[HN Gopher] The Cellular Secret to Resisting the Pressure of the...
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The Cellular Secret to Resisting the Pressure of the Deep Sea
Author : Brajeshwar
Score : 78 points
Date : 2024-09-11 16:00 UTC (3 days ago)
(HTM) web link (www.quantamagazine.org)
(TXT) w3m dump (www.quantamagazine.org)
| andrewflnr wrote:
| > Archaea lipids behave differently than those found in bacteria
| and eukaryotes
|
| That's a hell of a thing to drop with no further explanation. I
| thought eukaryotes were supposed to have evolved from basically
| archaea, or at least very archaea-like ancestors. How do
| eukaryotes end up sharing chemistry with bacteria but not
| archaea?
| Sniffnoy wrote:
| Bacterial genes migrating from the mitochondria to the nucleus
| -- or at least, that's the theory I read in "The Vital
| Question" by Nick Lane.
| unddoch wrote:
| It's one of the problems with the 'current' model of
| Eukaryogenesis. Eugene Koonin has recently suggested an
| interesting two stage model based also on shared virus
| phylogenies: https://www.nature.com/articles/s41564-023-01378-y
| adrian_b wrote:
| The eukaryotes share most of their metabolic paths with
| bacteria instead of archaea, not only their membrane
| composition.
|
| Because all the known eukaryotes have their origin after the
| symbiosis with the bacteria that have become mitochondria and
| most of the genome of the mitochondria has been moved to the
| nucleus, one possibility is that all the bacterial
| characteristics of the eukaryotes come from the ancestor of
| mitochondria.
|
| There are alternative hypotheses, e.g. that there have been a
| few other symbiosis events with some bacteria, before the
| symbiosis with the ancestor of mitochondria, so some of the
| bacterial characteristics are inherited from different
| bacteria.
|
| A possibility is that some of the differences between archaea
| and bacteria have arisen after the divergence between archaea
| and eukaryotes, so the bacterial characteristics of the
| eukaryotes would be primitive. However this supposition has
| become more unlikely during recent years, because some evidence
| has accumulated that appears to support a closer relationship
| between eukaryotes and some of the archaea than with the other
| archaea, in which case all characteristics shared by all
| archaea would predate the divergence with the eukaryotes.
| kleton wrote:
| Archae have ether linkages in their lipids, bacteria and
| eukaryotes have glycerol esters.
| blackeyeblitzar wrote:
| So is the idea that the behavior of the deep sea membrane, which
| is like a compressed spring, could be mimicked in artificial
| materials to resist high pressures?
| noisy_boy wrote:
| Very interesting - it is as if the healthy membrane shape is the
| target bytecode to which the varying "source" shapes in varying
| categories of jellies converge to under varying
| temperature/pressure conditions in order to live.
| jcynix wrote:
| Interesting small creatures, which (as a side note) can have
| enormous ecological impacts as the Wikipedia article mentions:
|
| "On the other hand, in the late 1980s the Western Atlantic
| ctenophore Mnemiopsis leidyi was accidentally introduced into the
| Black Sea and Sea of Azov via the ballast tanks of ships, and has
| been blamed for causing sharp drops in fish catches by eating
| both fish larvae and small crustaceans that would otherwise feed
| the adult fish."
|
| https://en.wikipedia.org/wiki/Ctenophora
| _Microft wrote:
| What would be a solution to carrying lifeforms elsewhere in the
| ballast tanks? Turning the water over regularily to reduce the
| distances that these creatures can travel aboard?
| littlestymaar wrote:
| I don't really understand what's the "problem" with high pressure
| for living things: they are full of water at the same pressure as
| the surrounding water so there's no risk to be _crushed_ , so
| it's not clear to me what "resisting the high pressure" means.
| bondarchuk wrote:
| It seems to be more about the different chemical properties of
| proteins under pressure, rather than structural problems that
| come with pressure difference. Just like e.g. water has a
| higher boiling point when pressurized, all kinds of chemical
| processes are different under pressure.
| sega_sai wrote:
| They talk about it in the article. The last figure shows what
| happens to the normal membrane at high pressures, it becomes
| too stiff/compressed and therefore cannot function (i.e. let
| things through etc)
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