Sunday, May 28, 2017
Reflection For Week of May 22-26 -- Genius Hour Update #3
Phew, a lot has happened this week, and all of it has been interesting! First, when I came back from the weekend and looked at my mini plates to see if the bacteria had grown blue, they had not! Given that the methylene blue (MB) was supposed to kill the bacteria and it appeared that the bacteria were actually metabolizing it, I decided it would be good to test this phenomenon again. I made up two plates with half of the agar blue and half of it normal, and one plate (accidentally, BECCA!) that was more of a marbled look. I then put blue bacteria from my original MB resistant plate on one of the half-and-half plates, blue bacteria from my original MB stock plate on the other half-and-half plate, and stock bacteria from the tube on the marbled plate. When I checked after 24 hours, all of the bacteria had grown on any agar that was without MB. When it came to bacteria growing on the MB, however, results varied. The resistant E. coli had grown a bit on the MB agar, but none of the stock bacteria had grown on the MB agar, regardless of whether it was from the tube or from the original MB stock plate. I am not sure as to why this happened. It is the original desired result, but it’s weird that it didn’t happen originally, and only worked on the stock bacteria this time. I will keep researching and see if I can think of anything that differed in this trial from the last one. At 72 hours, the results were the same on the two half-and-half plates, but the growth on the marbled plate had changed. Not only did it now have mold, there were also now big and large colonies all over the plate. Each colony was a different shade of blue, depending on the amount of MB available for it to pull up in the agar. The colonies in the dark blue part were very blue, whereas the ones in the lighter blue area were lighter blue. Even the colonies that grew in a basically normal agar grew with a blue tint, because they drew MB from the agar close by, I’m assuming. This confirmed that the bacteria seem to be somehow metabolizing the MB. When researching why/how they might be doing this, I found an article that said they may be reducing MB into a colorless form. I’m a little confused as to why/how they are doing this since MB was supposed to kill them...but I will keep researching. In the meantime, I also made a liquid environment for my bacteria to see if we can see anything further with that. I added MB to one of the flasks, and it would be amazing if I showed up Monday to find the liquid clear, or at least a lighter shade of blue. Lastly, today I tried to do an oil immersion in order to better see the E. coli, but wasn’t able to see anything. I repeated the procedure with stock bacteria from the tube and was successful, so I will try it again on Monday with the blue bacteria, this time somehow suspending it in liquid, because that worked well with the stock E. coli.