I defended my thesis in April, and turned in my dissertation at the end of May, but I haven't left my grad lab yet. Here's what I've been up to, and what's coming up next.
First I'm wrapping up some things. I've been revising and polishing two papers (one is done and submitted, the other will follow shortly), doing a few experiments for my last project, and getting things ready to hand off to the next person.
Most of my dissertation work was about watching the motions of one protein, TcpP, that is involved in the pathway for producing cholera toxin in Vibrio cholerae. Cholera toxin is the compound (a protein complex) that makes you so very sick if you contract cholera. TcpP (along with another protein, ToxR) activates the transcription1 of the toxT gene. The ToxT protein activates transcription of the cholera toxin genes.
Aside from its role in cholera toxin production, TcpP is interesting because it (and ToxR, too) is bound to the inner membrane of the bacterium. In order to activate transcription, TcpP and ToxR must bind to the DNA, but somehow they manage to do this without leaving the membrane. Since DNA tends to be compacted into the center of the cell2, it's pretty remarkable that two proteins on the membrane can find a specific region of DNA and bind to it. There aren't many proteins that bind DNA while bound to a cellular membrane, but there are a few besides these two.
To learn more about TcpP and how it pulls off this trick, we labeled it with a fluorescent protein and watched it move around the cell. My part of this project is done. Another grad student will watch ToxR move around to learn more about how these two proteins interact. So I'm updating my index of data files, checking that any protocols I've revised are up to date, and commenting the Matlab code I've written that he might use for analysis.
My other dissertation project was a collaboration with my labmate Jess, who has been studying fluorescence enhancement by plasmonic surfaces. I've been learning about plasmon-enhanced fluorescence for years, and it still seems a little bit sci-fi to me: by shining light on metal nanoparticles, you can create an enhanced electric field that makes fluorescent molecules shine brighter and longer.3 Jess has been enhancing fluorescent proteins using nano-structured gold surfaces. A while back we began pairing my fluorescently labeled bacteria with her plasmonic surfaces, to see if we can get enhancement inside live cells. We had some success [$] with our initial experiments, and the project has grown from there. Just because my dissertation is done doesn't mean this project is, though. I've been busy with experiments and trouble-shooting throughout June, and Jess will carry it on after I leave.
My last week as a Biteen lab member will not be spent in lab, but at the Single-Molecule Approaches to Biology Gordon Research Conference in Italy. I like the GRC conference style, and I can't wait to hear all the latest and greatest research in the field. It doesn't hurt that the conference is at a resort in Tuscany, either.
After the conference, it's time for vacation. My husband will meet me in Italy, and we'll tour parts of Italy and Germany and visit some friends of mine from my time as an exchange student. Then it's back to the States so my husband can get back to work and I can enjoy a couple of weeks of unemployment (and prepare for the next job).
Mid-August I start my new job. For the next year, I will be a visiting instructor at Lyman Briggs College at Michigan State. (Yes, I'm going to be an adjunct.) I'm excited to move to Briggs: the program is interesting, the faculty I've met have all been delightful people, and this job feels like the right thing for me right now.4 Briggs students take science classes that emphasize active learning, and "HPS" courses (history, philosophy and sociology of science) that give them context for science in their lives. As I said to several people while interviewing, Briggs is the kind of place I'd have loved to attend as an undergrad. I'm delighted to teach there. It's gonna be great.
1: transcription: just like you can talk about transcribing text, i.e. copying words from one place to another, we talk about transcribing genes: copying nucleic acid "words." The nucleic acids are slightly different—DNA is copied into RNA—but both kinds of nucleic acid "words" are the instructions for building proteins.
The process of decoding RNA to protein parts is called "translation." Again, it's just like text, translating from one language (e.g. French, or, in the case of genes, nucleic acids) to another (e.g. English or, for proteins, amino acids). Stitch those translated words together, and you get functional sentences (or proteins!).
2: In eukaryotic cells, such as your own human cells, DNA is stored in the cell nucleus. Bacteria don't have nuclei, but they still keep their DNA kind of bundled up in the middle.
3: It's more complicated than that, but that's the general idea.
4: It's a one-year position, and that suits me fine. My long-term goal is still to get a tenure-track position or a permanent position off the tenure path—I want more certainty in my employment than adjuncting is likely to supply. For the next year, though, I'm very happy to teach at Briggs.
A one-year appointment also means I will go through the whole job application process again this fall. Yay