Tuesday, January 20, 2009

Transgenic microbes

Bacteria were the first organisms to be modified in the laboratory, due to their simple genetics.These organisms are now used in a variety of tasks, and are particularly important in producing large amounts of pure human proteins for use in medicine.
Genetically modified bacteria are used to produce the protein insulin to treat diabetes. Similar bacteria have been used to produce clotting factors to treat haemophilia, and human growth hormone to treat various forms of dwarfism. These recombinant proteins are much safer than the products they replaced, since the older products were purified from cadavers and could transmit diseases.Indeed the human-derived proteins caused many cases of AIDS and hepatitis C in haemophilliacs and Creutzfeldt-Jakob disease from human growth hormone.
In addition to bacteria being used for producing proteins, genetically modified viruses allow gene therapy. Gene therapy is a relatively new idea in medicine. A virus reproduces by injecting its own genetic material into an existing cell. That cell then follows the instructions in this genetic material and produces more viruses. In medicine, this process is engineered to deliver a gene that could cure disease into human cells. Although gene therapy is still relatively new, it has had some successes. It has been used to treat genetic disorders such as severe combined immunodeficiency, and treatments are being developed for a range of other currently incurable diseases, such as cystic fibrosis, sickle cell anemia, and muscular dystrophy.

For instance, the bacteria found that cause tooth decay are called Streptococcus mutans. These bacteria consume left over sugars in the mouth, producing acid that corrodes tooth enamel and ultimately causes cavities. Scientists have recently modified Streptococcus mutans to produce ethanol.[citation needed] These transgenic bacteria, if properly colonized in a person's mouth, could possibly reduce the formation cavities. Transgenic microbes have also been used in recent research to kill or hinder tumors, and fight Crohn's disease.[citation needed] Genetically modified bacteria are also used in some soils to facilitate crop growth, and can also produce chemicals which are toxic to crop pests.

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