Researchers apply computing power to crack egg shell problem

Jul 09, 2010
OC-17 binding to calcium carbonate

(PhysOrg.com) -- Researchers at the University of Warwick and the University of Sheffield have applied computing power to crack a problem in egg shell formation. The work may also give a partial answer to the age old question "what came first the chicken or the egg?"

The answer to the question in this context is "chicken" or - at least a particular chicken protein. There is however a further twist in that this particular chicken protein turns out to come both first and last. That neat trick it performs provides new insights into control of crystal growth which is key to egg shell production.

Researchers had long known that a chicken eggshell protein called ovocledidin-17 (OC-17) must play some role in egg shell formation. The protein is found only in the mineral region of the egg (the hard part of the shell) and lab bench results showed that it appeared to influence the transformation of (CaCo3) into calcite crystals. The mechanism of this control remained unclear. How this process could be used to form an actual eggshell remained unclear.

University of Warwick researchers Mark Rodger and David Quigley, in collaboration with colleagues at the University of Sheffield, have now been able to apply a powerful computing tool called metadynamics and the UK national supercomputer in Edinburgh to crack this egg problem.

Dr David Quigley from the Department of Physics and Centre for Scientific Computing, University of Warwick, said: “Metadynamics extends conventional molecular dynamics (MD) simulations and is particularly good at sampling transitions between disordered and ordered states of matter.”

Using these tools The Warwick and Sheffield researchers were able to create simulations that showed exactly how the protein bound to amorphous calcium carbonate surface using two clusters of “arginine residues”, located on two loops of the protein and creating a literal chemical “clamp” to nano sized particles of calcium carbonate.

While clamped in this way, the OC-17 encourages the nanoparticles of calcium carbonate to transform into “calcite crystallites” that form the tiny of nucleus of crystals that can continue to grow on their own. But they also noticed that sometimes this chemical clamp didn’t work. The OC-17 just seemed to detatch from the nanoparticle or “be desorbed”.

Professor Mark Rodger from Department of Chemistry and Centre for Scientific Computing, University of Warwick, said “With the larger nanoparticles we examined we found that the binding sites for this chemical clamp were the same as the smaller nanoparticles but the binding was much weaker. In the simulations we performed, the protein never desorbed from the smaller nanoparticle, but always fell off or desorbed from the larger one. However in each case, desorption occurred at or after nucleation of calcite.”

The researchers had therefore uncovered an incredibly elegant process allowing highly efficient recycling of the OC-17 . Effectively it acts as a catalyst, clamping on to particles to kickstart crystal formation and then dropping off when the crystal nucleus is sufficiently large to grow under its own steam. This frees up the OC-17 to promote more yet more crystallisation, facilitating the speedy, literally overnight creation of an egg shell.

The researchers believe that this new insight into the elegant and highly efficient methods of promoting and controlling crystallisation in nature will be of great benefit to anyone exploring how to promote and control artificial forms of crystallisation.

Explore further: Scientists develop pioneering new spray-on solar cells

More information: The paper entitled “Structural Control of Crystal Nuclei by an Eggshell Protein” by Colin L. Freeman , John H. Harding , David Quigley , and Professor P. Mark Rodger, is published in Angewandte Chemie International Edition, DOI:10.1002/anie.201000679

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User comments : 11

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bottomlesssoul
not rated yet Jul 09, 2010
I wonder if one day we can grow MWCNT this way. I imagine a giant bio-factory in GEO growing a tether to Earth to start the space elevator. Maybe float a bunch of these over Mars and the Moon while we're at it and pwn the solar system. Cool!
Sonhouse
not rated yet Jul 10, 2010
All it needs to be is 100 times the strength of steel...
FredJose
2.3 / 5 (3) Jul 10, 2010
Great research by the team!

Hopofully it'll lead to growing other man-made materials as suggested by the last paragraph.

Does raise the usual hackneyed question though - just how on earth did this ability develop from a single cell? Consider all the necesary mechanisms that need to be in place for the egg to be shaped the way it is and also to be made of the exact material that it consists of. Then what are the control mechs that are required to initiate and stop egg production? How would random mutations have any idea as to what the end-product should look like?
How to enclose the vital life-carrying ingredients without damage?
How to preserve said life-carriers in a state condusive to forming the chick and giving birth. What are the instructions that initiate growth and what stops it? Where do those instructions come from?
Lots to think about.
A_Paradox
1 / 5 (1) Jul 11, 2010
Does raise the usual hackneyed question ... just how on earth did this ability develop from a single cell? ... How would random mutations have any idea as to what the end-product should look like? ...


Excuse me but the answer is "evolution". Random mutations DO NOT "have any idea" what the end-product should be. Yes of course this is amazing but that is because we are looking at a process which has been brought to its current effectiveness by a hundred million years of ecological winnowing. The fact is our bone cells must do something similar and the mollusks have been creating calcite [yes?] shells for several hundreds of millions of years.

Another point of view is the idea that DNA evolved after the first RNA arose through interactions on the surfaces of crystals which were precipitating at ocean spreading centres and volcanic hot spots. So it may be that the real genius of shell and bone growing animals was to rediscover parts of the very oldest living processes.
kevinrtrs
1 / 5 (1) Jul 15, 2010
to its current effectiveness by a hundred million years of ecological winnowing.

