteria that are resistant to all known types of antibiotics.
In the current study, the researchers examined what happens when two sister colonies of Penibacillus dendriticiformis (a special bacterial strain characterized by sophisticated social behavior that Ben-Yaakov discovered years ago) are grown side by side, on a hard substrate with little food. To their surprise, they found that the two colonies not only prevented each other from growing into the border area between the two, but also caused the death of all the cells near the border in the neighboring colony. This latter conclusion arose from the fact that the killing of the cells across the border ceased when the transmission of chemical messages between the two colonies was blocked. "It seems that a signal coming from one colony causes a rigid behavior in another: it begins to deplete its own population. Thus, each colony grew in a different direction and the meeting between them was avoided," says Ben-Yaakov.
All along the way in his war against bacteria, says Ben-Yaakov, we do not properly assess the enemy. In the process of developing drugs, most researchers are not at all aware of the importance of the cooperative behavior and social intelligence of the bacteria. Thanks to them, the colony can learn from past experience how to solve problems in the present and spread the new solutions among its members and in other colonies. Meanwhile, patients continue to demand antibiotics for every sore throat, and doctors continue to prescribe antibiotics for everyone who needs them.
Bacteria know how to extract information from the environment, talk to each other, divide roles and create group memory. Using a chemical language with many meanings, the bacteria can turn their colony into a giant "brain" capable of processing information and drawing conclusions. "In my opinion, this is social intelligence," says Ben-Yaakov.
"If we want to defeat the bacteria, we must first recognize that they are not simple, mindless and incapable creatures, as they were perceived until recently by the scientists," Prof. Ben-Yaakov concludes. He and his colleagues are already vigorously pursuing their research to find practical applications for these discoveries.
12 תגובות
light:
Mutation occurs in an individual and not in a group.
Therefore - as soon as there is a bacterium that does not commit suicide in response to instruction - it gains an advantage.
This type of advantage means that its percentage in the population increases until the suicide instruction stops having an effect.
So why do we find bacteria in nature that obey the suicide command?
Probably because this instruction is engraved in the genome in a way that is very difficult to change.
Probably also that bacteria that stopped obeying the instruction really overcame their brothers but also harmed their host and killed it too quickly before it had time to infect others and thus cut the branch they were sitting on.
It should be understood that a reaction mutation to another substance has a very low probability for several reasons:
One is that you have to "learn" at least two things in order for it to work - both to produce the material under stress conditions and to learn to react to it by committing suicide.
This is very unlikely in itself.
The second is that this is a mutation of communication - one that has no effect when it occurs in a single individual because the individuals around him will not respond to the signal he transmits.
It is not impossible because a single bacterium that is not in a state of stress creates around it a "family" of bacteria that carry the new mutation and in a state of stress it may be that the family it creates will be large enough to function, but this is still another factor that lowers the likelihood of this development.
1. It is clear that any new antibiotic can be useful in the fight.
2. What is bad about not committing suicide is the damage to the colony, as described in the article. Now it would be advantageous to ignore the substance, or alternatively to commit suicide in response to another substance. In the article they claim that it is unlikely that the bacteria will undergo an evolution that will protect them from this antibiotic due to its naturalness - what about naturalness and resistance? What may be argued is that in an environment that is not saturated with this substance there is a disadvantage for those who do not react to it and not an advantage, but antibiotics may reach the environment through sewage and therefore the bacteria may be vaccinated in it between now and then.
Besides - this is another family of drugs and if resistance develops we will have to think about something else (in case the development of such resistance does not cause the bacteria to destroy themselves - then the development of this mechanism shows that it has an advantage)
Even without the taxes, those who did not commit suicide had exactly the same advantage.
After all, when this substance is secreted - some of the bacteria commit suicide and some do not.
What's wrong with being in a part that isn't?
But now the intention is to attack them with this material massively. That is, the environmental conditions are going to be changed so that an advantage will be obtained for those who "ignore" the signal to commit suicide.
light:
Because it is a substance they themselves secrete to encourage their own kind to commit suicide.
This behavior is important for their survival and therefore evolved.
As you understand from the story, the bacteria have been using "suicide encouragement" for ages and therefore they already had all the possible opportunities to develop resistance and yet they didn't do it.
Why wouldn't the bacteria undergo an evolution that would protect them against the new substance?
Soon he will also find a way to communicate with the bacteria and they will demand to talk to the leader... 🙂
The so-called victory in points….
Where is Dan Halutz when you need him?
Ariel,
L - A: The same problem should exist anyway even without Hinduism. The chemical secreted by bacteria causes 'other' bacteria to destroy each other. The Hindu idea only perfects the process.
L-B: When it comes to mutational events - anything is possible. It is impossible to talk here about victory in a 'war', but in 'battles' that may never end. But also victory in battles, as you know is important, and when you are in the middle of a battle - enough for trouble at the time. In the next battle there is a new survival trick against the dynamic enemy. If we don't win the battles now, we will surely lose the war. The fights keep us in a state of constant relative advantage, an advantage of excess survival, even if we are not awarded a knock out.
Eddie, great idea but if so there are a few questions you need to find out:
(a) The substance secreted by your engineered bacteria signals the bacteria to die. Why should your engineered bacteria survive and thrive and continue to secrete the correct chemical messages if they kill it too?
(b) Obviously, over many generations, many different mutations will occur in the genetic information of your genetically engineered bacteria. In one of these events, at random, the bacterium will stop excreting the above-mentioned chemical substances. This first bacterium will be the basis for an entire colony of bacteria that will no longer excrete the above-mentioned substance and may also no longer be sensitive themselves. How do you make sure that the information you have engineered does not "turn off" throughout the evolution of the bacteria?
To summarize my opinion on the matter, we are not fighting static creatures that do not change but evolutionary creatures that are constantly groping in all directions randomly and constantly changing randomly. The creatures better adapted to survive will be able to pass on their genetic information.
Great idea.
I thought of an idea for further research: genetic engineering of bacteria so that they secrete the 'correct' chemical messages at all times, regardless of stress situations and without the need for external intervention to disperse the required chemical substance.