Chapter 16 bacteria

Watching TV, we will think that we are fighting in a perilous crisis, surrounded by bacteria chasing us, and the reason why we are protected from infection and death is only because chemical technology is protecting us. Engraved in killing bacteria.We were instructed to spray disinfectant everywhere, in the bedroom, in the kitchen, and especially in the bathroom, because our own germs seemed to be the most dangerous.We took the aerosol, added deodorant for good luck, sprayed the nose, mouth, armpits, secret wrinkle, even the inside of dear telephone receiver.We apply strong antiseptics to the small pimples and wrap them tightly with plastic wrap.Plastic has become the new protector. We wrap the plastic cups in hotels with plastic sheeting.We UV-lighted the toilet seat and sealed it like a state secret.In the world we live in, all kinds of microorganisms are always trying to get close to us, trying to tear us down into cells.It is only because we are fearful and defensive that we are able to live in the world as a whole.

We still think that the perpetrators of human diseases are a group of organized and modern demons.In this enemy line, the most conspicuous ones sitting in the tent of the Chinese army are bacteria.We judged that they would have a good time doing bad things.They come to us for profit, there are too many of them, disease seems inevitable, we human beings have such living conditions, there is nothing we can do about it.If we succeed in eradicating a disease, there is always a new one waiting to take its place. These are hallucinations of paranoia on a social scale.The reason is partly the need to make enemies and partly because our memories of the past are still fresh.Until just a few decades ago, germs were a real household pain.Although there are still a few who survive, we are aware that death is not far away every moment.Every action we take, we take our family through life and death.We had lobar pneumonia, meningitis, streptococcal infections, diphtheria, endocarditis, typhoid fever, various septicemias, syphilis, and tuberculosis was everywhere and everywhere.Most people are now free from most of these diseases, thanks to antibiotics, scientific research, civilization, and money.But we have not forgotten the past.

In real life, however, we are never, even at worst, the objects of relative indifference to that vast bacterial kingdom.Bacterial illness is not routine.Truth be told, the fact that bacterial disease is so rare, and given the sheer number of bacterial populations on Earth, has an element of uncertainty.The occurrence of disease is usually caused by the fruitless negotiation for symbiosis, when one of the symbiotic parties crossed the border line, or because of the misunderstanding of the border agreement in the biological world. Some bacteria are only harmful to humans when they produce exotoxins, and in a sense, they only produce exotoxins when they are themselves sick.Bacillus diphtheriae and Streptococcus diphtheriae produce toxins only when they are attacked by phages; viruses provide the code for toxin production, and uninfected bacteria are not informed by codes.We have diphtheria, which is a viral infection, but the virus does not infect us.Instead of being involved in a head-to-head match with toxins, we seemed to stumble into someone else's trouble.

Some microorganisms have a special ability to attack the human body. I can think of a few, probably Mycobacterium tuberculosis, Treponema pallidum, Plasmodium, and others.But they don't do themselves much good in the evolutionary sense that they can cause disease or death.Disease-causing is perhaps the bane of most bacteria, whose lives are more dire than ours.A person carrying the meningitis pathogen is not fatally dangerous even without chemotherapy.In contrast, meningitis pathogens are unlucky enough to encounter people, and their life-threatening risks are too great.Most meningitis pathogenic bacteria are smart and only stay on the surface of the human body, staying in the nasopharynx.When encephalitis is prevalent, the nasopharynx and nasopharynx of most carriers are the places where pathogenic bacteria stay.Generally speaking, they are harmless to people there.Only in a few people for unknown reasons do they cross the line.At this time, both humans and bacteria suffer together, and most of the time, it is the meningitis pathogen that suffers more.

Staph bacteria live all over our bodies.Most other bacteria are not adapted to live on human skin, and this strain seems to have adapted to the conditions there.It is strange to see them so many, and ourselves so alone, and yet have so little trouble with them.Few of us suffer from boils, and most of them are due to the meddling of our own white blood cells.Streptococcus hemolyticus is our closest companion, even so close that it has the same antigen as our muscle cell membrane.We get ourselves into trouble by responding to their presence in the way rheumatic fever does.We can carry Brucella for a long time in the cells of the reticuloendothelium without feeling their presence at all.For some unknown reason, probably related to the immune response in our body, we feel them periodically, and this sensory response is the clinical symptom.

