CATDOLL : CATDOLL: Flies and mosquitoes reproduce and survive in what humans consider to be the most unclean places. How do they resist bacteria?

Flies and mosquitoes reproduce and survive in places that humans consider to be the most unclean. What magic weapon do they have to resist bacteria?

Flies and mosquitoes have lived in a dirty and messy environment for a long time. In the long history of biological evolution, they have evolved antibacterial proteins with strong immune ability in their bodies - the components are "antimicrobial peptides" that can protect themselves from bacteria invasion. Take flies as an example. They contain two antimicrobial proteins (BF64 and BD2) known as "insect defensins" in their bodies, which show antibacterial, antifungal and protozoan activities. This antimicrobial protein has a strong bactericidal effect, which is nearly a thousand times more powerful than penicillin. .

Just resist a few bacteria, fungi and toxins. If people are forced to eat garbage, they will evolve into a species that is immune to these things.

Why do flies have more than 400 viruses but never get sick themselves?

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In a nutshell, flies have antibodies to certain viruses, and the antibodies have specific resistance to viruses, so they themselves will not get sick.

The key problem is that we use human imagination to imagine the physiological mechanism of flies to resist viruses, so the question raised by the original poster will arise. Let me make an analogy. Human saliva is a kind of venom to snakes, but it is fine to humans. If it were in the snake's perspective, it would also be surprised: My God, humans carry so much venom, why don't they kill us? That's the reason. What I said is just an analogy, I hope you don't have other ideas.

Flies, these little creatures that often stay in the dirtiest places and eat the dirtiest things, are covered with bacteria all over their bodies, which endanger our health all the time. However, these bacteria do not cause any harm to the flies themselves. Because some pathogenic microorganisms, although they can survive or reproduce in the body of the vector, are harmless to the vector itself. Moreover, scientists have recently discovered that there is an antibacterial substance in the body of flies called antimicrobial peptides

Now, the answer seems to be very simple, but when my daughter asked me yesterday, I couldn't give a reasonable answer. Especially, I remember that I never explored any problems when I was a child. Now I think about it and feel a little ashamed. Many problems and phenomena seem so simple and natural now. But maybe we rarely explore these simple problems and the reasons behind these natural phenomena. I don't know if my friends of the same age have the same feelings as me?