Yeast Growth at RT in D2O and DI water. Anthony Salvagno. Figshare.
Retrieved 18:10, May 23, 2012 (GMT)
First let me explain the experimental setup:
- This is a carry over from yesterday’s experiment. With the setup here.
- Every hour I took data from the cultures I inoculated. I put 500ul in semi-micro cuvettes to measure in the nanodrop.
- After I take data, typically I store the measured cuvettes at RT on the lab top in a cuvette holder (the cuvettes are sealed with PE caps).
- Originally I did this because I wanted to take a picture to compare the growth after the full experiment was completed, but I noticed with e. coli that the cultures continue to grow at RT, so a picture wouldn’t reveal anything or be accurate.
- After this experiment I decided to use the nanodrop to compare the growth at RT from all the samples (with the more recent samples having less time to incubate at RT for obvious reasons).
Linked above is the results of the experiment with the excel file I used to compile the data.
Now it’s time for some notes:
- Originally I had compared the growth of these samples to the original data. But realized that the comparisons weren’t valid because each sample grew over 5 hours and the samples were independent of each other at this point.
- It is interesting to note that the D2O sample is almost the same in every sample, except in hours 4 and 5 where the growth is more from incubation at 30C than RT (~25C). But even those two data points are almost identical.
- The DI sample has more steady growth in each sample. I should compare these values to what they were when they were removed from the incubator.
I don’t know if this data is useful but I thought it was interesting so I thought I’d share it with the world. If you have any suggestions for this particular experiment let me know (comment, twitter, email, snail mail, etc)!
Based on the results from yesterday I’ll be carrying out the next phase of the experiment. I set up starter cultures to grow in DDW, DI water, and D2O so I can do hourly time points tomorrow starting early and hopefully getting about 7 hours of data (instead of 5 like yesterday).
I had grown yeast on solid media yesterday and got a bunch of colonies today, so I plucked three colonies and inoculated them in the liquid media stated above (YPD broth).
Here is the data courtesy of figshare:
S. cerevisiae growth in DI Water, DDW, 50% D2O, and 90% D2O. Anthony Salvagno. Figshare.
Retrieved 22:01, May 22, 2012 (GMT)
I would say this data is pretty exciting. Unlike the E. coli data (which was all over the place), there is a clear difference in growth rates between the D2O samples and the H2O samples. Also the growth between the DDW and DI (the H2O samples) were almost identical! That’s pretty solid.
Yesterday I created a starter colony of yeast from the lyophilized yeast that I ordered from ATCC.org. Today I’m doing growth in different water types and checking the growth every hour just like the e. coli experiments. Here is my setup:
- Make YPD broth with DDW and D2O.
- the bottles of both come in 100g quantities which means there is 90-ish ml of D2O and 100-ish ml of DDW
- I had 91ml of D2O –> 4.55g of YPD powder
- 100ml of DDW –> 5g of YPD powder
- suspend powder in water types and filter via syringe. DO NOT AUTOCLAVE
- the reason is because of deuterium exchange. The powder is ultrapure and the water is pretty pure itself, so filtering should be just fine.
- To make diluted cultures:
- I have 4 samples: 1) DI water 2) DDW 3) D2O and 4) 50% D2O in 50% DI water
- Put 9ml of each water type into a test tube (except for the 50/50 mix which should be 5ml of d2o and 4ml of di water)
- Add 1ml of starter culture (which is made from DI water)
- put in incubator
- take time points every hour in semi-micro cuvettes using nanodrop. I fill them with 0.5ml of each culture.