An oblong flattened gland located deep in the abdomen is responsible for the release of a hormone which reduces blood sugar. By now it would have been certain that the hormone we are speaking about is "insulin". Insulin is produced by specialized cells namely islets of Langerhans. When there is a disturbance in these cells it leads to variation in blood glucose level. When the islets are destroyed it leads to a condition namely type 1 diabetes. The islet cluster contains a cell type namely beta cell as well. Beta cells are responsible for sensing the blood sugar and release the necessary amount of insulin to maintain normal blood sugar levels. Type 1 diabetes is an auto immune disorder where the body's immune system mistakenly attacks and destroys its own cells because of which body can no longer produce insulin and hence cannot convert food into energy for the body's cells. Pancreas not only aid in maintaining blood glucose level but they also produce certain pancreatic juices which aids in digestion .Hence in type 1 diabetes although islets cells do not produce Insulin pancreas work normally with other function. In Type 2 diabetes patients there is lowered insulin production level in the body and it is normally seen in middle aged people and old aged people with various causes ranging from genetic to environmental ones like obesity.
In the absence of insulin production there is build up in blood glucose. Insulin is a mediator which provides the fuel for cells activity by transferring blood glucose to the cell and thus activating a series of signaling pathways. Since in the absence of insulin, cell is deprived of energy it results in expression of some of the symptoms like fatigue, infections, decrease in eye sight, numbness, increased thirst, and delayed healing of bruises or cuts. Our body in most of the cases has an alternative, and start utilizing the fat deposit as a source of energy which results in accumulation of toxic ketone bodies. It is clear from the fact that insulin is required by our body to keep all the vital organs safe and performing in our body. Thanks to the advancement in the field of Biotechnology, we are now able to produce insulin using the bacterial cells.....
It was in 1921 when the Canadian scientists Fredrick G. Banting, Charles H. Best, J.J.R. Macleod and James B. Collip discovered insulin and isolated the protein form dog's pancreas. The journey thus started continue and people were able to isolate and purify insulin from bovine, but the major setback was our body was able to sense it as a foreign and produced immune response making the hormone non functional. The vast researches in the area lead to the artificial synthesis of the hormone by the 1980's progresses and scientists. Scientists discovered the gene responsible for the insulin production on chromosome 11 and decoded the amino acid sequence of the protein insulin. This revolutionized the concept of insulin production!!!!
It is now possible to produce insulin in lab by using a common bacteria namely Escherichia coli. The amino-acid sequencing is fed with the known data of insulin protein sequence and machine synthesizes respective DNA. The insulin gene is a protein consisting of two separate chains of amino acids, an A above a B chain, that is held together with bonds. The insulin A chain consists of 21 amino acids and the B chain has 30.These two chains can be synthesized separately by splicing the long gene into two mini-genes: one that produces the A chain and one for the B chain, in an amino acid sequencing machine. These two DNA molecules are then inserted into plasmids which are introduced to E.coli bacteria through a process of transfection next to marker lacZ gene which aids in selection of the bacteria who have successfully taken up the insulin DNA and later also used to find and cut, allowing the insulin to be readily removed so that it does not get lost in the bacterium's DNA. The advantage with E.coli is it has a short generation time of 20 minutes and hence a huge population of bacteria is produced in a very short span of time. After the cells have multiplied in the huge fermentation tank they are taken out of the tank to broke open out and isolate the Bacterial DNA . The bacterium's DNA is then treated with cyanogen bromide a reagent that splits protein chains and separates the insulin protein from the DNA. Thus obtained proteins are then mixed together to undergo a reduction-reoxidation reaction to conjugate the A & B chains. Thus obtained protein is then purified further through chromatographic techniques.
Thus after a complete quality testing and with a manufacturer specific conjugation protein isulin, the first genetic pharmaceutical product is released. There is a vast research going on to improving the insulin peaking hours by conjugating the protein that aids in systematic release of the hormone. The hope is very widened up with work going on insulin pump devices, drug delivery options, aerosol and others in order to make Diabetes seem as a deficiency and not a disease.
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