Rob Knight look what's inside you. See what's inside you

We live in an era of a real revolution in microbiology. The latest technology has allowed scientists to dive into the world of microscopic creatures that inhabit our body and make amazing discoveries in this world. It turns out that microbes, which live in unthinkable quantities in almost every corner of our body, play a much more important role than we previously thought: not only our physical health depends on them, they determine our mood, our tastes and our very personality. We hear about these scientific breakthroughs first-hand: the author of the book, Rob Knight, is one of today's leading microbiologists, creating the science of the future before our eyes.

A series: TED Books

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by the LitRes company.

1. Microorganisms in our body

So, let's try to estimate how many microbes live inside us.

If we count by weight, then in the body of an adult they are on average about one and a half kilograms. This makes your microbiota one of the largest organs, rivaling the brain in terms of weight and only slightly inferior to the liver.

We already know that in terms of absolute cell count, microorganisms outperform humans by a ratio of ten to one. What if we compare our DNA? Each of us has approximately twenty thousand human genes. And at the same time, we carry between two and twenty million microbial genes. This means, alas, that genetically we are at least 99% microbes!

Lest you be so offended, look at this from the point of view of the complexity of the human device. Each human cell contains many more genes than a microbial one. It's just that there are so many microbes in your body that the sum of all their genes outweighs yours.

The organisms that live in us and on us are very diverse. Most (but not all) are unicellular. They represent all three main branches of the evolutionary tree. Representatives of the kingdom of archaea live in the intestines - unicellular organisms that do not have nuclei; the most common of these are methanogens, which exist without oxygen, help digest food, and release methane gas (cows also have them).

Next come the eukaryotes: skin mycosis fungi and yeasts that colonize the vagina and sometimes the intestines. But bacteria dominate over all - for example, Escherichia coli ( Escherichia coli), E. coli, which we associate primarily with indigestion, which occurs due to poorly washed greens. However, harmless and beneficial varieties of this bacterium are almost always present in our insides.

And every day, thanks to new technologies, we learn that this world is even more diverse than we thought before. It is as if we were walking through the ocean with a trawl with very large cells, and then, after examining the catch, we would conclude that only whales and giant squids are found in the sea. Now we have discovered that the life we have inside is much more diverse. For example, you might assume that any two bacteria in your gut that pounce on your last sandwich are very similar to each other, like, say, anchovies or sardines. But in fact, they have no more in common than the sea cucumber (holothurian) and the great white shark: they are two creatures with completely different behavior, food and ecological role.

So where are all our microbes located and what is their role? To find out, let's take a tour of our body.

They say that Napoleon, returning from a military campaign, wrote to the Empress Josephine: “I will be in Paris tomorrow evening. Don't take a bath." He preferred the natural smell of his adored wife, and concentrated. But why, when we are left without soap, deodorants, powder and perfume for a while, does it start to smell so bad from us? Mainly because of the microbes that feed on our secretions and make them even more smelly.

Scientists are still trying, sorry for the pun, to sniff out what practical purpose the activity of the creatures that live on our largest organ, the skin, serves. One thing is for sure: they contribute to the formation of our body odor, including those components of this odor that attract mosquitoes. As already noted, blood-sucking insects really prefer the smells of some people to others, and microbes are to blame. They break down substances that the skin releases into volatile compounds that mosquitoes may or may not like. Moreover, different types of mosquitoes prefer different parts of our bodies. For example, for Anopheles gambiae, one of the main carriers of malaria, the most attractive smell is not the smell of the armpits, but the smell of the hands and feet.

In this regard, a tempting solution arises: if you rub an antibiotic on the skin of your hands and feet, you can prevent the attack of this type of mosquito, because by killing germs, you kill the smell.

The microbes that live on our skin—like all other microbes—do not necessarily exist specifically for our benefit. But they, being conscientious residents, really help us a lot: by the fact that they live on us, they prevent other, harmful microbes from infecting us. Various microbes live in different areas of the skin, and the diversity - the number of species - is not necessarily proportional to the number of microbes present in a particular area. Sometimes it's just the opposite. To use an American analogy, imagine that Vermont (pop. 600,000) is as ethnically diverse as Los Angeles (ten million), and Los Angeles has become as mono-ethnic as Vermont. You have a huge number of germs on your forehead and under your arms, but relatively few species; and vice versa, on the hands (palms and forearms) there are relatively few microbes, but they are very diverse. The microbial communities on the hands of women tend to be more diverse than those of men, and this difference persists despite handwashing, suggesting that the reason, albeit still unknown, lies in biological differences.

