For many years, researchers from all over the world have debated the question: how do bacteria move? A new international study sheds light on the movement mechanism of those microscopic creatures, through a reexamination of the proteins that make them up
When an English nurse named Claire Beecham suddenly finds herself in the middle of the 18th century, dealing with intrigue, wars, and people who suspect her of being a spy or a witch - her medical knowledge helps her survive and save others. But at the same time, Beacham encounters the difficulty of convincing her new acquaintances that the medical information she is giving them from the future is indeed reliable. So, for example, when she tells them about the existence of bacteria - she encounters their doubts about the existence of those invisible creatures that are constantly circulating in the human body and also cause diseases.
But even Beecham, the heroine of the book and TV series "Alien", returned to the past well equipped with current information - apparently the learned nurse also had large knowledge gaps on the subject of bacteria, like all medical professionals in the 21st century.
Although bacteria have already been studied a lot, even nowadays big questions about them remain unanswered. One of those questions concerns the movement of these microscopic creatures, which move thanks to a small organ that curls up (a movement reminiscent of a propeller or a wine opener). Until now, the mechanism that enables the same stunting - remains a mystery. But recently researchers found an explanation for the strange phenomenon: A new international study He found that the bacteria's ability to move is made possible by the fact that the protein that makes up their movement organs has a variety of different shapes, which were not known until now. So what exactly is the connection between the movement of bacteria and proteins?
Protein - it has many forms
Bacteria move by means of a rod: an organ that resembles a whip or a tail. Prof. Yoram Gershman, a biochemist and microbiologist at Oranim College and the University of Haifa, explains that until recently the assumption in research was that every bacterium - and accordingly, its rod as well - is made up of a protein of one shape. But in the new study, this concept was challenged, and advanced measures were used to test it.
Until recently, studies similar to this, who dealt with the movement of bacteria, were carried out using a formation technology (which includes, among other things, the freezing of the protein as a crystal - that is, as a material that consists of a repeating basic structure). "The disadvantage of this process is that a crystal is characterized by identical parts, and thus, with this method, the proteins get a single shape," explains Gershman.
On the other hand, in the new study the researchers used a cryogenic electron microscope (cryo-EM), as well as advanced computer modeling. According to Gershman, in the new technology, unlike the one that has been used up until now, the proteins undergo deep and rapid freezing, in a process that preserves the variety of their different forms. Furthermore, the type of microscope used by the researchers allowed them to examine the proteins at a very high resolution, which is not possible with a normal optical microscope.
Pleasant as a propeller
"Until now, it was not clear how the curled structure of Shotton is obtained, from only one form of protein," explains Gershman. "Just like Lego: if we only have identical parts of a certain type, we will be limited in terms of the shapes we can build." Indeed, in the research it was discovered that the protein that makes up the shoton does not have one fixed form, but can exist in at least 11 states, in each of which its molecules have a different structure; It is the variety of these situations that allows a curled structure to form, thus allowing the bacteria to move.
So instead of walking, flying or swimming in the ways we know, bacteria move using the base of the rod, which rotates inside their cell membrane, pushing them forward - and all this, due to the varied shape of the proteins that make them up.
Brothers to Evolution
And that's not the only thing the researchers discovered when they used the advanced microscope. Besides the movement mechanism, the researchers examined Archaea - microorganisms (microscopic creatures) also called "primitive bacteria"; Creatures despite their name, they are actually more similar to eukaryotes (Eukaryotes, a group of creatures that includes, among others, humans, animals and plants). Archaeons are single-celled creatures that live in the most extreme environments on Earth, such as the bottom of the ocean, acidic pools and oil reservoirs.
"The bacteria and the archaeons split evolutionarily about 4 billion years ago, and their shuttles are also very different," explains Gershman. "But when the researchers looked at the archaeons' sheets, they discovered that there too, similar to bacteria, the protein that makes up the sheet can exist in 10 different states, a characteristic that allows the sheet to curl."
This means that both the bacteria and the archaeons, independently of each other, developed the ability to move by curling the rod through the combination of the different protein structures. This phenomenon, in which different species that develop separately - "find" a similar evolutionary solution due to similar needs, is called "convergent evolution".
Nano-robots that swim in blood vessels
According to Gershman, the new research may have implications in several practical aspects. "Bacteria use whips for various purposes, such as swimming and sticking to surfaces, and thus they also swim inside our bodies, and inside devices that are connected to our bodies, such as catheters or infusion tubes," he explains. "Bacteria swimming in medical devices can cause infections and inflammation, and the better we understand how they do this, the more we can learn how to deal with this phenomenon."
In addition to this, Gershman says that the new discoveries may also contribute in the field ofMicro-robots and the nano-robots. "Today, they are already trying to develop engineered systems that will swim inside our veins and arteries and perform various medical operations - for example, they will lower the cholesterol level in the blood or heal wounds," he elaborates. "But in order to do this, it is necessary to build a kind of tiny engine that will allow these systems to move. A good understanding of how the rod works may allow us to build a system similar to it. If the nanorobots are built of proteins, similar to bacteria, they will have another advantage: they will be biodegradable." , he concludes.
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