A new study at the Hebrew University follows the evolutionary processes of bacteria exposed to antibiotics using a physical approach to biological problems and discovers how bacteria fight the drug
Antibiotics have changed the face of modern medicine, but their effectiveness is threatened by the increasing ability of bacteria to cope with them. The widespread use of antibiotics encourages evolutionary processes in bacteria, during which they develop coping strategies with these drugs. The evolutionary changes may lead to complete resistance of the bacteria to a certain antibiotic drug, or to a reduction in the effectiveness of antibiotic drugs.
Researchers from the Institute of Physics at the Hebrew University followed the evolutionary process undergone by bacteria that were exposed to high concentrations of antibiotics. The researchers found that the bacteria survived thanks to genetic mutations, which became fixed in the population over time. These mutations allowed the bacteria to develop a "pause mechanism" that delays the start of their growth for a certain time, thus increasing their resistance to the drug. In light of the results, the researchers developed a mathematical model of the process: the model led them to hypothesize that the administration of the antibiotic at a fixed frequency allows the bacteria to "predict" the appearance of the drug, and suspend their growth for the period of time required to survive.
The research was carried out in Prof. Nathalie Laban's laboratory at the Rakeh Institute of Physics in the Faculty of Natural Sciences of the Hebrew University, by doctoral student Ofer Friedman in collaboration with researchers from the Broad Institute at Harvard and MIT. The study was published in the journal Nature.
To test their hypothesis, the researchers exposed a population of bacteria to antibiotics for three hours every day. Already after ten days, they realized that the bacteria were using a new survival tactic: as a result of exposure to repeated cycles of antibiotic treatments, the bacteria developed a "pausing pattern" that caused their growth to stop during their exposure to the drug. The antibiotics the researchers used attack the bacteria during their growth, so stopping the growth turned out to be a very effective strategy.
The results showed that the bacteria can develop tolerance within a few days. This is the first time that research shows that bacteria can develop a mechanism to delay growth, in order to survive exposure to antibiotics.
To test their hypothesis, the researchers tested three separate bacterial populations, exposing them to antibiotics daily for different periods of time, 3, 5 or 8 hours. Remarkably, each of the populations adapted by lengthening the delay according to the duration of antibiotic exposure.
This understanding of the way bacteria adapt to antibiotic treatments may help scientists improve antibiotic treatments in the future.
In the next step, after identifying the mutation responsible for the delay mechanism of the bacteria, the researchers are interested in collecting clinical data to check if this mechanism is also active in people who are treated with antibiotics. The experiment may affect the way doctors will treat with antibiotics - for example, changing the frequency in which the medicine is given. The discovered mechanism may also explain the failure of antibiotic treatments in several diseases. In the future, the discovery may lead to the development and use of drugs that maintain constant concentration levels in the body.
7 תגובות
Bamba
Besides empty statements, do you have anything smart to say?
In the meantime, you are like Ehud, trying to hurt anyone who doesn't think like you.
Bamba
I wrote a thesis on evolution, so I understand a little.
Request for help
Bacteria have no brain.
Besides, it also says: "After they identified the mutation..."
Miracles
Once again: they didn't ask you what you read on Wikipedia and you didn't understand.
You were asked a concrete question.
Request for help
The question is what do you mean by the word "mind". A brain like ours, and also of simpler animals, is made up of nerve cells. There are worms whose brains contain less than 1000 cells and there is a human brain that contains about 100 billion cells.
On the other hand - the explanation for the genetic mechanism is more complex from "accidental mutations". You need both inheritance and choice. Let's start with a simple example - imagine that a bacterium has some kind of cyclical mechanism that developed due to some reason (tides and ebbs, day and night, sleeping and waking up of the animal it inhabits - and in our case - the eating time of humans, which is the time when medicine is taken). Suppose there are genes that control the cycle time of this mechanism, and that random mutations change this time. So - it is not impossible that bacteria will form that are scheduled according to the time of taking the antibiotics.
There are more amazing cases. There are butterflies that migrate from Mexico to North America and back. The migration time is several generations in the life of the butterflies, and each generation actually has to navigate a different part of the way. This patent also developed with the help of evolution, although here the explanation is probably more complex.
Note that there are mechanisms that were previously used for one purpose, and in the course of time were "converted" to another use. Look at the vertebrate tail and think how many different functions the tail has in other animals (around 10 I think).
Whoever understands, can answer the question. Is it a random mechanism of mutation, or does the bacterium have some kind of 'brain' that builds this defense system. Thanks.
Bacteria are much smarter than you think
They survived billions of years for a reason
I assume that the bacteria do not develop resistance, but because of the rapid pace of the culture creating mutations, mutations are also created with a delay mechanism that under suitable conditions becomes dominant