Moreover, we found that the germs living on your left hand are different from those living on your right. You can rub your hands, clap your hands, and touch the same surfaces with both hands - each still develops a separate microbial community. This fact inspired Professor Noah Firer of the University of Colorado at Boulder and I to try to reproduce one of the most famous discoveries in general biology. At one time, trying to explain the distribution and distribution of organisms on isolated islands and the relationship between species diversity and occupied territory, the British biologist and anthropologist Alfred Russel Wallace, along with other scientists, developed a complex theory of biogeography. Wallace, a contemporary of Darwin, who simultaneously and independently developed the doctrine of natural selection, mapped a line that runs through modern Indonesia and Malaysia and separates the Asian fauna (monkeys and rhinos) from the Australian (cockatoo and kangaroo). Firer and I wondered if it was possible to draw the same "Wallace line" on a computer keyboard between the G and H keys - this line, in theory, should separate halves of the keyboard with clearly different microbial populations. We also wanted to see if the space bar would have more types of microbes, simply because it is much longer than all the others.

Our results confirmed the existence of a kind of "Wallace line," but we found something much more surprising: each finger and its corresponding key were characterized by approximately the same microbial community. We were also able to determine the owners of a computer mouse with an accuracy of up to 90% from the microbial profile of the palm. The microbial community on your hand is very different from similar communities of other people (in terms of species diversity - an average of 85%), which means that each of us, in addition to the usual ones, also has microbial fingerprints.

We went further and conducted experiments to find out how many times you need to touch an object to leave a distinct microbial trail. This study is still too incomplete to be used in court. But television has, let's say, a more simplified standard of evidence, so shortly after we published an article on this topic, another episode of Crime Scene Investigation: Miami was shown, where the plot was based on a forensic examination of a microbial fingerprint.

Meanwhile, forensic microbiologist David Carter moved from Nebraska to Hawaii to set up a “body preserve” there. "What it is?" - you ask Forensic scientists often face the task of determining how long ago the death of a person whose corpse they examine has occurred. In Carter's "reserve" the bodies of the dead donated by relatives and various institutions are stored in various conditions, and scientists constantly analyze the rate of their decomposition. At the same time, a striking continuity of microbial communities is observed. Just as colonies of lichens appear first on a bare rock, then, in succession, mosses, grasses, weeds, shrubs, and finally trees, the decay process also proceeds in a certain order.

Answer: insects still have to find the dead body, while microorganisms are always there, and this can be useful in cases where there are no insects at the crime scene.

Nose and lungs

The next point of our tour of the body will be the nose. Certain types of microbes live in the human nostrils, including Staphylococcus aureus ( Staphylococcus aureus), which causes staph infections in hospitals. Thus, healthy people seem to often be the “home” for dangerous microbes. We believe that in this case, the explanation may be as follows: other bacteria living in our nose do not allow Staphylococcus aureus to take over, or rather, take over the nose. Another interesting observation: the environment strongly influences what kinds of microorganisms settle in our nose. Children with a more diverse nasal microbial population, such as those living in rural areas near animals, are less likely to develop asthma and allergies in the future. It turns out that tinkering in the mud is sometimes useful.

Going down into the lungs, we usually find only dead bacteria. The inner surface of the lungs, which is exposed to air, contains a cocktail of antimicrobial peptides: tiny proteins that instantly kill bacteria that get there. However, in the lungs of patients with cystic fibrosis or the human immunodeficiency virus (HIV), dangerous microorganisms are sometimes found that contribute to the development of pulmonary diseases.

Scientists are still arguing about whether each of us has a separate community of microbes in the throat, or only those microbes that come from the mouth are present there. However, it is already known that the germs in the throats of smokers are different from those of non-smokers, which probably means that smoking is not only harmful to ourselves, but also to the creatures that live inside us.

Mouth and stomach

Chances are, you've only heard of the bad bacteria in your mouth—the ones that cause gum disease and tooth decay. One of them, Streptococcus mutans ( Streptococcus mutans), is the same creature that destroys our teeth. It appeared, apparently, in connection with the development of agriculture, when the diet of our ancestors was sharply enriched with carbohydrates, especially sugars.

Just like the rats we unwittingly domesticated and feeding on our garbage, some bacteria have learned to live in our bodies. Fortunately, most of the "domesticated" bacteria are beneficial - they form a biofilm that keeps out the "bad" bacteria. Oral microbes can even help regulate blood pressure by relaxing the arteries with nitric oxide (the nitrous oxide cousin you've encountered in the dentist's chair) that they release.

