h a l f b a k e r yI think this would be a great thing to not do.
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if there were more ocean nutrients there
would be more ocean creatures n fish
ocean life like plankton could make the
heme protein with a different metal atom
that is much more plentiful as described
at
[link]
Molybdenum is near three times as
plentiful as Fe there is also about as
much
U as Fe
both these atoms support the valences
that wikipedia associates with the heme
protein
molybdenum is genetically addressed as
part of numerous enzymes right now
engineering this new hemoglobin gene
creates vast new amounts of marine life
it is further possible to create marine life
that likes eating kelp as it gets sufficient
heme building material from kelp
wikipedia: Molybdenum has several
common oxidation states, +2 +3 +4 +5
and +6. The highest oxidation state is
common in the molybdenum(VI) oxide
MoO3 Molybdenum is present in
approximately 20 enzymes in animals,
including aldehyde oxidase, sulfite
oxidase, xanthine oxidase.[6] In some
animals, the oxidation of xanthine to uric
acid, a process of purine catabolism, is
catalyzed by xanthine oxidase, a
molybdenum-containing enzyme. The
activity of xanthine oxidase is directly
proportional to the amount of
molybdenum in the body
oceanic nutrients
http://www.seafrien...ter.htm#composition
[beanangel, Apr 06 2008]
Photosynthesis review
http://bioweb.wku.e.../Photosynthesis.asp
Iron, yes. [bungston, Apr 07 2008]
Re: oceanic molybdenum
http://www.ncl.ac.u...html?ref=1206550130
References Nature, 27 March 2008; if I can find the direct link, I'll replace this one. [lurch, Apr 09 2008]
Article in Nature
http://npg.nature.c...bs/nature06811.html
OK, never mind, I won't replace the previous - this is not as reader friendly as one would hope. [lurch, Apr 09 2008]
[link]
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Wouldn't all the whales develop a weight problem? |
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uh, [Treon], you may wish to note that your authoritative source gives the atomic weight of Molybdenum as 0.09594 - not exactly an auspicious start for another of your wild-eyed arm-wavings. |
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Also note that in order to make the change, you would merely need to destroy the entire base of the aquatic food chain, and then modify every member of the food chain from there on up (y'see, they eat each other, and get nutrients - or would, anyway, if they were the right ones) - including all dependent land life. Killing every living thing on the planet hoping your replacements work doesn't sound to me much like "promoting abundance". |
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actually they could all live together, fish
that liked the taste of molybdenum
plankton would have more protein |
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also of the few hundred numeric items at
the site I think it is possible the .01 ppm
is accurate |
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First - how many plankton have
haemoglobin? I have an idea that the
answer is approximately "none", but I
may be wrong. It has happened before. |
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Second - what's important is not just
the oxidation states of the metal ion,
but also its ability to coordinate
molecular oxygen. It's not going to be
a simple swap-out. Also, if it were that
simple an evolutionary leap, it would
already be widespread in marine life.
Some organisms use copper instead of
iron, but none has made the switch to
molybdenum, as far as I know. |
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Third - genetic engineering magic.
Suppose you create this newly-
engineered haemoglobin. Do you have
any idea how closely haemoglobin (and
its synthesis and breakdown) are
coordinated with other pathways? You
think you're just going to switch this
and it'll all work fine? Nope. |
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Fourth - so, you've created your new
super-plankton (actually new super-
jellyfish, super-crabs, super-barnacles,
and super-lots-of-other-species,
whose larvae make up much of the
plankton). You're just going to colonise
the oceans with these and expect
everything else to fit in? |
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Dumb, beany. Not joined up, not
thought out, not thought through. |
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I'm creating aquatic humans creating much oceanic surplus goes with that |
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What, is this you without the falsies? |
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I am sure there is tremendous evolutionary pressure to come up with ways to do photosynthesis without iron. Such a plant would have a ginormous selective advantage. The fact that heme is so tightly conserved doesn't mean that a molybdenum-containing heme is not possible, though - it may be that it is not possible to evolve towards it because the intermediate steps are no good. This is where things are going to get tricky with GMO: it may be possible to intelligently design structures that would not have evolved. It might be possible to give an organism metabolic abilities which are new to the Earth. Those critters might have the power to kick ass. |
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As I type this I wonder about that "aquarium strain" of Caulerpa. That thing behaves exactly like a GMO-boosted organism would - for example if beanangel (really Treon? How can that be?) inserted a labcrafted Mo Heme. I wonder if anyone has sequenced it. |
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//I am sure there is tremendous
evolutionary pressure to come up with
ways to do photosynthesis without iron.// |
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I think you're confusing haemoglobin with
chlorophyll. Chlorophyll uses magnesium,
not iron, and the seas are awash with
magnesium. |
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//your authoritative source gives the atomic weight of Molybdenum as 0.09594//
You had to tell him this? Next he'll be building spacecraft with the stuff. So light it just floats out of the atmosphere! |
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As usual, an interesting idea but well wide of the mark. |
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What's in a name? A [Treon] by any other name is still as bananas... |
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Yes but, we're not supposed to have two accounts!! So how can he answer himself? |
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Young Max, I am always happy to help with your ongoing edification. Linked find a review of photosynthesis, including diagrams, in which you will see that chloroplasts use iron, and magnesium, and other nifty tricks to work their wonders. |
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Old Bung, I am indebted. Forgot
ferrodoxin. But this is still a nuts idea. |
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Please, tell us that was deliberate ... |
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Some sea creatures utilize other metal ions in their oxygen metabolism. Weird ones, like vanadium and stuff. It gives them weird colored blood. |
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// weird colored blood // |
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You show us yours and we'll show you ours ..... |
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Yes, tunicates use vanadium and
horseshoe crabs (I think) use copper.
