Shrimp molt

Has anybody else noticed how intellectual this thread has become? I haven't done this much homework reading since college. I feel like I ought to receive an honorary Ph.D. in marine biology.

Anyway, I have access to one more database. I'm going to check for a solid reference. One worthy of citation in a bibliography. If this is unable to yield any solid results, I may just have to give up. What are the odds of someone out there doing a study on the role of iodine in crustacean molting? Better yet, what are the odds of us finding it?
 
I figured the aquaculture guys would really want to know this, because it affects their income, but I sifted through the aquaculture databases and came up with zip.

Dangit, were zooming around on the Information Superhighway! Where's the information?
I feel like I ought to receive an honorary Ph.D. in marine biology.
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First you need to be stressed and drink a lot for 5-7 years.
 
Originally posted by mogurnda
First you need to be stressed and drink a lot for 5-7 years.
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LOL...I'm in Year 2 of that process. Not marine bio, but I definitely concur.

I'm venturing dangerously close to a chemistry discussion here, but should we be thinking more broadly? Maybe it's not iodine specifically that causes the (hypothetical) molt, but some characteristic of iodine. What naturally triggers B-ecdysone release?
 
Hmm...just thought of something else. Iodine CAN be used to force molting...of feathers on poultry. Wouldn't that be a hoot if that was what kicked off this whole idea?
 
What naturally triggers B-ecdysone release?
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I can tell you off the top of my head for insects, but not crustacea. I'll read some this weekend.

That's been bounced around before. Habib from salifert sent me a whole bunch of references about molting, including chickens, when I whined before. For some reason, I found it hilarious. I just think chickens are funny.

Signing off for now.
 
Chickens are funny. Naked chickens are funnier still. So far the best study I have been able to come up with is "The Bacterial Expression of the Shrimp Molt-inhibiting Hormone (MIH): antibody production, immunocytochemical study and biological assay" by Pei-Li Gu, Ka Hou Chu, and Siu-Ming Chan at the University of Hong Kong. They don't get into the specifics of iodine's role, but they do come very close. It deals mainly with supressing the molt with neuropeptides from the CHH/MIH/GIH family.

Boogie, ecdysone is secreted by the Y-organ, but I don't know the specific mechanism that causes the Y-organ to release it.

I'm not sure what's scarier, the fact that there are people actively studying crustacean hyperglycemic hormone, or the fact that we're interested in it. The database is not yet exhausted, the search continues...
 
Mogurnda and Boogiechillin, I think you both will like what I have found. Your original thoughts about iodine NOT being necessary for a molt may just be right after all. The following is a quote from the book "Without a Backbone" by Ronald Shimak, Ph.D.

"There is a persistent myth in the reef aquarium hobby that iodine is necessary for crustacean molting. This is definitely not the case. In fact, iodine may stimulate molting by acting as a poison that short-circuits part of the molt cycle. Healthy small crustaceans, such as cleaner shrimp, will shed an exuvium that is almost transparent and colorless. The molting process influenced by excess iodine results in a less transparent, often colored, molt or exuvium. This indicates that the animal was not able to salvage all of the necessary material from the cuticle and after the molting has occurred may be at a nutritional disadvantage."

This is probably the reason no one can find anything about iodine as a chemical used in stimulation of ecdysis.... because it isn't! If this guy is correct, then iodine in excessive quantities is a poison, and the molt stimulated by it is simply the crustaceans reaction to the poison. Almost like losing a leg I suppose.
 
But, there is still a definitive lack of research out there showing that ANYTHING can jumpstart a molt, let alone iodine. It's all fine and well for Shimek to say it's bad, but we can't find any REAL research showing that iodine can be used to initiate molting. Much as I like and respect Ron Shimek's work in aquarium literature, he really hasn't done a whole lot in terms of scientific publications...he's got about a half dozen cites in BIOSIS and he teaches marine bio in the middle of Montana. He's a great guy, knows a lot about captive systems and sand bed infauna, but experimentally, as a grad student who is very familiar with evaluating research, I wouldn't pin a whole lot on his findings...
 
Boogiechillin,
You took the words right out of my mouth! I think RS is great for invertebrate ID, but he doesn't have a track record as an experimental biologist. In his articles he tends to generalize from a small observation, and then the Ron-keteers regurgitate it as gospel.
I have been too busy to do any reading this weekend, and I shouldn't even be logged on right now, but I have a stack of papers that describe the hormonal events that lead to a molt. I don't think they've figured out the physiological link between body size and molting, but this is a good excuse to sit with some papers.

Kreblack,
That helped. Did the good Dr mention his source for the molt info? By the way, I certainly didn't mean you in my diatribe about the ronketeers.
 
The entire discourse presented by Dr. Shimak contains not a single footnote or bibliographical reference. I therefore thought he was expounding on his own research. I was unaware that Dr. Shimak had such notariety. I didn't take it personally, Mogurnda, this is my first foray into his works. He certainly does write as if he is THE authority on crustacea. He had me convinced, anyway.
 
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