Recombinant Dna Informative Speech

So now that we know what recombinant DNA is, we are going to look at its purposes.
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Recombinant DNA is used to insert a gene for production of a protein of interest
The production of heat and drought resistant crops can alleviate world hunger around the world.
Production of clotting factors can treat bleeding disorders such a Haemophilia which casues bleeding into the joints and can be life threatening.
Hepatitis B vaccines are made with the help of yeast cells
It is used for the production of insulin which is used for treating diabetes which we are now going to look at in more detail.
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Insulin is an endocrine hormone produced by the pancreas
It helps keep your blood sugars from getting too high (known as hyperglycemia)
and from getting too low ( hypoglycemia)
Diabetes is caused by a deficiency of insulin or by the body not responding to the insulin being made
Insulin is vital for keeping blood sugar levels on track, as hyperglycemia can lead to neuropathy, kidney failure and retinopathy which can lead to blindness.
Patients with type 1 diabetes have a lack of insulin due to the destruction of insulin producing beta cells in the pancreas
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Insulin is composed of two peptide chains which are linked together by 2 disulphide bonds. The B chain is 31 amino acids long making it longer than the A chain which is 21 amino acids long. There is also a disulphide bond within the A chain.
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Insulin molecules can form dimers in solution due to hydrogen bonds between the C termini of B chains. They have the ability to transform into hexamers in the presence of zinc ions. These hexamers diffuse poorly in blood. This results in the slow absorption of insulin which is an undesirable characteristic for manufactured insulin. There’s a way of creating insulin that reduces the chance of forming dimers and hexamers. To do this, lysine and proline residues on the C-terminal end of the B chain are reversed. This doesn’t change receptor binding, maintaining the efficiency of the process.
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To start the process we need to make the DNA to place into the plasmid. DNA is made using the protein sequence on insulin chains A and B. DNA polymerase is used to form the 2nd strand. These double stranded dna fragments are now ready for ligation.
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DNA recombination can now begin.
In step 1, a suitable cloning vector DNA is chosen. In this example, plasmid from an E.coli cell is being used
Step 2 shows the plasmid being cut using restriction enzyme, leaving behind two ‘sticky ends’ which will bond to the human insulin gene in step 3
In step 3, the gene is inserted into the β-galactosidase gene on the plasmid and ligated by DNA ligase.
The plasmids have a tetracycline resistance gene
In step 4, the engineered plasmid is inserted into new bacterium which will divide and start producing insulin.
Tetracycline is added and any bacteria that don’t have the recombinant DNA will be killed off
This insulin can then be harvested and used by diabetics
So we have looked at an example of where bacteria is used to make recombinant DNA. So, what other biological materials can be used? Yeast, a member of Kingdom Fungi, is a eukaryote. Yeast is used to make Hep B vaccines. A part of the Hep B virus gene is inserted into yeast cells. This codes for Hepatitis B surface antigen (HBsAg). The yeast cells multiply and the antigen can then be harvested and purified.
Why do we need to make vaccines and treatments using recombinant DNA?
Well, before now, many vaccines were made using plasma derived. In 1983, HIV, the virus that causes AIDS was discovered. We know now that this is transmitted through blood, however, before this was known, plasma derived vaccines were administered not knowing what blood borne diseases the donor carried. This resulted in patients developing AIDS. This also happened with haemophilia treatment
To avoid this, scientists discovered a way to produce the vaccines without blood donations ie DNA
recombination.