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Louis Pasteur, French microbiologist, chemist, and the founder of modern microbiology. Just as Newton pioneered classical mechanics, Pasteur pioneered the field of microorganisms. He was also a scientific giant.

Pasteur conducted a number of exploratory studies throughout his life and achieved significant results. He was one of the most accomplished scientists in the 19th century. He spent his life proving three scientific questions: (1) Every fermentation is due to the development of a microbacterium. This French chemist discovered that heating can kill the annoying bacteria that make beer bitter. of microorganisms. Soon, "pasteurization" was applied to various foods and beverages. (2) Every infectious disease is the development of a microbe in an organism: Pasteur saved the French silk industry by discovering and eradicating a bacterium that attacked silkworm eggs. (3) The virulence of infectious microorganisms can be reduced under special cultivation, turning them from germs into vaccines for disease prevention. He realized that many diseases were caused by microorganisms and established the germ theory.

Louis Pasteur is praised by the world as "the most perfect person to enter the kingdom of science." He is not only a theoretical genius, but also a person who is good at solving practical problems. His two papers published in 1843 - "Study on the Phenomenon of Twin Crystals" and "Crystalline Morphology" - pioneered the study of the optical properties of substances. From 1856 to 1860, he proposed a new theory of the nature of fermentation based on the metabolic activity of microorganisms. The "Records of Lactic Acid Fermentation" published in 1857 is a classic paper recognized by the microbiology community. After 1880, he successfully developed various vaccines such as chicken cholera vaccine and rabies vaccine. His theory and immunization methods caused major changes in medical practice. In addition, Pasteur's work successfully saved France's struggling winemaking, sericulture, and livestock industries.

Pasteur is considered the most important figure in the history of medicine. Pasteur's contributions spanned several disciplines, but his reputation centered on his defense and support of germ theory and the development of vaccinations against disease.

Pasteur was not the first discoverer of germs. Before him, Kirula, Henry Bao and others had put forward similar hypotheses. However, Pasteur not only enthusiastically and bravely put forward the theory about germs, but also proved the correctness of his theory through a large number of experiments and convinced the scientific community. This was his main contribution.

Obviously the cause lies in bacteria, so it is obvious that only by preventing bacteria from entering the human body can we avoid getting sick. Therefore, Pasteur emphasized that doctors should use disinfection. Joseph Hinst, who proposed to the world the use of antisepsis in surgery, was influenced by Pasteur. Toxic bacteria enter the body through food and drinks. Pasteur developed a method of sterilizing beverages, later called pasteurization (heat sterilization).

When Buster was 50 years old, he focused his attention on malignant carbuncles. It was an infectious disease that harmed livestock and other animals, including humans; Pasteur proved that the cause was a specific bacterium. He injected animals with an attenuated form of the bacterium Bacillus carbunculus.

In 1881, Pasteur improved the method of reducing the virulence of pathogenic microorganisms. He observed that animals that had suffered from a certain infectious disease and recovered were immune to the disease in the future. Accordingly, sheep and chickens were immunized with attenuated anthrax and chicken cholera pathogens respectively, and were successfully used. This method greatly stimulated the enthusiasm of scientists. People have since known that using this method can prevent many infectious diseases.

In 1882, Bathod was elected as an academician of the French Academy. In the same year, he began to study rabies, proving that the pathogen existed in the saliva and nervous system of infected animals, and made a live salty vaccine, which successfully helped people obtain rabies. immunity to the disease. In accordance with Pasteur's immunization method, medical scientists created vaccines to prevent several dangerous diseases, successfully eliminating the threats of typhoid fever, polio and other diseases.

When it comes to rabies, people will naturally think of Pasteur’s popular story. In the era when germ theory was dominant, Pasteur did not know that rabies was a viral disease, but he knew from scientific practice that the toxicity of infectious substances would be reduced by repeated passage and drying. He injected rabbits multiple times with rabies medullary extracts containing the pathogen, and then injected these attenuated liquids into dogs. After that, the dogs could resist the infection of normal strength rabies virus.

