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Scientists Debunk Myth that Pearls come from "Grains of Sand"

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  • Ramona
    replied
    Dave: Thanks for the paper link. Very informative. I should have been more clear. I did not think that you can do it without mantle cells. I was more thinking about how to make them produce nacre a bit faster. I agree with you that the factors at the level of the secretion apparatus are too complex to dissect. One would have to identify the master regulator of the entire program at the top to artificially induce the program. That could probably be done through evolutionary comparison of gene expression. Downstream would be more divergent. However, at the level of a transcription factor it should be conserved. I am sure there are labs doing it in one way or another. However, the genetics of molluscs seem to be quite complex. Therefore, if I had to manipulate nacre secretion, I would simply try to enhance the natural process and present mantle cells with a trigger. Yet, I know close to nothing about pearl farming, so my ideas should be taken with - ahem - a grain of sand.

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  • CortezPearls
    replied
    Originally posted by Lagoon Island Pearls View Post
    Thank you. I'm no scientist, but cautious of being naively misleading.
    Which is a far cry from the myths created so many years ago.
    Common sense and the ability to observe Nature without prejudice is a Science. You are as much a scientist as I am...and really: I am just a Pearl Farmer.

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  • Lagoon Island Pearls
    replied
    Originally posted by Caitlin View Post
    I am learning from you.
    Thank you. I'm no scientist, but cautious of being naively misleading.

    Which is a far cry from the myths created so many years ago.

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  • Caitlin
    replied
    Thanks, Dave! I am learning from you. Thank you.

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  • Lagoon Island Pearls
    replied
    Here's a parasitic example in the form of two blisters from today's collection.Click image for larger version

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  • Lagoon Island Pearls
    replied
    I should note this paper. http://www.daveleblanc.ca/pdf/Checa_..._formation.pdf

    Checa alludes to the same thing. I've observed "spherules" in similar folds of the periostracum, but then again I am not convinced these give rise to pearls as a single factor in every instance. It seems more likely, perforations made in the mantle by these serve as a point of entry for parasites.
    Last edited by Lagoon Island Pearls; 06-21-2011, 07:00 AM.

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  • Lagoon Island Pearls
    replied
    Originally posted by Ramona View Post
    labs that study biomineralization use polysaccharides in the process.
    They claim conchiolin induces aragonite. I'm not so sure, insomuch as it only has an affinity for calcium carbonate and provides a water-tight barrier so mineralization can take place. But let's say it is true, then it's probably only in the presence of mantle epithelial cells.

    The conchiolin coated bead would calcify, but thats about all. There's a big difference between bodily fluid and pallial fluid. As Doug says, these cells are regulated by hormones, and not as a single function, but in very complexed combinations.

    The pallial group of epithelial cells simply do not appear spontaneously where none are present.

    In my studies, more than 99% of natural pearls occur in the mantle and/or extrapallial space, irrespective of the cause. Pearls from the body mass of mussels are very rare. When I do find them, they are most often proteinaceous or calcareous, rarely nacreous.

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  • Caitlin
    replied
    That is trippy stuff! Keep on, keep on, I'm all ears......after work of course

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  • Ramona
    replied
    Of course there is also a natural source of chitin that may also be willing to produce proteins, such as the N16, Pif80, and Pif97 proteins mentioned in the article: Budding yeast. It may be hard to form that cake into perfect beads, but since Chinese pearl farmers use muck for "nucleation".... Sorry, I have to stop the craziness and get back to work.

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  • Ramona
    replied
    I agree that the signal inside the cell is hormonal. But I am having some evil thoughts about turning natural pearl production into something unnatural. Could it be that some of the parasites and pathogens that invade molluscs have a chitin outer layer? Then, just commercially available chitin coated beads may be helpful in stirring up that immune system. I am asking, because labs that study biomineralization use polysaccharides in the process. A search of Pubmed with "nacre and chitin" turned up some articles of which one is linked below:

    http://www.ncbi.nlm.nih.gov/pubmed/20397648

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  • CortezPearls
    replied
    The oyster's immune system is very simple -and this is very fortunate, else the grafting of tissue would be as complicated as with Humans- but it is indeed there. The monitoring system cannot be discarded, it is quite in place: the oysters have chemo-receptors and their primitive nervous system helps them to recognize a physical threat.

    The "regulator" or system in charge of the defensive mechanism for "attackers" are HORMONAL. And there lies the problem of lab-culture (tissue culture) of pearls: to be able to identify and then synthesize these hormones. To do so...it is quite costly with present technology. So, it seems we are always worrying about others Hormones (aren't we???), be them oysters, Humans or pets.

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  • Ramona
    replied
    I don't consider myself to be the last word or anything close. But, being Biologists we have always wondered at Life's amazing strategies, patterns, shapes, etc. Life is simply MAGNIFICENT. But we are also Engineers and we wonder and tinker: how does the animal do that? Can we fool it? Can we make it do our will?
    Along these lines, I wonder whether oysters have a way of recognizing invaders and whether their natural response is to induce nacre secretion for encapsulation of the invader. At least some reports indicate that mussels, snails and abalone can increase shell thickness in response to pathogens. This may be a response akin to nacre secretion for natural pearl production. I remember I looked it up some time ago and found that at least some mollusks can adjust shell thickness within 1-2 generations when exposed to high levels of pathogens. I don't have the original references to it anymore, but a short time of response in my opinion would rule out natural selection and suggest that some molluscs have a monitoring system, whose activation may result in upregulation of secretion of shell material. This makes sense as mussels and oysters cannot simply swim away when exposed to parasites. The obvious conclusion for me would be that there are signaling mechanisms in place that can upregulate nacre secretion when needed. Therefore, once the signal(s) are known , they could be used to artificially induce pearl production, perhaps by coating nuclei with the signaling molecule.

    Some report on the presence of an immune system:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039611/

    Shell thickness:
    http://evolution.berkeley.edu/evolib...060901_mussels
    http://www.int-res.com/abstracts/meps/v276/p115-123/

    This may also sound familiar:
    http://journals.cambridge.org/action...ine&aid=144863

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  • Caitlin
    replied
    Send them to India to be drilled.

    Anyone here who knows a good drilling place in India? I have some abalone seed pearls, really tiny, and that was where i was told to send them.

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  • CortezPearls
    replied
    Yes Caitlin, we do get many of those tiny ones. Hard to drill...but we have made some "pav?" style jewelry pieces with them. We keep storing them until we have 10 kilos or more, then we'll figure out what to do with them. Any ideas?

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  • Caitlin
    replied
    Lovely pearls. Do you get those tiny ones often? Do you ever drill them/ sell them?

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