The microbiome affects human genes, with gut microbes accounting for about 80% of the total weight and 1.27 kg

Someone is an island, and you are inextricably linked to the microbiome from birthThere are trillions of microbiomes in our bodies, including bacteria, fungi and viruses that live in our skin, genitals, mouth and digestive tractIn fact, human cells are not the largest number of cells in the human body, the number of symbiotic microorganisms far exceeds the number of human cells, the weight of more than 1.27 kg, of which intestinal microorganisms account for about 80% of the total weight of human microorganismsThey are a complex ecosystem, a large society that helps the body shape the digestive system, immune system, nervous system and other parts of the body for the benefit of mankindBut symbiotic microbes can still be self-contained, in order to expand their own interests, in the survival and evolution of the battlefield of cooperation and competition with each otherThey can be our partners, but not always our friendsEven in the most harmonious symbiotic relationship, there is conflict, selfishness and betrayalin the gut symbiotics with the most, microbes can easily switch roles between prebiotics and diseaseMany diseases are now thought to be affected by the gut microbiome, such as cancer, autoimmune diseases, multiple sclerosis and autism spectrum disordersIn addition, some gut microbes can also affect the role of some drugsIn terms of the number of cells, or the number of genes that encode proteins, the microbial community that lives in the body exceeds the human body itselfNow, scientists are thinking: Is there a symbiotic microbe in control of the human body, besides ourselves? Two new research espublished recently by Nature has revealed some of the secrets of gut microbes controlling the bodythe first-ever map of molecular compounds in a mouse's entire organ, and how they are modified by microorganisms, in the article global chemical effects of the microbiome with the microbiome new bile-acid conjugation, , which was published on Nature on February 26, 2020Surprisingly, they found that microbes control a variety of new amino acid modification structures of bile acids in mice, which are also present in humansresearchers analyzed 768 samples from 96 parts of 29 different organs in mice from four sterile mice and four mice with normal microorganisms (SPF)Using mass spectrometry informatics, the researchers identified inactive molecules in each mouse organ and compared the data with the reference structure in the GNPS database, a mass spectrometry library developed by Dorrestein and collaboratorsIn the end, the researchers obtained molecular maps in mice with and without microbesComparing the map found that up to 70% of the intestinal chemistry of mice was determined by their gut microbiomeEven in distant organs, such as the uterus or brain, about 20 percent of the molecules in mice with gut microbes are different from those in sterile micethe researchers went a step further and found a specific molecular family of differences between microbes and mice without microbes, namely bile acidBile acid is mainly produced by the liver of mice or humans, helping to digest the oil and can act as a signal ingenuity molecule to transmit information throughout the bodyThe team found previously unknown bile acid modifications in mice with a normal microbiome, but not in sterile miceUsually the host liver enzyme adds amino acids to the bile acid, especially glycine and taurineHowever, in mice with normal microbial communities, the team found bile acids labeled with other amino acids (phenylalanine, tyrosine, and leucine) but not in sterile mice, suggesting that the microorganisms determined the new amino acid modification of bile acidsThis provides more possibilities for the effects of microorganisms on human healthresearchers were equally curious about whether the human body also had the same type of microbially modified bile acid, creating the Mass Spectrometry Search Tool (MASST) and searching 1,004 mass spectrometry human samples in a common sample setThey also analyzed about 3,000 fecal samples from the American Gut Project, a large citizen science project at the University of California, San Diego School of Medicine, using mass spectrometryThe researchers found that the unique microbial-modified bile acid observed in mice was also found in 25.3 percent of human samples, which were higher in infants and in patients with inflammatory bowel disease or cystic fibrosisbile acid plays a very important role in fat metabolism by transmitting information from the gut to other parts of the body by activating bile acid receptors in the intestines, and negative feedback when activated by bile acid receptors inhibits the secretion of bile acidsIt also helps regulate the levels of triglycerides in the liver and the body fluids in the intestines, and therefore plays an important role in liver disease and obesityMany of the drugs currently being developed also treat liver disease by activating bile acid receptorsThe study found that microbially modified bile acid sirritated the receptor, suppressing the expression of the gene that produces bile acid in the liverThe findings raise additional possibilities for the role of microorganisms in driving the liver and other diseases, as well as affecting the activity of therapeutic drugs, and point a new direction for future drug designs for receptors another article on The Nature on 27 February, Mutational signature in colorectal cancer ford by genotoxic pks s e Using organ-like models, the Ruben van Boxtel and Hans Clevers research groups at the Udlerinstitute's Institute in the Netherlands presented evidence that pathogenic gut bacteria can cause mutations in