We humans have always paid attention to our own health, but for a long time we have ignored the very critical part-the impact of microorganisms on the human body. As a human symbiosis, changes in human colonies often indicate changes in health.
The human microbiota is a biological community of tiny cells that reside in the human body. The human body and the microbial community form an "ecosystem". Only 43% of the human body’s cells belong to humans, and the other parts are composed of microbial cell populations of non-human tissues-from the desert-like skin surface to the microbial tribes on the lips, and micro-towns with microbial colonies in the mouth. Even each tooth is a unique community, and our intestines are a metropolis filled with hundreds of billions of microbes...Each microbe performs its own duties and performs its own responsibilities.
In order to more effectively understand the microbial community tribe in the human body, many microbiological scientists have carried out interdisciplinary research. Professor Rob Knight, a pioneer in the field of human microbiology research, is the director of the Microbiology Innovation Center at the University of California, San Diego, and the initiator of the "Earth Microbiome Project" and the "American Gut Project". Professor Rob's laboratory research involves the study of human, animal and environmental microbial communities and the development of corresponding computing technologies. A large number of microbiological researchers are based on his research results to carry out their work.
Based on his research results to carry out the work
Professor Rob Knight is on the TED stage, showing many aspects of the impact of microorganisms on our daily lives
Micro-ecological diversity is more complex than the earth
The human microbe is a super-complex system, and its ecological diversity even exceeds that of the earth's biological diversity. From the world map, different places have different biological distribution, which reflects the diversified characteristics of different regions. Microbes have a similar distribution, but under the microscope, all microbes look similar.
By observing the DNA of microorganisms to classify, the "Human Microbial Engineering" project draws DNA bases and develops visual computer technology that can transform trillions of sequence data into more intuitive and effective distribution maps. Researchers extracted microbial data from different parts of 250 healthy volunteers. The dense spots represent a certain body part, and different body parts have different microorganisms. The microbial colonies in the mouth and intestine of the same person are worlds apart. Comparing the biological distribution map of the earth, the ecological difference of microbes in the human body is even greater than the difference between hundreds of kilometers on earth.
The distribution map of human microbes is like separate continents
No one can match the number of microorganisms
Human DNA is almost identical. The DNA of you and Passerby is 99% similar, but in terms of the microbes in the stomach and intestines, you and the person next to you may only have 10% similarity.
These different microorganisms each perform different functions, from digesting food to interacting with various diseases and metabolic drugs, and so on. How do they do this? Part of the reason is that their numbers far exceed our own physiological data.
In terms of cell number, there are about 10 trillion cells in a human individual, but there are 100 trillion microbial cells in our body. Their number is 10 times ours.
Compare from the amount of DNA: each of us has 20,000 human genes, while the microbes on the body have 2 to 20 million microbial genes.
So no matter how we look at it, we are far surpassed in number by our microbial symbionts.
When we leave traces of human DNA, the things we touch will also leave the DNA of our microorganisms. You can even compare the information on your palm with the information carried on the mouse you use every day, with a matching rate of 95%.
The microbiome will change with the region, environment, and eating habits
There are about 100 trillion microbes living in the human intestine-they have the function of protecting you from infection, helping digestion and regulating the immune system. However, as the human body adapts to modern life, we begin to lose some normal microorganisms; at the same time, in developed countries, diseases caused by the loss of diversity of intestinal microorganisms are soaring.
Professor Dan Knights, a computer biologist at the University of Minnesota, was studying primate microbes and discovered that the external environment can cause changes in the microbiota.
The researchers tracked and studied two species living in the jungles of Vietnam and Costa Rica, the Vietnamese white-rumped langur and the Costa Rican monkey. Using their feces for DNA sequencing and comparison, it was found that their microbial populations are completely different in different regions. The microbiota in the intestines of wild animals, like lush tropical rain forests, presents complex diversity; while the microbiota of captive animals will gradually converge with other captive primates. The health of the animals in the zoo is not very good. There are problems such as obesity, weight loss, gastroenteritis, diarrhea, and bloating. Some animals can hardly survive. The intestines of captive monkeys are dominated by Bacteroides and Prevotella, which have the same microbiota as the intestines of modern people.
The two monkey populations that grow in the wild have completely different microbial communities. In the zoo, the microbiomes of these two monkeys are converging and becoming more similar, even though they come from zoos on different continents, and their geography and diet are different.
The researchers also studied the microbiota in developing countries and Americans. The imbalance of the microbiota in Americans has led to a significant increase in obesity, diabetes, and other similar diseases. Not only do people who have lived in the United States for several generations have this problem, but also new immigrants and refugees.
