Tag Archives: d2o effects on life

My #SciFund Proposal (a work in progress)

I just wanted to get this up today. Here is my #SciFund proposal on Google Docs. It is publicly open for comments. I won’t have a rough draft done until later today or early tomorrow so be sure to check back frequently. But in the spirit of open notebook science, I figured everyone deserves a chance to see the evolution in real time.


DDW Effects on Microorganisms

D2O1: Day 5

E. Coli and Yeast Incubation

I’m showing Alex some sterile technique and how to inoculate yeast and e. coli via liquid media and solid (agar) media.

Today we plucked a few colonies of yeast from our starter batch (which may need to be replenished soon) and streaked the cells onto some YPD plates. One plate is in an incubator/shaker at 24C and the other is sitting at RT. We also inoculated a colony in 10mL of YPD.

For the E. coli, we did essentially the same thing, but we are doing 1 plate of LB media (agar) and 1 10mL test tube of LB broth.

Tomorrow we will try for some OD readings, and then we will try to setup time point growth experiments. It should be noted this is all in regular H2O. Right now I want Alex to get familiar with the process and then we will start doing some DDW and D2O studies probably in a couple of weeks.

D2O1: Day 4

D2O1: Day 3

D2O1: Day 2

D2O1: Day 1

RCD: Day 7

Some notes:

  • Sorry for the poor picture quality. I’ll have to figure out something better.
  • I studied every sample and there is exactly one sprout and it is in the sample that has been in D2O for over a month. This is due to one of two reasons: 1) It sprouted before addition to D2O, or 2) there is significant H-D exchange in this sample and the seed eventually sprouted. I’m guessing it is a fluke since there are no other sprouts.

D2O1: Day 0

Some things to note:

  • all D2O mixes are mixtures between D2O and DDW
  • SMOW (Standard Mean Ocean Water) is 15mM D2O
  • 1% D2O is 37.5 times more D2O than SMOW so figure ~562mM D2O
  • Because of an unforeseen sunburn (which probably was foreseen by someone) I didn’t get to keep on my schedule. So these were in the fridge until today, a full week after setup. I’ll keep an eye on the sprouting to make sure that everything proceeds as normal, but this may be a throw away experiment.
  • Also, recall that there was a mishap with the 20% D2O sample. There is a huge air bubble in there and that might negate this sample.

D2O effects on tobacco seeds setup (D2O1)

Didn’t expect that one did you? The purpose of this experiment is to study a much more narrow range of D2O mixtures based on the RC experiments. We want to determine if there is some amount of D2O that maximizes growth in tobacco seeds. If there were it would be somewhere between none and 5% in my opinion, and could quite possibly be right at the natural water amount of D2O (15mM).

So this experiment will be setup exactly like the RC experiments but we’ll be tracking length with some software after the images are acquired. Here is how I setup the experiment:

  • There are 8 samples of tobacco seeds and each sample contains 35-42 seeds.
  • The 8 amounts of D2O are:
    • pure DDW (no D2O)
    • standard mean ocean water (15mM D2O)
    • 1% D2O in DDW
    • 5% D2O in DDW
    • 10% D2O in DDW
    • 20% D2O in DDW
    • 25% D2O in DDW
    • 33% D2O in DDW
  • I know the amounts are strange but I figured in following experiments I will do different amounts for a more robust data set.

Below is a table of the amount of D2O and DDW in each sample and the number of seeds in each sample as well:

And here is the setup:

  1. I began by preparing 8 15ml falcon tubes with the water required as shown in the table above. I used a 1mL, 2.5uL, and 100uL pipettemen to make sure the amounts were as accurate as physically possible (for me).
  2. I then setup 8 analyslides and poured the amount of seeds shown above into each sample chamber.
  3. I added the water from the first step to the chambers and then closed them.
  4. I then sealed the chambers with the vacuum grease and placed the samples in the fridge to synchronize their growth. I will remove them on Monday for Day 0 pictures.

It is important to note that there was a mishap with the 20% D2O in DDW sample. As I was closing the slide, about 1/3 of the water and a couple seeds leaked out (clumsy hands). I don’t anticipate much of a problem with the experiment except for the added exposure to atmosphere so at the end of the trial I will probably discount the results from that sample.