[HN Gopher] Unique bacteria that survive by employing multicellu...
       ___________________________________________________________________
        
       Unique bacteria that survive by employing multicellular behavior
        
       Author : PaulHoule
       Score  : 20 points
       Date   : 2025-04-15 18:54 UTC (3 days ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | linguistbreaker wrote:
       | Love the writing as well as the content here.
       | 
       | Especially fascinated by the coordinated replication.
       | 
       | Also curious about magnetotactics - why would such a small scale
       | organism need to orient to such a large scale phenomenon (the
       | earth's magnetic field)? Wouldn't it make more sense for this
       | electromagnetic sense to be used for smaller scale orientation in
       | their environment?
        
         | gschaible wrote:
         | Magnetotaxis in bacteria (and some protist) is passive. The
         | organism will biomineralize a ferromagnetic mineral, such as
         | magnetite or greigite, and in a magnetic field they will
         | passively orientate. This is not active orientation, meaning
         | that even when the organism is dead it will still orientate in
         | the field.
         | 
         | Their movement in the magnetic field is however active. The
         | theory behind the magnetotaxis is that it allows them to know
         | what direction is up. In the northern hemisphere, the magnetic
         | poles come in from above and go down. So to a bacterium, North
         | is down.
         | 
         | Why care what direction North is? if you are sensitive to
         | oxygen, which MMB are, and oxygen diffuses in from the
         | atmosphere above, your magnetotaxis would tell you the
         | direction to swim to get away from toxic levels of oxygen. Wild
         | how evolution works!
        
       | guelo wrote:
       | Since these bacteria can't live on their own I don't understand
       | what differentiates them from true multicellular organisms.
        
         | linguistbreaker wrote:
         | The article says "individual cells within MMB consortia are not
         | genetically identical, they differ slightly in their genetic
         | blueprint."
        
         | gschaible wrote:
         | Hi there, first author of the paper here. We would argue that
         | they are a true multicellular organism, which is rather
         | unconventional for Bacteria. They do indeed have some level of
         | genomic heterogeneity between individual cells within a single
         | consortium but it appears this is actually purposefully
         | maintained by the organism, likely to facilitate their
         | evolution. They have a large genome (8 Mb) compared to E. coli
         | (4 Mb) and have duplicate genes that are under higher rate of
         | evolution (dN/dS) compared to the rest of the genome.
        
       | trhway wrote:
       | the next stage on that way i guess is
       | https://en.wikipedia.org/wiki/Portuguese_man_o%27_war - a
       | "colonial organizm"
       | 
       | "a Portuguese man o' war constitutes a single organism from an
       | ecological perspective, but is made up of many individuals from
       | an embryological perspective."
        
       | colingauvin wrote:
       | I am technically an author on this manuscript, if anyone has any
       | specific questions. I probably can't answer them, but I can text
       | the first author. (Was not expecting to see this on HN today)
        
       ___________________________________________________________________
       (page generated 2025-04-18 23:00 UTC)