After immigrating to a new country, it will cause dramatic changes in the microbiota in the body, which are more likely to lead to obesity and other modern diseases or Western diseases. The researchers investigated two groups that immigrated to the United States from Southeast Asia. After they came to the United States, their microbiota lost about 20%; and those who became obese after immigrating to the United States lost 1/3 of their original microbiota. .
The changes in the microbiota appear on the axis of Professor Dan Knights’s graph. The microbial communities of humans and animals in different regions, the distance between each other indicates the difference between each other
After immigrating to a new country, the microbiota in the body will change drastically, making it more prone to obesity and other modern diseases or western diseases.
Bacteria implantation, cancer diagnosis and health improvement
In recent years, there have been many studies on the correlation between microorganisms and diseases, including inflammatory bowel disease, heart disease, colon cancer, multiple sclerosis, depression, autism, and even obesity.
Obesity has a great impact on health. Now we can judge whether a person is fat or thin only through the microbial colonies in the intestines, with an accuracy rate of 90%, while the accuracy rate of gene sequencing can only reach 60%. It can be seen that the importance of human microorganisms is no less than that of genes.
Professor Rob studies the relationship between microbial communities and obesity. Raised a lot of mice in a sterile film, and then tried to add some more important microorganisms in comparison:
The researchers thought from this that a microbial flora can be designed and added to food to achieve the effect of weight loss.
In order to improve the health of children with Kwasukol’s disease (kallergic malnutrition), the diseased colonies were transplanted to mice, and the mice’s body weight was reduced by 30% within three weeks. Later experiments found that supplementation of peanut butter can quickly recover their children The healthy microbial community of mice can be used to try corresponding treatments on children.
Rob's laboratory has also been exposed to some special cases. For example, C. Diff disease, which is a terrible diarrhea, patients have to go to the toilet nearly 20 times a day, and antibody treatment for up to 2 years has not been effective. Later, some microorganisms were extracted from the intestines of healthy people and implanted into the intestines of patients. All the symptoms of the four patients disappeared one day later, and their flora was more similar to that of healthy people.
In March 2020, Professor Rob and his interdisciplinary team announced a new method of cancer diagnosis in the journal Nature: machine learning methods are used to identify the microbial DNA features in the blood, which can easily diagnose whether a patient has cancer or not. What kind of cancer.
Researchers used the Cancer Genome Atlas database to analyze tumor samples from tens of thousands of cancer patients, covering 33 types of cancer. Through hundreds of machine learning algorithms, only the microbial data in the patient's blood can be used to identify the type of cancer. After testing, this model has a recognition rate of more than 81% to 86% for various cancers. Compared with most cancers that require surgical biopsy to be diagnosed, it is faster, more convenient and cheaper.
The infinite future of microbes
Human microorganisms have many functions. They can help our digestion, regulate the immune system, protect the human body from diseases and produce the necessary vitamins for the human body, and even affect our behavior. The role of microorganisms in affecting human health is something we have never imagined before, and there is still a need to increase the understanding and research on microorganisms.
For example, we know that some people recruit mosquitoes more because of the existence of different microorganisms on our skin. Some microorganisms produce chemicals that are easily detected by mosquitoes. Therefore, can we use some microorganisms to repel mosquitoes?
The microorganisms in a certain fruit fly determine what kind of mates it can attract. This has not been verified in humans. However, Professor Rob believes that the microorganisms in the human body can also be found. They can release the taste of attracting the opposite sex. Do we Can replace certain perfumes accordingly?
All these microorganisms that are not yet known to us, how might they serve mankind in the future?
Let us re-look at the microbes in the human body instead of treating them as enemies as before.
Knowledge link
The first microbial flora of the human body comes from the mother
Although the human body's own genome will not change, the human body's microbiota can be changed.
The micro-organisms in the babies born during the normal birth are basically similar to those in the mother’s vagina. The micro-organisms in the babies born by caesarean section are closer to the microbial flora of the mother’s skin. This may also explain that babies born by caesarean section are more likely to suffer from asthma, allergies, and even obesity. . Mammals are usually born through the birth canal, and thus obtain protective microorganisms that have co-evolved with the mother. Babies delivered by caesarean section lose this protection.
Changes of microbial colonies in infant excrement
Based on the data map of human microbial engineering, Professor Rob observed the changes in the flora of a newborn during the growth of a newborn (as shown in the right picture) by comparing it with the data of 250 healthy adults.
The yellow ball represents the change of the microbial colony in the baby's excrement. Samples are taken every week. On the first day, the baby's microbial colony is similar to that of the mother's vagina. It can be inferred that he is a normal child. Subsequently, the yellow ball moved downward, approaching the adult fecal colony at the bottom. The microbial flora of infant feces changed every week, and the weekly difference was much larger than the difference between adult individuals, and then the magnitude of the difference gradually It becomes smaller until it is close to the adult fecal colony, which takes about two years.
