[HN Gopher] "We argue that mitochondria are the processor of the...
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       "We argue that mitochondria are the processor of the cell" (2022)
        
       Author : breck
       Score  : 57 points
       Date   : 2024-06-23 12:15 UTC (10 hours ago)
        
 (HTM) web link (www.cell.com)
 (TXT) w3m dump (www.cell.com)
        
       | macawfish wrote:
       | From one machine analogy to the another... Mitochondria have been
       | observed moving between cells. These are living organisms!
       | Reducing their role to that of "microprocessor" seems
       | suffocating.
       | 
       | https://www.quantamagazine.org/social-mitochondria-whisperin...
        
         | epgui wrote:
         | For my masters' degree I studied extracellular free
         | mitochondria and extracellular vesicles containing
         | mitochondria. It's a wild world.
        
           | breck wrote:
           | Very interesting.
           | 
           | Can you tell more? What was that like? What was your day to
           | day? Wet lab/dry lab, etc?
           | 
           | What % are extracellular? Did you study mitoribosomes at all?
           | 
           | No detail is too small!
        
             | epgui wrote:
             | Wet lab. It was horrible. 6 years of dishwashing and
             | monotony. I write software now and am much happier.
             | 
             | The numbers were very difficult to reproduce and sensitive
             | to tiny variations in experimental conditions, to the point
             | of mystery. My MSc took me 6 years rather than 2, and
             | that's with a >90% scope cut.
             | 
             | I can say that there was a "comparable" proportion of
             | freeMitos to mitoMPs in the samples I was studying, which
             | were induced from 786-O and 786-O/VHL cell cultures using a
             | variety of agonists (atypically low concentrations of
             | A23187, compared to literature, and serum-starved cell
             | culture medium, seemed to work best; usual concentrations
             | of A23187 seemed very violent on the cells, which is
             | relevant if you're trying to ascertain anything about
             | physiologic conditions). Shockingly, a very sizeable
             | proportion (10-50% of EVs above a certain detection
             | threshold, probably near 100-150nm) of total EVs were
             | either mitoMPs or freeMitos.
             | 
             | I did not study mitoribosomes.
             | 
             | I was trying to optimize conditions for the generation of
             | EVs (literature is lacking here) and flow cytometric
             | techniques for measuring EV subpopulations. Mitochondria
             | gum up the tubes and require special care. Experiments that
             | measure EVs without controlling for the presence of
             | mitochondria are IMO inherently suspect.
             | 
             | There is a really great paper published by L Boudreau in
             | the journal Blood with better results than anything I ever
             | achieved, it's very interesting stuff:
             | https://pubmed.ncbi.nlm.nih.gov/25082876/
        
         | mathgeek wrote:
         | The idea of comparing evolved structures to the current height
         | of technology is usually an oversimplification. It's amusing to
         | think back to when the switchboard was compared to the brain,
         | for example. It wasn't that long ago that we considered the
         | brain and a computer to also be quite similar, but we know it's
         | only in certain aspects.
        
           | exe34 wrote:
           | it's called a model. all models are wrong but some are
           | useful. the plugboard model of the brain was useful in the
           | sense it suggested pieces working together and functional
           | connections varying for different activities.
           | 
           | nobody is suggesting the brain runs an instruction set or a
           | compiler - but it does compute in a general sense.
        
             | soloist11 wrote:
             | Everything computes in a general sense, even atoms. But one
             | could just as easily say everything is "just" mathematics
             | because all models of reality are mathematical. In general
             | I think it's important to be wary of totalizing ontologies
             | and metaphysics of reality that reduce everything to a
             | single universal substance (monadology) or activity like
             | computation (computationalism).
        
             | sublinear wrote:
             | > nobody is suggesting the brain runs an instruction set
             | 
             | What happened to all those idiots saying the universe is a
             | simulation and we have no free will?
        
               | edmundsauto wrote:
               | Those people still exist alongside all those idiots who
               | think we have free will and that the universe is the
               | embodiment of existence ;)
        
             | EnigmaFlare wrote:
             | It's an analogy, not a model. It's useless for making
             | predictions or testing hypotheses. Even pretty useless for
             | conveying understanding.
        
               | Teever wrote:
               | An analogy is a way of expressing a model in a highly
               | compressed verbal state.
        
               | mathgeek wrote:
               | The term we're looking for is likely "analogical model"
               | https://en.wikipedia.org/wiki/Analogical_models
        
             | stefan_ wrote:
             | Except sometimes you lose control and you grifters
             | pretending your model is the real deal and the singularity
             | is near.
        
       | akira2501 wrote:
       | The cellular environment is such a mess it's not a surprise that
       | environmental changes are observed by many types of bodies within
       | the cell. It's hard to think of it like a "processor," though,
       | when almost all of it's messages are non specific broadcasts and
       | not direct targeted messages.
       | 
       | To me it seems like RNA is the processor, DNA is the RAM, and
       | mitochondria are voltage regulation modules. That they're all
       | environmentally sensitive is a consequence of how the machine is
       | constructed.
        
         | fsloth wrote:
         | "To me it seems like RNA is the processor, DNA is the RAM,..."
         | 
         | Is there anything resembling a von Neumann machine in the
         | biochemistry, though?
         | 
         | Would Turing machine analogues be more useful?
        
           | tomlue wrote:
           | Epigenetic modifications, such as methylation, are made to
           | DNA by specific proteins. These modifications alter the
           | transcription process from DNA to RNA, which in turn affects
           | protein expression. This includes the expression of the
           | proteins responsible for epigenetic changes themselves. In
           | essence, the proteins that modify DNA also control the
           | expression of their own building instructions through a
           | feedback loop.
           | 
           | I guess that feels a bit like a von neumann machine to me,
           | but I'm not sure the analogy is super helpful.
        
           | WJW wrote:
           | Both Turing and Von Neumann machines (and the lambda calculus
           | by Church) were designed to be minimal implementations that
           | were still powerful enough to be provably complete in a
           | mathematical sense. Mother Nature is under no such
           | constraints: she happily constructs massively parallel
           | "computers" with millions of global variables, each being
           | written to by every core. That human minds cannot debug such
           | systems is not Her problem. The only constraint is if it
           | works, and it does.
        
         | dtech wrote:
         | Wouldn't RNA be the RAM and DNA be long term storage? Most of
         | the work and "decision making" - at least in current organisms
         | - is done by proteins.
        
           | akira2501 wrote:
           | There are many different types of RNA with different
           | purposes. They all act in concert to produce proteins. mRNA
           | encodes proteins, tRNA brings the proteins into
           | transcription, rRNA actually acts as a protein itself to help
           | drive this machine.
           | 
           | DNA is environmentally sensitive and it can be altered. Your
           | entire genome is not being produced all the time. Different
           | proteins are copied based upon the conformal structure of DNA
           | which changes based upon the cellular environment. The entire
           | structure is copied often and no one particular set of DNA in
           | your body is "the original."
           | 
           | It has aspects of long term storage but then it's utilized in
           | a way that long term storage almost never is. And all cells
           | get their own copy which may be unique in several ways. So
           | RAM seems like a better metaphor to me.
        
           | acchow wrote:
           | Given the billions of years of compression involved, these
           | structures could occupy any number of latent spaces with all
           | sorts of different meaning.
        
       | carrozo wrote:
       | Mitochondria is the powerhouse of the cell!
       | 
       | https://knowyourmeme.com/memes/mitochondria-is-the-powerhous...
        
         | xanderlewis wrote:
         | and a monad is a monoid in the category of endofunctors.
        
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