Most bacteria are obsessed with eating and drinking, constantly changing the structure of organic molecules so that they can be used to meet the energy needs of other life forms.Collectively, these bacteria are inseparable from each other and live in interdependent communities in soil or ocean.There are some bacteria that become symbionts of higher organisms in more specialized, local relationships, living in their tissues as working parts.Root nodules of legumes would neither form nor function without rhizobia.It is a large number of rhizobia that cluster in the root hairs and form an intimate relationship with them, so that it takes an electron microscope to distinguish which membranes belong to bacteria and which belong to plants.Insects carry colonies of bacteria.The fungus cells appear to be tiny glands in the insect's body.No one knows what they are doing, only that what they do is important.The microbial community in the animal gut becomes part of the animal's nutritional system.And of course the mitochondria and chloroplasts, the official inhabitants of all living things.

On closer inspection, the most malicious microbes—the ones that really seem to want us to get sick—really look more like bystanders, homeless people, and occasional strangers who come to shelter from the cold.They invade the human body whenever they have a chance, and reproduce. Some of them will reach the deepest tissue of our body and break into the bloodstream.But it is our response to their presence that makes us sick.The gunpowder our bodies use to fight bacteria is so fierce and involves so many defense mechanisms that they can be more dangerous to us than invaders.We are covered with explosive devices; we are covered with landmines.

It is the information brought by bacteria that makes us overwhelmed. Gram-negative bacteria are the best example of this.They produce lipopolysaccharide endotoxins in the cell walls, and our tissues seem to have gotten the worst news when exposed to these macromolecules.Once we sense tyrosan, we may resort to all available defenses.We'll bomb, defoliant, intercept, cordon off and destroy every organization in that area.White blood cells become active, become more phagocytic, release lysozyme, become sticky, cluster together, block capillaries, and cut off blood supply.Serum defensins act accordingly, releasing chemotactic signals and recruiting leukocytes from the whole body.The blood vessels become hypersensitive to adrenaline, and the physiologically focused response suddenly takes on a tissue-necrizing quality.Pyrogen is released from white blood cells, and fever is added to hemorrhage, necrosis, and shock.Everything is messed up.

All of this seems like needless panic.Endotoxins are not inherently toxic.But once perceived by the cells, it can appear hideous, or frightening.Cells believe that the presence of endotoxin means the presence of Gram-negative bacteria.So they rise up to resist this threat, and no one can stop their actions. I thought that only highly evolved, highly civilized animals would be fooled by this.But that's not the case.Horseshoe crab is a very primitive fossil animal with ancient origin and undeveloped civilization.But it is as prone to collapse in the face of endotoxins as rabbits and people.Bang (Bang) proved that injecting a very small dose of endotoxin into the body cavity of the horseshoe crab will cause a large number of blood cells to coagulate, block the blood vessels, and the gelatinous clot will interrupt the blood circulation.It is now known that the blood coagulation system of horseshoe crabs is mainly involved in the reaction-probably the ancestor of our human blood coagulation system.The drawn blood cells will coagulate with the addition of a very small amount of endotoxin.The spontaneous disintegration of the whole organism after systemic injection of endotoxin can be explained as a mistake made by the organism: well-intentioned but fatal.This reaction mechanism itself is quite good. As long as it is used properly and properly, its effect on dealing with the invasion of a single bacterium is still admirable: it calls blood cells to the scene, expels coagulable proteins, bacterium is trapped in the net, and loses its ability to move. The whole thing was over.Only when encountering the signal of a large number of endotoxin free molecules, reminding the body of the existence of a large number of vibrio, the horseshoe crab panicked and resorted to all means of self-defense, which destroyed itself.

This process is basically a response to signals, a bit like the pheromones secreted by slave ants, which cause panic in the victim ant colony, leading to chaos and disintegration of the victim ant colony. I think it is likely that most of our diseases are acquired in this way.Sometimes the mechanism of indiscriminate killing is immune, but often, as in the case of the horseshoe crab, it is some more ancient memory.We tear ourselves to pieces by signals, and we are more vulnerable to signals than any herd of carnivorous beasts.In effect, we are at the mercy of our own Pentagon.Most of the time it is.