A few things I want to point out about that graph. Although clearly Threonine practically eliminates growth, the graph is by no means indicating it is solely necessary. Examining the graph shows that colony size was affected negatively also in the absence of other amino acids, just more so in the case of Threonine. If we look at the graph for Glycine, you have over 1,000 number of colonies. In the case of Cysteine, you have under 600. This could support the idea of a broader amino acid supplementation. For instance, it could be that Threonine must be converted to Glycine which is then converted to some other amino acid, whereas direct supplementation is more efficient. Let me know if you have any thoughts on that.
A few things I want to point out about that graph. Although clearly Threonine practically eliminates growth, the graph is by no means indicating it is solely necessary. Examining the graph shows that colony size was affected negatively also in the absence of other amino acids, just more so in the case of Threonine. If we look at the graph for Glycine, you have over 1,000 number of colonies. In the case of Cysteine, you have under 600. This could support the idea of a broader amino acid supplementation. For instance, it could be that Threonine must be converted to Glycine which is then converted to some other amino acid, whereas direct supplementation is more efficient. Let me know if you have any thoughts on that.
Okay, one last thought and then I promise I'll shut-up for a while... Probably the reason why eliminating glycine did nothing is because glycine is more or less encapsulated, if I may use that word, in the chemical structure of every amino acid. In other words, it is much more likely that the body can create glycine out of any other amino acid supplied.
Chemical structure of glycine above.
Chemical structure of Threonine and Cysteine below.
See how you can more or less take the glycine chemical structure and overlay it on top of the structure of Threonine and Cysteine? To my understanding, you can do that with any amino acid for glycine. Consequently, it makes sense to me that eliminating glycine from the experiment had the least effect in their results. It is easy to synthesize it from other amino acids. So, as long as there are other present, the body will provide the glycine needed.
My point is that glycine supplementation would likely cut down on the body "cannibalizing," if you will, other amino acids for glycine requirements. This could be very important, as you cannot as easily convert glycine to threonine.
I really am convinced that broader amino acid supplementation is key for stem cell creation and also then for their use in building tissue etc. I still have quite a lot to learn though...
I'll leave it alone now after reiterating that quote above from the study regarding glycine:
"Previous works of our group have shown that glycine is an essential amino acid, which must be present in the diet in large amounts to satisfy the demands for collagen synthesis."
I expect the body is hijacking other amino acids to get its needs, when glycine is not present in the diet "in large amounts."
Edited by jgkyker, 26 January 2019 - 09:51 PM.