Science Buddies: "Ask an Expert"

Hello
Right now I am still not able to see what I am heading up with the ideas of what I want to experiment on so I was thinking that now I want to shine the UVB reptile lamp on berries and some other food to see because of antioxidants in berries does UVB damages its DNA.

Hi,

You could UV-irradiate blueberries but what would that prove? What would you compare it to?

You need to use a single type of organism like yeast. Then you can add whatever you want to the culture and irradiate the cells with UV for various lengths of time and measure the size of the DNA. This would make a great project with a clear hypothesis ("Blueberry extract protects yeast from UVB") and repeatable experiments. You have to do repeats in order to test your data statistically. That is how it has to be done scientifically.

When is your project due? Are you running out of time?

Think about this and let us know. We'll help you with whatever you want to do.

Sybee

Hello
Thank you for the suggestion but I can not culture anything and I can't use microorganisms but I could use bread yeast. I wanted to UV irradiate blueberries and canned tomatoes and then use the comet assay silver stain to see if the antioxidants in blueberries help protect them from not damaging by radiation and I will compare it to canned tomatoes and irradiate them as I believe that radiation will damage the tomatoes DNA but not blueberries as they have the antioxidants. So basically I want to test that "Does antioxidants really protect us from UV radiation or any type of radiation?"

You should use yeast.

Tomatoes are as high in antioxidants as blueberries and UV irradiating them would probably not result in more DNA damage--there might even be less than in blueberries: http://www.whfoods.com/genpage.php?tnam ... ce&dbid=44

Another thing--UV does not penetrate anywhere near as well as X-rays. If you shine UV on a blueberry it will only affect the outer layer. You will have to mash the berries into a smooth mixture and irradiate them in a thin layer no more than 3 mm deep. UV will not penetrate the mixture very far because it will be scattered by all the particles.



Sybee

How would I use yeast if u cannot culture it.

Just buy some bread yeast, add a measured amount to some sugar water, put 5 mL or so into a Petri dish with or without antioxidants and expose it to UVB for a certain length of time. You can use different amounts of antioxidant and different exposure times as one of your independent variables. You will have to do some reading and thinking about this to come up with concentrations and exposure times.

After you have done all the treatments and exposures, go have lunch and come back in an hour or so and extract the DNA from the yeast. Once you have the DNA you can store it in the refrigerator at 4 C for several days until you are ready to run it on the gel.

This is not 'culturing' anything. It is just an experiment with harmless bread yeast!

Sybee

Thank you so much.

Hi,

Just wanted to check back with you to see how your project is progressing. We spent a lot of time planning your experiments and having to use alternatives when you were unable to do a procedure. Did you succeed in working with yeast? This was a really interesting project and I would like to know what happened.

Thanks,

Sybee