Lab Skills You Stopped Being Proud Of

Molecular biologists who were in graduate school in the 90’s learned how to isolate plasmid DNA from E. coli cultures by a method called “boil-prep” during their first lab rotation. This process involved mixing the bacterial cell pellet in a little bit of detergent, salt and sucrose, dabbed with some fresh lysozyme, and then you are ready to cook, literally! Bacterial cell membranes are disrupted by boiling this soup in a beaker of water over a Bunsen Burner for one minute, and the debris (containing the broken cell membrane and attached chromosomal DNA) is collected by centrifugation in a microfuge at top speed for 10 minutes. Then comes the step that differentiates a true master of lab skills versus a rotation student—if you knew just the right amount of bacterial culture to begin with and handled the E coli pellet by the right techniques, a skillful lab person could collect nearly all the liquid without disturbing the pellet. Pouring out the plasmid-containing supernatant without dislodging the goo on the side/bottom of the tube was such a desirable skill that would not only give you your plasmid but also give you admiration from fellow lab members. That is, of course, if you were doing it before the mid-90’s, because after the introduction of miniprep spin columns by Qiagen, nobody, even the true masters of boil-preps (or its contemporary alkali prep that also involves pelleting by centrifugation and careful removal of tiny volume of liquids surrounding small pellets) would be showing off those skills any longer.

It is actually never easy or fun to collect liquid surrounding small amount of beads or pellets as you always have to struggle to remove as much liquid as possible while trying not to lose any of the beads

Some of the old-timers used to also be very proud of being able to pour a “sequencing gel” (a very thin ~40 cm x 30 cm polyacrylamide gel). I still remember the first time I reported to the second rotation lab at USC. After describing the lab research, the PI showed me around the lab and complained how “Sarah destroyed all my sequencing gel plates”. But consider this, in order to avoid any greasy spot on either plate, you needed to wash both of them fanatically if not religiously. Why? You would have just about a minute’s time to pour non-polymerized acrylamide without leaking from the sides or bubbles forming anywhere in the DNA running lanes, and then inserting a pair of paper-thin combs, all at a speed quicker than TEMED/AP-catalyzed acrylamide polymerization. Good thing that after capillary sequencing was invented, we all happily retired our sequencing-gel pouring skills with a collective sigh of relief.

Technology will always move forward, so will the skills lab researchers will be required to perfect. Using a spin column is very much a “skill-less” technique in contrast to collecting pellets and washing beads after centrifugation, but when there is a choice, people will chose the method that requires “less skills”, such as the spin-column format as the preferred platform for the new FP-nAb™ products.