Quantifying the DNA...
So we quantified the DNA once I was in the Netherlands. Then we put it on a charged piece of paper called nitrocellulose paper so the DNA stuck to it. Then we just took antibodies and incubated this nitrocellulose paper which now has a DNA sample stuck to it with the antibody. We can't actually see this antibody but what we can do is take what's called a secondary antibody. The second antibody recognizes the first antibody. This antibody has some sort of group on it that you can see, like a dye. While you are doing all this you can't see any of this, you're just sitting there doing your data, hoping this all works. And then you actually see this clearly. Then you actually then see how much of the photoproduct is present.
What's kind of interesting is that in this column and in this column you see the standard curve for damaged DNA so we know exactly how many photoproducts there are in the other columns - apprently none. So, it's possible that they are actually not damaged products, which may be why they're doing excision repair. Maybe they can't repair whatever damage they're getting through photolyase. Or maybe their photolyase is so efficient it's already fixing the damage before we can even see it. We don't know at this point. Maybe we'll try it again next time. But here's science in action, everyone.
Another thing that we started to do in the lab is the comet assay. What you do here is you prepare a microscope slide with the liquid: you embed your cells into the agar. You pour a very thin gel on a regular microscope. At that point you take DNA and damage it. What I'm hoping ultimately is when we take actual samples from nature that are already damaged, if the DNA is actually broken, what you'll see is a little tail. When you put the slide under the current, the DNA will move towards the positive electrodes and the broken bits will will start to escape. Most of the DNA is not damaged. In cells where the DNA is not damaged at all, you're going to see this little round ball where the nucleus was
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