Caddis fly larvae live in water, and build tube-like protective cases. Different species use different materials - some use sand, some use pieces of plants, some use very small snail shells, etc.
So.
MaxCo. is beginning a program to establish caddis-fly- based gold panning in some of the Buchanan estate's trout streams.
We begin by seeding a section of stream with gold-plated nickel particles, approximately sand-grain sized.
A few months later, we trawl the stream with a powerful electromagnet. This will recover most of the plated nickel particles, but also any caddis fly larvae which have selected a few of the particles to include in their tubes. We then autoclave that section of the stream (to eliminate all the other caddis fly larvae). The harvested larvae are allowed to reach maturity, and the adults are released along that part of the stream.
Year after year we repeat this process, using a progressively weaker magnet to select for larvae who use more and more of the gold-plated nickel particles in their tubes.
Ultimately, we have a race of caddis flies that uses the gold-plated particles almost exclusively in building their tubes. We then release the adults of these larvae along the full length of the stream.
This breeding population will tirelessly scavenge the river bed for minute particles of placer gold, creating millions of tiny, solid-gold tubes.
Then...ah, hang on, I'm still working on the next bit. But finding centimetre-long tubes, each made of a few hundred milligrams of gold, has got to be easier than panning. In fact, the population would thrive only in gold- rich areas - the presence of the adults would therefore tell you where to wade in and start trawling for the larvae.-- MaxwellBuchanan, Jun 17 2014 Deep-sea snail shell http://www.newscien...r.html#.U6yD_rAU99ANewScientist [Skewed, Jun 26 2014] Iron-plated snail https://www.esa.org.../iron-plated-snail/esa [Skewed, Jun 26 2014] Garden Snail http://en.wikipedia.../wiki/Cornu_aspersaWikipedia (scroll down to the short ecology section) [Skewed, Jun 26 2014] Prior "Art" https://www.google....AQ&biw=1536&bih=837 [AusCan531, Jun 27 2014] We're going to need a bigger...autoclave.-- normzone, Jun 17 2014 Project like that would take time. But if you have those Immortality Pants working, a perfect hobby!
I think Vonnegut had an immortal alien who bred flowers as a hobby.-- bungston, Jun 17 2014 //But finding centimetre-long tubes, each made of a few hundred milligrams of gold, has got to be easier than panning.// - as you develop the perfect caddis fly, are you not also developing a breeding programme of kingfishers or some similar bird which will selectively seek out gold-coloured caddis fly larvae cases?-- hippo, Jun 24 2014 [hippo], that is probably the best idea I have heard in the last 30 minutes.-- MaxwellBuchanan, Jun 24 2014 I feel suitably honoured-- hippo, Jun 24 2014 48 and counting.-- MaxwellBuchanan, Jun 24 2014 I think breeding any species to mind radioactive material is going to be tricky. I suppose you might convince gorillas or chimps to be annoyed by it, if they had suitable detectors; but fish are generally pretty indifferent to just about everything.-- MaxwellBuchanan, Jun 24 2014 I thought Sturton was doing this, back in February?
I was trawling through a back catalogue of incredibly inventive, humorous and wonderfully written posts (i.e. mine*) and spotted it...
* Don't worry I couldn't even type that with a straight face.-- not_morrison_rm, Jun 26 2014 Was he? The sly old bugger. I really ought not to let him use my login details here.-- MaxwellBuchanan, Jun 26 2014 I like it, (seems) elegantly doable.
You do appear have a thing for insects at the moment though don't you?
Could we maybe not bioengineer an animal to lay down other minerals besides calcium (for gold, being not that plentiful, as well as) instead / as well? After all there are snails with metal shells in deep sea vents so there's at least one creature out there that does it, maybe we could find some clues on how to in their genome.
No idea how we'd go about that, a research project for you [Max]?
If we can suitably modify that into a pigeons DNA so it will lay down any traces of gold from the food it consumes in it's eggshell then we just have to collect the shells after they hatch & burn them on a steel mesh over a drip tray to collect the melted gold.
Do it with Geese & you've got the real goose that laid...
Of course the (GM) idea was already mooted in a bond film (I think it was?) using coral polyps to filter gold out of see water.-- Skewed, Jun 26 2014 //snails with metal shells in deep sea vents// Linky? I'm intrigued (or possible gullible).
//the (GM) idea was already mooted in a bond film (I think it was?) using coral polyps to filter gold out of see water// Ditto.