Another species, Plaut's wand ( Fusobacterium nucleatum), usually present in the mouth of a healthy person, but can also contribute to the development of periodontal disease. F. nucleatum is of interest because these bacteria are found inside colon tumors, but we do not yet know if this is the cause or the effect: whether F. nucleatum causes cancer, or is it simply a reaction to the conditions in which the tumor develops.

The microbial population of the mouth is also highly diverse. Even different sides of the same tooth can be colonized by different microbial communities, depending on a variety of factors, including oxygen access and chewing habits.

In the stomach, where the environment is almost as acidic as in a car battery, only a few species of organisms can survive, but they play a huge role. One of these bacteria, Helicobacter pylori ( Helicobacter pylori, H. pylori), has coexisted with humans for so long that, by studying its strains in representatives of different nations, one can find out which peoples are related to each other and with whom they contacted during the migration process.

H. pylori plays a key role in the occurrence of ulcers of the stomach and small intestine, when, as a result of the destruction of the mucous membrane, gastric juice begins to corrode tissues. Initial symptoms include halitosis and burning pain in the stomach, followed by nausea and bleeding. For many years, doctors considered stress and malnutrition to be the cause of ulcers and recommended rest, rest, exclusion of spicy foods, alcohol and coffee, prescribed milk and antacids. Patients experienced relief, but rarely recovered completely.

In the 1980s, Australian physicians Barry Marshall and J. Robin Warren showed that most ulcers are caused by a bacterium. H. pylori therefore, treatment should include antibiotics or antibacterial drugs, such as those containing bismuth. Marshall was so convinced he was right that he personally drank the culture H. pylori- and earned gastritis (which he quickly cured) and the Nobel Prize (which he shared with Warren).

However, today we know that more than half of the entire population of the Earth are carriers H. pylori. Why don't the vast majority of them have ulcers? Apparently, this bacterium is just one of many risk factors for this disease: necessary, but not sufficient. It turned out that many healthy people can be carriers H. pylori, as well as a number of other bacteria that we associate with diseases. One of the goals and hopes of microbiome science is to figure out how and why these microorganisms sometimes suddenly attack us.

Intestines

Next we move on to the intestines. We believe that this is the largest and most important microbial community in the human body. If you are a microbe living in a person, then this is your capital. A metropolis up to ten meters long, full of winding streets and nooks and crannies. Microbes are expanse here: warmth, an abundance of food and drink, and sewerage at hand. From a microbial point of view, our gut is like New York City and some Eastern oil capital at the same time - countless population and available energy.

Absorption of nutrients from food into the blood mainly occurs in the small intestine. Water is absorbed in the large intestine, and also, with the help of enzymes secreted by beneficial microorganisms, fiber is broken down, which comes from the small intestine in an undigested form. This releases even more energy. Living in the digestive tract, gut microbes govern our metabolism to a great extent. They determine what we can eat, how many calories we absorb, what nutrients and toxins we are exposed to, how drugs affect us.

From a scientific point of view, another fact about this important microbial community is of great importance: it is very easy to obtain samples from here. Germs, dead or alive, are simply thrown out, usually after morning coffee. Basically, feces contain microorganisms from the last, distal, section of the colon. Despite some difference in the composition of the communities of the small and large intestines, this difference is generally insignificant compared to the differences between the microbial communities of two different people. That is, your bowel movements are a ready-made portrait of your gut's unique microbial community.

True, to some extent, the picture that we get by analyzing feces is distorted. For example, E. coli Often referred to in headlines as a terribly formidable bacterium that occasionally finds its way into food due to poor sanitation, it's actually not necessarily dangerous in and of itself. We know about it only because it is found in feces (if it is found in vegetables or meat E. coli this is a sign of faecal contamination). In fact, there are not so many of these bacteria in the intestines of a healthy person: only one cell per ten thousand cells of other microorganisms. By its fame E. coli owes to the fact that, among other microorganisms, it plays the role of a weed, like quinoa or dandelion, and grows best of all in a Petri dish. The same is true of a number of other bacteria, whose role we have exaggerated for decades for one reason only: they are easy to grow in the laboratory.

Most of the microbes in our gut are far less stable, and we don't yet know how to grow them. in vitro(in this case, in the laboratory). Basically, they belong to two large groups of bacteria - firmicutes ( Firmicutes) and bacteroids ( Bacteroidetes) - and play an important role in the digestion of food and the absorption of drugs. In addition, they have been associated with a number of diseases, including obesity, inflammatory bowel disease, colon cancer, heart disease, multiple sclerosis, and autism. That's why a discovery like next-generation sequencing has made a real revolution. We can finally see what has been invisible until now.

