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Week 3- The Art of Streaking

This week ended up being pretty short due to a family trip and the 4th of July holiday. I was out of town with my family on Monday and Tuesday. We stayed in Chiloquin, in the Klamath Basin, and fished all day in my dad’s drift boat on the Williamson River. I caught some trout, and it was a lot of fun! I was thankful that my mentor was understanding and flexible so that I could join my family on this trip. Since I was out of town Monday and Tuesday, Wednesday was a pretty busy day! Our to-do list for the day took up an entire sheet of paper, but we got it all done!

We’ve been going through plates like crazy, so on Wednesday I had to make more media and pour more plates. We repeated the carbon source experiment (that I’ve explained in previous blogs) to see if our results were repeatable. This time around, we checked the test tubes more frequently so that we would have a better estimate of when each tube began oxidizing. Thankfully, the tubes oxidized in the same order as they did last time; just what we wanted! The test tube with Pseudomonas putida and xylan (a complex carbon source) started to oxidize before the test tube with P.putida and glucose. From this observation, my mentor and I have a hypothesis that the bacteria oxidize manganese as a way to help it break down complex carbon sources for food. I took plenty of photos, and scrapbooked them into my notebook. I re-streaked my conjugation plates today because it was still too hard to pick out single colonies, even after I diluted the plates last week. My mentor Kati re-taught me her mechanical method of streaking, which is something that just takes practice to master. Lucky for me, I had close to 20 plates, each divided into quadrants, to practice streaking. I also did some more Replica Plating (a process I learned last week) on Wednesday because I needed to move the conjugated bacteria onto plates of a different media where they could begin oxidizing.

On Friday I checked on the plates that I re-streaked on Wednesday and recorded my observations on which mutants had begun showing Mn oxidation. There really wasn’t anything too significant yet, so I will have to wait until Monday to see which mutants oxidize Mn most efficiently. My mentor and I decided that Friday would be a good tidy-up day, but since there was hardly anyone else in the lab to contribute dirty dishes and such, we didn’t have quite enough stuff to fill an autoclave or dishwasher. Oh well, now it is all ready to go for Monday. We did dry out the desiccator in the oven though, so we can check one of our chores off of the list! Next week I have to give a mid-term presentation, along with the other undergraduate interns, about my project thus far. On Friday my mentor and I sat down and she helped me outline what I should include in the presentation. I always benefit from these reflection processes because having to articulate what I’m doing out loud really strengthens my understanding.

That's all for this week. Next week I will embark on the next stage of my project, using the mutants with the random transposon insertion that I made in my conjugation experiment.