Question about horn shape of abalone pearls

[GemGeek]

Yes. Mainly because being so highly nacreous in nature, all of the necessary components are present in the blood, pallial fluid and digestive juices. Protein, calcium and most importantly... bicarbonate. HCO3 is vital in the pH regulatory system. It's very important because digestion requires high acidity, whereas other tissues within the same anatomy (especially nerves or even an empty stomach, for that matter) could become damaged. There is a fine line outside the acceptable range of pH, where proteins are denatured and digested or enzymes lose their ability to function.

To me, this seems more plausible than the introduction of foreign epithelial cells.

So, the cells "repurpose"? Would that be a reaction to damage, or a reaction to environmental changes? (Like when frogs change sex?)

 

[SteveM]

So, the cells "repurpose"? Would that be a reaction to damage, or a reaction to environmental changes? (Like when frogs change sex?)

This is where we started?epithelial cells being so highly specialized in their function.

That gonadal abalone pearls have not been studied to a greater degree is not surprising, given the disconnect between gemology and mollusk biomineral biology. No one is arguing the pearls' anatomical origin, but it would be nice to understand the process?now that the question has been asked.

 

[Isi]

In pearl culturing, pteriidae (pearl oyster) gonads are targeted for bead insertion due to their convenient shape.

I understand that in pearl culturing, gonads are targeted also because they are not very much innerved, and consequently the risk of rejection by the mollusk is minimized. Could this account for the fact that it is current to find big sized horn shaped pearls in abalone ? Because, not feeling hurted in the gonad area, the animal is not in a hurry to get rid of its pearl and lets it develop ?

 

[SteveM]

I understand that in pearl culturing, gonads are targeted also because they are not very much innerved, and consequently the risk of rejection by the mollusk is minimized. Could this account for the fact that it is current to find big sized horn shaped pearls in abalone ? Because, not feeling hurted in the gonad area, the animal is not in a hurry to get rid of its pearl and lets it develop ?

You know more than you're letting on! My reference above resulted from reading about Mikimoto's early experiments with various types of mesh material to hold the bead and mantle tissue together long enough for a sac to form. The lack of gonadal nerves was not mentioned in my limited reading, but it makes sense.

Meanwhile, I put the existence of gonadal pearls to one of the world's leading nacre researchers. As mentioned, there is little exchange between pearldom and the latest science so abalone gonadal pearls were a revelation to him:

That is totally amazing and I have to recognize my absolute ignorance as to what may cause nacre formation in the hepatopancreas. Probably some histological examination is needed to compare the different epithelia and compare then to that of the mantle.

I subsequently found this article from McGraw-Hill Higher Education on epithelia. It would seem that our conjecture (that calcification of the hepatopancreas incites the epithelial cells of the gonadal surface adjacent to the hepatopancreas to alter function from lubrication to biomineralization) is on the right track.

You heard it here first…

 

[pattye]

Fascinating, to say the least! Woo hoo!! This is indeed a five star thread!

 

[Lagoon Island Pearls]

No one is arguing the pearls' anatomical origin, but it would be nice to understand the process?now that the question has been asked.

My kingdom for a live sample.

Like archaeology, whether artifacts or pearls, their greatest value is "in situ". Little do most realize, shucking the meat, digging out the pearl and feasting on the prize, frustrates good science.

I would love the opportunity to age a horn pearl against it's shell, to determine at what point in it's lifetime it formed.

More questions...

If (near) equal, then the possibility arises the loops or ducts became blocked or twisted during or following torsion (provided the gonads are developed at that age)?

If the pearl is younger, then which environmental effect did the deed? Examination of the shell might provide some answers (ie) parasite or predator attack? Perhaps something persisting, like an octopus, seastar otter etc? This would greatly stress the animal, to a point of giving rise to CO2 level changes, thus affecting blood acid/base levels, hence soft tissue damage or auto-immune reaction?

 

[Lagoon Island Pearls]

We've laid this right in the lap of science. But probably we've gotten about as close as we're going to get...

Right.

Even if I wanted to research this, abalone is strictly off-limits in Canada.

That was a major woe with Dr. Peter Fankboner's abalone pearl culture here in Canada. I think I'll try and dredge up some of his papers, since he's been long retired.

Perhaps some of the avid divers in this discussion group might take heed and preserve a found specimen for later examination.

 

[Caitlin]

Fascinating, to say the least! Woo hoo!! This is indeed a five star thread!

I already voted- now others need to vote too!

 

[Tango]

I agree with you Caitlin, very interesting views in this thread.

 

[Tango]

I forgot,
I?ve seen this pearl formations in cultured abalones so it?s not probably that they are the product of a pedrator attack, I think it?s some kind of a chain reaction produced mostly by a bacteria or protozoo.

 

[SteveM]

I?ve seen this pearl formations in cultured abalones.

Can you provide any more details about these discoveries? Did you keep the pearls?

 

[Tango]

I don?t because usually they are stick to the inside shell and it?s a symptom of a undetermined disease wich start with high levels of conchiolin growth inside the animal. I?m supposing this is the same process that develop a natural pearl but maybe I?m wrong.

Next week I?m going to the abalone farm, I?ll try to find some especimens and take some pictures of them so you can all judge for yourself.

 

[SteveM]

Thanks, look forward to the pictures.

 

[Tango]

As I promised,
Here are two pictures of an abalone suffering of the disease I told you about.
You can see the hollowness and horn shape of the conchiolin deposits. The picture is not very clear but inside the horn there is some nacar "growing".

 

[SteveM]

Perfect images, it looks like that specimen with the hardened gonad has been caught in the act.

(Admin, I think we need a sixth star for this thread.)

 

[GemGeek]

That is so cool!

 

[New Zealand Natural Pearl]

Conical - Gonad

Conical - Gonad

Hi There - Nice to be back

We believe the conical and Wing shapes are formed
by under water storm damage .

From our observation, abalone found in severely currented
and heavy surf zones contain more of these pearls.

Our conclusion is, these shells are damaged by the ocean,rocks
strong current etc which causes the fine membrane, which starts
at the Gonad area and finishes by the tail of the shell to be damaged
and causes the phenomenon. Nacre goes into repair mode (overload)
and plugs up these gaps.

With conical Pearls the density Generally grows and pushed the
Gonad back into its real position.
In some cases the Damage is too sever, the animal
looses the battle with the result it may look diseased. (Tango Photo)

THAT OUR STORY AND WE ARE STICKING TO IT !!!!!!!!!!!!!!!!!!!!!!!!!!![/ATTACH][/ATTACH][/ATTACH][/ATTACH]

 

[GemGeek]

So in the last photo, you've flipped it upside down?

 

[SteveM]

Our conclusion is, these shells are damaged by the ocean,rocks
strong current etc which causes the fine membrane, which starts
at the Gonad area and finishes by the tail of the shell to be damaged
and causes the phenomenon. Nacre goes into repair mode (overload)
and plugs up these gaps.

With conical Pearls the density Generally grows and pushed the
Gonad back into its real position.
In some cases the Damage is too sever, the animal
looses the battle with the result it may look diseased. (Tango Photo)

This is difficult to follow. By 'membrane' is mantle inferred, and damage to mantle, not shell, the reason for excessive nacre production? How is the appearance of nacre inside the mineralized gonad in Tango's photo to be explained?

 

[Tango]

I agree with you Steve, we need to remember that the abalone shell is one of harder materials in nature, the cinetic force needed to break the shell would be huge (7280 psi, fracture resistance). And, this a cultured animal, not exposed to the sea.
Tango