Genitals

First of all, I must confess my own ignorance: we still know very little about the microbes that live outside and inside the penis. It must be said that microbiology, a science that began with the fact that the Dutch scientist Anthony van Leeuwenhoek examined sperm under a microscope, among other things, has not studied the male genitalia properly. Nevertheless, some progress has already been made.

I have a colleague (who wants to remain anonymous to avoid becoming the prey of TV people) who is studying the spread of sexually transmitted diseases (STDs) among teenagers. Part of his work is related to the study of the adolescent penis microbiome. To do this, he regularly needs sperm samples, moreover, obtained regularly and immediately after intercourse. So, when this man receives a phone call from one of his “clients,” my colleague, in his usual attire—long hair, leather jacket, and gold chain around his neck—gets into a white lab van and goes to sample your sons’ penises. Of course, all this is solely for the sake of science. And there are such conscious parents who sign an official consent to this!

Either way, there hasn't been enough research done in this area so far (perhaps partly because too many people start giggling silly when describing the topic), and so my colleague's work could be a milestone in creating the penis microbiome - in disease and in good health.

The vagina, unlike the penis, has been studied very well. The microflora of a healthy adult woman of European origin is usually dominated by only a few types of lactic acid bacteria from the genus Lactobacillus ( Lactobacillus). Don't worry, these aren't the bacteria that turn milk into yogurt, but they're close relatives that also produce lactic acid, keeping the vagina acidic. Here is what Jacques Ravel, professor of microbiology and immunology at the University of Maryland, has shown in his work: the species that dominate the vaginal microbial community of a particular woman can change over time, including at different periods of the menstrual cycle, when iron-processing cells develop due to blood flow bacteria deferribacter ( Deferribacter). A woman's vaginal bacteria can change even with a change in sexual partner.

Until recently, almost all research on the vaginal microflora has focused on the fight against STDs. Scientists have been studying the role of vaginal microbes in a disease called bacterial vaginosis, and have also tried to determine whether vaginal microbes can help or hinder the transmission of various sexually transmitted infections, including HIV.

However, it turned out that not all healthy vaginal microbiomes are alike. The new findings suggest that the microbial communities of healthy women, particularly Hispanics, African Americans, whites and Asians, vary greatly by ancestry. And, as we shall see, to some extent, vaginal microbes can determine our fate.

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The above introductory fragment of the book Look what's inside you. How the microbes that live in our body determine our health and our personality (Rob Knight, 2015) provided by our book partner -

See what's inside you. How microbes living in our body determine our health and our personality

The Enormous Impact of Tiny Microbes

ROB KNIGHT

WITH BRENDAN BUHLER

TED, the TED logo, and TED Books are trademarks of TED Conferences, LLC

TED BOOKS and colophon are registered trademarks of TED Conferences, LLC

Cover and interior design by MGMT. design Illustrations by Olivia de Salve Villedieu

CORPUS ® Publishing

To my parents, Alison and John, with gratitude for their genes, their ideas and their microbes

Foreword

We know who you are: a human being, a bipedal animal with infinite possibilities of mind, an heir to all things, who has never read a single user agreement to the end - just tick where necessary. And now get acquainted, it's you too: trillions of tiny creatures that live in your eyes, ears and vast estates, called your intestines. And this inner microcosm can change your understanding of your diseases, your health and yourself.

Thanks to new technologies (many of which have been developed over the past few years), scientists today know more about the microscopic life forms inside us than ever before. And what we learn is amazing. These single-celled organisms - microbes - are not only much more numerous than we thought, they live in unimaginable numbers in almost every corner of our body and play a much more important role than we could ever imagine: so many aspects of our life depend on them. health and even our personality.

The collection of microscopic creatures for which our body serves as a home is called the human microbiota (sometimes also microflora and microfauna), and the totality of their genes is called the human microbiome. And, as is often the case with scientific discoveries, new facts about the microcosm make us humble our egos. Astronomy has already explained to us that our planet is not at all the center of the universe, evolution has taught us that man is just one of the animal species. Compiling the human microbiome teaches us that in the home of our body, our own voice is drowned out by a chorus of independent (and interdependent) life forms with their own agendas and agendas.

How many micro-organisms are inside us? You are made up of about ten trillion human cells - but your body contains about a hundred trillion microbial cells. That is, you are, to a large extent, not you.

