October 04, 2016 at 02:25AM

Today I Learned: 1) Qiagen midiprep kits* come in at least two varieties, which use mostly the same reagents but different columns. I also learned that you can buy columns, which are, as far as I can tell, by far the limiting reagent in the kit. That makes buying midis much, much cheaper. *these are kits for extracting plasmid DNA from medium-sized numbers of bacterial cells. For small numbers of bacterial cells, you use a miniprep kit; for large numbers of bacterial cells, you use a maxiprep kit. 2) A yearly subscription of Asimov, widely considered the best magazine in short-form science fiction by a fair margin, costs less than $40. Moreover, you can get a pack of old magazines at $15 for 12 magazines. Not to sound too much like an ad here, but I'm rather surprised how cheap sci-fi short stories are if you're not buying them in book form. 3) The tracrRNA in the CRISPR system (which is the bit of RNA that is recognized by Cas9 and causes an associated gRNA to be loaded) has to have the right sequence, not just the right secondary structure. With a few exceptions, chainging the sequence in a structure-preserving way destroys the function of the tracrRNA.