This is just another way to say that the map is not the territory. Anything that tries to describe reality in simpler terms than actual reality is likely just going to end up being a leaky abstraction rather than a hard law. And nature is very fuzzy along the boundaries of whatever concepts you are going to come up with.
If you dropped me off in vacuo (eg in deep space), I wouldn't meet the definition of "alive" either. But the fact that my life require a specific environment doesn't phase us or challenge our definition of life at all.
Not only do I need certain physical conditions (temperature, pressure, molecular gas composition, etc), but I also need to eat, so actually me being "alive" is dependent on specific biological conditions too. My Minimum Viable Environment actually includes other organisms, yet this doesn't challenge the fact that I'm defined as alive.
Certain parasites can only live or reproduce within another organism. This is even more extreme, but it still doesn't challenge our definition of them as being "alive."
This new organism requires a specific "environment," and that "environment" happens to be inside another organism. So what? We're totally un-phased by this requirement when it occurs in other examples.
Perhaps it's better to think of this not as a spectrum between alive and non-living, but as a hierarchy of how constrained (vs unconstrained) is the "environment" required to support life processes.
My biology is a bit rusty but I really have to wonder — are plants and animal cells even “alive”?
Take away the mitochondria and bacteria… can cells live on their own?
If no, then are we that all that different than this microbe?
Might even be sheer arrogance to think that we are the “host” (much like cats/dogs domesticating humans). Maybe we only exist to serve the mitochondria (:->
There are a few weird cases of prokaryotes that don't have mitocondrias. Apparently they had mitocondrias, but they steeled the interesting parts and get rid of them (over gazillions of years). From https://en.wikipedia.org/wiki/Metamonad
> These flagellates are unusual in lacking aerobic mitochondria. Originally they were considered among the most primitive eukaryotes, diverging from the others before mitochondria appeared. However, they are now known to have lost aerobic mitochondria secondarily, and retain both organelles and nuclear genes derived ultimately from the mitochondrial endosymbiont genome. Mitochondrial relics include hydrogenosomes, which produce hydrogen (and make ATP), and small structures called mitosomes.
> Take away the mitochondria [...] can cells live on their own?
Neither can live without the other. Too much genetic exchange has taken place in some distant ancestor where critical genes were deleted from mitochondria and moved to the host. Meanwhile host cells became utterly dependent on mitochondria for energy production. Or you might say: the mitochondria were producing so much excess ATP the host cells started evolving to depend on that much energy being available.
The exceptions are later cases (like a few organisms that have copied energy production from the mitochondria genome then later lost the mitochondria entirely).
For all purposes mitochondria are zombie archaea (not bacteria). Hollowed out empty shells retaining just enough function to perform aerobic respiration and reproduce. There is little pressure to evolve away from this local maxima. What benefit would the host cells derive from getting rid of the mitochondria? Not much. And having those critical functions isolated in what amounts to a pseudo-organelle with its own DNA protects it from a lot of sources of damage/error.
So... are we obligate symbiotes? Or have mitochondria hyper-evolved to such a point they are just organelles in our cells - just ones that carry their own DNA instead of relying on the cell's main DNA? Like much of biology... a bit of both in a fuzzy mix without a clear line.
My bio is rusty but I remember that archaeon are into extreme situations. Is it so weird to find an example of one essentially “offloading” some functionality to its host? Especially in a diluted environment like the oceans
I really hate how shitty science reporting has become, you can tell all science journos aren't actually current or well read in the science they report on. This isnt some new miracle find this is a well described and growing phylum https://en.wikipedia.org/wiki/Nanobdellota Having genome reduced symbionts of dinoflagellates is an even more common and general phenomena, its almost the definition of a dino to have a weird zoo of peculiar friends and things becoming endo symbionts. This finding is definitely cool, but I dont understand why the article has to make out its a "breakthrough" or "astounding" rather than actually the more astounding thing is how normal this very weird thing is!
The article should have at least tipped its hat to mitochondria:
>But unlike a virus, Sukunaarchaeum has its own ribosomes, cellular structures that synthesize proteins, and it can replicate itself without the help of a host.
Yes and this is true of mitochondria as well: Their own DNA, a own complex set of membranes, a private customized set of ribosomal proteins and tRNAs, and the ability to replicate within the “host”. Mitochondria are also perfectly happy to be swapped from cell to cell.
I wonder if or how these nanobiobots contribute to the fitness of their hosts.
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[ 3.3 ms ] story [ 53.2 ms ] threadNot only do I need certain physical conditions (temperature, pressure, molecular gas composition, etc), but I also need to eat, so actually me being "alive" is dependent on specific biological conditions too. My Minimum Viable Environment actually includes other organisms, yet this doesn't challenge the fact that I'm defined as alive.
Certain parasites can only live or reproduce within another organism. This is even more extreme, but it still doesn't challenge our definition of them as being "alive."
This new organism requires a specific "environment," and that "environment" happens to be inside another organism. So what? We're totally un-phased by this requirement when it occurs in other examples.
Perhaps it's better to think of this not as a spectrum between alive and non-living, but as a hierarchy of how constrained (vs unconstrained) is the "environment" required to support life processes.
Take away the mitochondria and bacteria… can cells live on their own?
If no, then are we that all that different than this microbe?
Might even be sheer arrogance to think that we are the “host” (much like cats/dogs domesticating humans). Maybe we only exist to serve the mitochondria (:->
> These flagellates are unusual in lacking aerobic mitochondria. Originally they were considered among the most primitive eukaryotes, diverging from the others before mitochondria appeared. However, they are now known to have lost aerobic mitochondria secondarily, and retain both organelles and nuclear genes derived ultimately from the mitochondrial endosymbiont genome. Mitochondrial relics include hydrogenosomes, which produce hydrogen (and make ATP), and small structures called mitosomes.
Essentially nothing can live on its own, certainly not animals.
Neither can live without the other. Too much genetic exchange has taken place in some distant ancestor where critical genes were deleted from mitochondria and moved to the host. Meanwhile host cells became utterly dependent on mitochondria for energy production. Or you might say: the mitochondria were producing so much excess ATP the host cells started evolving to depend on that much energy being available.
The exceptions are later cases (like a few organisms that have copied energy production from the mitochondria genome then later lost the mitochondria entirely).
For all purposes mitochondria are zombie archaea (not bacteria). Hollowed out empty shells retaining just enough function to perform aerobic respiration and reproduce. There is little pressure to evolve away from this local maxima. What benefit would the host cells derive from getting rid of the mitochondria? Not much. And having those critical functions isolated in what amounts to a pseudo-organelle with its own DNA protects it from a lot of sources of damage/error.
So... are we obligate symbiotes? Or have mitochondria hyper-evolved to such a point they are just organelles in our cells - just ones that carry their own DNA instead of relying on the cell's main DNA? Like much of biology... a bit of both in a fuzzy mix without a clear line.
The article should have at least tipped its hat to mitochondria:
>But unlike a virus, Sukunaarchaeum has its own ribosomes, cellular structures that synthesize proteins, and it can replicate itself without the help of a host.
Yes and this is true of mitochondria as well: Their own DNA, a own complex set of membranes, a private customized set of ribosomal proteins and tRNAs, and the ability to replicate within the “host”. Mitochondria are also perfectly happy to be swapped from cell to cell.
I wonder if or how these nanobiobots contribute to the fitness of their hosts.