But this does not mean that a person is just a receptacle for tiny creatures that accidentally got inside his body and spread diseases. In fact, we live in balance with the entire community of microorganisms inhabiting us. Their role is not limited to the role of passive passengers - they are involved in fundamental life processes, including digestion, immune responses, and even behavior.

The totality of microbes within us represents something like the unification of various communities. Different parts of the body are inhabited by different groups of species that have specialized functions. The microbes that live in the mouth are different from those that live on the skin or in the gut. We are not just individuals; each of us is an ecosystem.

The diversity of microorganisms helps to explain even such individual characteristics that we used to attribute to chance or bad luck. Why do some of us love mosquitoes so much? For example, these little demons hardly bite me, while they fly to my friend Amanda like bees to honey. It turns out that some of us really tastier from the point of view of mosquitoes, and the main reason for such a selective “appetizing” is the differences in the composition of the microbial communities that live on our skin (more on this in chapter 1).

And that's not all: the variety of microbes that live on and inside us is amazing. You've probably heard that if we compare DNA, then all of us humans are about the same: our genome is 99.99% the same as the genome of any other person, such as your neighbor. But this does not apply to the microflora of your intestines: only 10% of microbes can match here.

This may explain the huge differences between people - from differences in weight to dissimilar allergies, from the likelihood of getting sick to the level of anxiety. We are just beginning to systematize - and understand - this boundless microcosm, but the conclusions of the first studies are already overwhelming.

The endless diversity of the microbial world is especially impressive when you consider that just forty years ago we had no idea how numerous single-celled organisms were and what an incredible number of species they numbered. Prior to this, the basic principles of the classification of living organisms were based on Charles Darwin's book "The Origin of Species", which was published in 1859. Darwin drew a tree of evolution, grouping all organisms according to common physical features: short-billed finches, long-billed finches, and so on; and for a long time this principle remained the basis of classification and taxonomy.

Traditional ideas about life were based on what people could see in the world around them - with the naked eye or through a microscope. Larger organisms were divided into plants, animals and fungi. The remaining single-celled organisms fell into two broad categories: protists (protozoa) and bacteria. As for plants, animals and fungi, we were right. But our ideas about unicellular organisms turned out to be absolutely erroneous.

In 1977, American microbiologists Carl Woese and George E. Fox proposed a new version of the “tree of life”, based on the comparison of various forms of life at the cellular level using ribosomal ribonucleic acid, a relative of DNA, which is present in any cell and is involved in protein synthesis. The picture was stunning. Woese and Fox found that single-celled organisms are more diverse than all plants and animals combined. As it turned out, animals, plants, mushrooms; all humans, jellyfish, dung beetles; any strand of algae, any patch of moss, climbing California sequoias; all lichens and forest fungi - all living things that we see around us - are just three shoots at the end of one branch of the evolutionary tree. Its main inhabitants are unicellular organisms: bacteria, archaea (which were first isolated as a separate group by Woese and Fox), yeast and some other life forms.

In just the past few years, there has been a breakthrough in our understanding of the microlife within us, which we owe to new technologies, most notably the advancement of DNA sequencing and the explosion of computer power. Today, through a process called next-generation sequencing, we can take cell samples from various parts of the body, quickly analyze the microbial DNA they contain, compare and combine with information from other organs to identify the thousands of microbial species that make our bodies their home. . In this way, we find bacteria, archaea, yeasts, and other single-celled organisms (particularly eukaryotes) whose combined genome is longer than our own.

The Enormous Impact of Tiny Microbes

ROB KNIGHT

WITH BRENDAN BUHLER

TED, the TED logo, and TED Books are trademarks of TED Conferences, LLC

TED BOOKS and colophon are registered trademarks of TED Conferences, LLC

Cover and interior design by MGMT. design Illustrations by Olivia de Salve Villedieu

CORPUS ® Publishing

* * *

To my parents, Alison and John, with gratitude for their genes, their ideas and their microbes

Foreword

How many micro-organisms are inside us? You are made up of about ten trillion human cells - but your body contains about a hundred trillion microbial cells 1
It should be noted that the latest report from the American Academy of Microbiology reduces this ratio to 3:1 mainly due to an increase in the number of human cells counted.

But in any case, the numerical superiority is on the side of microbes. See: http://academy.asm.org/index.php/faq-series/5122humanmicrobiome.

. That is, you are, to a large extent, not you.