//No idea how we'd go about that, a research project for you [Max]? // It probably wouldn't be difficult to use directed (ie in vitro) evolution to modify an existing metal-binding protein to bind gold. The main problems would be (a) getting a high enough affinity (as gold ions are very, very scarce in sea water) and (b) ensuring that the protein still did whatever it was meant to do.-- MaxwellBuchanan, Jun 26 2014 I can give you links for the snail.
<link>
But the 'bond' film is a recollection from when I was 8-12. It was really just the idea of coral bred to lay down gold in preference to calcium in it's shell that stuck with me from it & I can't find anything on-line (gold & coral just turns up lots of nail varnish adds).
In all honesty it could have been anything bond or saint like from (given the recalled 'look & feel' of the production values etc.) the 60's or 70's.
<later edit> The concept of gold deposited in egg shells can be found in some books by Melanie Rawn from 1989 (fantasy granted, they're dragon shells).-- Skewed, Jun 26 2014 Ah, we have a more local snail.
Apparently the common garden snail deposits heavy metals (such as led) in its shell.
Scroll down to the short 'ecology' section in the Wikipedia link.-- Skewed, Jun 26 2014 //probably wouldn't be difficult to use directed (ie in vitro) evolution to modify an existing metal-binding protein to bind gold//
Hmm...
I'm a bit slow sometimes but it occurs that calcium, is a metal?-- Skewed, Jun 26 2014 Yes, it is. But I may be missing your point.-- MaxwellBuchanan, Jun 26 2014 So you have an existing metal binding protean (?) in any animal that uses calcium for its skeleton, exoskeleton or shell?
More convenient to work with easily available animals than go chasing after exotic deep sea variants.
<later edit> Though I presume (?) having examples of ones (to work with) that that bind different / more unusual metals would help identify the relevant processes?-- Skewed, Jun 26 2014 [fixed]
I think if you mucked about with the machinery of [exo]skeletal deposition, you'd have problems.
Howevertheless, there are many metals which are used (and bound) by various proteins, some of which are non-essential. There's an arthritis drug based on gold ions, which suggests that some [human] protein can bind gold - so I'd start with that and see if it can be evolved to have higher affinity for gold (and lower affinity for whatever metal it normally binds).-- MaxwellBuchanan, Jun 26 2014 I think you'll find that gold is somewhat different, chemically speaking, to nearly any other heavy metal. Certainly very much different to something as active as Calcium.
See [max]'s reference above to gold ions being rather rare in seawater (and certainly even more rare in freshwater). He's making a bold understatement here. I'm not entirely sure you could train anything to be able to "taste" gold in water. Maybe you oculd get it to use visual cues to identify gold.-- Custardguts, Jun 26 2014 (posted previous before [max]'s latest anno showed up.
A protein that binds gold? Really? How does that work, chemically speaking? Is it a physical fit, based on the size of the gold ion, or does the protein actually bond the gold? Surely it would be very susceptible to substitution by, well, nearly anything else in solution?-- Custardguts, Jun 26 2014 Yup, definite problem if all the cells shared the same mod, but say you mosaicked it in some fashion so only a small % of the cells carried the gold binding gene mod & the rest continued to deposit calcium as normal.
<later edit>
//suggests that some [human] protein can bind gold//
Well the old rhyme says 'enough gold to....', so (assuming it has a use, isn't just residue from consumed food?) presumably the body has a mechanism to acquire & transport it to where it's needed.-- Skewed, Jun 26 2014 //not entirely sure you could train anything to be able to "taste" gold in water. Maybe you oculd get it to use visual cues to identify gold.//
Yes, the idea was to use visual cues to select gold flakes or grains.
//A protein that binds gold? Really? How does that work, chemically speaking?// No idea, alas. There are plenty of proteins that bind various metal ions (including magnesium, zinc, calcium and many others) - I presume that it has to do with the size and charge of the ion.
I doubt there's a protein that has evolved specifically to bind gold ions, but if gold is used in a drug, it's likely that there's a protein that _can_ bind gold (as well as some other more common metal). In much the same way, some of the toxicity of arsenic arises because it binds to important proteins that have evolved to recognise other ions.-- MaxwellBuchanan, Jun 26 2014 Sorry [Max] I appear to have hijacked your idea / discussion into a completely other course.
[LimpNotes] a nice link :) & far more on target relevance wise than mine, another newbie?-- Skewed, Jun 26 2014 [pNote] - that is an awesome link. If I could bun links, I would bun that link.
[Skewed] - not at all. Consider it less of a hijacking, and more of a chauffeuring.-- MaxwellBuchanan, Jun 26 2014 Kind of you to see it that way, I'm off now though, it's a little late, & I'm knackered.
[pNote] forgot to offer a welcome, so welcome :)-- Skewed, Jun 26 2014 random, halfbakery