Thursday, February 17, 2011

Don't Try This in YOUR Lab!!

So after having driving the recruits around the city (it didn't help that I went to be around two the morning of and had to get up at seven thirty), I was very tired, but I still had to do a genomic DNA preparation from my yeast samples.

Here's a bit of background for the lay person.  I am knocking a gene out of the DNA of the baker's yeast, S. cerevisiae.  In order to do this and track it, I replace the gene with a selectable marker.  In my case I am using uracil (something necessary to grow), but other people use antibiotics and a variety of other things.  After knocking out the gene, I streak the yeast on a plate that has everything the yeast needs to grow except for uracil.  So the ones that have my marker can make their own uracil and will grow on this plate.  I then take a single colony of yeast from that plate and innoculate a culture with some of the cells.

The next step is to take out the genomic DNA and make sure what is there is what you wanted to put in.  In some cases, the flanking strands of your favorite gene can match other places in the genome, so if it has integrated in the wrong place, the gene you wanted to knock out will still be there.  And to do THIS I extract the DNA from the cultures I made.

It starts with a centrifuge.  You are supposed to put them in for five minutes to sediment them for collection.  I attempted to put the glass culture tubes in the fuge, but realized that it would not work very well because the lid wouldn't close.  So I transferred my cultures to shorter glass culture tubes and put them in the centrifuge and pressed "start."

The centrifuge usually makes a whirring noise.  As it is speeding up it sounds like a plane trying to reach a certain speed.  And when using these you are supposed to monitor the sound coming from them.  So I stood there and almost immediately the noise of the centrifuge was not right.

The noise:  "KSSHHH!"

I had failed to realize that "swinging bucket" meant if things were in the wrong place, or too high up as the culture tubes are, it would hit the center rotor of the centrifuge.  So now, without further ado:


So as you can see, the centrifuge basically turned the culture tubes to glass dust.  It was teh messy and difficult to scoop out of the pot.  :P

The remains of the tubes.

 So the moral of this story: don't do this.  Ever.  It's not a good idea.

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