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Enzyme pathway in human gut microbiome that converts A to universal O type blood

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Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#11

Post by pkaye »

JamesBarney wrote: post #9
est31 wrote: post #6

Earlier quoted context omitted.

The discovery only touches the ABO group system. While the ABO group system is the most important one, there are over 36 blood group systems. The Rh blood group system is important, too: If a Rh(D) negative person gets Rh(D) positive blood for the first time, it works but they can develop antibodies for it and if they get such blood a second time, they can get major issues. In fact, there are more people (and thus po…

How much more valuable is O- blood donation than your typical donation? Curious because some writers suggest it's probably better to work and donate the proceeds than take the time to donate blood but they didn't go specifically into my blood type(O-).

O- blood is the universal donor type. Used when blood type is unknown or lack time to determine like trauma injury. About 7% of the population has this blood type. If the donor is CMV negative their is even more critical for immune deficient patients. O- donors can only accept O- blood so it is important they keep donating to give to other O- patients.

O+ is second best assuming recipient is RH+. O+ is the most common in the population.

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#12

Post by hirenj »

The whole ABO system really hints at just how tricky prediction of activity from amino acid sequence is.

The transferase that puts the A (GalNAc) or B (Galactose) sugar on switches specificity at the slightest hint of a sequence variation.

Look at the two enzymes found in this paper - one was classified as a CBM (i.e. only that it bound sugars) and the other in a family that primarily removes galactose.

As an aside, you have to appreciate this genomic arrangement where the bacteria are helpful enough to put all the genes needed to do one job (in this case break down blood antigen) in one place. That way, if you know what one thing does, you can jump to conclusions about what the others do (e.g. see a recent paper by Crouch et al).

Final point - if you are wondering where the hell we pick up antibodies to the different blood type antigens so early, if I remember correctly, it's because we develop antibodies to bacteria that ALSO have the blood type antigens.

Glycobiology is insanely cool.

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#13

Post by hirenj »

sthgrau wrote: post #10

I wonder if this is to allow safe digestion/absorption of blood types that might otherwise cause rejection problems.

It's likely there for either bacterial warfare, or degradation/metabolism of the mucus layer in the gut (or both).

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#14

Post by magduf »

pkaye wrote: post #11
JamesBarney wrote: post #9

Earlier quoted context omitted.

How much more valuable is O- blood donation than your typical donation? Curious because some writers suggest it's probably better to work and donate the proceeds than take the time to donate blood but they didn't go specifically into my blood type(O-).

O- blood is the universal donor type. Used when blood type is unknown or lack time to determine like trauma injury. About 7% of the population has this blood type. If the donor is CMV negative their is even more critical for immune deficient patients. O- donors can only accept O- blood so it is important they keep donating to give to other O- patients. O+ is second best assuming recipient is RH+. O+ is the most commo…

>O- donors can only accept O- blood so it is important they keep donating to give to other O- patients.

Actually, this isn't quite true, according to what I've read. When an O- person needs blood, they usually give him O+ blood, not O-, because they want to preserve it (and because they may not know the patient's blood type). The first time this happens, it's no big deal, but then the Rh- recipient develops antibodies to the Rh factor. So the next time the O- person gets a transfusion, they probably die.

I'm an O- person, so I wasn't too thrilled to read this. Luckily I haven't received any transfusions yet, so I have one free "life"; after that, it's game-over.

I hope this new research works out.

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#15

Post by rscho »

magduf wrote: post #14
pkaye wrote: post #11

Earlier quoted context omitted.

O- blood is the universal donor type. Used when blood type is unknown or lack time to determine like trauma injury. About 7% of the population has this blood type. If the donor is CMV negative their is even more critical for immune deficient patients. O- donors can only accept O- blood so it is important they keep donating to give to other O- patients. O+ is second best assuming recipient is RH+. O+ is the most commo…

>O- donors can only accept O- blood so it is important they keep donating to give to other O- patients. Actually, this isn't quite true, according to what I've read. When an O- person needs blood, they usually give him O+ blood, not O-, because they want to preserve it (and because they may not know the patient's blood type). The first time this happens, it's no big deal, but then the Rh- recipient develops antibodie…

Can be true if local shortage. Usually not true, as we'll do everything we can to respect the major antigens.

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#16

Post by pkaye »

magduf wrote: post #14
pkaye wrote: post #11

Earlier quoted context omitted.

O- blood is the universal donor type. Used when blood type is unknown or lack time to determine like trauma injury. About 7% of the population has this blood type. If the donor is CMV negative their is even more critical for immune deficient patients. O- donors can only accept O- blood so it is important they keep donating to give to other O- patients. O+ is second best assuming recipient is RH+. O+ is the most commo…

>O- donors can only accept O- blood so it is important they keep donating to give to other O- patients. Actually, this isn't quite true, according to what I've read. When an O- person needs blood, they usually give him O+ blood, not O-, because they want to preserve it (and because they may not know the patient's blood type). The first time this happens, it's no big deal, but then the Rh- recipient develops antibodie…

If they don't know the patients blood type would they check for the Rh antibodies before using O+ blood?

Some other interesting stuff. I'm on a kidney transplant list. When I was evaluated, they had me repeat the blood sample draw for blood type twice by two different people. They want to make sure there is no errors in classifications. Another thing is those of us with O blood type have to wait much longer for kidney transplants because we are universal donors for organs also.

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#18

Post by apathy »

hirenj wrote: post #12

The whole ABO system really hints at just how tricky prediction of activity from amino acid sequence is. The transferase that puts the A (GalNAc) or B (Galactose) sugar on switches specificity at the slightest hint of a sequence variation. Look at the two enzymes found in this paper - one was classified as a CBM (i.e. only that it bound sugars) and the other in a family that primarily removes galactose. As an aside,…

Posts like yours are the reason I come here. Great stuff. And yes glycoPTMs are insane.

Re: Enzyme pathway in human gut microbiome that converts A to universal O type blood

#19

Post by magduf »

pkaye wrote: post #16
magduf wrote: post #14

Earlier quoted context omitted.

>O- donors can only accept O- blood so it is important they keep donating to give to other O- patients. Actually, this isn't quite true, according to what I've read. When an O- person needs blood, they usually give him O+ blood, not O-, because they want to preserve it (and because they may not know the patient's blood type). The first time this happens, it's no big deal, but then the Rh- recipient develops antibodie…

If they don't know the patients blood type would they check for the Rh antibodies before using O+ blood? Some other interesting stuff. I'm on a kidney transplant list. When I was evaluated, they had me repeat the blood sample draw for blood type twice by two different people. They want to make sure there is no errors in classifications. Another thing is those of us with O blood type have to wait much longer for kidne…

>Another thing is those of us with O blood type have to wait much longer for kidney transplants because we are universal donors for organs also.

It's two things: we're universal donors, but non-universal receivers. We can give blood to anyone (Rh factor is an extra complication here), but we can only receive O blood, not any other type, so we're really screwed when we need something. Us O- people are even worse.

>If they don't know the patients blood type would they check for the Rh antibodies before using O+ blood?

In a trauma case, they probably don't have time to type your blood at all, so they just give you O+. There's lots of O+ available, but not much O-. Rh- people could have a real problem if they've already had an Rh+ transfusion, but oh well...

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