Eating too well at night may lead to diabetes, working late at night may cause cancer, heart attacks often occur in the early hours of the morning, and most of the most serious industrial accidents in human history occur in the early hours of the morning… All of these are tricks of the biological clock. Therefore, the health enlightenment of
the Nobel Prize in Physiology is that the annual Nobel Prize in Physiology has been promulgated. The American scientists Jeffrey Hall, Michael Rosbash and Michael Young discovered the “control of the circadian rhythm”. The molecular mechanism of the company” was awarded. If you don’t understand what this means, then you can put it in layman’s terms that these three scientists are actually studying “clocks”, but they are not studying those that can be bought, worn on your hands or hung on the wall. Clock, but the biological clock ticking in our body.
How does the “clock” tick around?
The biological clock is a wonderful physiological function. The day and night of animals and the spring and autumn of plants are already known biological clock phenomena. The fatigue of traveling across time zones and the sleepiness of night shifts are the most direct feelings that the biological clock brings to us. Although the phenomenon of biological clocks is very common, for a long time, scientists did not understand the tiny clock hidden in the body, where it was, and how it ticked around.
In order to find this clock, scientists have stripped the adrenal glands, pituitary gland, thyroid, and pancreas of the animals in animal experiments, or applied electric shock, and even drunk these animals with alcohol. Exhausted means, the animal’s biological rhythm remains unchanged. It was not until the 1970s that scientists removed the suprachiasmatic nucleus located in the hypothalamus of the mouse and found that the biological rhythm of the mouse finally disappeared. Scientists then realized that the main biological clock of humans and other mammals is the suprachiasmatic nucleus. Take people as an example. In daily activities, although the internal organs and skin of the human body cannot be light-sensitive, the suprachiasmatic nucleus can feel the intensity of external light through the eyes, thereby generating “clock timing” and adjusting the circadian rhythm.
Subsequently, scientists further discovered that the biological clock phenomenon does not necessarily require the participation of the brain, it is a biological rhythm phenomenon that can be completed in a single cell alone. For example, cyanobacteria, the simplest prokaryotes on earth, also have their own biological clock. Cyanobacteria obtain energy from sunlight through photosynthesis, and use carbon dioxide and water to produce organic molecules and oxygen. Under the action of the biological clock, cyanobacteria can start photosynthesis in advance before sunrise. This feature allows them to absorb energy as soon as the sun appears, which is one step ahead of those organisms that rely solely on light to initiate photosynthesis. After sunset, the photosynthesis of cyanobacteria will also be shut down in accordance with the instructions of the biological clock, which prevents its own energy from being wasted at night, and the energy saved can be used to repair DNA damaged by the sun during the day.
Although the mechanisms that humans and cyanobacteria regulate their own biological clocks are very different, our circadian rhythms and cyanobacteria have some similarities. This shows that the biological clock phenomenon is a very important basic survival skill formed during the evolution of life on earth, and it must be regulated by biological genetic material. As a result, scientists began to look for clues to the biological clock from genetics. So far, scientists have discovered biological clock genes in a large number of species, from bacteria to fruit flies, and then to humans. Many of these genes are named with “Clock” (meaning clock) and “Per” (short for Period). , Meaning period) and “Tim” (short for Timeless, meaning eternal) and other words.
The three Nobel Prize winners explained to us how genes set up a clock system for living things from the perspective of fruit flies. In the 1980s, Jeffrey Hall, Michael Rosbash and Michael Young found two proteins in the body of Drosophila, named Per and Tim. The Per gene and Tim gene code for Per and Tim respectively. The genes of these two proteins, the latter is also sensitive to light. At night, the Per gene encodes Per protein, which increases the content of Per protein. When the Per protein accumulates more and more in the cell, it will react with the Tim protein, and then inhibit the coding activity of the Per gene. During the day, Per protein is degraded by cells, and the content will become less and less. At this time, the inhibitory effect of it and Tim protein on Per gene will be weakened, so the content of Per protein will recover again at night. In this way, the oscillation period of Per protein level is exactly 24 hours, synchronized with the circadian rhythm. Although the mammals to which we humans belong are more complicated, the mechanism of the internal clock in cells is similar to that of fruit flies. Two proteins called Clock and Bmal1 interact to establish the periodic rhythm of human cells. It can be seen that only by relying on molecular materials such as genes and proteins, nature has built an accurate clock.
The body clock is like a band
Scientists have told us that there is a master biological clock in the suprachiasmatic nucleus of the human brain, which controls the circadian rhythm of the human body, and the Nobel Prize winner has told us that a single cell in the human body can assemble a single cell with only genes and proteins. Basic biological clock. This shows that there is more than one biological clock inside the human body, but a group.
If you compare this group of biological clocks to an orchestra, then the main biological clock of the suprachiasmatic nucleus is the “chief conductor” of the orchestra, and the biological clocks of each part of the body are the “members” who play different instruments. These “team members” are located in the liver, kidney, spleen, pancreas, heart, stomach, esophagus, muscle, skin, and even small cell tissues, and specifically control the activities of each organ and tissue. For example, the circadian clock in the liver regulates the production of sugar molecules in the liver and the release time of sugar molecules into the blood; the retention and release of sodium, potassium, and chloride depend on the commands of the kidney’s circadian clock; before dawn, the heart’s circadian clock genes Sends a signal to the heart to remind it to prepare for the body’s awakening, so heart disease often strikes at dawn…
The “environment” of the “team members” is different, and the way to regulate the periodic rhythm of the organs is not exactly the same, but It must be coordinated through the “commander-in-chief” to make the human body function smoothly. Scientists have done experiments. If the cell tissues in various organs of animals are cultured in vitro, the cell tissues will not show the biological clock phenomenon even if they survive. However, the basic biological clocks of individual cells in these tissues (genes, protein content) The periodic oscillation) is still there, but the cycle of the biological clock of each cell is different, so it is impossible to form a whole that can express the biological rhythm. Subsequently, the scientists put the suprachiasmatic nucleus cells in the culture environment, then the biological clock phenomenon will appear in these cell tissues, which shows that the suprachiasmatic nucleus can coordinate the biological clocks in the various organs of the body. Experiments on mice have also confirmed this. In mice whose suprachiasmatic nucleus has been damaged, the circadian rhythms between different organs have gradually become chaotic. However, if the suprachiasmatic nucleus is replanted, the rat can make some organs The biological clock cycles become synchronized.
So in the human body, how does the “commander-in-chief” contact the “team members” everywhere in the body so that they can coordinate with each other? Scientists believe that there are two ways. First of all, the suprachiasmatic nucleus is a part of the human brain. It is full of nerve cells. They can convey time information to the whole body through nerve fibers that are connected to the whole body. Secondly, the suprachiasmatic nucleus can also transmit time information to another part of the human brain called the pineal gland. The pineal gland periodically secretes a substance called melatonin according to the rhythm of the suprachiasmatic nucleus. This hormone enters the blood and recirculates throughout the body, acting like a “timer”, reporting to each organ and even each cell what time it is. However, only our body can understand the time information conveyed in our body. These time information cannot enter our consciousness, nor can we know the time of day from the cycle of the biological clock. For example, if we wake up in the dark, if we don’t look at the watch, we cannot know whether it was day or night. It is even more impossible to know the specific points.