human cell cancer colorectal cancer has always been one of the most high-profile cancers in the world Intestinal microbes have long been thought to be associated with the development of cancer in colorectal cancer Although previous studies have reported that 60 percent of colorectal cancer patients have a type of E coli (E) in their intestines that can cause genetic toxicity coli), which produces a substance that causes a MUTATION in DNA, colibactin (a group of genes called pks in the E coli genome) Colibactin was able to ennines in the double strands of alkydized DNA in in vitro cultured cells and mouse colorectal cancer models, causing double-stranded fractures and, in turn, DNA damage and cancer But the link between pks and E coli and the mutation sites of human colorectal cells is unclear In this latest study, scientists used organ-like models that simulate the human intestine to study the problem Organ-like organs are mini-versions of 3D organs grown in petri dishes The researchers placed stem cells removed from the intestines in a suitable growing environment, which rapidly reproduces and develops into a mini-version of the intestine, which can reproduce the characteristics of the intestines from the tissue The researchers then injected the cultured intestinal organ cavity with pks plus E coli, and tested e coli, which did not produce the genetic toxin substance, as a negative control through immunostaining tests, the researchers found that pks and E coli can also cause double-stranded crosslinking and DNA double-stranded damage in human intestinal organs After five months of culture of the intestinal organs and the continuous injection of pks and E coli, the researchers sequenced the genome and found that the proportion of single-base replacement in the experiment group injected with pks and E coli increased significantly, with significant T-base replacement (Figure 3) And in the position of the mutated thymus in the upper three bases tend to be 3 adenines These genetic mutations are also present in tumor samples in real patients researchers compared and analyzed the genomes of more than 5,500 tumor samples from the UK and the Netherlands, and found that some of the mutations found in organ-like experiments concentrated in samples of colorectal cancer origin, and that the most common mutations in colorectal cancer were consistent with mutations, deletions and insertions after organ treatment The results suggest that exposure to the pks and E coli, which can produce colibacin, is likely to directly cause a mutation in colorectal cancer This study provides an important reference for further detection of the pathogenesis of colorectal cancer and clinical diagnosis and prevention there are many different Strains of E coli in the human gut, and perhaps more than one strain can secrete substances that cause genetic mutations in human cells, and may need to re-evaluate the function of other strains of secretion and the corresponding E coli probiotics in the future But there is no doubt that the study suggests that the detection and removal of E coli in the gut may help reduce the risk of colorectal cancer in a large number of people more than two studies have shown that microbes can influence the expression of human genes as well as possible genetic mutations This suggests that our genotypes and phenotypes are not entirely determined by our own genes, but may be determined by the genes of other organisms While we still don't know how many microbes can regulate human genes, what effects these regulations can have on downstream genes, or how we can intervene to improve human health, it still offers a new direction for the future treatment of human diseases Research on gut microbiomes has been showing a surge in recent years as evidence mounts on the importance of the gut microbiome for health These studies link the microbiome to a variety of chronic human diseases, and researchers often use experimental animal models to provide evidence of the role of microbiome in chronic diseases However, many causal inferences are difficult to verify in the crowd In the January 23 issue of Cell, Professor Jens Walter of the University of Alberta in Canada published an article reflecting on the study of intestinal flora He believes that many researchers have tried to explain the relationship between host pathology and changes in microbial populations using data from human microbiota-associated (HMA) rodents, but this cross-species inference is unconvincing and exaggerates the role of the gut microbiome in human disease The two articles in Nature, which provide for this, have found corresponding evidence in human samples and human organ models that these microbes can directly regulate human cells or cause mutations, which is enough to prove that gut microbes play an important role in human health research on human microbes, although it has been going on for many years, is still in its infancy, and the effects of microorganisms on humans are likely to be far greater than we thought Both studies, which are shared, describe only the regulation of symbiotic bacteria on human health, but as a symbiotic whole, the effects will be mutual, and our eating habits, hygiene habits, etc can easily affect the symbiotic bacteria on the body Who is the cause and who is the cause of this mutual influence? How many symbiotics are there in us, which are they beneficial and what are they harmful? Or under what conditions is beneficial and under what conditions is harmful? What should we do to live in peace with the symbiotic bacteria in our bodies and achieve a win-win situation? to make us live healthier lives and avoid getting sick? Maybe it's time to reacquaint yourself with the microbes in the body Source: Return, Global Science