One thing that puzzles me about the microbiome is how some of the anaerobic bacteria that cannot survive exposure to oxygen got there. For instance Akkermansia mucinophilia (I've probably mangled that - sorry) can't survive much exposure to O2 at all. Further, it's not present in one hunter-gatherer society that's been studied (the Hadza - what might be the very last hunter-gatherers), but it is present in populations eating a more modern diet.I've been reading about Akkermansia as there's evidence that it produces glucagon-like peptide. GLP-1 agonist are in the news a lot of late (Ozempic, Wegovy - and I've probably mangled those as well). As best I can figure their primary route of action seems to be reducing gut motility. Is that wrong? It's most probably incomplete as I'm an amateur here...