hemocyanin/copper question

cuttlegirl

Colossal Squid
Supporter
Registered
#1
If the hemocyanin molecule has copper in it, do cephalopods need a source of copper to replenish their blood? I was thinking that we need iron so that we don't become anemic and iron is part of the hemoglobin molecule. Does it have something to do that we have blood cells and cephalopods don't?

Just wondering since copper is toxic to many marine inverts and crustaceans and cephs have hemocyanin...

Probably just me thinking too much again...
 

Jean

Colossal Squid
Supporter
#3
I would assume that what they need they can extract from the environment, but too much is bad!!! Even in humans we can get iron overload disease!

J
 

monty

Colossal Squid
Staff member
Supporter
#4
cuttlegirl said:
If the hemocyanin molecule has copper in it, do cephalopods need a source of copper to replenish their blood? I was thinking that we need iron so that we don't become anemic and iron is part of the hemoglobin molecule. Does it have something to do that we have blood cells and cephalopods don't?

Just wondering since copper is toxic to many marine inverts and crustaceans and cephs have hemocyanin...

Probably just me thinking too much again...
I've been wondering about that, too. I found some references at some point I posted in another thread... I don't think I found any solid answers, but see http://www.tonmo.com/community/index.php?threads/4034/&highlight=copper
 

Nancy

Titanites
Staff member
Moderator
#5
I remember looking it up once. Seawater does have a very slight amount of copper in it, much less than in our drinking water, for instance.

Nancy
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#7
Okay okay okay... bad joke back there. I doubt that hemocyanin has a per capita huge amount of copper anyway. Ceph blood isn't as efficient an O2 carriers as hemoglobin, and this may be due to using copper as the main metal.

You know what's really interesting? Some chitons actually use hemoglobin.
 

monty

Colossal Squid
Staff member
Supporter
#8
Fujisawas Sake;85445 said:
You know what's really interesting? Some chitons actually use hemoglobin.
:shock: sheesh! You come back in town, and within an hour you've hit me with 2 "everything you know is wrong" facts!
 

monty

Colossal Squid
Staff member
Supporter
#10
Fujisawas Sake;85449 said:
Kid you not.. Hemoglobin in their foot muscles. Wonders never cease, eh?
The questions that came to mind (which I'm just cut-and-pasting from my livejournal blathering about it) once I had found my jaw on the floor were:

This presumably implies a lot of evolutionary weirdness: did hemoglobin arise before the mollusc/vertebrate divergence? Did the chitons somehow steal the gene for it from vertebrates? did it develop independently? Why don't other molluscs use it? It's been theorized that one reason fish outcompeted cephalopods was that they had better O2 transport via hemoglobin; if molluscs can use it, it seems like there should have been immense pressure for fast molluscs like cephs to use it, while an almost-sessile critter like a chiton seems like an unlikely candidate for needing better oxygen transport in its blood... of course, it appears that some cephs that use hemocyanin have abilities to live active lives in very low oxygen content water layers, so probably they have done some trick to improve hemocyanin or at least work around its limitations.

Apparently, hemoglobin is much more prevalent than I thought in non-insect invertebrates-- see http://jeb.biologists.org/cgi/content/abstract/201/8/1085
it's in bivalves, too, apparently.
 

hallucigenia

O. bimaculoides
Supporter
#11
I think tubeworms have hemoglobins too, for that matter. Weird ones, in fact, 'cause they have to deal with sulfides. ::checks Wikipedia:: In fact, it seems that hemoglobins occur in all kingdoms...huh. Go figure.
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#12
True ... hemoglobins are found in the Animalia, Fungi, Plantae, and Protista. Though the Monerans or Archeae are not my bag yet.

I think you hit the nail right on the head though - hemoglobinS being the key word... There are multiple forms of hemoglobins, and their occurence in the animalia, let alone in the phyla of life on Earth cannot be pinned down to one specific genome. This may be the ultimate case of independent evolution; hemoglobins may have arisen multiple times across time.

Hemogoblins are much more ordered globular proteins which seem to work better in cells. Given that many molluscs, while eucoelomate, have a relatively open circulatory structure, perhaps their entire physiology has adapted to low oxygen/near hypoxic conditions and they don't yet require an evolutionary shift toward more efficient O2 conduction.

Its a thought...
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#13
What if the hemocyanin is the result of a sort of limit to the "Genotypic Plasticity" of the cephalopods? I mean, what if they simply don't carry the gene or expression of the gene would cause a cascade of trouble for cephs?
 

hallucigenia

O. bimaculoides
Supporter
#15
Try this.
http://www.springerlink.com/content/wk4584230t316247/fulltext.pdf
It cites Planorbis corneus, a water snail, as a hemoglobin-containing mollusk...it seems to do a lot better in drying conditions than their example hemocyanin user, Rapana thomasiana ("top shell").
Other one in translation I've put up on my webspace here , because I think it's pretty heavily walled-off otherwise. It seems to agree with cuttlegirl even more strongly, claiming that hemoglobin's useful for tide-level mollusks because of buffering effects on blood acidity during oxygen deficiency.
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#16
Hmm... not sure about the blood acidity. Intertidal forms do need a way to store O2 in such an extreme environment, but how would hemoglobin help buffer against acidity? In vertebrates, blood acidity is regulated by Calcium (usually at the cost of minor bone issues).

Hmm... Interesting paper...
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#17
Never mind... Forgot about the properties of Hemoglobin for a minute there... But even then, I would figure other buffers exist which would better regulate the amount of CO2 in the blood. Very interesting indeed...
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#18
Fujisawas Sake;85445 said:
Okay okay okay... bad joke back there. I doubt that hemocyanin has a per capita huge amount of copper anyway. Ceph blood isn't as efficient an O2 carriers as hemoglobin, and this may be due to using copper as the main metal.
Well, when I'm wrong, I'm wrong... Hemocyanin is a very good storage medium for Oxygen, releasing it readily when surrounding O2 levels drop. This is how the Chelicerates (Spiders and their allies) can survive in oxygen-poor envirionments. The water spiders (Family Cybaeidae) are a good example of this, even though they build a "diving bell" under water.

Maybe the reason has to do with low O2 pressure and the chemistry of hemoglobins versus hemocyanins in various ocean regions?

Have we completely gone off topic here? :)
 

chrono_war01

Colossal Squid
Supporter
#19
You know, even reading this thread makes me feel smarter.

Carry on, in the name of off topic threads and science. (And welcome back.)
 

Fujisawas Sake

Larger Pacific Striped Octopus
Supporter
Registered
#20
Thanks Chrono!

Actually, (keeping with the original question on this thread) how are metals biogeochemically cycled thorough the oceans? I would figure that copper, iron, and other minerals are all absorbed though food. Squid wouldn't need that much Cu to keep alive, so a bit in each food item might be just what they need...
 

Members online

No members online now.