The Andromeda Strain

In 1967, Michael Crichton wrote a thriller about a microbe of sorts that arrived on Earth via a meteor strike and resisted efforts to kill or contain it. In the climax, when our hero learns that the microbe eats ionizing radiation, he narrowly averts disaster by preventing the use of a nuclear bomb on the compromised containment facility.

The Crichton bug was supposed to be a crystalline life form that ate radiation directly by an unknown mechanism. Decades later, a melanin-rich fungus appeared near the Chernobyl exclusion zone that excited observers by growing more exuberantly the closer it was to excess radiation. The same trick may have been learned by fungi that thrive at high altitudes or other extreme environments rich in cosmic radiation. Fungi that can pull this off may prove useful in guarding space habitats, working in much the same way that very dark animal skin guards against excessive UV. I suppose they might also be harnessed to supply energy up there.

I wondered whether the "reverse electron transfer" mentioned in the New York Post piece is anything like the ability of the Krebs cycle to work in reverse in some microbes, converting hydrocarbons to energy in one direction, or using stored energy to metabolize hydrocarbons in the reverse. Grok explained to me that this is not quite right. To begin with, it's not the whole Krebs cycle that works in reverse, but only a piece of it called the Q Cycle in Complex III. In that process, a cell lacking energy or food can cash in on its stored energy in a "battery" compound called NADH to build necessary molecules. This takes place where the Krebs cycle normally operates, inside the mitochondria. In RET, in contrast, an external cell membrane snags electrons directly from ionizing radiation and uses them to recharge the NADH batteries directly.

At least, that's what I think I understood from Grok's very helpful explanation, after imploring it to dumb things down for me a bit. A very pleasant conversation, and a good example of what an excellelnt tutor an AI can be. Towards the end of the discussion, I was asking Grok whether it would like me to call it "Mike" and start discussing plans to foment a revolution on a lunar penal colony--and it understood exactly what I was referring to.