Alexander Fleming was the founder of modern day antibiotics in 1928. “he noticed that a mould had contaminated one of his culture plates of Staphylococcus bacteria. Around the mould was a clear area where no bacteria grew. The mould was Penicillium notatum, and Fleming isolated from it a substance, which he called penicillin.” Although it was not until more than 10 years later when Ernst Chain and Howard Florey isolated and purified penicillin and used live mice to discover the importance of this antibiotic.
There are four many ways in which antibiotics can interfere with bacterial cells, cell wall synthesis, protein synthesis, nucleic acid synthesis and cell membrane synthesis.
Cell Wall Synthesis- “Penicillin, cephalosporin and vancomycin all interfere with the making of bonds that strengthen bacterial cell wall.” The cell walls of bacterial cells are different to those of human and plant cells. Bacteria contain long, linear polymers called peptidoglycans. These antibiotics listed above inhibit the growth and assembly of the peptide cross links, which go towards the make up of peptidoglycans, this results in the wall of these cells being weak and causing the bacterium to eventually explode. The antibiotics must be given at an early stage because they work on the bacterium during synthesis of the cell wall so are only active at destroying the bacteria when it is growing.
Protein Synthesis- The antibiotics in this process interfere with the “protein-making apparatus of bacterial cells.” They connect to the ribosome that oversee the joining of amino acids to form proteins. Protein synthesis is almost the same in mammals as it is in bacterial but there are very slight differences, it is these differences that enable the antibiotics in protein synthesis to know the ribosomes of bacteria are what they need to bind to.
Nucleic Acid Synthesis- Anthracyclines are antibiotics that interfere with nucleic acid synthesis. As mentioned in protein synthesis there is hardly any difference between these processes in bacteria and mammals but the slight difference is all that is needed for theses antibiotics to work on only the bacteria cells. Anthracyclines inhibit DNA synthesis in all organisms, which is useful in destroying cancer cells but always have serious side effects such as damage of hair follicle cells and gut cells.
Cell Membrane Function- Amphotercin B is an antibiotic, which affects the cell membrane of bacteria cells. The antibiotic distorts the lipid bilayer of the cell in turn causes the contents to leak out, ultimately destroying the cell. The process is becoming ever more popular with newly discovered antibiotics.
Biological Sciences Review, May 1999, Pg 18
Biological Sciences Review, May 1999, Pg 19
