By Marissa Totten
Phage Hunting Lab: (after hearing a presentation by Dr. Fisher last summer, I knew this was) the class I wanted to take more than any other at JHU . . . the list of biology classes on the university’s website just had to remind me of that. Even though I may have almost forgot to sign up for it, the important thing is that I didn’t.
Being the dork that I am, I went out searching for the perfect dirt sample the day after Dr. Schildbach sent out his email. I wanted something unique, something exciting, something disgusting. The answer to all that? The Hudson River; honestly, who really knows what’s festering in that water? There had to be some undiscovered phage lurking on the banks of this cesspool. To be fair, I wanted to represent both ends of the spectrum of this river, so I got a soil sample from a normal plant growth area and another from the most disgusting stagnant water I could find.
Thanks to the failure of direct plating, I am currently forging ahead with my more disgusting sample and lately, as expected, the phage have been nothing but difficult. All was going fairly normal up until we started streaking. No matter how isolated the plaque I chose to streak was, two morphologies kept continuously popping up, leading me to seven rounds of streaking before I finally had a pure population.
Now many, many, many, many dilutions later I still have not gotten a web plate that will allow me to get to my HTL (high titer lysate). These phage just won’t behave. During my second round of MTL (medium titer lysate) dilutions I had successful acquired a web plate from my 10-3 dilution. So I went on to plate six more of that dilution. But of course, things just had to get weird. All I got out of that batch was half a web plate and five other plates with a wide range of plaque concentrations. Next: the “perfect web plate” calculations. The result of plating those? Contamination. Everywhere. Some kind of yellowish brown organism that left brown fluid all over the place. Fighting back comic disbelief, I quietly re-plated the dilution calculations. The result of that? Still more contamination. I really don’t know where it’s coming from. At this point I feel like a little kid playing chutes and ladders; getting almost all the way to the top, but then landing on square 87 and having to slide all the way down to square 24.
Even though I don’t really say that much and despite all that hassle, this is without a doubt my favorite class. I love spending so much time in a lab and using the lab equipment (diluting has been committed to muscle memory). I’m sure I’ll be looking at my phage soon enough.