'Microorganism' is a misnomer when it comes to centimetre-long Thiomargarita magnifica:
Lurking on rotting leaves sunken in the mangroves of Guadeloupe in the Caribbean live some extraordinary thread-like creatures. These filament-like organisms, up to a centimetre in length, are the biggest single-cell bacteria yet to be found. Named Thiomargarita magnifica, they live by oxidizing sulfur, and are 50 times bigger than any other known bacteria.
[...] There are other whoppers in the Thiomargarita bacteria family, but the next-largest is only around 750 micrometres in length. Other filament-like bacteria are also found in the mangroves, but these all consist of tens or hundreds of cells. "What is very unique about the T. magnifica is that the entire filament, which is among the longest filaments in the mangrove, is just one cell," says Volland.
[...] Now that T. magnifica has been discovered, Gros expects other teams to go off in search of even larger bacteria — which might be hidden in plain sight, he says. Petra Levin at Washington University in St Louis, Missouri, says that the discovery challenges conventional wisdom that bacteria have lower size limits than eukaryotic cells. "There's probably an upper limit on cell size at some point, but I don't think it will be peculiar to bacteria or archaea or eukaryotes."
"We really should not underestimate evolution, because we can't guess where it's going to go," says Levin. "I would not have guessed this thing exists, but now that I see it, I can see the logic in the evolution to this point."
Journal Reference:
Volland, J.-M. et al. Science 376, 1453–1458 (2022). DOI: 10.1101/2022.02.16.480423
(Score: 2, Informative) by Anonymous Coward on Monday June 27 2022, @11:07AM (10 children)
Limit of eucaryotic cells is, as far as my knowledge goes, a few centimeters. The whole problem cells get is that they need a counter-pressure against the high osmotic pressure within the cells, else they burst open. Eukaryotic cells have some feats that help with that (plants for example employ a cell wall), Bacteria only have a plasma membrane, which is characteristic of their classification.
(Score: 1, Interesting) by Anonymous Coward on Monday June 27 2022, @11:31AM (2 children)
Interesting. Is that perhaps the reason for this (from a different article [lbl.gov])?
(Score: 1, Interesting) by Anonymous Coward on Monday June 27 2022, @11:44AM
That's indeed interesting. That "structure that has a membrane", resembles the nucleus in eukaryotic cells. Seems like this organism has a lot of work to give in various biological research fields.
(Score: 0) by Anonymous Coward on Monday June 27 2022, @11:52AM
I think the "internal organization" of cells has only limited influence on the cell size limit. I don't think you can conclude that the presence of some nuclear structure-like organelle allows for bigger cells by definition.
(Score: 2, Interesting) by shrewdsheep on Monday June 27 2022, @12:49PM (1 child)
The human body has cells up to 2 meters long. These are sensory neurons from the toes reaching all way up to the brain. Another type of cells which might get very long are muscle cells. The pregnant uterus can contain cells >10 cms. Life usually finds a way around even seemingly unalterable limits.
(Score: 1, Informative) by Anonymous Coward on Monday June 27 2022, @01:05PM
And whales can be more than 25 meters long... https://www.nature.com/scitable/blog/brain-metrics/the_measure_of_a_whale/ [nature.com]
(Score: 1, Interesting) by Anonymous Coward on Monday June 27 2022, @01:03PM (2 children)
https://www.nature.com/scitable/blog/brain-metrics/the_measure_of_a_whale/ [nature.com]
Sometimes I think animals aren't that different from single celled creatures and the initial main reason brains developed was to solve the problem of controlling a multicellular body and not really to solve the problem of thinking. Worms aren't that smart. If it really is that easy to have a group of cells become far more intelligent than a single cell then why are groups of humans not that much smarter than the individuals they are composed from?
(Score: 0, Interesting) by Anonymous Coward on Monday June 27 2022, @01:40PM (1 child)
Two things here:
1) A bacterium and a yeast cell are both single celled, yet they are more different than a human and a cucumber. Let that sink in.
2) Plants are multicellular, yet don't have a brain, so that can't be the reason a brain developed. The brain does more than only thinking, it also controls signal in- and output, as well as some hormonal regulation. Even then, I think there is more to it.
The group of cells that compose an organism have given up specific functions and specialized to form the organism. It's a survival strategy to become multicellular, just like hives. As for the reason why a group of people don't become more intelligent when the group expands, there can be multiple reasons (group think, conflicting interests, etc.). Sociology might give answers to that.
(Score: 0) by Anonymous Coward on Tuesday June 28 2022, @03:59PM
(Score: 0) by Anonymous Coward on Monday June 27 2022, @03:52PM
https://memory-alpha.fandom.com/wiki/The_Immunity_Syndrome_(episode) [fandom.com]
(Score: 1) by khallow on Tuesday June 28 2022, @12:43PM