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Per Clostridium tetani, it's an obligate anaerobe presumably killed by normal concentrations of oxygen. So how does it survive and reproduce in soil and in human blood full of oxygen? Even if it's spores are extremely hardy, they would still grow into bacteria which, as I understand, theoretically should die quickly. Brandmeister^talk 08:48, 8 February 2025 (UTC)[reply]

The oxygen in blood is stored in red blood cells, not free and so not a danger to bacteria. As for soil I don't know the exact chemistry of it but I would think oxygen is depleted by organisms that use it like we do, and not replenished by photosynthesis which doesn't take place underground. --2A04:4A43:909F:F990:D0:B7A6:F407:709A (talk) 09:14, 8 February 2025 (UTC)[reply]

Various anaerobic bacteria live in soil. Other common examples are those that cause Digital dermatitis and Foot rot in cattle. {The poster formerly known as 87.81.230.195} 94.8.123.129 (talk) 10:55, 8 February 2025 (UTC)[reply]

Also Clostridium botulinum, producing the neurotoxin causing botulism.  ‑‑Lambiam 20:24, 8 February 2025 (UTC)[reply]

Bacterial spores only germinate when environmental conditions of viability of the reactivated cell are met, which for the genus Clostridium (and obligate anaerobic bacteria in general) means the environment needs to have a very low concentration of free oxygen. Otherwise the spores can remain dormant for an indefinitely long period.  ‑‑Lambiam 20:40, 8 February 2025 (UTC)[reply]

And tetanus in fact "prefers" hypoxic areas in the body—hence the textbook case of infection resulting from a nail puncture, contaminated needle, bite wound, or other sharp object trauma, which introduces the spores into a deep wound where they're able to germinate. Tetanus spores ingested (such as by grazing herbivores) or that contact surface wounds rarely cause infection, because of the ambient oxygen plus outcompetition by existing skin/gut flora.

While C. tetani is frequently benign in the soil or in the intestinal tracts of animals, it can sometimes cause the severe disease tetanus. Disease generally begins with spores entering the body through a wound.[5] In deep wounds, such as those from a puncture or contaminated needle injection the combination of tissue death and limited exposure to surface air can result in a very low-oxygen environment, allowing C. tetani spores to germinate and grow.[2] As C. tetani grows at the wound site, it releases the toxins tetanolysin and tetanospasmin as cells lyse.[1]

To my understanding tetanus doesn't frequently cause bacteremia; the symptoms of infection result from the toxins it secretes which then diffuse into the blood and lymph which spreads them in the body.

There's a well-known phenomenon with some parallels, the Warburg effect, where cancerous tumors generally show preference for anaerobic metabolism and wind up promoting a hypoxic tumor microenvironment around the tumor. Among other things this "frees them" from the need to ensure and maintain a robust blood supply to the tumor to keep the oxygen coming—which impedes the body's immune system from detecting and getting at them, because the blood is what white blood cells travel around in. And the hypoxic environment also hinders those same WBCs, because WBCs need oxygen! --Slowking Man (talk) 20:58, 8 February 2025 (UTC)[reply]

From chemical nomenclature:

The prefix mono- is never used with the first element.

This sentence immediately made me think of monosodium glutamate. Is the "never used" sentence wrong, or is there some reason that MSG doesn't disprove the rule? Nyttend (talk) 11:56, 8 February 2025 (UTC)[reply]

That part of IUPAC nomenclature applies to covalent-bonded binary compounds A-B. So iodine monochloride not "monoiodine chloride" or "iodine chloride". MSG is an ionically-bonded salt, where the glutamic acid could in principle take one or two sodium counterions but in MSG only has one. Mike Turnbull (talk) 12:23, 8 February 2025 (UTC)[reply]

The MSG article shows that the IUPAC name for the substance is "Sodium 2-aminopentanedioate". As it was originally named and patented back in 1908 by Ikeda, long before nomenclature rules, I assume that hardly anyone uses the IUPAC name. Mikenorton (talk) 12:24, 8 February 2025 (UTC)[reply]

... actually, sodium (2S)-2-ammoniopentanedioate if you want to name the naturally-chiral version systematically, rather than trivially. IUPAC naming is a nightmare. Mike Turnbull (talk) 12:38, 8 February 2025 (UTC)[reply]

Hi, thank you; I know the difference between ionic and covalent, but I'd completely forgotten that I was reading a section about covalent only! Sorry for the absentmindedness that looked like cluelessness. Nyttend (talk) 19:43, 8 February 2025 (UTC)[reply]

Now, we learn in school that no prefix attached to the first element is preferred over mono-. But look at iodine pentoxide. Georgia guy (talk) 15:54, 8 February 2025 (UTC)[reply]