Antibiotics refer to a class of secondary metabolites produced by microorganisms (including bacteria, fungi, actinomycetes) or higher animals and plants that have anti-pathogens or other activities during their life, which can interfere with the developmental functions of other living cells. Chemical material. The commonly used antibiotics in the clinic are extracts from microbial culture fluids and chemically synthesized or semi-synthetic compounds. There are currently no fewer than 10,000 natural antibiotics. The antibacterial or bactericidal action of antibiotics and other antibacterial agents is mainly aimed at killing the mechanism of "bacteria and human (or other animals and plants)". There are four major mechanisms of action: 1. hinder the synthesis of bacterial cell walls, resulting in low bacteria. In the osmotic pressure environment, the expansion and rupture die, and the antibiotics acting in this way are mainly lactam antibiotics. Mammalian cells have no cell walls and are not affected by such drugs. 2. Interact with the bacterial cell membrane to enhance the permeability of the bacterial cell membrane, open the ion channel on the membrane, and let the useful substances inside the bacteria leak out of the bacteria or the electrolyte balance is out of balance and die. Antibiotics that act in this manner are polymyxin and gramicidin. 3. It is used in combination with bacterial ribosomes or their reaction substrates (such as tRNA and mRNA) to inhibit protein synthesis. Antibiotics that act in this manner include tetracycline antibiotics, macrolide antibiotics, aminoglycoside antibiotics, chloramphenicol, and the like.

Introduction

Antibiotics are secondary metabolites of pathogens or other activities produced by microorganisms (including bacteria, fungi, actinomycetes) or higher plants and animals that can interfere with the development of other living cells. Chemical substances. The commonly used antibiotics in the clinic are extracts from the culture liquid of the genetically engineered bacteria and compounds synthesized or semi-synthesized by chemical methods. After the 1990s, scientists expanded the scope of antibiotics, collectively referred to as biopharmaceuticals. It is mainly used to treat various bacterial infections or pathogenic microbial infections, and generally does not cause serious side effects to its host.

Classification

The production of antibiotics varies according to their types. For example, penicillin biosynthesis by microbial fermentation, sulfonamides, quinolones, etc. can be produced by chemical synthesis; and semi-synthetic antibiotics are antibiotics prepared by biosynthesis. Various derivatives made by chemical, biological or biochemical methods for molecular structural modification. According to the chemical structure can be divided into: quinolone antibiotics, β-lactam antibiotics, macrolides, aminoglycoside antibiotics, etc.; according to the use can be divided into antibacterial antibiotics, antifungal antibiotics, antitumor antibiotics, antiviral antibiotics Animal antibiotics, agricultural antibiotics and other microbial drugs (such as pharmacologically active ergots produced by ergot, which have the effect of contracting the uterus)

Discovery history

It has long been known that certain microorganisms have an inhibitory effect on the growth and reproduction of other microorganisms, and this phenomenon is called antibiotic. With the development of science, people finally reveal the essence of antibiotics, find substances with antibiotic effects from certain microorganisms, and call this substance antibiotics, such as penicillin produced by Penicillium, produced by Gray Streptomyces. Streptomycin has obvious antibacterial effects. Therefore, a class of chemical substances produced by certain microorganisms in the course of life that inhibit or kill certain other pathogenic microorganisms is called an antibiotic. Because some of the antibiotics originally discovered have a major killing effect on bacteria, antibiotics were once called antibiotics. However, with the continuous development of antibiotics, antibiotics, anti-chlamydia, anti-mycoplasma, and even anti-tumor antibiotics have been discovered and used in clinical practice. It is obviously not known as antibiotics, and it is more practical to call antibiotics. The emergence of anti-tumor antibiotics indicates that the chemicals produced by microorganisms have the effect of inhibiting the proliferation or metabolism of cancer cells in addition to the effects of inhibiting or killing certain pathogenic microorganisms. Therefore, the definition of modern antibiotics It should be: a chemical produced by certain microorganisms, a substance that inhibits the proliferation of microorganisms and other cells called an antibiotic.

When the British bacteriologist Fleming cultivated bacteria in a petri dish in 1929, it was found that there was no bacterial growth around the colonies grown by Penicillium accidentally falling on the medium in the air. He believed that Penicillium produced a certain chemical substance. Secretion into the medium inhibits the growth of bacteria. This chemical is the first antibiotic found - penicillin.

During the Second World War, Fleming and two other scientists, Flory and Qian En, worked hard to extract penicillin into a material that would be used to subdue bacterial infections. Because during the war, drugs that prevent war-wound infections are important strategic materials. Therefore, the United States put the development of penicillin in the same position as the development of atomic bombs. In 1943, the news spread to China, when Zhu Zongming, a microbiologist who was engaged in scientific research in the back of the Japanese, also isolated penicillium from the mold of the mildew, and penicillin was produced from the penicillium.

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