By Chang Ha
Back in April, during the second week of SOHOP (Spring Open House and Overnight Program), I visited the Homewood Campus in hopes of learning something new about Johns Hopkins and its college life. After all the pre-scheduled events , I was finally introduced to my host who was willing to spread his wisdom to us confused souls from his hands-on, “real” college experience.
That was the phrase that I remembered most vividly from his recommended list of classes. From the whole list of suggested classes, the word “Phage” and “Hunting” stood out the most for various reasons. (And one class NOT to take: with professor *CENSORED*.)
“That’s the name of the class?” or “That doesn’t sound too official” or “That actually sounds quite interesting” came to my mind as I was thinking about what kind of class it could be.
Here I am now, writing this blog post. I am usually very indecisive, but I can say this one thing with full confidence and determination.
This is the best class that I have ever taken in my life. Hands down.
At the first day of class, I was provided with a brand new lab coat. Wearing that white, professional-looking garment made me not only motivated, but also very excited. I found myself feeling motivated to do work – which was unthinkable.
Wow, I am actually in a college lab.
Then, we were introduced to the pipettes, goggles, all the other sterile equipment which were at our disposal. Then I watched the professor demonstrate how to use the pipette with an aseptic technique. Then she discarded the pipette.
She discarded the pipette
The simple act of throwing a piece of equipment into a trash bin came to a shock. I then realized that this is college laboratory, not an hour-long, boring, and grumble-inducing high school chem lab anymore. We cared that much about the actual result than simply imitating a lab experience.
This was my first impression from the first few days of phage hunting which left me with confidence that I will like this course throughout the whole semester.
I then began my journey to hunt for phages.
I collected my soil sample just outside of my dorm in hopes of finding plaques. I made sure that the soil was not too dry or too damp (for some reason I believed that that would change the result of the experiment). I then brought the sample to the lab and did “Direct Plating” and went through the “Enrichment” process.
For direct plating, we flooded our soil sample with Phage Buffer solution and plated it directly onto the agar dish.
Sadly, no plaque.
Well, it was hard for me to confirm that, because I initially had absolutely no idea of what I was looking at. For me, (at that time) the “good plates” were supposed to contain several holes, and the “bad plates” were not supposed to contain holes. Mine had no holes.
Instead, my plate was contaminated. The content of the plate was cracked, smelled nothing like the M. smeg (bacteria that we were using to grow phages) but instead smelled something closer to E. coli (or the professor said so). I then realized that my errors were actually displayed in front of our eyes. I failed to follow the aseptic procedure correctly, and this was the result.
It was as if the agar plate was yelling:
Still clueless, I moved onto the Enrichment process, where I had to filter the soil sample and dilute it into 100, 10-1, 10-2, 10-3,and 10-4 dilutions with the phage buffer. Remembering my error from the previous experiment, I made sure to take extra care in following the standard phage lab procedure and not contaminate my dish with the ‘evil’ contaminants again.
Then I found plaques.
It was one of those few moments where I was genuinely proud of what I have accomplished. I found my plates in pristine conditions with no cracks, and with a number of small blank regions which were nothing close to the regular bubbles that sometimes formed on the plate.
I then moved on to streaking, where I would try to isolate my dish full of beautiful plaques with a series of streaking in order to purify and collect a single type of phage only. After four or five different delightful (yes, delightful) series of streaking, I came to a conclusion that I finally got a single, pure phage.
As of now, I am currently doing a titer assay, a process in which the number of phage in a volume is calculated. Although the process is slow, I am happy to see that my babies (phages are babies) are growing and thriving well under my care.
Overall, the class of phage hunting shed new light on me in terms of how college and real life is different from what I have experienced so far. I am learning rapidly, and am learning a lot of valuable lessons in an effective manner.
It’s hard to believe that I am getting all these valuable experiences in a class that I may not be in, had it not been for my host from the SOHOP event. For that, I thank you very much Hunter.