Week 7: I’ve Been a Busy Bee!

Charlotte B -

Hi everyone!

It has been a very busy week in the lab with a variety of different tasks! On Monday I started by finishing my last plate which included my December and January samples. I was very excited to finish the data collection part of my project (or so I thought) …. When my mentor and I were reviewing the data from all of my plates we noticed that my samples from June and July had VERY high absorbance values. Their absorbance values were above 1.o, whereas all of my other samples had values in the range of about 0.4-0.8. It’s not good to have an absorbance value above 1.0 because it could mean your samples are too concentrated and this could cause inaccuracies in measurements by the spectrophotometer. My mentor said it is entirely possible that pollens collected in the summer do just have much higher protein concentrations, however, to make sure she is going to have me run two more plates next week. The first plate will be the exact same samples again. If the absorbance values are still above 1.0, then I will have to run a second plate where we will dilute the June and July samples even further. We would want to dilute the samples so that we can have all the data fit on a straight-line curve making for easier calculations!

Speaking of calculations, I spent a lot of time on excel this week. Since I’ve never used excel before my mentor started by giving me a couple of YouTube videos to watch about basic excel commands and how to create a graph for the Bradford protein assay. My mentor also helped walk me through doing the calculations for an entire plate of samples. The math is actually a lot more complicated than I expected because there are three different tubes of samples I have to think about and convert between. The first tubes are the original 4 mL tubes that contained only pollen. The second tubes are the smaller 1.7 mL tubes that contained 1350 mL of pollen and 150 mL of NaOH. Finally, the third tubes are my 15:1 diluted samples. Sometimes when I’m doing the math I get really confused about which “tube” of sample I’m supposed to be thinking about! Luckily though, my mentor helped me set up a nice and organized chart to follow so I don’t get too lost. I forgot to take a photo, but I’ll include a picture of one of my data tables next week. Once I got the hang of excel, I was able to finish the calculations for four of my plates! Woohoo!

Additionally, this week I also worked on rewriting the “Problems” section of my project proposal packet. My mentor helped me brainstorm LOTS of potential errors that could be made during a Bradford protein assay. This included not breaking the pollen grains up enough in the bead beater, reading the samples at an incorrect wavelength, interfering substances within the pollen unintentionally reacting with Coomassie, pipetting errors, and contamination due to outside sources. Talking about all the room for error definitely made me realize how important it is that I redo the June and July samples!

I’m writing this blog a little bit earlier this week since I leave for St. Louis tomorrow to attend WashU’s admitted students’ day. I’m very excited! I hope everyone has a great week and thank you for reading!

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Comments:

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    Kristen Sanders
    It sounds like your project is going really well! Excel is incredibly helpful with math like this, but it takes some getting used to, so I'm glad you've had success with it. Have fun at WashU! I'd love to hear more info about it in next week's post (assuming you're allowed to mention things like that).
    Sophia DiPonio
    Hi Charlotte! What a busy week! Sounds like a couple bumps in the road have popped up but you’ve been able to handle them well. Have fun at WashU!
    telsi_c
    It sounds like you've learned a lot this week! I'm excited to see the results from redoing the June and July samples. Have fun at WashU!
    claire_s
    Hey Charlotte! I'm glad things are going well, and it sounds like you're making a lot of progress! How do you determine what wavelength to read the samples at?
    azumi_v
    Hi Charlotte! Glad you were able to learn so many new things and get so much done! Have the best time at WashU
    Charlotte
    Hi Claire! Good question! In its unbound state, Coomassie exists mostly in a reddish-brown form with an absorbance peak around 470 nm. However, when it binds to proteins, the dye stabilizes in a blue form, shifting the absorbance peak to 595 nm which is why we read the samples at a wavelength of 595 nm!
    Charlotte
    Thank you, Sophia, Telsi, and Azumi for wishing me a great trip to WashU! I had the best time. :)
    Charlotte
    Hi Ms. Sanders! Yes, Excel has been incredibly helpful to me! I originally asked my mentor if I could just use my calculator, but I am now realizing how silly of a question that was. Also, I can't wait to share a little more about my trip to WashU in my next blog!

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