Thinking outside the box.

[JamesJR]

hey everyone. I was writing this thread because I wanted to post things of interest I have found to those of you who are scientifically inclined and hopefully in a way that will be understandable to those of you who are not. I have a biochemistry degree and I had been unnemployed for a while so I have had extra time to research and rethink things that I had once held as fact. before we go any further I want you guys to know that this is just a discussion and I would love to hear any criticisms you may have.

1). In my old reef tank I used to add an amino acid supplement to my tank because I was told it would help my corals. I never really gave much thought to it but I noticed that it really didn't make much diiference so I stopped using them altogether.
Later I got to thinking. If the water corals are surrounded by is so low in nutrients like we are told, and competition for food is so intense, how are they able to survive and still be able to grow in such a competitive environment?

Well before I go any further, I will review a little bit of the basics.
In digestion large complex molecules are broken down into their basic building blocks. In the case of sugars they are broken down into smaller units in glycolysis and are then fed into the krebs cycle to be further broken down, ultimately leading to CO2. In the case of proteins, they are broken down into amino acids. Well, what you probably weren't told in basic courses is that intermediates in the krebs cycle can be used to make amino acids and vise versa. What this does is it enables organisms to to survive and use the precious molecules efficiently without wasting any potentially usefull energy.

Well, I pulled up a paper that agreed with my original thinking: that most corals are able to synthesize virtually all of their amino acids on their own. There is some variation, but many of them can make as many as 19 of the 20 or so amino acids on their own. I am wondering if bacteria or the zooanthellae are able to augment any deficiencies in the corals metabolism.

Here is the paper if you are interested.
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1218179&blobtype=pdf

I would love to hear discussion and I will post more interesting things I have found if interest permits.

 

[Hammercoral]

Never felt the need to add amino acids myself. Photosynthesis is going to create more than enough precursers for any amino acids that the corals would need. Technically the coral is not doing all the work, the symbiotic bacteria drive photosynthesis

 

[billsreef]

If the water corals are surrounded by is so low in nutrients

That is the part that often confuses people. Yes the tropical waters around reefs are low in nutrients, ie nitrogen and phosphorous compounds, as compared to northern nutrient rich waters. However, that is strictly in reference to dissolved nutrients in the water, it does not take into account the nutrients tied up in biomass. All those fish, corals, and the plankton that those fish and corals eat supply the needed nutrients It's not so much that the reefs are nutrient poor, but rather that the available nutrients are very tightly recycled on the reef

 

[JamesJR]

I should have been more specific, but you are right.

 

[Lobster]

<a href=showthread.php?s=&postid=8460569#post8460569 target=_blank>Originally posted</a> by Hammercoral
Never felt the need to add amino acids myself. Photosynthesis is going to create more than enough precursers for any amino acids that the corals would need. Technically the coral is not doing all the work, the symbiotic bacteria drive photosynthesis

Maybe not.

To quote RHF:

"Doesnt photosynthesis create enough glucose for the coral itself?

In this experiment, apparently not for the fastest growth under these conditions... Some (maybe all) corals cannot synthesize enough of certain amino acids (such as aspartic acid). "

 

[JamesJR]

First off, corals are not able to use photosynthesis, it is the xooanthellae that does this. Second, that link is talking about how carbon is fixated into the carbonate skeletons of corals.

Second, I think that aspartic acid would definately be an amino acid a coral could make from krebs cycle intermediates.

Oxaloacetate + NADPH + NH3 --> Aspartate.

It may be a slow process because of low oxaloacetate concentrations, but definately would happen.

 

[billsreef]

The secret is to look at just how much of the animal is devoted to catching and eating food. All those pretty polyps full of nematocysts and each containing a mouth and gut aren't just for show They are eating what they can't make.

 

[JamesJR]

That is true, But what I think is that their metabolisms are simply able to fill in any gaps, so if they happen to have one shortage in one metabolite, they can make up for it with another.

I read an interesting thing yesterday, I am not sure if it is true, but it is
staggering to me anyways. I read that they found out that the coral genome for Acropora (Millepora?) has roughly the same number of genes as the human genome!

http://www.abc.net.au/science/news/stories/s1423576.htm

 

[blackheart]

I see your organic chemistry is done correctly however i dont see a picture or hydrogen flow charts which i am going to have to take points off for. What you arent seeing is that these coral do not absorb larger molecules through the water even if they where readily avalible. If you wanted to add nutrients to the water than adding precurser to the amino acids would be a good idea. The coral will steal its atp from the xooanthellae inorder to run its kreb cycle so it needs precursers. amino acids out of the system cannot bbe processed by these organisms. what does benifit are probably smaller org. that will digest this and grow and end up being eaten by the coral which the coral will then break down and rebuild in anyway it sees fit.

 

[blackheart]

also bill is correct the nematicyte located in the polyps of the corals should be a large indicator that this is a main source of food (protiens) for the animal. Also check the charge on the amino acids being suplimented into the tank. remember that the coral is absorbing positivly charged compounds and such so if your amino acids have a negative charge they might have a tough time even getting near the corals receptor site. Speaking of that have you done any research on receptor sites see what going on there that might make things clearer.

 

[geckel]

<a href=showthread.php?s=&postid=8472506#post8472506 target=_blank>Originally posted</a> by blackheart
I see your organic chemistry is done correctly however i dont see a picture or hydrogen flow charts which i am going to have to take points off for. What you arent seeing is that these coral do not absorb larger molecules through the water even if they where readily avalible. If you wanted to add nutrients to the water than adding precurser to the amino acids would be a good idea. The coral will steal its atp from the xooanthellae inorder to run its kreb cycle so it needs precursers. amino acids out of the system cannot bbe processed by these organisms. what does benifit are probably smaller org. that will digest this and grow and end up being eaten by the coral which the coral will then break down and rebuild in anyway it sees fit.

It's not a problem of lacking enough precursor molecules (unless the coral is starving). The relative amounts of amino acids that an organism synthesizes are highly regulated within their relative metabolic pathways (which are further complicated by interactions between pathways) which involve the activation and inhibition of key enzyme catalyzed rxns. The precursors would only be modified to enter pathways as fuel which is the same result as a routine feeding.

Using the above example.......If you found a way to supplement oxaloacetate (assuming uptake into the cell without modification) it would be automatically be part of the gluconeogenic pathway (since it is in the cytosol) as an intermediate between the conversion of pyruvate to phosphoenolpyruvate. The reaction that produces aspartic acid occurs in the mitochondria so the additional oxaloacetate would never even affect the relative amounts of that amino acid.

Also, coral do not get ATP from zooxanthellae but rather make ATP from the glucose produced by the zooxanthellae. The ATP is not required to run the kreb's cycle........is needed for glycolysis though.