Vitamin B12 produced by gut bacteria modulates cholinergic signalling

[helvella]

I simply can't help but think that this has some relevance to Pernicious Anaemia.

But goodness knows what! And the lack of access precludes reading it all to try to find out.

Seems such an odd bit of genetics that we developed an incredibly complex system to grab a tiny bit of B12 from our food, which can and does go wrong, yet we might be hosting sufficient bacteria which are manufacturing B12 within our bodies.

I know I'm far from the first to say that but this paper might be prising open the door to seeing why that might have been a beneficial route to take.

Vitamin B12 produced by gut bacteria modulates cholinergic signalling

Woo Kyu Kang, Jeremy T. Florman, Antonia Araya, Bennett W. Fox, Andrea Thackeray, Frank C. Schroeder, Albertha J. M. Walhout & Mark J. Alkema

Nature Cell Biology (2024)

Abstract

A growing body of evidence indicates that gut microbiota influence brain function and behaviour. However, the molecular basis of how gut bacteria modulate host nervous system function is largely unknown. Here we show that vitamin B12-producing bacteria that colonize the intestine can modulate excitatory cholinergic signalling and behaviour in the host Caenorhabditis elegans. Here we demonstrate that vitamin B12 reduces cholinergic signalling in the nervous system through rewiring of the methionine (Met)/S-adenosylmethionine cycle in the intestine. We identify a conserved metabolic crosstalk between the methionine/S-adenosylmethionine cycle and the choline-oxidation pathway. In addition, we show that metabolic rewiring of these pathways by vitamin B12 reduces cholinergic signalling by limiting the availability of free choline required by neurons to synthesize acetylcholine. Our study reveals a gut–brain communication pathway by which enteric bacteria modulate host behaviour and may affect neurological health.

Rest of article is behind a paywall.

nature.com/articles/s41556-...

Caenorhabditis elegans - a nematode worm!

en.wikipedia.org/wiki/Caeno...

[Technoid]

The colon(large intestine) has a lot of B12 producing bacteria but thats too late - absorption of B12 happens at the ileum, the end of the small intestine.

Here's a link to the full paper:

rdcu.be/dvqJN

[helvella in reply to Technoid]

Yes - but that has always seemed an odd evolutionary track to take! The idea that some creature, somewhen might have been able to exploit that on-board B12 generator seems feasible - but we might understand that even if it happened, it didn't persist for a good reason.

However, I was thinking things like the B12 from oral sources, or injections via the gall bladder, passing down the gut and affecting cholinergic signalling.

[Technoid in reply to helvella]

This (animal ag promoting) site claims that, for ruminants:

"* On average, between 3 to 13% of dietary cobalt is converted into cobalamin;

* Only 1 to 3% of the vitamin B12 synthesized in the rumen is absorbed in the small intestine."

So it seems for cows, their digestive system did evolve to absorb adequate B12 without any dietary B12 requirement, as long as they get enough cobalt (which may or may not be the case depending on soils or farming method)

from praisetheruminant.com/rumin...

[Rexz in reply to Technoid]

Oh how I wished I were a cow! 🤣

[Technoid in reply to Rexz]

😂

[Narwhal10 in reply to Rexz]

You ain’t seen the udders (others) 🤪🤪🐮

[Rexz in reply to Narwhal10]

🫣😜

[Rexz]

I have this full text study and yes, the subject of the study is a worm as you've indicated. As Technoid responded we have plenty of B12 producing bacteria in our colon which is just a bit to late for us. You're right in that us humans and also apes took a wrong turn on our evolutionary trek or could it be that our maker made a boo boo?? 🤔

Btw there are seemingly vegetarian apes that get their total B12 requirements from insects. Yum.🤮

[MorningMist in reply to Rexz]

Maybe it was by design that we absorb b12 in the ileum and then produce b12 further along in the colon to replace what our bodies have taken from the environment. Nutrient recycling.

[Rexz in reply to MorningMist]

Well that's an interesting twist! Love it! 😊

[MorningMist in reply to Rexz]

Well it’s just an attempt to make a bit of sense of what otherwise appears to be a crazily complicated and illogical process.

[Rexz in reply to MorningMist]

Oh it's not just B12... This crazily complicated and illogical biological machine we live in, it's just amazing that we even wake up each morning. 🤯

[MorningMist in reply to Rexz]

in the interest of evolution it was probably meant to be that way but our modern way of thinking has upturned the apple cart.

[Technoid in reply to Rexz]

"Btw there are seemingly vegetarian apes that get their total B12 requirements from insects"

and, IIRC Rexz, also from eating poop, which of course is a great B12 source 🤪

[Rexz in reply to Technoid]

Oh my, yummy!!! I'm thinking that's an acquired taste though? 🙃

[tomdickharry]

I don't know its detailed action, but it's an example of how bacteria, viruses, and parasites modify the host systems to suit their own lifestyles, ie., guarantee their survival.

[Narwhal10]

helvella,

Apologies this does not stay on topic. However, I have just accessed your blog spot and wow, double wow. Great work which over the course of however long, I will have a jolly good read.

Keep up the great work and thank you ever so much.

🤓

[helvella in reply to Narwhal10]

Thank you!

I am always open to corrections and (hopefully) constructive criticism.