In 1885, people sent a 9-year-old boy who was badly bitten by a mad dog to Pasteur for rescue. After hesitating for a while, Pasteur injected the child with the above-mentioned extract with a very low toxicity, and then Then gradually inject the more toxic extract. Pasteur's idea was to develop resistance to rabies before the incubation period passed. As a result, Pasteur succeeded and the child was saved. In 1886, he also rescued another 15-year-old shepherd boy, Joupillo, who was seriously bitten while rescuing a companion who was attacked by a mad dog. The sculpture that now records the boy's heroic deeds and Pasteur's great achievements is located in the Pasteur Museum in Paris. Outside the institute. Pasteur, who invented the rabies vaccine in 1889, also pointed out that the pathogen was a "filterable supermicroorganism" that could pass through bacterial filters.

Pasteur's most famous achievement is the development of a technology for vaccinating people. This technology could make people resistant to the terrible disease rabies. Other scientists applied Pasteur's basic ideas to develop vaccines against many serious diseases, such as typhus and polio.

It was he who conducted many more experiments than others and convincingly explained the production process of microorganisms. Pasteur also discovered the phenomenon of anaerobic life, which means that certain microorganisms can survive in an environment lacking air or oxygen. Pasteur's research on silkworm diseases was of great economic value. He also developed a vaccine against chicken cholera.

Pasteur is often compared to the British doctor Edward Jenner. Jenner developed a vaccine against smallpox, and Pasteur's methods can and have been applied to combat many diseases.

In September 1854, the French Ministry of Education appointed Pasteur as the dean of Lille Polytechnic and head of the Department of Chemistry. There, he became interested in the alcohol industry, and an important process for making alcohol is Fermentation. At that time, an alcohol manufacturing factory in Lille encountered technical problems and asked Pasteur to help study the fermentation process. Pasteur went deep into the factory to inspect and brought various beetroot juices and fermented liquids back to the laboratory for observation. After many experiments, he discovered that there was a spherical body in the fermentation broth that was much smaller than yeast. When it grew up, it became yeast.

Soon after, buds grow on the bacteria. After the buds grow up, they fall off and become new spherical bodies. In this continuous cycle, the beetroot juice is "fermented" . Pasteur continued his research and found out that the alcohol and carbon dioxide gas produced during fermentation were derived from the decomposition of sugar by yeast. This process can occur even in the absence of oxygen. He believed that fermentation is the anaerobic respiration of yeast and controlling their living conditions, which is a key link in winemaking.

Pasteur figured out the secret of fermentation. From then on, Pasteur finally became a great microbiologist and the founder of microbiology.

At that time, the French beer industry was very famous in Europe, but the beer often turned sour. The entire barrel of aromatic and delicious beer turned into sour slime that made people grin, and had to be poured out. The wine merchants complained endlessly, and some even went bankrupt as a result. In 1865, the owner of a brewery in Lille asked Pasteur to help treat beer ailments and see if he could add a chemical to prevent the beer from becoming sour.

Pasteur agreed to study this problem. He observed it under a microscope and found that there was a spherical yeast cell in the liquid of unspoiled aged wine and beer. When the wine and beer became sour, There are thin stick-like lactobacilli in the wine. It is this "bad guy" that breeds in the nutrient-rich beer and makes the beer "sick". He put the closed wine bottles in wire baskets, soaked them in water and heated them to different temperatures, trying to kill the lactobacilli without boiling the beer. After repeated experiments, he finally found a A simple and effective method: as long as the wine is placed in an environment of 50 or 60 degrees Celsius for half an hour, the lactobacilli in the wine can be killed. This is the famous "pasteurization method". This method is still used today. The sterilized milk sold in the market is sterilized in this way.

At that time, the brewery owner did not believe in Pasteur's method. Pasteur was not in a hurry. He heated some samples and did not heat others, telling the brewery owner to wait patiently for a few days. Months later, the result was that the heated sample had a pure wine taste when opened, while the unheated sample was already sour.

When Pasteur became a legendary figure in France, the sericulture industry in southern France was facing a crisis. A disease caused a large number of silkworms to die, which severely hit the silk industry in the south. , people asked Pasteur for help again, and Pasteur's teacher Duma also encouraged him to take up this burden.

"But I have never dealt with silkworms!" Pasteur said uncertainly.

"Wouldn't this be better?" Teacher Duma encouraged him.

When Pasteur thought that France lost 100 million francs every year due to silkworm disease, he no longer hesitated. As a scientist, he had the responsibility to save the French sericulture industry that was on the verge of destruction. Pasteur accepted the appointment from the Minister of Agriculture and went alone to Alet, a sericulture-stricken area in southern France, in 1865.

