Per a UH seminar today by Harold Helgeson of UC Berkeley, proteins have folding stability (they work best when folded into "balls") at very low pH, like -2, and at these pH values, temperature extremes of 200+ degrees C and (important for those ice microbes on Europa & Mars) very low temperatures also. Even at moderate pH of 6-8, many common proteins are stable to 80-90 degrees C (Why so high? We succumb at 40+ C), which suggests that we all have a common, thermobarophilic ancestor. Prof. Helgeson has the thermodynamic data to support these conclusions (he's an expert), and he suggests that John Baross and Jody Deming's earlier data on short doubling times at 250+ degrees C from "black smoker" hydrothermal vent cultures may be correct, i.e., these organisms are productive and actually don't care if the compounds break down over longer exposure periods at high (or low) temperature and pH because they are rapidly finished with them!
As someone who has directly observed apparent colonies of microbes, probably Archaea, living in 140-200 degree C vent waters on Loihi Seamount off Hawaii in 1996-98, this was an exciting and encouraging seminar. The mats were white to clear, attached to sulfide-encrusted rock and billowing in the vent waters. I've seen a lot of inorganic hydrothermal deposits and none ever flexed or wiggled like that. Oh, and we have video.
His research team is also working on amino acids, RNA and DNA stability. I'll see if Prof. Helgeson has publications on the topic and will post.
Gary
PS. Helgeson suggests that through evolution WE are the ones living in the extreme environment, from a thermobarophilic organism's (grandma's) point of view!
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- Microbes barely surviving on ocean floors LARRY KLAES
- Re: Microbes barely surviving on ocean floors Gary McMurtry
- Re: Microbes barely surviving on ocean floors Rob Bourgeois