The endless diversity of the microbial world is especially impressive when you consider that just forty years ago we had no idea how numerous single-celled organisms were and what an incredible number of species they numbered. Prior to this, the basic principles of the classification of living organisms were based on Charles Darwin's book "The Origin of Species", which was published in 1859. 2
Available online: Project Gutenberg, www.gutenberg.org/files/1228/1228-h/1228-h.htm.

Darwin drew a tree of evolution, grouping all organisms according to common physical features: short-billed finches, long-billed finches, and so on; and for a long time this principle remained the basis of classification and taxonomy.

Well, new computer algorithms, in turn, greatly simplify and facilitate the interpretation of this genetic information. In particular, we can now make a microbial map of the body that allows us to compare microbial communities in different parts of the body and in different people. Much of this information has come from the Human Microbiome Project ( Human Microbiome Project), carried out under the auspices of the US National Institutes of Health ( US National Institutes of Health, NIH). The study cost $170 million and involved more than 200 scientists who have collected and analyzed at least 4.5 terabytes of data to date. And this is just the beginning; other international projects such as “Research on the Composition of Biota of the Human Gastrointestinal Tract” ( Metagenomics of the Human Intestinal Tract Consortium, MetaHIT), constantly adding and analyzing new data.

The cost of these analyzes is decreasing all the time, thanks to which more and more people can make a complete census of the microbes living in their bodies. Ten years ago, to analyze your microbiome, you would have to pay a hundred million dollars. Today, this kind of information will cost as little as a hundred bucks—so cheap that doctors will soon order such studies as a routine medical procedure.

But why are doctors interested in the composition of your microbiome? Because there are more and more studies that prove the connection between our microbes and many of our diseases, including obesity, arthritis, autism and even depression. And this connection, in turn, immediately opens up new prospects for treatment.

What does not affect our microbiome - drugs, diet, number of sexual partners, even whether you are the first child with your parents! As you read the following pages, you will see that micro-organisms are deeply involved in almost every aspect of our lives. They really make us look differently at the question: “What does it mean to be human?”

1. Microorganisms in our body

So, let's try to estimate how many microbes live inside us.

So where are all our microbes located and what is their role? To find out, let's take a tour of our body.

Leather

As already noted, blood-sucking insects really prefer the smells of some people to others, and microbes are to blame. They break down substances that the skin releases into volatile compounds that mosquitoes may or may not like. Moreover, different types of mosquitoes prefer different parts of our bodies. For example, for Anopheles gambiae, one of the main carriers of malaria, the most attractive smell is not the smell of the armpits, but the smell of the hands and feet.

The microbes that live on our skin—like all other microbes—do not necessarily exist specifically for our benefit. But they, being conscientious residents, really help us a lot: by the fact that they live on us, they prevent other, harmful microbes from infecting us. Various microbes live in different areas of the skin, and the diversity - the number of species - is not necessarily proportional to the number of microbes present in a particular area. Sometimes it's just the opposite. To use an American analogy, imagine that Vermont (pop. 600,000) is as ethnically diverse as Los Angeles (ten million), and Los Angeles has become as mono-ethnic as Vermont. You have a huge number of germs on your forehead and under your arms, but relatively few species; and vice versa, on the hands (palms and forearms) there are relatively few microbes, but very diverse 4
E. A. Grice et al., “Topographical and Temporal Diversity of the Human Skin Microbiome,” Science 324, no. 5931 (May 29, 2009): 1190–92; E. K. Costello et al., “Bacterial Community Variation in Human Body Habitats Across Space and Time,” Science 326, no. 5960 (December 18, 2009): 1694–97.

The microbial communities on the hands of women tend to be more diverse than those of men, and this difference persists despite handwashing, suggesting that the reason, albeit still unknown, lies in biological differences. 5
F. R. Blattner et al., “The Complete Genome Sequence of Escherichia Coli K-12,” Science 277, no. 5331 (September 5, 1997): 1453–62.

Wallace, a contemporary of Darwin, who simultaneously and independently developed the doctrine of natural selection, mapped a line that runs through modern Indonesia and Malaysia and separates the Asian fauna (monkeys and rhinos) from the Australian (cockatoo and kangaroo). Firer and I wondered if it was possible to draw the same "Wallace line" on a computer keyboard between the G and H keys - this line, in theory, should separate halves of the keyboard with clearly different microbial populations. We also wanted to see if the space bar would have more types of microbes, simply because it is much longer than all the others.

Our results confirmed the existence of a kind of "Wallace line," but we found something much more surprising: each finger and its corresponding key were characterized by approximately the same microbial community. We were also able to determine the owners of a computer mouse with an accuracy of up to 90% using the microbial profile of the palm. 7
N. Fierer et al., “Forensic Identification Using Skin Bacterial Communities,” 107, no. 14 (April 6, 2010): 6477–81.