Silkworms suffer from a mysterious disease that makes people feel very uncomfortable when they see it. The sick silkworms often raise their heads and stretch out their legs like cat claws to scratch people; The silkworms are covered with brown and black spots, as if they are covered in pepper. Most people call this disease "pepper disease". Some of the diseased silkworms die soon after hatching, while others struggle to survive until the third or fourth instar, but cannot survive and eventually die. A very small number of silkworms form cocoons, but the silkworm moths that emerge are incomplete, and their offspring are also diseased silkworms. The local sericulture farmers tried every means, but still could not cure the silkworm disease.

Pasteur observed with a microscope and found a small, oval-shaped brown particle that infected silkworms and the mulberry leaves that raised silkworms. Pasteur emphasized that all infected silkworms and Contaminated food must be destroyed and made from scratch using healthy silkworms. In order to prove the contagiousness of "pepper disease", he painted mulberry leaves with these disease-causing particles. Healthy silkworms ate them and immediately became infected with the disease. He also pointed out that the pathogens of silkworms placed in the upper grid of the silkworm rack can be transmitted to the silkworms in the lower grid through the falling silkworm feces.

Pasteur also discovered another disease of silkworms-intestinal disease. The bacteria that cause this silkworm disease live in the intestines of silkworms, causing the entire silkworm to turn black and die. The body is as soft as an air sac and can easily rot.

Pasteur told people that the method to eliminate silkworm disease is very simple. Eliminate diseased moths through inspections, curb the spread of the disease, and use the eggs of diseased moths to hatch silkworms. This approach saved the French sericulture industry.

Pasteur invented many things in his life and made outstanding contributions to biological science and medicine. By chance, he found a panacea for taking chicken.

Chicken cholera is a rapidly spreading plague that is extremely violent. Once chickens raised at home are infected with chicken cholera, they will die in large numbers. Sometimes, people see some chickens that were looking for food just now, but after a while their legs suddenly trembled, and then they fell down and died after struggling a few times. When some peasant women were closing the chicken coop at night, they were still glad to see that all the chickens were dead and lying in a mess in the nest. In 1880, the terrible chicken cholera was prevalent in rural France, and Pasteur was determined to conquer the plague.

In order to clarify the cause of chicken cholera, Pasteur used the culture of pure chicken cholera bacteria as a breakthrough. He tried many kinds of culture solutions. He concluded that chicken intestine was the most suitable breeding environment for chicken cholera bacteria. The vector of infection is chicken feces. He tried many experiments, but they all failed. In confusion and disorder, he had no choice but to relax, stop his research work, and rest for a while.

After a few days of rest, Pasteur began research and experiments again. At this time, they discovered the "New World". He used old culture fluid to inoculate chickens, but the chickens were not infected, as if the cholera bacteria had lost its effect on the chickens. What's going on? Pasteur followed the example and finally discovered that the toxicity of cholera bacteria gradually weakened due to the effect of oxygen in the air. So, he injected a few days', 1 month's, 2 months' and 3 months' worth of bacterial liquid into healthy chicken bodies respectively, and conducted a set of comparative experiments. The chicken mortality rates were 100%, 80%, and 50% respectively. % and 10%. If the bacterial solution is injected for a longer period of time, although the chickens will also get sick, they will not die. The matter did not end there. He used fresh bacterial liquid to inoculate the same batch of chickens again. To his surprise, almost all the chickens that had been inoculated with the old bacterial liquid were safe, while the chickens that had not been inoculated with the old bacterial liquid died. Pure light. Practice has proved that any chicken that has been injected with a low-toxic bacterial solution and then injected with cholerae bacteria that is poisonous enough to cause death will also be resistant, and the disease will be mild or even have no effect at all.

The method to prevent chicken cholera has been found! This accidental discovery led Pasteur to confirm the principle of attenuated disease immunity, which led to his idea of ??creating a vaccine against anthrax. Although the British doctor Jenner invented the cowpox vaccination method before him, Pasteur was the first person to consciously create a successful immune vaccine and widely use it to prevent many diseases.

“Will, work, and success are the three major elements of life. Will will open the door to your career; work is the path to your career; at the end of this path, there will be success to celebrate your efforts. As a result...as long as you have a strong will and work hard, you will be successful one day." This is a wise saying by Pasteur about success.

