Since this past Friday (Sept 23, 2011) the cooling system at CHTM has been down. I’m not sure if it is turned off for the impending winter or temporarily broken. This means that right now the lab is a toasty 92F and has been that way all weekend long. Unfortunately this can potentially mean a lot with regards to my seed growth experiments. Now I’m not sure if this is actually the case, but I think with regards to the experiments it may be in the best interest to scrap Try 2 for both the Repeating Crumley and the DDW Effects on Seed Growth until the temperature becomes a bit more stabilized. Now I will still record data and keep track of the experiments, but I will not include these results in any final markups. But that doesn’t mean I can’t learn something from these experiment!
This is the setup for the second trial of deuterium depleted water effects on plant growth. For the most part the experimental setup is identical to the first trial which you can find here. There are a few notable differences though so let’s run through the prep:
- 5 seeds of two differing varieties from The Tobacco Seed Company are used in each sample (trial 1 had 3 seeds per sample). I am using Dark Virginia and Virginia Gold #1 variety seeds.
- there are 5 different water types: 99.9% deuterium depleted water (ddw), deionized water (di water), tap water, 33% deuterium oxide (d2o) mixed with di water, and 33% d2o with ddw. The d2o mixtures are new additions to this experiment.
- The samples are stored in semi-micro cuvettes and sealed with a silicon top (maybe it’s rubber).
- The seeds are added to a cuvette and then 2.5ml of a water is added to the sample. This volume minimizes the air bubble in the sample to minimize hydrogen/deuterium exchange with the water.
- There are 10 samples of seeds and 10 more samples of seeds that are presoaked in their respective water buffers.
- Seed growth is tracked using a Nikon D40 DSLR with a 10x magnifying lens. The samples are arranged on some Thor Labs optomechanics to make image taking simpler.
I’m going to shorten this title to DDW Effects 2: Day X and it should be noted that I won’t post every day. Just as things happen. It’s not critical for this experiment that we track growth or time. I’m just noting phenotypical differences in the development, like the hair. I’ll be posting a setup page soon and that will contain all the information pertaining to this project.
This first post is a picture of the seeds and some have already begun to sprout. I didn’t have the abilities to take Day 0 pictures because my station was torn to shreds (I was redesigning a way to easily take pictures of every sample for this and the RC experiment). Now everything is up and running and should proceed smoothly. Here are the pictures:
Some shorthand explanation: the caption format is “seed subspecies, water type”
- vg – virginia gold; dv – dark virginia
- ddw – deuterium depleted water; di – deionized water; tap – tap water; d2o – deuterium oxide
- “33% d2o in xx” means I mixed 33% d2o with xx water (either ddw or di water) by volume. For instance in 3mL of sample, 1mL is d2o and the other 2mL are the water type specified.
Hydrogen has several isotopes and one of them, deuterium, exists quite naturally in water to form . In previous experiments and several papers by Gilbert Lewis, it has been found that life is hindered in the presence of . While this may be true, my PI Steve Koch wondered if life had found a use for it because naturally occurring water has about a 17mM (millimolar) concentration of deuterium.
To put that number into perspective, when I do a typical polymerase chain reaction of DNA I add 10mM of each base of DNA (which is less than the amount of naturally occurring deuterium) to create millions of copies of a DNA template from an amount that is 1000x less then what the reaction yields. In fact most chemicals in most of my buffers on the order of the amount of naturally occurring deuterium.
So you can see it isn’t a stretch to think that nature has found a use for since it is quite abundant and life has been constantly evolving for billions of years. I want to test this hypothesis in a variety of different organisms:
- Tobacco Seeds – to act as a foil to Lewis’ experiments in which he grew tobacco seeds in pure .
- Mustard Seeds – from what I’m told mustard seeds are the powerhouse of the botanical genetics world much like Drosophila and S. cerevisiae are in their respective genetic fields.
- Escherichia coli – another molecular biological powerhouse that is very easy to grow and may be easy to see results with. We just got the facilities to be able to grow E. coli and damn it I want to use them!
- Saccharomyces cerevisiae (Yeast) – I know a guy who grows yeast for his experiments and I’m sure it wouldn’t be a stretch to get him to do so in deuterium depeleted water.
So the idea would be to try to grow these in regular water and in deuterium depleted water (no ), and in the case of E. coli and yeast, perhaps in pure because I don’t think those experiments have been carried out yet. Hopefully I will be able to conclusively state whether or not life has developed a need/use for which would be a very interesting discovery indeed!