[DIYbio] Re: Making contact to a Professor (Dr. Krichevsky)

I saw him on 123people and thought about registering...
But then I browsed his public profile and as I clicked on one article,
it said ''member couldn't be found''. The same happened with his other
articles.

I think he has abadonned his profile there....

Is anyone registred at linkedIn?? To see if his profile hasn't been
deleted.

_____

You said it, the plants they are now producing are very dim. So it
would be less problem that they're propagated because when the company
brings out the brightly glowing plants, consumers would like that even
more.

On 5 Feb., 04:54, Anselm Levskaya <levsk...@gmail.com> wrote:
> I don't know much about the state of this particular company, but what
> they're trying to do is pretty hard.
>
> Having used the lux operon before in bacteria, the first thing to note
> is that it's pretty dim, even at the maximum output levels in a
> healthy, dense culture.  It's much less bright than a glowstick, say.
> Requiring very dark adapted eyes to appreciate.
>
> Getting a healthy dose of photons out of a biochemical pathway
> requires a lot of energy.  I imagine simply putting the lux pathway
> into plants didn't result in a species bright enough to really impress
> a consumer market.  It will take a lot of work to direct more of the
> plants' resources into the precursors necessary to fuel the
> photochemical event.
>
> Almost all bioluminescent systems use a catalytic enzyme called a
> "luciferase" that activates a species specific "luciferin" with an
> electron-donor that ultimately ends up generating a peroxide
> intermediate with strained bonds whose decay is high-energy enough to
> cause a singlet-state excitation and quick photo-emission.
>
> The lux system typically only generates 10^3 photons/sec/bacterium,
> which can briefly result in a dim glow in a dense oxygenated culture
> (10^12 bacteria/mL * 10^3 = 10^15, but only when you shake them to
> oxygenate all the cells).  Some species of krill and fish can push
> 10^12 photons from their light emitting organs ~continuously.
>
> Note that 1 lumen is ~ 10^15 photons/sec, and a weak nightlight bulb
> is typically around 10^17 photons/sec, so we're talking about subtle
> effects here.  American fireflies can pulse brighter by controlling
> the photochemical reaction rate and can get up to 10^14 photons/sec.
> I'm not sure what the bioluminescent record holder is.  These bugs
> probably control brightness by constricting oxygenation of their
> photocytes, wherein the luciferase is found near peroxisomes and the
> luciferin is bunched up in cytoplasmic granules.
>
> Here are some general refs:http://anselmlevskaya.com/papers/bioluminescence.pdf - marine
> bioluminescence reviewhttp://www.photobiology.info/Viviani.html- discussion of terrestrial
> bioluminescence

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