When it comes to "microorganisms", many friends have the impression that most of them are related to "dirty", "disease" and "contagious", while friends who know more about microorganisms will think that microorganisms also have many positive effects - they are all right. In recent years, a large number of studies have fully demonstrated that microorganisms play a vital role in maintaining human health and the overall harmony of the global environment. At the same time, the emergence of frightening emerging infectious diseases is accelerating around the world. The story of microorganisms is sometimes exciting, sometimes creepy. Today, let's briefly talk about the interesting things about microorganisms.
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Microorganisms, small and huge
As the name suggests, these organisms are very small, and most of them must be observed with the help of a microscope, so that their aggregates can be detected by the naked eye.
For example, the size of the bacteria is so small that an average needle can hold 1,000 to 100,000 bacteria. And the virus is even smaller than you can imagine. Depending on the type of virus, a single needle tip may hold 1 million or more viruses.
A teaspoon of seawater contains about 5 million bacteria. Of course, life itself would not have existed without these bacteria helping to degrade dead plants and algae. However, in the same teaspoon of water, the number of viruses can be ten times greater than that of bacteria.
Not only in water, but one teaspoon of average soil contains about 240 million bacteria and 600 million viruses. The population of the entire North American continent is less than 600 million.
However, if we change the algorithm, we will find that microbes can also be associated with the word "huge".
Take fungi as an example, the large-scale individual fungi we are most familiar with are mushrooms, which are all called in the vegetable market. Some fungi are even larger, such as a fungus called Honey Ring, which occupies more than eight million square meters of forest floor in eastern Oregon.
If weight were to be compared, it is estimated that the combined weight (or biomass) of all plants and animals on Earth is equivalent to about 560 billion tons of organic carbon. A study by scientists at the Weisman Institute and the California Institute of Technology shows that 80 percent of the Earth's biomass is made up of plant bodies.
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The second largest component of the Earth's biomass is bacteria (about 51×030 in number), which account for 15% of the global biomass. Fungi and archaea together have more biomass than animals. What's even more amazing is that the biomass of the virus exceeds that of humans.
Seeing this, who would dare to underestimate microorganisms?
Lonely? No, I'm all-inclusive
In a classic popular science book on microbiology, it is mentioned that Orson Welles said that "we are born alone, live and die...... but if you look at it more often, you will find that the actual situation is just as Whitman said, "I am vast and broad, I am all-encompassing".
Why?
Microbes are everywhere, since the dawn of life, and in us. The gastrointestinal tract of a healthy person is home to about 40 trillion bacteria. Basically all of these bacteria are harmless or have health benefits. Like the intestines, skin, mouth, respiratory tract (lungs and nasal cavities), and vagina, each of these places is a small ecosystem where microorganisms thrive. The microbial community that our bodies carry, known as the human microbiome, collectively weighs about 1.4 kilograms, which is close to the weight of our brains.
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The National Institutes of Health launched the five-year Human Microbiome Project (HMP) in 2008 and it has been a great success. The project's findings are truly staggering, and it is no exaggeration to say that we humans, or Homo sapiens as they are known in evolution, are in fact advanced microbial delivery systems that have evolved over a long period of time. As American journalist Michael Spector said, "Microbes are the ingredients of human beings themselves. ”
It is estimated that there are 37.2 trillion cells in the human body, and the large intestine, where the vast majority of microbes in the body live, is home to 39 trillion bacteria. The human genome has about 30,000~40,000 genes, and our microbiome is estimated to contain 2 million~8 million unique genes. It can be said that the human microbiome carries genetic information hundreds of times larger than the human genome.
In this sense, 99% of the genetic information carried by the human body actually originates from microorganisms. Just as individuals have unique fingerprints and genes, each person has a different microbiome. In fact, many researchers believe that the microbiome can be seen as a newly discovered essential organ for the human body.
Attacking drug-resistant bacteria? Take a hair of the dog that bit you!
Resistance to antibiotics (antibiotic resistance) refers to the ability of microorganisms to resist antibiotics, and the microorganisms in this case can be of any kind, and the biological genetic mechanisms of drug resistance are also different.
A large number of patients have died from drug-resistant pathogens. A project funded by the Welcome Trust estimated in 2016 that 700,000 people worldwide die each year from drug-resistant pathogens. Without a new response, or without more effective medicines, that number will rise to 10 million by 2050. This means that every 3 seconds, someone dies from antibiotic-resistant microorganisms, which is twice the number of cancer deaths currently per year. In 2013, the U.S. Centers for Disease Control and Prevention estimated that drug-resistant bacterial infections cause more than 2 million illnesses in the U.S. each year, with 23,000 deaths.
The World Health Organization (WHO), after analysing data from 114 countries, published a report in 2014 stating that antibiotic resistance has become a major public health threat worldwide. Experts from the World Health Organization have found that antibiotic resistance is already present in "every region of the world". Simple infections that could have been easily cured decades ago have evolved into serious infections that can kill patients.
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Antibiotic resistance is a paradigm that shows the evolution of species. The more antibiotics we put into the environment, the greater the evolutionary pressure on bacteria to develop resistance. In other words, the selection pressure brought about by antibiotics has led to the phenomenon of competitive "drug" selection in bacteria, and bacteria that have evolved resistance genes can survive. Therefore, the main cause of the antibiotic resistance crisis is the misuse of large quantities of antibiotics in the environment.
So, who is to blame for the misuse of antibiotics? Sadly, it is none other than us human beings.
In this regard, phages, which are also microorganisms, may be able to help, as one type of phage can only infect certain types of bacteria. This precision makes phages an attractive treatment because they can selectively attack harmful bacteria without affecting other beneficial bacteria. Antibiotics, by contrast, inhibit or kill hundreds of billions of bacteria without choice, whether they are friends or foes, or bystanders who have nothing to do with disease.
So, can bacteria become "resistant" to bacteriophages?
Unlike antibiotics, phages evolve rapidly. As a result, many antibiotic-resistant bacteria are unable to escape the attack of bacteriophages. In order to avoid bacterial resistance to phage therapy, several phage combinations are often used. This strategy is similar to the combination of many different antibiotics to treat tuberculosis and other bacterial infections, which makes phage therapy very promising.
Yogurt is the work of microbial fermentation
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To this day, the view of microbes as humanity's mortal enemy remains unchanged. However, we should recognize that this perception reflects only a small part of the role played by microorganisms. Thanks to scientific advances in the past few years, we now know that the vast majority of microorganisms (bacteria, archaea, fungi, protists) are either harmless to humans or indispensable to human health, and they are our close friends.
"Microorganisms Everywhere"
China Science and Technology Press
Author: Philip Peterson
Translators: Qi Zhongxia / Zeng Hui
This is a book about the two sides of the microbe:
They can both bring benefits to human health and be pathogens, wreaking havoc and destroying our bodies and causing serious harm to humans.
The author, Dr. Philip Peterson, a world-renowned expert in infectious diseases, explores the knowledge and understanding of microbes through a historical lens, from early plagues and epidemics to recent outbreaks of infectious diseases such as human acquired immunodeficiency syndrome (AIDS), Ebola, Zika and coronavirus.
The book also discusses other important topics in the field of contemporary infectious diseases, such as how to deal with the growing anti-vaccine movement, why vaccination is important, and the rise of fecal transplantation as a cutting-edge treatment.
Planning and production
Source丨"Ubiquitous Microbes", China Science and Technology Press