Grey Wheel Dancer of the Sword

The struggle between organisms is endless. Bacteria can "eat" our meat. Of course, there are also little guys who feed on bacteria, that is, bacteriophages, a virus that specifically "eats" bacteria. What is a virus?

What is a virus? Many people may not be able to distinguish the relationship between it and bacteria. There are many well-known diseases, some are caused by bacteria, such as cholera or tuberculosis; while some are caused by viruses, such as flu and rabies. Their pathogenic mechanisms are completely different. Bacteria are like an army that invades the human kingdom. They have their own structure and organization and can live independently. Viruses are like drugs that can be infected. People do everything until they are exhausted.

Therefore, viruses can contaminate the kingdom's bacteria or bacteria. Once the bacteria are contaminated with phage, they will use all their resources to synthesize the protein and DNA needed by the phage, and finally they will die of exhaustion.

In detail, bacteria are tiny cells. They are smaller than most of our body cells, but they are indeed small cells that can complete a complete life cycle. Viruses are much smaller than bacteria. They are a small box made up of proteins and oligosaccharides containing DNA. If you zoom in, you can directly observe the atoms that make up it. Because they are too small, scientists have not been able to observe them through a microscope for a long time, so they think they are some kind of toxic substances. Now, under normal circumstances, we define a virus as an existence between life and non-life, and also call it "non-cellular structure life." Viruses that eat bacteria

The first person to see bacteriophages will be amazed by their rather sci-fi shape. They look like tiny mechas, robots with bionic spiders; especially their polyhedral shape also reveals a cyberpunk style. , More and more like a man-made object.

So why is it such a shape? What is interesting about bacteriophages? Let us get to know it!

The entire bacteriophage family is very large, ancient and abundant. They appear on the earth almost together with bacteria, almost 3 billion years ago. The number of bacteriophages is very, very large, and their number is more than all other life on earth (including all bacteria) combined. There may be more than 10^31 (10000……000, a total of 31 zeros). The global environment with the most bacteriophages is sea water. More than 70% of the bacteria in the sea may be infected with bacteriophages.

The International Commission on Taxonomy of Viruses (ICTV) classifies bacteriophages based on morphology and nucleic acid. There are a total of 19 families of phages, of which only two families use RNA as the main genetic material, and five families are enveloped viruses.

In the bacteriophage family with DNA genomes, only two are DNA single-stranded structures. Among the virus families with double-stranded DNA genomes, 8 are circular genomes and 9 are linear genomes. Nine families only infected with bacteria, nine families only infected with archaea, and one family was infected with both bacteria and archaea.

And our most common, seemingly small robot named T2 bacteriophage, specifically targets E. coli, is a potent bacteriophage. The so-called potency means that it will kill the invading bacteria. In contrast, there are some milder bacteriophages. Their relationship with bacteria is like humans and roundworms, which can be parasitic in bacteria for a long time.

Mildness is an inevitable product of natural co-evolution, because too strong lethality sometimes cuts off the source of infection and prevents oneself from continuing to spread. Therefore, the choice to maximize the benefits is to "last forever", so even if the phage infection rate is So high, bacteria can still survive

Regardless of its complex shape, there are actually only two main structures-DNA and shell. There is a wealth of information recorded in DNA, mainly used to synthesize the outer shell, including the head, neck ring, tail sheath, tail tube, base plate, spikes and tail filaments. Guide to Invading Bacteria

So how do they infect bacteria? First of all, we have to understand one thing-the virus itself has no power, it only spreads in a solution environment, so if you want to catch the bacteria, you must have a corresponding structure. The six cute calves are for this purpose. , Their molecules are structurally attractive to the molecules of the outer capsule of the bacteria, so when the phage randomly contacts the surface of the bacteria under the Brownian motion of water molecules, the tail will stick to the bacteria instead of the head.

At the tail we can see a structure called a spike, which also peels off the protective layer of bacteria at the molecular level. This is different from macroscopic puncture. It is separated by the attractive force of molecules, and then they are sealed together. DNA in the head also enters the bacteria due to thermodynamic movement.

We know that the genetic material of bacteria is DNA, and its working principle is to convert its own information into protein through ribosomes in an environment rich in various molecular raw materials inside the cell. In the same way, after the phage DNA enters the bacteria, its DNA will also use existing raw materials and ribosomes to synthesize proteins. These are the various structures that make up the shell of the phage.

Of course, this DNA will not only "steal" the raw materials of the bacteria to synthesize its own shell, but also replicate itself. After a certain period of time, the inside of the bacteria will be filled with things synthesized by phage.

Then there is the last step to form a virus, and the most interesting step-assembly. We may be amazed by its complex structure. In fact, these are all due to the molecular structure. They randomly collide with the thermodynamic Brownian motion in the bacterial body fluid, and the appropriate structures will stick together by themselves, such as on the substrate. There are 6 molecular protruding points, this position can be combined with one end of the tail wire, other structures are not good, so the 6 calves will be successfully combined in the collision, and become a delicate and magical phage. Delicate relationship

Then the outer shell of the bacteria that has been sucked up by the phage will collapse, and the phage inside will rush away, come into the environment, and continue to infect other bacteria. Among them, the speed of replication is the key to determining whether the phage is potent. If it replicates too fast, the bacteria will die suddenly, and if it replicates slowly, it is similar to a parasitic relationship.

Therefore, the relationship between bacteria and phages is also very delicate, just as if the slave owner does not create a clean environment for the slaves and treat them to a doctor, if the slaves die, there will be no slaves to exploit (Southern Black Slave Plantation in the United States). Bacteriophages even protect bacteria in some cases~www.wuxiaspot.com~ For example, the Soviet Union and France tried to treat bacterial infections with bacteriophages, but then scientists discovered that bacteriophages not only became less effective because of their reduced potency, they even helped bacteria build a The protective layer prevents other drugs from taking effect. There is quite a meaning of "it is only I can bully, you all stay away!"... Why is there a punk head structure

So why does the phage have a very sci-fi style head? In fact, it is also very easy to understand. First of all, molecules can form geometric structures spontaneously, such as the hexagon of ice crystals, because the angle between water molecules and hydrogen is 120 degrees. The head of the phage is a regular tetrahedron with 12 vertices, 30 sides and 20 equilateral triangles. Each angle is 60 degrees, which is compatible with the atomic structure of its molecules.

Using this structure is also the most economical and reasonable way to form a closed space at the molecular level. Not only bacteriophages, but many viruses also use this structure, such as the adenovirus in the figure below. Similarly, the spiral structure that makes up the tubular structure is also a natural product of the special angles of the molecular structure. Although these structures are subtle, they are not incomprehensible. They have nothing to do with aliens and creations.

This is the boundary of life as we know it now, one of the viruses that has been hovering on the boundary between life and non-life: a brief knowledge of bacteriophages, the application of bacteriophages will be very extensive, and biologists are also working hard to study them, and As mentioned in the title, bacteriophages may be a reference for nanorobots, and our research on bacteriophages may have important guiding significance for the manufacture of organic nanorobots in the future.

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