Hi everyone!

For the last two weeks, I have been continuing to work on my Toluene experiments. Turns out that the results were not as promising as we had hoped since the E. coli conjugates do not seem to be breaking down the Toluene. :-( I have been testing different conditions to see if the toluene will degrade in more stressful environments, and some seem to be working a little better than the others. One possibility is that the original stock solution has been contaminated, since it has been sitting in the refridgerator for a while now. We should probably make a new stock solution on Monday. Hopefully Ruoting and I will be able to find advantageous conditions for the E. coli soon. :-D

Annie

Harry Potter and the Deathly Hallows
5 days. 4 hours. 27 minutes. 07 seconds.

The experiment is working! :-D

I can't believe we're almost half way through these seven weeks! Wow, times goes by really fast. I wish I could have a time machine because I need more time to do my project, haha. Speaking of my project, we finished the first part of it last week. :-D I took measurements of the toluene samples three times a day, and Ruoting took samples to the flow cytometer at UNC to see if horizontal gene transfer between the P. putida and E-coli was occuring. We found that all the bottles, or our "bioreactors," were reacting just as we had expected, except for the ones with E-coli and its conjugate-they weren't degrading toluene. Ruoting and I were very sad. :-( But then, on Saturday, we started a new batch that had lower amounts of toluene, and today, I measured the concentrations, and they went down! That was really exciting. So I'm hoping that the decrease in concentration is due to the E-coli working. Another possibility is that the toluene is escaping from the bottles into the air, but that is very unlikely since they are vaccum sealed. So yay, this week has been really productive, and we might have discovered something! Now I'm going to lunch; I have this McDonald Southern Chicken Sandwhich coupon that I want to use... ;-)

I really liked the AIDS talk that was given last week, and I was shocked that people with salaries over $12,000 couldn't get financial aid for therapies and medicines in North Carolina. Now I have this urge to write a letter to our congressmen about this issue... It'll probably not do any good, but I'll write it anyway. And then we can all sign it! :-)

Hi guys!

This week, I've been prepping for my project, which is the study of transfer rates of plasmids between bacteria in batch bioreactors. A bioreactor (that one is quite complicated-->) is a vessel where environmental conditions like the amounts of different gases, flowrates, temperature, and pH can all be controlled; but for our experiment, we are going to use bottles with vaccum seals instead. Next week, in the bioreactors, we are going to test six different concentrations of bacteria. We have already made triplicates of each combination of bacteria so that if one sample is faulty, then we still have two other ones to study, and we'll study how they're similar to or different from each other, of course. Right now, I have 34 bottles of solutions waiting to be inoculated with the bacteria on monday. I'll come in on sunday to watch my mentor prepare the bacteria so that I can learn how for later; something I've learned this week is that scientific research has no time constraints! Anyway, today, I also have to make a calibration curve comparing different amounts of toluene. The graph will become our standard, and the measurements we obtain from the bioreactors will be compared to the calibration curve. The optimal slope should be .999; hopefully we'll get that number today. My mentor Ruoting told me that I'll be very busy next week with the 34 bioreactors, so I'll be having an extremely productive few days in the lab! I'm really excited to see how the data turns out because we'll be testing to see whether an E-Coli conjugate with P. Putida's plasmid exists.

Have a lovely weekend,
Annie

Toxic fumes and E-coli

Hey,

My name is Annie Chen, and I'm working in Dr. Gunsch's Civil and Environmental Engineering lab this summer. My project is the study of plasmid transfer rates between different bacteria. Plasmids are DNA molecules that can move from one bacterium to another freely. I'm going to be building a bioreactor to manipulate the conditions under which Pseudomonas putida (P. putida) transfers its plasmids to E-coli. The plasmid in P. putida has the code for the degradation of toluene, which is an anthropogenic compound that smells like nail polish remover. Toluene (C7H8 *organic chemistry!* :-D) is released into the atmosphere by the volatilization of petroleum fuels and paint thinners and it also leaches into water during the disposal of fuels. The liquid can cause irreversible brain damage if a person breathes its fumes for extended periods of time. So if you ever see me forgetting where I am and what I’m doing, or fainting, you know what happened. ;-) Hopefully, the results of the experiment will be used in other bioreactors to help degrade toluene more efficiently. Exciting stuff, isn’t it?

This week, I’ve been mostly working in the lab, measuring the concentrations of toluene to see its rate of degradation. Figuring out how often I need to respike the solutions of toluene is very important because the P. putida needs to eat the toluene to obtain nutrients, or else the bacteria will starve! My mentor Ruoting taught me how to use the Gas Chromatograph machine, the autoclave, and the spectrophotometer, inoculate bacteria and make Basal media for the P. putida. Yup, that’s about it. I can’t wait for next week!

À demain, mes amis!

Annie