After receiving my MS in Biology at Idaho State University, I came to Iowa to complete a PhD. After two years in a great program, I left. Partly because I just didn't have the time to devote to my studies. As the father of 6 children, I felt I needed to spend more time focusing on my young family rather than ignoring them in order to further my own desires. I probably could have stayed in and finished with a mediocre thesis but I have too much respect for the degree to have done that. I write this because I have seen so many people come out of graduate programs with doctoral degrees that really didn't deserve them. Case in point. We have a post-doctorate fellow in our lab who has been with us now for 7 months. I still have to remind her to write in her lab notebook. My boss asked me to teach her how to column purify protein. I first had her transfect a flask of HEK 293 cells (a well established kidney cell line) with a DNA construct containing our gene of interest. The cells would then use their machinary to produce our protein. The protein was engineered to have what is called a histidine tag expressed with our protein. This enables us to purify our protein by running the cell lysate over sepharose beads that have Cobalt attached to them. Cobalt and histidine form a chemical bond which allows you to keep your protein of interst bound to the beads while everything else just passes on by. After washing the beads a number times to remove anything that is bound in a non-specific manner, you can then elute your protein of interest by washing the beads in a solution containing Imidizole and if the Voodoo king is smiling on you, you will have purified protein. Anyway, this is a fairly long and drawn out proceedure. After guiding our Post-doc through the proceedure, having her run the samples on a polyacrylimide gel, and then staining the gel with silver to see the protein, I was pleased to see the elution profile I had predicted for her. I then told her that since the silver stain was non-specific, I wanted her to run the gel again, transfer the proteins to a nitrocellulose membrane and probe the membrane with an antibody specific for our protein. I told her that if we saw the same profile, we could be assured that we had pulled off the purification. She looked at me blankly and said, "How can we do that? There is no his-tagged protein in that solution." I stared at her for a moment, not really sure what she meant, but assured her that this is what we needed to do. She again told me that wouldn't work. I was still scratching my head. She informed me that she had done the entire experiment with a solution from a non-transfected flask of cells. She tried to tell me that this was a good negative control. I continued to stare at her not believing what I was hearing. Why would you even try to purify a protein that you knew wasn't there in the first place? That is not a good negative control - especially since we got a result.
I find it hard to believe that someone with a PhD in the biomedical sciences never once thought to question me or the procedure. The difference between a PhD and a lab tech is that a PhD is supposed to be able to think critically. This Post-doc has yet to rise above the level of a newly minted lab tech. I am sure she will eventually but it is getting tiresome waiting.
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3 comments:
So, did the person whom you write about look at the post, make a mean comment and then delete it?
That was a fairly blunt posting. I hope this person did not read it.
Dad Clark
It was Michelle. She was being a goof.
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