The Results Post- cryo protection:
As you can see from the picture above, the environmental bacteria, after incubation, displayed a great deal of growth. You can compare the bacteria with the one in previous blogs: the color, colony formation, and characteristics are identical! This proves that cold is a good method to preserve bacteria. Also, note how the bacteria on the bottom of the picture is growing rampant. However, it is important to notice that it is not growing in the presence of our bacteria, on the top of the picture. This indicates that one of the two bacteria has an antibiotic property.
ELISA
This test uses the theory of how antigens and antibodies react in order to test for the presence of the HIV virus in different samples (1,2,3, and 4). An antigen is an antibody generator. It is a protein, a carbohydrate, (etc.) that signals the production of antibodies when an unidentified substance is present within the body. The antibodies are created to kill the antigen present; they also remain within the body to kill the antigen if it is ever present in the body again. IN FACT, this is how vaccines work! Vaccines dump huge amounts of antigens into the body. Then, the body creates antibodies against them. Once this production takes place, the person no longer has to worry about getting the specific illness (unless, of course, the virus mutates) because the body now has a set of antibodies to fight it off.
As stated previously, the ELISA uses antibodies to detect the presence of HIV virus. Antibodies are present within a specific serum. The HIV antigen (GP 120) is reacted with the antibody serum provided in the experiment. After, a sheep enzyme is also added. This enzyme binds to Human Ab (a human antibody) creating a blue color. This color appears because there is a blue substrate attached to the sheep enzyme that is visible when it reacts with Human Ab.
The procedure:
1. To execute this experiment, first we added 15 micro liters of the antigen to each of the wells using a pipet.
2. After letting the antigen sit for 5 minutes, we dumped out the solution and patted the wells dry on a stack of paper towels. After, we used a pipet to add wash buffer to each of the wells. We dumped the buffer out and patted the wells dry with paper towels once again. This procedure was executed twice.
3. After, we added the antibody serums! In the first 3 wells, we added 50 micro liters of positive control. In the next 3, we added 50 micro liters of a negative control to each well. These were used to compare the results with our unknowns (1,2,3, and 4). Finally, 50 micro liters of 1,2,3, and 4 were added to wells 7,8,9, and 10 respectively.
4. These were then left to sit for 5 minutes; after, we used the wash buffer again, executing the same procedure for washing found in step 2.
5. Next, 50 micro liters of the secondary antibody was added to each of the wells. After sitting for 5 minutes, they were also rinsed using buffer solution (using the same procedure found in step 2).
6. Finally, we added 50 micro liters of the substrate into each of the wells. If a blue color appears the test is positive for the HIV virus.
The results:
Luckily, only the positive control had a blue color present. This means that none of the unknowns (1,2,3, and 4) have the HIV virus within them. How does this work? The blue color appears when the secondary antibody binds to the Human Ab antibody. Human Ab is a component of the HIV virus (along with an antigen). Because the HIV virus was not present in the samples, the secondary antibody had nothing to bind to. Thus, the blue substrate could not be released.
Food Purity
This next exercise was a "technique of immunology" that we used to test for food purity. To do this we had to make numerous wells in the agar plate provided. We then filled them with various solutions to see how the substrates would react with one another.
Antibody - Antigen Reaction in Agar:
We had to make wells in the agar medium and fill them with selected solutions. In this experiment, we made 4 wells that were placed in a "Y" formation. The 4 solutions were 1) Bovine Albumin, 2) Goat Anti-horse Albumin, 3) Goat Anti-bovine Albumin, and 4) Goat Anti-swine Albumin. A white line will appear if the samples react with each other. We will observe this in the next lab.
Testing for Food Purity:
This test can be used to determine food purity in hamburger meat. A raw hamburger extract was made for our experiment. It is going to be tested with Goat Anti-horse Albumin, Goat Anti-bovine Albumin, and Goat Anti-swine Albumin. Depending on the results of the reaction, we will be able to determine if the meat is contaminated (based on the reactions with a particular antibody).
Join us next time for results!
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