How life's forms modify and evolve the Earth: cyanobacteria (Introduction)

by David Turell , Monday, January 06, 2025, 22:34 (29 days ago) @ David Turell

These and similar bacteria communicate with each other by nanotubules made of lipids:

https://www.quantamagazine.org/the-ocean-teems-with-networks-of-interconnected-bacteria...

"Prochlorococcus bacteria are so small that you’d have to line up around a thousand of them to match the thickness of a human thumbnail. The ocean seethes with them: The microbes are likely the most abundant(opens a new tab) photosynthetic organism on the planet, and they create a significant portion — 10% to 20% — of the atmosphere’s oxygen. That means that life on Earth depends on the roughly 3 octillion (or 3 × 1027) tiny individual cells toiling away.

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"Muñoz-Marín had a hunch about the identity of these mysterious structures. After a battery of tests, she and her colleagues recently reported(opens a new tab) that these bridges are bacterial nanotubes. First observed in a common lab bacterium only 14 years ago, bacterial nanotubes are structures made of cell membrane that allow nutrients and resources to flow between two or more cells.

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"It was vesicles that Muñoz-Marín and her colleagues, including José Manuel García-Fernández, a microbiologist at the University of Córdoba, and graduate student Elisa Angulo-Cánovas(opens a new tab), were looking for as they zoomed in on Prochlorococcus and Synechococcus in a dish. When they saw what they suspected were nanotubes, it was a surprise.

"Nanotubes are a recent addition to scientists’ understanding of bacterial communication. In 2011, Sigal Ben-Yehuda first published images(opens a new tab) of tiny bridges, made of membrane, between the bacteria Bacillus subtilis. These tubes were actively transporting material: The researchers showed that green fluorescent proteins produced in one cell of the network quickly percolated through the others. They found the same result with calcein, a small molecule that is not able to cross bacterial membranes on its own. These cells were not existing placidly side by side; their inner spaces were linked, more like rooms in a house than detached dwellings.

" It soon became clear that B. subtilis was not the only species producing nanotubes. In populations of Escherichia coli and numerous other bacteria, small but consistent fractions of cells were spotted with nanotubes. In experiments, scientists watched cells sprout the tubes and then investigated what they carried. Moving across these bridges from cell to cell were substances such as amino acids(opens a new tab), the basic building blocks of proteins, as well as enzymes and toxins(opens a new tab). Bacteria, biologists now think, have probably been making these structures all along. Scientists simply hadn’t noticed them or realized their significance.

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"The latest findings are particularly eye-opening because Prochlorococcus and Synechococcus are not your average dish-dwelling bacteria. They live in a singularly turbulent environment: the open ocean, where water movement might reasonably be expected to break the fragile tubes. What’s more, they are photosynthetic, meaning that they get most of what they need to survive from the sun. What need could they have for trading through tube networks? There has been another sighting(opens a new tab) of nanotubes in marine bacteria, but those microbes are not photosynthetic — they gobble up nutrients from their immediate environment, a lifestyle in which swapping substances with neighbors might have a more obvious benefit.

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"...to see whether the links were in fact nanotubes, they performed versions of the now-canonical experiments with green fluorescent protein and calcein described by Ben-Yehuda and Dubey. The networked cells lit up. The team also confirmed that the links were indeed made of membrane lipids and not protein, which would instead suggest pili. They were convinced, finally, that they were looking at bacterial nanotubes.

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“"this [new] paper shows that this transfer is both happening within and between species,” he said. “This is super interesting.” In a previous paper(opens a new tab), he and colleagues also noticed different species of bacteria connected by nanotubes.

"This kind of cooperation is probably more common than people realize, said Conrad Mullineaux(opens a new tab), a microbiologist at Queen Mary University of London — even in environments like the open ocean, where bacteria may not always be close enough to form nanotubes.

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"Kost, Ben-Yehuda and Mullineaux agree that the new paper’s findings are intriguing. The authors have done all the right tests to ensure that the structures they are seeing are in fact nanotubes, they said. But more work is needed to explain the significance of the finding. In particular, a big open question is what, exactly, Prochlorococcus and Synechococcus are sharing with each other in the wild. Photosynthesis allows these bacteria to draw energy from the sun, but they must pick up nutrients such as nitrogen and phosphorus from the environment. The researchers are embarking on a series of experiments with Rachel Ann Foster(opens a new tab) of Stockholm University, a specialist in nutrient flow in the ocean, to trace these substances in networked cells."

Comment: life works best with cooperative cells. This finding in bacteria tells us multicellular organisms were built into the design to appear at some point.

Note: I'd like to continue to present design suggesting science papers when they appear.