Video: Bacteria versus antibiotics: a visual experiment
2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55
What is "evolution"? First of all, this is a natural development, accompanied by a change in the genetic composition and adaptation to the environment. In other words, organisms gradually mutate in order to survive in difficult environments.
And now we are talking not only about animals, but also about the bacteria that surround us. Scientists from Harvard Medical School have filmed an amazing video showing us the evolution of the bacteria E. coli. We invite you to watch it.
The essence of the experiment was as follows: to demonstrate how bacteria adapt to difficult environmental conditions for their survival. For this, a giant rectangular Petri dish measuring 60 x 120 centimeters was created. The nutrient solution was not uniform. The bowl was divided into 9 rectangular sections. The two outer sections contained a normal nutrient solution in which bacteria can freely multiply. But in each subsequent section, antibiotics were added, and the closer the section is to the middle of the bowl, the higher the concentration of antibiotics was.
Thus, as soon as the bacteria reached the border with the next section, they had no choice but to evolve in order to withstand the threat to their lives. New strains of antibiotic-resistant bacteria continued to multiply further, and so section by section, old colonies died, and new ones continued to slowly but surely move towards the victorious center of the Petri dish. Of course, in the video you will see a multiply accelerated recording of this process, because the whole experiment took the Harvard scientists 11 days.
The experiment has not only scientific but also educational value. The large space of the MEGA arena allows for visual observation of mutations and natural selection during the spread of the front of the bacterial population.
As antibiotic resistance continues to increase, numerous parallel evolutionary lines emerge in the bacterial population, which differ in phenotype and genotype.
By studying bacteria at the forefront and behind the front of the bacterial population, scientists have discovered several interesting things. It turned out that evolution is not always driven forward by bacteria that are most resistant to antibiotics. Oddly enough, sometimes the most resistant lineages are trapped behind the more sensitive bacteria. Apparently, this is due to "premature" mutations, when some bacteria are ready to survive in a higher concentration of antibiotic, which will appear in the future, but has not yet appeared. In such a situation, potentially more adapted bacteria give way in the front to their congeners, which are adapted precisely to the actual concentration that exists at the moment.
To test this theory, scientists took samples of isolated colonies of bacteria with "premature" mutations and forcibly placed them in front of the front. As expected, they survived in conditions in which the main bacterial front could not survive.
The scientists also found that better adaptation to a weak antibiotic effect later accelerates adaptation to higher concentrations (pictured below). Everything is like people who are better able to adapt to deteriorating living conditions if changes occur gradually and imperceptibly.
Recommended:
Mysterious bacteria making electrical wires
Discoveries force researchers to rewrite textbooks; rethink the role of mud bacteria in the processing of key elements such as carbon, nitrogen and phosphorus; and review how they affect aquatic ecosystems and climate change
Second Brain: How Gut Bacteria Control Our Minds
We are accustomed to the fact that the brain controls our behavior - but what controls the brain? It turns out that sometimes silent passengers-microbes strive to take control. Bird In Flight examines how not to give up decision making to bacteria
How gut bacteria heal and protect your brain
Think of a situation where your stomach was twisting because you were nervous, anxious, afraid, or perhaps overjoyed. Maybe it happened on the eve of the wedding, or when you had to take an important exam, speak in front of an audience
Nuclear reactions in light bulbs and bacteria
Science has its own forbidden topics, its own taboos. Today, few scientists dare to study biofields, ultra-low doses, the structure of water … One of such hot topics in the literal and figurative sense is the so-called low-energy nuclear reactions
The secret of the purest water of Lake Baikal: bacteria
In the central part of the lake, water can be drunk without boiling. Scientists of the Irkutsk Limnological Institute of the Siberian Branch of the Russian Academy of Sciences have solved the mystery of the special purity of the water of Lake Baikal. It turns out that the natural cleaners of the reservoir are bacteriophage microorganisms - viruses that destroy pathogenic bacteria