② Increase the permeability of bacterial plasma membrane. Plasma membrane is cell membrane, which has the functions of maintaining osmotic barrier, transporting nutrients and excreting wastes in bacteria, and participates in the synthesis of cell wall, bacterial protein, enzymes and DNA. When the cell membrane is damaged, the permeability increases, leading to the leakage and death of important nutrients (nucleic acids, amino acids, enzymes, phosphoric acid, electrolytes, etc.). ) in the cytoplasm of bacteria, it produces bactericidal effect. Such as polypeptides (polymyxin B and thiomycin) and polyenes (nystatin, amphotericin, etc.). ).
③ Inhibition of bacterial protein synthesis. Protein was synthesized by bacterial cells with activated amino acids, mRNA, tRNA and rRNA as raw materials with the participation of many important enzymes. Ribosome in cytoplasm is the site of protein synthesis, and the process of protein synthesis can be divided into three stages, namely, initial stage, extension stage and termination stage. Different antibiotics have different effects on the third phase, some can act on the third phase, such as aminoglycosides, and some only act on the extended phase, such as lincosamine.
④ Inhibition of bacterial nucleic acid synthesis. Bacterial nucleic acids, including DNA and RNA, have the function of regulating protein synthesis. Neomycin, griseofulvin and rifampicin can inhibit or hinder the synthesis of DNA or RNA in bacterial cells. Because it inhibits the synthesis of nucleic acid in bacterial cells, leading to bacterial death.