Genetically modified bacteria
Encyclopedia
Genetically modified bacteria were the first organisms to be modified in the laboratory, due to their simple genetics. These organisms are now used for several purposes, and are particularly important in producing large amounts of pure human protein
s for use in medicine.Leader 2008 — Fee required for access to full text.
The first example of this occurred in 1978 when Herbert Boyer
working at a University of California laboratory took a version of the human insulin
gene and inserted into the bacterium Escherichia coli
to produce synthetic "human" insulin.
The drug industry has made good use of this discovery in its quest to produce medication for diabetes.Walsh 2005 — Fee required for access to full text. Similar bacteria have been used to produce clotting factors
to treat haemophilia
, and human growth hormone to treat various forms of dwarfism
.Bryant 2007 — Fee required for access to full text. These recombinant proteins are safer than the products they replaced, since the older products were purified from cadaver
s 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.
For instance, the bacteria which cause tooth decay are called Streptococcus mutans. These bacteria consume leftover sugars in the mouth, producing lactic acid
that corrodes tooth enamel
and ultimately causes cavities. Scientists have recently modified Streptococcus mutans to produce no lactic acid. These transgenic bacteria, if properly colonized in a person's mouth, could reduce the formation of cavities. Transgenic microbes have also been used in recent research to kill or hinder tumors, and to fight Crohn's disease
Genetically modified bacteria are also used in some soils to facilitate crop growth, and can also produce chemicals which are toxic to crop pests.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s for use in medicine.Leader 2008 — Fee required for access to full text.
The first example of this occurred in 1978 when Herbert Boyer
Herbert Boyer
Herbert W. Boyer is a recipient of the 1990 National Medal of Science, co-recipient of the 1996 Lemelson-MIT Prize, and a co-founder of Genentech. He served as Vice President of Genentech from 1976 through his retirement in 1991....
working at a University of California laboratory took a version of the human insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....
gene and inserted into the bacterium Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
to produce synthetic "human" insulin.
The drug industry has made good use of this discovery in its quest to produce medication for diabetes.Walsh 2005 — Fee required for access to full text. Similar bacteria have been used to produce clotting factors
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
to treat haemophilia
Haemophilia
Haemophilia is a group of hereditary genetic disorders that impair the body's ability to control blood clotting or coagulation, which is used to stop bleeding when a blood vessel is broken. Haemophilia A is the most common form of the disorder, present in about 1 in 5,000–10,000 male births...
, and human growth hormone to treat various forms of dwarfism
Dwarfism
Dwarfism is short stature resulting from a medical condition. It is sometimes defined as an adult height of less than 4 feet 10 inches , although this definition is problematic because short stature in itself is not a disorder....
.Bryant 2007 — Fee required for access to full text. These recombinant proteins are safer than the products they replaced, since the older products were purified from cadaver
Cadaver
A cadaver is a dead human body.Cadaver may also refer to:* Cadaver tomb, tomb featuring an effigy in the form of a decomposing body* Cadaver , a video game* cadaver A command-line WebDAV client for Unix....
s and could transmit diseases. Indeed the human-derived proteins caused many cases of AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
and hepatitis C
Hepatitis C
Hepatitis C is an infectious disease primarily affecting the liver, caused by the hepatitis C virus . The infection is often asymptomatic, but chronic infection can lead to scarring of the liver and ultimately to cirrhosis, which is generally apparent after many years...
in haemophilliacs and Creutzfeldt-Jakob disease
Creutzfeldt-Jakob disease
Creutzfeldt–Jakob disease or CJD is a degenerative neurological disorder that is incurable and invariably fatal. CJD is at times called a human form of mad cow disease, given that bovine spongiform encephalopathy is believed to be the cause of variant Creutzfeldt–Jakob disease in humans.CJD...
from human growth hormone.
For instance, the bacteria which cause tooth decay are called Streptococcus mutans. These bacteria consume leftover sugars in the mouth, producing lactic acid
Lactic acid
Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3...
that corrodes tooth enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...
and ultimately causes cavities. Scientists have recently modified Streptococcus mutans to produce no lactic acid. These transgenic bacteria, if properly colonized in a person's mouth, could reduce the formation of cavities. Transgenic microbes have also been used in recent research to kill or hinder tumors, and to fight Crohn's disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
Genetically modified bacteria are also used in some soils to facilitate crop growth, and can also produce chemicals which are toxic to crop pests.
Bacteria-synthesized transgenic products
- InsulinInsulinInsulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....
- Hepatitis hej B vaccine
- Tissue plasminogen activatorTissue plasminogen activatorTissue plasminogen activator is a protein involved in the breakdown of blood clots. It is a serine protease found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown...
- Human growth hormoneGrowth hormoneGrowth hormone is a peptide hormone that stimulates growth, cell reproduction and regeneration in humans and other animals. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior...
- Ice-minus bacteriaIce-minus bacteriaIce-minus bacteria is a common name given to a variant of the common bacterium Pseudomonas syringae . This strain of P. syringae lacks the ability to produce a certain surface protein, usually found on wild-type P. syringae...
- InterferonInterferonInterferons are proteins made and released by host cells in response to the presence of pathogens—such as viruses, bacteria, or parasites—or tumor cells. They allow communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors.IFNs belong to...
Further reading
- Karl Drlica Understanding DNA and Gene Cloning: A Guide for the Curious, 4th Edition ISBN 978-0-471-43416-0.