Who did the winnowing? Some intelligent agent, perhaps? Time is not a magic elixir that somehow manages to produce new complex things from dust. If you just leave something in-organic in it's natural state it stays that way. It doesn't grow into some living thing over time. Cannot happen, doesn't happen, hasn't been observed to happen, will not happen.
The first RNA did not have arise through interaction on the surface of crystals - do you have substantial proof of that or are you just following the speculation of other scientists?
Nobody has any definitive idea of where life comes from since no-one can go back into the past and produce documentation of how life started.

There's only one book on life that describes how life came about in a credible way - the Bible. You probably don't believe in it - it's just so much nonsense to you - so I can understand that you have to accept evolution.
kevinrtrs
1 / 5 (1) Jul 15, 2010
Another point of view is the idea that DNA evolved after the first RNA arose


Have you had a detailed, in-depth look at just what is required to form RNA? Did you examine the chemical and physical obstacles that need to be overcome before you can even come close to having an RNA molecule?
If not, then please disillusion yourself of an "RNA world" point of view by reading up on HONEST papers on the topic - not ones that just glibly wave the hand to dismiss the obstacles.

Furthermore - DNA cannot begin to "evolve" until life actually starts. Evolution requires life - it's in the definition. So you can't have life until you have DNA but then you can't have DNA until you have life. Back to the chicken and egg - a vicious circle.

By the way, God made the chicken first and THEN reproduction started. That's only logical.
Ethelred
not rated yet Jul 20, 2010
Consider all the necesary mechanisms that need to be in place for the egg to be shaped the way it is and also to be made of the exact material that it consists of.
Wrong way to look at it UNLESS you don't want real answers. The material is the material that worked. It could have been something else if the resources available were different. Diatoms, for instance, don't have carbonate structures they have silicates instead.
Then what are the control mechs that are required to initiate and stop egg production?
The control mechanisms would have developed in tandem with the evolution of eggs. Keep in mind that eggs do not always have hard shells. Many species have leathery shells. All that really happened was that a pliable sack was stiffened up with carbonates and the sack is just a lining.

Continued
Ethelred
not rated yet Jul 20, 2010
How would random mutations have any idea as to what the end-product should look like?
Two things wrong there. One evolution is not dependent on random mutations only. It depends mostly on Natural Selection. Which, being a process, has no ideas at all much less goals. It is simply the pruning, by failure to reproduce, of mutations that didn't help increase reproduction.
How to enclose the vital life-carrying ingredients without damage?
That isn't how it happens. Egg cells grow and multiply then connect with whatever the parent has produced to sustain the egg. THEN the egg is grown around the package, sack then shell.
How to preserve said life-carriers in a state condusive to forming the chick and giving birth.
Those changes that failed to do help with this died out. Those that helped had an advantage and become predominant in the species.

Continued
Ethelred
not rated yet Jul 20, 2010
What are the instructions that initiate growth and what stops it?
Mostly homeobox genes. You can look this stuff up if you really want answers.
Where do those instructions come from?
From the DNA via evolution by Natural Selection from the environment. Think of a block of marble that is about to be sculpted. The mutations (marble block) are carved away to match the sculptors needs(the environment kills that which has the wrong mutations.) Yes its harsh but that is what the evidence shows. There is no designer there. Just random mutations combined with selection by the environment.
Lots to think about.
Indeed. How about you do some more of that? I have. There are answers. Some are now known and some are still to be found. That we don't know everything doesn't mean that a book written long ago is right despite the evidence that clearly shows it is wrong about how the world and life got started.

Ethelred
Ethelred
not rated yet Jul 20, 2010
Who did the winnowing? Some intelligent agent, perhaps?
No, the environment.
The first RNA did not have arise through interaction on the surface of crystals - do you have substantial proof of that or are you just following the speculation of other scientists?
No it didn't have to. It could have been formed in tide pools, near the deep sea vents, on clays or something we haven't thought of yet. Sure its speculation. Sure you are claiming goddidit. What did god? I prefer speculation that is based on natural law as opposed to going on pure ignorance.
There's only one book on life that describes how life came about in a credible way - the Bible.
Nothing credible there. The world is very old not young. The order that life developed in the real world does not match that of the Bible. The Bible even has things growing without a Sun.

Continued
Ethelred
not rated yet Jul 20, 2010
You probably don't believe in it - it's just so much nonsense to you - so I can understand that you have to accept evolution.
It does fit the evidence as opposed to a book written long ago by men that knew even less than you.
Furthermore - DNA cannot begin to "evolve" until life actually starts.
Well until there is a self replicating molecule. Yet you keep harping on this even when discussing evolution which DOES occur.
By the way, God made the chicken first and THEN reproduction started. That's only logical.
That is only religious not logical. Logic makes it clear that the egg came first. Something that was almost a chicken laid an egg that had the last mutation that qualified it as an early version of chicken.

Anytime you want to discuss this instead rabbiting off like Mabarker does I will pleased to do so. Logically and rationally without vitriol.

So is it good-bye again or will you engage in discourse?

Ethelred