The Effects of Garlic Powder on Drosophila Flies with Tumors
A Directed Research Project
To determine if garlic powder had any effect on Drosophila flies that have tumors, an experiment was conducted that lasted four weeks. Furthermore, if the garlic powder did have an effect, the experiment was broken down by different concentrations of garlic powder. Within the first half of the experiment, virgin female flies containing the RET gene (ret proto-oncogene) were collected from Drosophila melanogaster stocks and bred with virgin male flies containing GAL4. Their offspring all had tumors visible on their eyes. The offspring were collected as virgins and separated from their parents. They were placed in containers that had different concentrations of garlic powder and were watched for the remainder of the experiment to see if the tumors changed. Within a few days, it was noticed that the garlic powder did affect some of the flies and that there was no noticeable difference between the different concentrations. More research needs to be conducted to understand the full impact of garlic powder on Drosophila containing tumors.
Tumors are caused when cells don’t go through apoptosis, so instead of dying they just keep replicating and building up. Energy is required for tumor growth, and therefore proteins that contain key growth-promoting functions are what are needed for the controlling of the tumor growth (Gonzalez 2013).
Crossing Drosophila with the RET gene and with the GAL4 system resulted in tumors being expressed in the eyes of the offspring. The RET gene’s (ret proto-oncogene) normal function is to provide instructions for producing signaling proteins inside cells (RET gene n.d.). The RET has other functions that are essential for the development of nerve cells in the intestine (enteric neurons), the autonomic nervous system, kidney development, and spermatogenesis (RET gene n.d.). When growth factor molecules attach to the RET protein, a series of chemical reactions occur that instruct the cell to undergo specific changes. These changes include the dividing or maturing of cells to do specialized functions (RET gene n.d.). The GAL4 system is composed of two components: GAL4 (a transcriptional activator) and a transgene controlled by an upstream activation sequence bound by GAL4 (Elliot and Brand n.d.), which in this case is the RET gene. Through a genetic cross, the RET was activated and a tumor formed.
Garlic has been used for a long time in medicinal practices, especially as a prophylactic and therapeutic agent (Schafer and Kaschula 2014). Research has been done on the extent of garlic’s effects on the body, focusing on how it reacts to cancer, “…garlic has been suggested to have both cancer-preventative potential as well as significant enhancing effects on the immune system” (Schafer and Kaschula 2014). Experiments have been conducted debating the limit of garlic’s effects and if it depends on the type of garlic. Results have been inconclusive, as people have conflicting data. Knowing about the potential health benefits garlic has towards cancer, I wanted to know if generic garlic powder used for cooking would have any effect on the tumors in Drosophila melanogaster, and if it did, does the quantity of garlic powder change the results.
Materials and Methods
Three kinds of Drosophila melanogaster flies were collected from stocks kept by Dr. Yaich. These three were wild-type, vas-RET2B Tm6B (RET), and GMR-GAL4 (GAL4). The wild-type flies were used only as a tool for comparison, and the RET and GAL4 flies were used for experimentation. The first step done was to clear the containers of all the parent flies, which needed to be done when there were plenty of pupa along the sides of the container. Anytime within hours to the next day, the pupa became adult flies and needed to be inspected under the microscope. Using CO2, I could put the flies to sleep long enough to inspect them under a microscope and use a paint brush to separate the males and females. I could tell the difference between the male flies and female flies by using Carolina™ Drosophila Manual (Flagg 2005). The female virgins were collected in separate containers (one for RET females and one for GAL4 females). Once enough were collected, males were added from their opposites - RET females with GAL4 males and GAL4 females with RET males. The RET female/GAL4 male offspring were the focus from this point forward because they possessed the tumors needed for the experiment to continue (See Image 1) and the other offspring never left the pupa state within the required time frame.
Once the Drosophila with tumors were no longer pupa, they were collected and dispersed amongst five different tubes containing McCormick brand garlic powder mixed into Instant Drosophila Medium Formula 4-24 purchased from Carolina Biological Supply Company. Before adding water to the Instant Drosophila Medium, it was measured out to approximately 1.3 grams and mixed with different amounts of the garlic powder. The control group didn’t get any garlic powder, receptacle 1 got .02 grams, receptacle 2 got .04 grams, receptacle 3 got .06 grams, receptacle 4 got .08 grams, and receptacle 5 got 1.0 grams. After the dry ingredients were all mixed together, water was slowly added and mixed together until the food was a good consistency for the flies, and then it was added to the containers. Once satisfied with the food mixtures, the tumorous flies were put into the containers, each one getting about seven flies each. The Drosophila were inspected every day for three days.
After being checked every day for three days, the flies had noticeable, yet gradual, changes. Changes weren’t being noticed until the second day of eating the garlic powder mixtures. Receptacle 1 and receptacle 3 both contained flies that were showing oddities in their tumors. The third day was the final day that data was recorded, and most of the flies seemed to be progressing at the same rate, no matter the difference in the amount of garlic powder (See Table 1). Most of the flies still had tumors, but some looked different than they had before – smaller, oddly shaped, or different colored (See Image 2).
After three days with the garlic powder mixed into their food, the tumorous flies showed clear indications of change. This result demonstrates that there may be some truth behind the cancer-combative speculations mentioned in the introduction of this paper. Although most of the flies showed no change after three days with the garlic powder, there were still flies in every experimental container that showed at least some alteration which means it can’t be completely ruled out either way. Perhaps given more time, all the flies could have shrunken tumors or no tumors at all, or in time their tumors could have gotten worse or not changed at all. More research is needed to find these answers.
Should this data be looked at and, from the small percentage of flies that showed change, the conclusion be that garlic does in fact combat tumors, then the next steps would be to figure out to what extents the garlic works, how it works, and if there are any side effects. Should this data be looked at and the conclusion be that garlic does not have any effect on tumors, the next steps would be to figure out why not and what could be added or changed to get a different result (perhaps cloves of garlic or garlic oil instead?). In either conclusion, more research needs to be done to figure out why only a small percentage of flies changed while the rest remained the same, why they changed at different rates, and why overall the amount of garlic powder in each container had no outstanding differences (with the exceptions of the first container that had four out of seven change and of the second container where a few flies had escaped so there was missing data for that particular container).
There were a few design flaws in this experiment. The first is time. Breeding and collecting the amount of flies necessary to carry out a decent experiment takes a lot of time and when there is only four weeks to conduct an experiment as such, the majority of the that time goes towards the breeding and collecting of the flies, and because they need to be collected as virgins, it all needs to have a fairly planned out schedule of when to clear the parents and when to collect the offspring. Another flaw is the amount of garlic used. I picked five tiny amounts of garlic I thought would work best, but there could have been more amounts, both lesser and greater than the ones used. Perhaps different results would have come from more variety. The last flaw is common error. The CO2 I was using to keep the flies still while looking at them under the microscope ran out as I was collecting their data, so a few escaped towards the end of the experiment. Another error was that the opposite cross’s offspring never became adult flies within the duration of my experiment, so I was unable to conduct the same experiment with them to compare against.
Were I able to do this experiment all over again, the steps I would take would be to carry it out again the way I did for this one, but give it more time to find out how time affects the results. In addition to that, it would be interesting to see what would happen if the amounts of garlic powder were lesser or greater than the amounts used in this experiment. Also, it would be interesting to see how the offspring of the tumorous flies (whether they be ‘cured’ or still tumorous) turn out, and if they too are tumorous, then whether the garlic powder would affect them the same way as their parents.