It all sounds very complicated, but in practice is quite easy. For the research I am doing, I am measuring acetylene reduction activity by an enzyme (nitrogenase) present in certain bacteria, in my case, a bacterium that lives in a symbiotic relationship with plants. Acetylene is a gas with the formula C2H2; the nitrogenase enzyme "reduces" acetylene to ethylene, a gas with the formula C2H4. After injecting a measured amount of acetylene into a vial containing the plant/bacteria symbionts, the vials are set aside to allow for photosynthesis and acetylene reduction to occur over time. At certain time intervals, a small amount of the gas phase is removed from the vials and injected into the GC to measure the relative concentrations of acetylene and ethylene present in the sample.
Below I have scanned in a print-out that I recorded during an acetylene reduction assay that I performed this past Friday. The first peak shown is that of methane gas (CH4), which is apparently present in the tank of acetylene already. The second peak is that of ethylene, the peak in which I am most interested. Finally, the third peak is that of acetylene, which is so large that our graph cannot fully capture it. There are two sets of peaks shown in this print-out. Sorry that the image is so straining on the eyes; the lines on the paper ended up standing out more than the red peaks.
Even though this whole process is very time-consuming, according to my professor/advisor, I had excellent data from my acetylene reduction assay. Apparently the bacteria in my plants are readily reducing acetylene, and increasing with time, a good indicator of the nitrogen fixation activity that the nitrogenase enzyme actually performs. Nitrogen fixation is the process by which nitrogen gas (N2), the largest component of air, is "fixed" by the bacteria into ammonia (NH3), which can be used up by the plants as a nutrient. So, you see, the good results from the acetylene reduction outweighs the amount of time that I spent in the lab.
I can imagine that at least several of you have no interest whatsoever in this information, and may find this information boring and useless. I can admit that it is a little bit boring to read about this stuff; science has to be experienced, not just read. So, believe me when I say that it is much more interesting in practice. Wanna try sometime?
4 comments:
What would you use your findings for? Why is this data important?
I remember doing assays on pieces of steel in a Matalurgy class. While it was not boring, it did not elicit the excitement that you obviously have about these tests. After assay on a piece of steel, it's hardness, tensile strength, elongation, ductility, elasticity and melting temperature were obtained. When a certain steel met an engineers requirements it was then possible to duplicate that steel in larger batches. For example: a known steel is used in a spring that out performs all other springs. Wanting to mass produce the spring would entail making large amounts of the exact steel used in that out performing spring.
The data that I am obtaining correlates with nitrogenase activity of the bacteria. The bacteria fix nitrogen gas from the air into a useful nitrogen source (ammonia) for the plants they live with.
By first getting a baseline measurement of the nitrogenase activity, I will be able to compare my experimental plants to these baseline plants to determine if there indeed was a change in nitrogen fixation activity. For my experiment, I am testing the effects of salt content in the water containing the plants (as the plants grow solely as ferns floating on top of water).
Oh cool!
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