This week I diluted ammonium acetate to be used in as a protein precipitating solution. All DNA is surrounded by a vast array of proteins. There are proteins in the cell walls and cytoplasm as well as chromatin proteins actually in the strands of DNA itself, wrapping the DNA into tightly wound bundles. The proteins can contaminate DNA samples, making tests hard to decipher. So to get rid of proteins and other cellular junk ammonium acetate is added to the solution. This caused the proteins to solidify out of solution, leaving the DNA behind.
This week I also collected some spider web samples to test my extraction process out on. I don't want to use up sources of black widow DNA just to make sure I can get DNA from webs, so I went out and collected samples from other species I could find on campus. I collected cellar spider webs from inside the lab, some abandoned looking web that could possibly have been a widow's web and the web from an orb weaver spider that is found on the chemistry department building. The orb webs were a little yellow in color, which I thought was super cool. The possible widow web might have too many leaves in it to use, but all the samples I collected from the environment had at least one contaminate it it: human hair, cat hair, leaves, dandelion seeds etc. Corri says that most of the contaminates will be washed out while the DNA is being processed, and because the primers we're building should be specific to spider DNA, only spider DNA should be amplified during PCR. We'll see.
Here is a picture I took of an extremely patient spider whose web I collected.
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