Louis Pas-teur (1822-1895) was a famous French microbiologist.

Pasteur was a professor at the University of Lille, the Université Normale de Paris and the director of the Pasteur Institute. During his lifetime, he made significant achievements in research on isomerism, fermentation, bacterial culture and vaccines, thus laying the foundation for industrial microbiology and medical microbiology, and pioneering microbial physiology, which was praised by later generations as "Father of Microbiology".

The first victory

Pasteur was the son of a French tanner and a veteran of Napoleon's army. His family was poor when he was a child. Pasteur was diligent and studious, coupled with his intelligence and artistic talent, he was likely to become a painter. However, he gave up painting when he was 19 and devoted himself to science.

Pasteur was first engaged in chemical research work - on the optical properties of tartaric acid. He experimentally prepared 19 different crystals of tartrate and racemic tartrate. When examining under a microscope, he found that these crystals could be mechanically divided into two categories - left-handed and right-handed crystals. They had the same polarization value but opposite optical rotation directions, thus revealing the "synchronicity" of tartaric acid. The phenomenon of isomerism”.

Pasteur's outstanding achievements in the field of chemistry have been valued and honored. However, he did not limit his sights only to the field of chemistry, but widely applied the principles and skills of experimental chemistry to fermentation problems, thereby opening up a new era in the history of human science.

Towards Glory

Pasteur switched from chemical research to biological research and discovered the selective effect of microorganisms on acids. In the process of studying the problem of wine sourness, it was clearly pointed out that fermentation is the function of microorganisms, and different microorganisms will cause different fermentation processes. It has changed the previous misconception that microorganisms are the product of fermentation and that fermentation is a purely chemical change process. At the same time, Pasteur proposed through a large number of experiments that changes in factors such as environment, temperature, pH value, matrix composition, and toxic substances affect different microorganisms in unique ways. For example, the optimal pH value for yeast fermentation to produce alcohol is acidic, while Lactobacillus prefers a neutral pH value.

Pasteur widely used the principle of microbial fermentation to guide industrial production, created "microbial engineering", and is respected as the "Father of Microbial Engineering".

Pasteur established his academic status in the study of fermentation problems, but he was not satisfied and still struggled at the forefront of scientific experiments because he firmly believed that "scientific experiments" could solve many problems. question is one of the most powerful pieces of evidence. In October 1868, he suffered a cerebral hemorrhage, which left him with tingling and numbness on the left side of his body, and eventually lost his ability to move. During this period, he still dictated a memorandum describing his ingenious experiment-how to detect silkworm eggs that had just begun to be infected with the disease. The final experiment was successful and pure "seeds" (ie, silkworm eggs) could be transmitted. throughout Europe and Japan. What a touching scientific research spirit! It was this spirit that made him a great microbiologist.

Immortal achievements

1. Pasteur denied the theory of spontaneous generation of microorganisms

Fresh food will spoil if left in the air for a long time. and found microorganisms in them. Where do these microorganisms come from? At that time, there was a view that microorganisms were inanimate substances from food and solutions and occurred naturally - the theory of spontaneous generation. Pasteur gave a powerful refutation to those who held this view through his ingenious experiments.

Pasteur designed a goose-neck flask (retort), now called Pasteur's flask.

The flask has a long, curved tube that communicates with the outside air. The solution in the bottle is heated to the boiling point. After cooling, air can re-enter, but because of the long downward-curved tube, dust and microorganisms in the air cannot come into contact with the solution, keeping the solution sterile and the solution can be stored for a long time. corruption. If the bottleneck breaks, the solution will quickly become rancid and a large number of microorganisms will appear. The experiment led to the convincing conclusion that the microorganisms in putrefactive substances came from microorganisms in the air. The gooseneck flask experiment also led Pasteur to create an effective sterilization method-pasteurization.

Pasteurization, also known as low-temperature sterilization, first heats the material required to be sterilized to 65°C for 30 minutes or 72°C for 15 minutes, and then rapidly cools it to below 10°C. This method does not destroy the nutrients, but also kills the vegetative bodies of bacteria. This method invented by Pasteur solved the problem of wine becoming sour and saved the French winemaking industry. The modern food industry mostly adopts intermittent low-temperature sterilization method for sterilization. It can be seen how great Pasteur's achievements were.