The microbial community on your hand is very different from similar communities of other people (in terms of species diversity - an average of 85%), which means that each of us, in addition to the usual ones, also has microbial fingerprints.

We went further and conducted experiments to find out how many times you need to touch an object to leave a distinct microbial trail. This study is still too incomplete to be used in court. But television has, let’s say, more simplified standards of evidence, so shortly after we published an article on this topic, another episode of Crime Scene Investigation: Miami was shown, where the plot was based on a forensic examination of a microbial fingerprint 8
"Crime Scene: Miami": " CSI Miami Season 9,” Wikipedia, http://en.wikipedia.org/wiki/List_of_CSI:_Miami_episodes#Season_9:_2010.E2.80.932011 .

Meanwhile, forensic microbiologist David Carter moved from Nebraska to Hawaii to set up a “body preserve” there. "What it is?" - you ask Forensic scientists often face the task of determining how long ago the death of a person whose corpse they examine has occurred. In the "reserve" of Carter, the bodies of the dead donated by relatives and various institutions are stored in various conditions. 9
For a very educational and entertaining introduction to the "garden of our body" see: Mary Roach, Stiff: The Curious Lives of Human Cadavers. New York: W. W. Norton, 2004.

And scientists are constantly analyzing the rate of their decomposition. At the same time, a striking continuity of microbial communities is observed. Just as colonies of lichens appear first on a bare rock, then, in succession, mosses, grasses, weeds, shrubs, and finally trees, the decay process also proceeds in a certain order.

Jessica Metcalfe, a postdoctoral fellow in my lab at the University of Colorado at Boulder, set up her own miniature “body sanctuary” using forty dead mice (they died in other cardiovascular and cancer drug experiments). Jessica found that she could correctly determine the time of death to within three days. This is about the same error as the currently used insect method. 10
Meagan B. Gallagher, Sonia Sandhu, and Robert Kimsey, “Variation in Developmental Time for Geographically Distinct Populations of the Common Green Bottle Fly, Lucilia sericata (Meigen),” Journal of Forensic Sciences 55, no. 2 (March 2010): 438–42.

Why then do we need a microbiological method?

Answer: insects still have to find the dead body, while microorganisms are always there, and this can be useful in cases where there are no insects at the crime scene.

Nose and lungs

The next point of our tour of the body will be the nose. Certain types of microbes live in the human nostrils, including Staphylococcus aureus ( Staphylococcus aureus), which causes staph infections in hospitals. Thus, healthy people seem to often be the “home” for dangerous microbes. We believe that in this case, the explanation may be as follows: other bacteria living in our nose do not allow Staphylococcus aureus to take over, or rather, take over the nose. Another interesting observation: the environment strongly influences what kinds of microorganisms settle in our nose. Children with a more diverse nasal microbial population, such as those living in rural areas near animals, are less likely to develop asthma and allergies in the future 11
O. S. Von Ehrenstein et al., “Reduced Risk of Hay Fever and Asthma Among Children of Farmers,” Clinical and Experimental Allergy: Journal of the British Society for Allergy and Clinical Immunology 30, no. 2 (February 2000): 187–93; E. von Mutius and D. Vercelli, “Farm Living: Effects on Childhood Asthma and Allergy,” Nature Reviews Immunology 10, no. 12 (December 2010): 861–68.

It turns out that tinkering in the mud is sometimes useful.

Going down into the lungs, we usually only find dead bacteria. 12
E. S. Charlson et al., “Assessing Bacterial Populations in the Lung by Replicate Analysis of Samples from the Upper and Lower Respiratory Tracts,” PloS One 7, no. 9 (2012): e42786; E. S. Charlson et al., “Topographical Continuity of Bacterial Populations in the Healthy Human Respiratory Tract,”

The inner surface of the lungs, which is exposed to air, contains a cocktail of antimicrobial peptides: tiny proteins that instantly kill bacteria that get there. However, in the lungs of patients with cystic fibrosis or the human immunodeficiency virus (HIV), dangerous microorganisms are sometimes found that contribute to the development of pulmonary diseases. 13
J. K. Harris et al., “Molecular Identification of Bacteria in Bronchoalveolar Lavage Fluid from Children with Cystic Fibrosis,” Proceedings of the National Academy of Sciences of the United States of America 104, no. 51 (December 18, 2007): 20529–33.

