Monday, April 25, 2016

Bacteria with a body, in the human sense, no nucleus required

Today I want to consider the wider implications of the discovery of a bacteria strain that does not live, as many bacteria do, in a co-ordinated colony of many closely packed bacterial cells under specific conditions but then normally lives as a dispersed group of fully independent separate individuals.

Instead this particular strain of cyanobacteria (earlier known as blue-green algae) is an obligate multi-celled being, which means that it looks and acts rather like us humans  ---- at least for bacteria.

These bacteria cells all live inside a single outer skin just like us, and the cells adhere to each other, like ours, and communicate with each other - again like us.

In addition, the cells are differentiated into doing different things, just as ours do. Finally, the various bacterial cells within the skin are now dependent on each differentiated other and could not survive on their own.

Nucleus-obsessed science

Now I have long ago stopped being amazed about what bacteria are really capable of or of the capacity of us humans to walk away from confronting such awkward facts.

But consider this : we are taught , on the very first day of BIO 101, that the biggest and most fundamental division in all life, is between those beings with nucleus and those without.

None of today's bacteria have nucleus but on the past a few developed one after a some big bacteria swallowed up (or was invaded by a) smaller bacteria and failed then to eat them or kill them as intended.

Because some of these new 'internal beings' had highly useful specialized abilities that worked best (safely) behind a barrier, natural selection kept them on, inside the bacteria cell but behind their own membrane and retaining the most unique of their DNA genes.


One bacteria invader turned sunlight, water and air into food and oxygen and is found inside plant and algae cells today.

The other bacterial invader scooped up potentially harmful oxygen so the bigger bacteria isn't harmed and then uses the oxygen to provide far more energy per unit of 'food' - powering the new chimera cell to take on much bigger body-building challenges, food supply permitting - it is found inside all animals today.

Possibly another of the small bacteria invaders even became the overall main nucleus of this new chimera, but most scientists currently think this unlikely.

I have never doubted what the advantages of adding these bacterial symbionts powerhouses to existing tiny lifeforms did to putting them on the eventual road to obligate multi-celled existence.

But I never could find a reason why a nucleus was deemed so necessary to the process.

Helpful yes, but not essential.

And this little obligate multi-celled bacteria suggests that this is truly so....

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