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Produce biphenyls and fluorescent proteins in plants and pour tritiated water over them
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When certain types of molecules are excited by the energy from a beta-emitting radioisotope, they scintillate, meaning they emit the energy they absorb as light. Scintillation cocktails used to detect beta-emission in radiometric assays contain biphenyl, triphenyl, and related compounds. These primary scintillants emit ultraviolet light at around 350 nm. Blue fluorescent protein (BFP) is a well characterized protein that absorbs UV light near this wavelength and emits blue light.

There are plants out there that synthesize biphenyl derivatives as secondary metabolites. Using a T-DNA insertional activation regime, a plant line that expresses these compounds at elevated levels could be generated. This plant line could then be transformed by BFP, making it "scintillation-ready." If one were to hydrate the plant either with tritiated water or a solution containing some other beta-emitting metal ion (e.g., potassium-40), the scintillant would excite the BFP, causing the plant to glow blue.

Cuit_au_Four, Oct 25 2013

Heavy water http://en.wikipedia..._biological_systems
Worthy of consideration [8th of 7, Oct 25 2013]

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       If this works it will be spectacular.   

       One (+) for the idea, and another for [bigsleep]'s anno.
normzone, Oct 25 2013

       This is not such a stupid idea.   

       Any idea what levels of biphenyls are needed? If it's feasible, you could create indicator plants and grow them around Chernobyl, Fukushima and Kidderminster.
MaxwellBuchanan, Oct 25 2013

       Oops. Forget I mentioned Kidderminster.
MaxwellBuchanan, Oct 25 2013

       It's very un-memorable so I don't think you need to worry much.
pocmloc, Oct 25 2013

       I don't know about the concentration of scintillant that is required. The scintillation could conceivably be quenched if the beta emission is absorbed by some molecule before it excites the biphenyl scintillant. I would presume, however, with a sufficient concentration tritiated water (hopefully a reasonable and safe value), a biphenyl molecule would always be suitably close to a triton.   

       On the other hand, color quenching might be a bigger problem given the abundance of pigments and other compounds with conjugated systems that are present in plants. A secondary metabolite such as the scintillant would likely not be present at a substantial concentration, so it would likely be necessary to bring the scintillant near the fluorophore, possibly by constructing a fusion protein that contains a scintillant-binding domain and a BFP domain. Bimolecular fluorescence is routinely used to observe interactions between biomolecules, so it's conceivable that this approach might work. The scintillant binding domain could be engineered by evolving an enzyme (e.g., some phenyl dioxygenase) that takes the scintillant as a substrate and mutating the catalytic residue so that it no longer metabolizes the scintillant. If this fusion protein binds the scintillant strongly enough, then it might not be necessary to enhance the level of biphenyl production.   

       Would this produce a luminance detectable by the human eye? In complete darkness, humans are capable of detecting very small numbers of photons, on the order of 10 to 100 per second. Certainly, the number of fluorphore and scintillant molecules would be many orders of magnitude larger than this, so even if only one percent of the scintillant emissions are captured by BFP, then light should be detectable.   

       Would it be safe? Tritium beta emissions do not penetrate the outer layer of skin, and something like GBq of tritiated water must be consumed before effects on one's health are noticeable. Tritiated water can also be easily diluted in the environment and cleared from the body in a matter of days. Only a small pitcher of radioactive water would be used to activate scintillation in the plant, so this should be completely safe unless this "activation fluid" was directly consumed. The plant should be kept outside, however, so that transpired, radioactive water does not accumulate and condense in the living space.
Cuit_au_Four, Oct 25 2013

       Tritium is not exactly inexpensive. And both heavy isotopes of hydrogen exhibit anomalous effects when absorbed at significant levels by organisms. Deuterium oxide exhibits surprising toxicity in higher life-forms. <link>   

       // Chernobyl, Fukushima and Kidderminster //   

       Fukushima's not that bad, radiation-wise …
8th of 7, Oct 25 2013

       // Tritium is not exactly inexpensive.   

       Perhaps under normal market conditions, although I hear Japan has a surplus at the moment.
Cuit_au_Four, Oct 25 2013

       So after receiving its first drink of tritium, this plant would start to glow.   

       Presumably this wouldn't happen all at once, like a light switch, but rather the individual plant cells would start to glow one at a time as the tritium reached them.   

       A time-lapse video of this happening could (a) offer interesting insights into the transport of water through plants, and perhaps more importantly (b) look really cool.   

Wrongfellow, Oct 26 2013

       Cool, new boutonnieres for nuclear lab.
wjt, Oct 26 2013

       /// Tritium is not exactly inexpensive.   


       Hardly anything seems to be glowing in the dark right now.   

       But by importing coolies with a sufficient number of coffee filter papers all those exciting elements can be harvested. Kind of East India Company II.
not_morrison_rm, Oct 29 2013


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