Scientists are still arguing about whether each of us has a separate community of microbes in the throat, or only those microbes that come from the mouth are present there. 14
E. S. Charlson et al., “Topographical Continuity of Bacterial Populations in the Healthy Human Respiratory Tract,” American Journal of Respiratory and Critical Care Medicine 184, no. 8 (October 15, 2011): 957–63.

However, it is already known that the germs from the throats of smokers are different from those of non-smokers, which probably indicates that smoking is not only harmful to ourselves, but also to the creatures that live inside us. 15
A. Morris et al., “Comparison of the Respiratory Microbiome in Healthy Nonsmokers and Smokers,” American Journal of Respiratory and Critical Care Medicine 187, no. 10 (May 15, 2013): 1067–75.

Mouth and stomach

Chances are, you've only heard of the bad bacteria in your mouth—the ones that cause gum disease and tooth decay. One of them, Streptococcus mutans ( Streptococcus mutans), is the same creature that destroys our teeth. It appeared, apparently, in connection with the development of agriculture 16
O. E. Cornejo et al., “Evolutionary and Population Genomics of the Cavity Causing Bacteria Streptococcus Mutans,” Molecular Biology and Evolution 30, no. 4 (April 2013): 881–93.

When the diet of our ancestors was dramatically enriched with carbohydrates, especially sugars.

Another species, Plaut's wand ( Fusobacterium nucleatum), usually present in the mouth of a healthy person, but can also contribute to the development of periodontal disease 17
J. Slots, “The Predominant Cultivable Microflora of Advanced Periodontitis,” Scandinavian Journal of Dental Research 85, no. 2 (January/February 1977): 114–21.

. F. nucleatum is of interest because these bacteria are found inside colon tumors 18
M. Castellarin et al., “Fusobacterium Nucleatum Infection Is Prevalent in Human Colorectal Carcinoma,” Genome Research 22, no. 2 (February 2012): 299–306; M. R. Rubinstein et al., “Fusobacterium Nucleatum Promotes Colorectal Carcinogenesis by Modulating E-Cadherin/BetaCatenin Signaling via Its FadA Adhesin,” Cell Host & Microbe 14, no. 2 (August 14, 2013): 195–206; A. D. Kostic et al., “Fusobacterium Nucleatum Potentiates Intestinal Tumorigenesis and Modulates the Tumor-Immune Microenvironment,” Cell Host & Microbe 14 (2013): 207–15; R. L. Warren et al., “Co-occurrence of Anaerobic Bacteria in Colorectal Carcinomas,” Microbiome 1, no. 1 (May 15, 2013): 16; L. Flanagan et al., “Fusobacterium Nucleatum Associates with Stages of Colorectal Neoplasia Development, Colorectal Cancer and Disease Outcome,” European Journal of Clinical Microbiology & Infectious Diseases: Official Publication of the European Society of Clinical Microbiology 33, no. 8 (August 2014): 1381–90.

But we do not yet know whether this is a cause or a consequence: whether F. nucleatum causes cancer, or is it simply a reaction to the conditions in which the tumor develops.

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Name: See what's inside you. How microbes living in our body determine our health and our personality (2016) RTF,FB2,EPUB,MOBI

Release year: 2016

Publisher: Corpus (AST)

Format: RTF,FB2,EPUB,MOBI

File: SmotriVnytri.rar

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Description of the book "Download for free Look what's inside you. How the microbes living in our body determine our health and our personality (2016) RTF,FB2,EPUB,MOBI"

Rob Knight
Publisher: Corpus (AST)
Series: TED books
ISBN: 978-5-17-091312-1
Genre: Educational literature, non-fiction literature
Format: RTF,FB2,EPUB,MOBI
Quality: Originally electronic (ebook)
Illustrations: colored
The size 10.3 MB

Description: We live in an era of a real revolution in microbiology. The latest technology has allowed scientists to dive into the world of microscopic creatures that inhabit our body and make amazing discoveries in this world. It turns out that microbes, which live in unthinkable quantities in almost every corner of our body, play a much more important role than we previously thought: not only our physical health depends on them, they determine our mood, our tastes and our very personality. We hear about these scientific breakthroughs first-hand: the author of the book, Rob Knight, is one of today's leading microbiologists, creating the science of the future before our eyes.

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Foreword

1. Microorganisms in our body

Leather

Nose and lungs

Mouth and stomach

Description of the book "Download for free Look what's inside you. How the microbes living in our body determine our health and our personality (2016) RTF,FB2,EPUB,MOBI"

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