2. Pasteur and the germ theory of disease

Starting from the study of silkworm diseases, Pasteur gradually solved the mystery of higher animal diseases, that is, diseases caused by germs , and finally conquered rabies, which had long threatened mankind.

From 1865 to 1870, he concentrated all his energy on the research of silkworm diseases. This study involved two pathogenic microorganisms. After figuring out the cause of silkworm disease, Pasteur proposed reasonable and feasible prevention and control measures, which helped the French silk industry get out of trouble.

Pasteur then concentrated on studying anthrax in animals. He successfully isolated and purified a bacterium from the blood of animals with anthrax (such as cattle and sheep), and confirmed that it was this Germs cause animals to become sick and die. This is the germ theory of animals contracting diseases. However, physicians and veterinarians at that time generally believed that diseases were caused by certain toxic substances produced in animals, and then, perhaps, these toxic substances turned into microorganisms. Later Pasteur also studied the gynecological disease puerperal fever. He believed that the disease was caused by nursing and medical personnel introducing microorganisms from infected women to healthy women, making them sick.

It can be seen that although Pasteur was not a doctor, his contribution to medicine was immeasurable. He laid the foundation for medical biology.

3. Pasteur and Immunology

In addition to studying anthrax, Pasteur also studied cholera in chickens. This disease causes mortality rates in chicken flocks to reach over 90%. After many attempts, Pasteur discovered that this pathogenic microorganism could grow well on a culture medium made of chicken cartilage. A small drop of fresh culture can quickly kill a chicken.

The most fortunate thing about Pasteur's research on this disease is that when certain chickens are inoculated with old, stale cultures, they almost always have only mild symptoms and recover quickly. healthy. When inoculated with fresh, virulent cultures, the chickens were so resistant to the disease that Pasteur had developed acquired immunity to chicken cholera in his experimental chickens. This is comparable to E. Jenner's use of cowpox to produce immunity to human smallpox.

After Pasteur successfully developed a method to prevent chicken cholera, he began to study methods to deal with anthrax. He cultured anthrax bacteria in chicken soup at a temperature of 42 to 43°C. In this way, the pathogen does not form spores, so a non-toxic strain can be selected for vaccination.

Pasteur was the first person in the world to successfully develop an attenuated active vaccine for anthrax, thus saving the animal husbandry from annihilation.

The pinnacle of glory

Pasteur’s research on rabies vaccines in his later years was the pinnacle of his career.

Although rabies was not a common disease, the mortality rate at that time was 100%. In 1881, Pasteur formed a three-person team to develop a rabies vaccine. In the process of searching for pathogens, despite many difficulties and failures, a highly virulent pathogen was finally found in the brains and spinal cords of rabid animals (currently observed with an electron microscope, it has a diameter of 25 nanometers to 800 nanometers and a shape like A bullet-like rod-shaped virus).

In order to obtain this virus, Pasteur often risked his life to extract it from sick animals. Once, in order to collect the saliva of a mad dog, Pasteur knelt at the rabid dog's feet and waited patiently.

Isn’t this noble spirit of dedication that puts life and death aside for the sake of scientific research worthy of learning and praise by our descendants?

Pasteur inoculated the isolated virus into the brains of rabbits for passage. When the rabies virus that had been passaged in rabbit brains for 100 times was injected into healthy dogs, a miracle happened. The dogs did not get sick. , the dog becomes immune.

Pasteur took out the rabies virus that had been passed down many times along with the rabbit spinal cord, hung it in a dry, sterilized hut, allowed it to dry naturally for 14 days and attenuated the virus, and then ground the spinal cord into an emulsifier. , diluted with saline to create the original Pasteur rabies vaccine.

On July 6, 1885, the nine-year-old French child Mestre was bitten 14 times by a rabid dog. After diagnosis, the doctor declared that he had no hope of survival. However, Pasteur gave him a daily rabies vaccine. Two weeks later, the child's condition turned around. Pasteur was the first person in the world to save a life from rabies. In 1888, in recognition of his outstanding contributions, the Pasteur Institute was established, of which he personally served as director.

Pasteur's rigorous and scientific experimental design, his noble sentiments indifferent to fame and fortune, and his dedication to the pursuit of truth regardless of personal safety will remain in our hearts forever.

Pasteur made immortal contributions to microbiology, immunology, medicine, especially microbiology, and is well-deserved as the "Father of Microbiology".