However, neither of these groups has
really taken over in a big way. |
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This suggests that it's not too difficult to
evolve iron-independent oxygen
transport, but that there's just no real
advantage in doing so. |
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//horseshoe crabs (I think) use copper//
So do octopus. Copper is more efficient than iron in cold environments with low oxygen partial pressure. |
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Aha. [Copro] - how does that fit with
phylogeny - I mean, is the distribution of
copper-based oxygen transport consistent
with a single origin, or has it originated
multiple times? |
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Dunno, I just thought it was a mollusc thing. I'll have to go looking.
[EDIT] Interesting; I knew they were an ancient species, but horseshoe crabs are more closely related to spiders and scorpions than crabs, so it would appear to be a multiple origin thing, or back to something common to molluscs and arthropods. |
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I am skeptical about the vanadium / oxygen thing. I do not think it is known what the vanadium does for the tunicates. |
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The copper thing is very nifty. I have seen phylogenetic trees for hemoglobin but I do not think they included those copper ones - hemocyanins? If someone turns up a review that deals with this please link it up. |
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I ran across a recent research publication which I think was [Treon]'s trigger (the usual - "cool! that plus a little genetic magic and..."). It referred to the idea that Mo is required for nitrogen fixation, but was not available to the early prokaryotic bacteria except in minute quantities. It became available when the bacteria had liberated sufficient oxygen, which dissolved in the ocean, reacting with insoluble deep ocean molybdenum, oxidizing it into a soluble form. The oxygen / moly catch-22 apparently held earth life hostage for almost 3 billion years, and when it finally ended in a positive feedback loop - well, hello, Cambrian explosion. Life everywhere. |
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[Treon]'s assertion that there is three times as much Mo in seawater as Fe is misleading. There is triple the amount by weight, but hemoglobin uses iron by the atom, not by weight. On a molar basis, Mo is around 70% more abundant than iron in seawater. |
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I believe there is good reason for hemoglobin to have not developed with molybdenum. Mo has an atypically high electronegativity relative to iron (and to its place in the periodic table), so if you got an oxygen atom stuck to it, it would be very difficult to get off. I think (can't prove, though) that such tight bonding also plays a role in molybdenum being so useful in enzymes and catalysts. |
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Also of note is the fact that while iron oxides are amphoteric, molybdenum's oxides are strongly acidic. |
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You show me yours, I'll show you oars. |
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[copro] in that case, it means that flipping
between copper and iron is fairly easy,
evolutionarily. In which case, there can't
be a huge advantage in moving away from
iron, or we'd all be doing it. |
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//Yes but, we're not supposed to have two accounts!! //
I'll bet he's got more than two. |
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good old lurch, stoking the flames.
/ Mo has an atypically high electronegativity relative to iron (and to its place in the periodic table), so if you got an oxygen atom stuck to it, it would be very difficult to get off./
Link up that publication about Mo and the Cambrian, if you would. |
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I was thinking of a different use for the putative Mo-heme. Oxygen poisons the nitrogen-fixing apparatus (which I did not know requires Mo). The N fixers used by legumes have acquired heme by some viral accident eons ago, and use it to scavenge oxygen and protect their N fixing chemistry. If Mo heme is even a stronger O binder it might work better because the legumes don't care if it never lets go |
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. Another idea would be to engineer legumes with heme from bloodworms or some similar critter which makes aerobic metabolism work in a marginally aerobic environment. This would be nice because the molecule already exists. But bloodworm heme still has to let go of the O, and so I would bet that leghemoglobin has the strongest O affinity of any hemoglobin. |
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Why fool with legumes and thier ability to fix nitrogen? Because they are tasty to man and beast - and the more N they fix, the happier we all are. |
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As regards the mysteries of [Treon], some of these beanangel posts were initially done under the name Treon - the author name switched but the annos remained. Tricky! Maybe Treon has hacked the HB but I cannot imagine that situation going on for too long. |
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[bungston], there's the link per your request. |
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I hadn't looked directly at the Nature article previously, just some reviews. (If you google "ocean molybdenum March 2008" you'll find a *lot* of reviews.) Now that I have, I think I may have over-simplified a summary that was already over-simplified. Ah, well... stone me. I'm in a dull mood anyway. |
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//stoking the flames// hand me those bellows, would you? |
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Those plankton are pretty dumb though, just the job for making vegetarian black pudding. |
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I know this takes us back quite a few annotations, but the vanadium in tunicate blood is not there for respiratory purposes, but may have the function of making them toxic to predators. |
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>>Makes another note on a sheet of legal paper with "TREON=EMERGENT AI? FTW" scrawled across the top; it is only one of many sheets in a loose pile<< |
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<Edits said sheet to "TREON=EMERGENT AI? FTL"> |
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<Edits said sheet to "TREON=EMERGENT
AH? WTF??"> |
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