OK I'm a cell biologist. I spend my time at a 'scope (as we microscopists like to say). And I have one thing to say to you and only one thing ... my brain is fried.
Here is my theory, if you sit in front of a microscope in the dark for more than four hours, energy is sucked out of your body, through your eyeballs and gets transferred to ... well I'm not sure. You are left feeling like a deflated Dictyostelium fruiting body that has let out all of its spores.
This lost energy, where did it go? Perhaps it dissipates into pure thermal energy, or maybe it ends up in the secret place where all the lost socks pile up (somewhere in Jersey?), but just maybe it ends up more nefarious places like inside the lumen of the endoplasmic reticulum, or worse yet into the prokaryotic periplasm. (Or for you psychoskeleton aficionados, inside the lumen of a microtubule? And yes, I'm aware that other things have been found there ...)
BTW Here's a couple of things that I've been wondering ... maybe someone out there in internet land can help me out on this ... the ER has ATP, that's inferred from the fact that it is loaded with chaperones (folding enzymes) and other proteins that utilize ATP, but here's a big mystery ... NO ONE KNOWS HOW THE ATP GETS THERE. Well at least this is as far as I know. Has there been any progress on this? And then there is the periplasm, you know that space between the inner and outer membranes of gram negative bacteria. Lots of stuff happens there. Proteins are folded, modified, integrated into membranes ... ALL WITHOUT THE HELP OF ATP. So whatzup with that? Well there are electrochemical gradients across the inner membrane including ionic gradients, redox-potential etc. but again it's not clear how a folding machine (like OMP85) could use these gradients to generate productive work.
OK now I've really tired myself out ... time to sit back, relax and watch Stewart & Colbert.
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Haemophilus influenzae has an ATP-dependent DNA ligase in its periplasm. But we know of no way to move ATP from the cytoplasm into the periplasm,. Furthermore, the periplasm contains phosphatases that strip the phosphates off of any nucelotides that wander in from the outside.
So we're speculating that maybe the ligase carries a single ATP along with it as it's transported across the inner membrane, acts once*, then is useless.
*No, we have no idea what it could be doing there.
Interesting. I was wondering about the state of knowledge in cell energetics just today. I was wondering, though, about the possibility of constructing a battery-like thing that would be embeddable in a living organism to produce power for electronics.
It'd leech off an artery or something and produce a small voltage from glucose and oxygen. I'd wondered if such an electrical energy souce should try to utilize some already-understood cell chemistry, or should just other novel chemistry.
Is that too creepy to think about, or what?
Cheers,
--Bob
Hmm interesting one, Alex. May be if we could harness the energy that we lose when in front of a microscope, and couple it somehow with the fluorophores, we could have an automatic anti-fade mechanism?
You can be second on the patent, if you like.
Thanks Rosie,
I knew that blogs were good for something! I should pose more questions on my blog. Are these phosphatases (or DNA ligases) found in all gram negative bacteria? Also what is a ligase doing in the periplasm?
They identified an ATP-transporter in the mid-90's, check out Kim et al., 1996 Biochemistry 35, 5418-25
Thanks Kirklain,
After looking at the paper I asked around the lab, and some folks here had seen the paper, but no one has seen a follow up on this mysterious "56kD protein". Anyone else?
Doing a little lit. search, has yielded that the yeast ATP transporter to be? Sac1p [1], whilst the mammalian version is still unknown but a possible candidate is associated with CFTR [2]. Anyway, more to read with this article: Hirschberg et al.,1998 Ann Rev Biochem 67, 49-69.
[1] Mayinger et al., 1995 JCB 131, 1377-86
[2] Pasyk and Foskett, 1997 JBC 272, 7746-51
my empathy on your scope=exhaustion point has caused me to de-lurk...
the microscope vendor's logic may go like this:
you tire easily looking through a microscope. through associative conditioning, you tire of the microscope itself. you attend a huge conference with lots of fantastic vendor booths (e.g. SfN). you see a new microscope. you pay no attention to the fact that said new microscope is very pricy, and pay a mint for new microscope. you look through new microscope with renewed enthusiasm.
and the cycle very soon begins again.
you see? it can all be reduced to strategic marketing and capitalism. if the vendors haven't realized this, they should :)