On September 3, 1928, when the British scientist Alexander Fleming returned from his vacation, when he walked into the laboratory, he had no mental preparation to make a discovery that shocked the world. Prior to this, Fleming had been conducting research on Staphylococcus aureus. Staphylococcus aureus is a common pathogenic bacteria that can cause a variety of infections. There have been reports that Staphylococcus aureus may produce mutant strains after long-term cultivation. Fleming tried to verify the above point. So before going on vacation, Fleming did not wash his bacterial culture medium, but piled them up indoors, intending to return for another observation. While Fleming inadvertently inspected these moldy culture media, a strange phenomenon caught his attention: around the colonization of a mold, the arrogant Staphylococcus aureus receded. The bacteria are still big and special. This illustrates the simple fact that this mold must secrete a substance that inhibits S. aureus. Witnessing this situation, Merlin Price, the former assistant of Fleming who came to chat, said: You did n’t find the lysozyme in the same way at first! (1921, Fleming inoculated his snot in the medium , Found lysozyme) Fleming extracted the mold and purified it and cultivated it in a new medium. Soon, he discovered that this mold can produce substances that kill pathogenic bacteria. This mold belongs to Penicillium genus, so in the paper published by Fleming on March 7, 1929, this bactericidal substance was named "penicillin" (penicillin). The prestige of penicillin is now pervasive, but at the time, the discovery of penicillin did not receive enough attention. The extraction of penicillin is difficult, the bactericidal effect is unclear (experiments show that its effect does not seem to be fast), and whether it can exert an effect against bacteria after being applied to the human body is not clear. In addition, Fleming was the first person to discover that Staphylococcus aureus developed resistance to penicillin. This discovery undoubtedly also undermined Fleming's confidence in penicillin. Fleming is a microbiologist rather than a chemist, and he is not able to isolate, purify, and prepare penicillin. Fortunately, chemists at Oxford University appeared in due course. The Penicillium in the hands of Ernst B. Chain and Howard Florey was taken from Fleming's strain. After the separation and purification of penicillin, it was found that penicillin performed very well in animal experiments. And this is already 1940. The World War II was fierce. The infection on the battlefield prompted the military to have greater determination and financial resources to invest in the research of antibacterial drugs, which enabled the rapid development of penicillin. Penicillin is a β-lactam antibiotic. These antibiotics all have a β-lactam ring and a sulfur-containing heterocyclic ring. Penicillin can bind to the penicillin-binding protein on the cell surface, preventing certain enzymes from functioning, thereby inhibiting the synthesis of mucins by cells, which is the main component of the cell wall. In other words, penicillin exerts its antibacterial effect by destroying the cell walls of bacteria. Human cells have no cell walls, so penicillin does very little harm to humans. For the first time in history, humans have antibiotics that are effective against pathogenic microorganisms. Today, in many novels that traverse the body, from time to time we can see the fantasy of modern people carrying penicillin back to the past to save the world. The meaning of penicillin to humans cannot be overstated. Handheld Water Light Meter,Water Light Meter,Handheld Meter,Portability Water Light Meter Yanbian Nabalu E-commerce Co., Ltd. , https://www.nabalubeauty.com