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Week 7: Supercalifragilisticexpialidocious

       As it sounds, this week was another busy week. It’s very strange that I only have a couple weeks left after this. Where has the summer gone?

      I looked over all of my current experiments, including one that had been started twelve days earlier. It was the streaking of the four main strains of putida that we have been using (KG4, KG51, KG152, and KG180) on lept and MSTM + glucose plates. And what it revealed proved interesting. In the lept, all of the oxidizing strains were oxidizing, while in the minimal media, only the KG4 and KG51 were oxidizing.  Similar results also occurred in the light vs. dark experiment. This led us to believe that the gene deleted from KG152, McoA, is solely responsible for oxidation in the minimal media. This brought up questions about the components of both lept and MSTM and how they differ from each other.
      On Tuesday, I got further into the experiment testing different concentrations of lignin by both plating it, and sub-culturing the remaining samples. Because the manganese oxides took awhile to be stripped from the bacteria, it did take the entire day.
      Wednesday was a very exciting day, because we got to take a trip to visit the main campus of OHSU. I met up with the group at the waterfront campus, and we took a tour of one of the labs there. This lab also happened to be the lab where a bunch of other Johnson fellows were housed, so I got to see some of my friends from my program, which was awesome. It was also really cool to see what kind of work they were doing on that side of OHSU. From there we got lunch, where we took the streetcar to some food carts – a true Portland experience. Then we took the tram up to the hill campus, where we met with some students in the graduate program. We took tours of their labs and found out about their projects and graduate school, in general. They were both pretty cool, and so were their projects! Our final activity was a walkthrough of the children’s hospital ending at a meeting with a woman from student services, who told us about the programs there. It was a short talk, and then we were finished. Overall, it was a valuable trip and a good excuse to get out of the lab for a day.
      It was back to work on Thursday, where I checked out my sub-cultures of all four strains in all different carbon sources from eight days before. The results were varied for each strand. Two things were notable, however. The KG152 strain was resisting oxidation in all samples except for the xylan. Also, visually the cellulose wasn’t oxidizing. But when tested with LBB, it showed that it was oxidizing. This brought up some questions about if the manganese was just being oxidized to Mn(III) and not all the way to Mn(IV). From there, I plated out the samples in water and lignin to see how they were growing. My plates from Wednesday were ready to be analyzed, and it looked like there was more growth with manganese, but it was hard to distinguish between the different lignin concentrations. They were all pretty similar.
      Friday brought new tests to marinate over the weekend. From past experiments, we found that the KG152 strain was hardly oxidizing manganese (if at all) in the MSTM media, compared to the lept media. So I broke down the components of both medias to see where they differed. We didn’t think the small amounts of chemicals in the minimal media was the issue, so we tested what components of lept are allowing for more growth. These components were yeast extract and casamino acids, which are a bunch of amino acids that form proteins. So I put together an experiment with the oxidizing mutants in minimal media with those lept components. Along with that, there was also a seminar for all of the interns. It was with graduate students regarding their experiences of the graduate school process. It was very interesting, and it definitely shined a light on something I hadn’t seriously thought about yet. It was extremely useful, and will play into my process of choosing a graduate school, when the time comes.