The semester is drawing to a close, so I thought I’d share a bit of what’s going on with me…
First of all, after a full rotation in Dr. Stein’s laboratory, I’ve transitioned into Dr. Stewart’s lab. While Stein Lab was very interesting, I think it was a little too genetic for my interests and really didn’t work for me personally. It’s a shame too because all the people there are really doing some important stuff. At any rate, I admit I feel much more at home in Stewart Lab.
Dr. Stewart studies motility and signal transduction. While those two terms may not be familiar to the average reader, they are explained easily enough. Motility is simply the ability to “move.” Bacteria move through a system called “chemotaxis,” where they can sense good chemicals “attractors” or bad chemicals “repellers” in their environment. For example, food might be considered “good” and an antibiotic might be considered “bad.” When they see an attractor they continue to go straight. When they see a repeller, they tumble randomly until they move in a beneficial direction (which activates straight swimming). Their movement is controlled by whether their flagella are moving clockwise or counter-clockwise.
How do bacteria “know” a good chemical from a bad one? How does that information influence the flagella? This is what Dr. Stewart and I are working on. The system for relaying such information is called signal transduction. Receptors on one end of the bacteria recognize components of the environment. Somehow the proteins in the rest of the cell carry signals from the receptor all the way to the motor of the flagella.
While there is a pretty good model for how this works in most bacteria, we have chosen a less widely known Bacillus species, Bacillus megaterium, to use as a model we can visualize with fluorescent markers. Essentially B. megaterium translates to “great beast” in English, which suits it because it is about 5 times larger than E. coli, one of the most commonly used bacteria.
So far I’ve spent my rotation measuring the length of each B. megaterium strain and testing it for motility on a special growth media. Now, after several weeks of little changes here and there, I’ve successfully transformed one of the strains so that it glows green under fluorescent light.
Check back in a little while…I should have an image of said bacterium for your viewing pleasure soon…assuming it’s ok with my PI and all.
[Bacteria Illustration from TreeHugger]