Cellular intelligence: started in bacteria (Evolution)

by David Turell , Wednesday, March 02, 2022, 00:14 (996 days ago) @ David Turell

DAVID: Exactly! Human biochemistry runs on many processes God put into original bacteria.

dhw: I thought you said: “Human biochemistry runs on many processes God put into original bacteria.”

Here is an example of an early bacterial process carried all the way to humans:

https://phys.org/news/2022-03-scientists-rare-discovery-protein-function.html

"Scientists have discovered that a human receptor protein has the ability to detect individual amino acids in exactly the same way that bacteria do.

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"Receptors on cell surfaces detect all kinds of nutrients—fats, sugars and vitamins, for example—but use different types of protein segments called sensors, and no common chemical detection mechanism is currently known.

"In this work, scientists discovered a universal sensor present in many different receptors that detects amino acids by precisely interacting with the two groups of atoms that are shared by all amino acids.

"'For the first time, we've found the universal way of detecting amino acids. Nearly every organism can do it through this mechanism," said Igor Jouline, senior author of the study and a professor of microbiology at The Ohio State University.

"'In our experience, it's very rare when we can extrapolate a very specific sensory function with such precision from bacteria to humans, because these life forms are separated by such a long evolutionary time—about 3 billion years."

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"This motif is located in an outer-facing segment of the protein that crosses a cell's outer membrane. Combining their computations with available experimental data, the team determined that this motif exists in proteins found in organisms spanning the tree of life, with the exception of fungi and a few plant species. Further analyses showed that all of the motif-containing proteins bind amino acids—and only amino acids.

"In bacteria, this sensor helps the organisms navigate toward amino acids, an important food source.

"'It's a part of a primitive nervous system for bacteria, which detects signals and helps them make decisions," Jouline said. "There's a spectacular parallel because in humans, this amino acid sensor is also a part of the nervous system. We identified this sensor in human calcium channels that modulate release of neurotransmitters from synapses in several neuronal tissues. Malfunctioning of these calcium channels results in neuropathic pain."

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"Though there may never be a definitive answer to the age-old question of what exactly bacteria and humans have in common biologically, Jouline has begun a broader search for sensors that have a role in sustaining life. (my bold)

"'Now we know where to look—not at whole proteins, but only at their segments that are involved in recognizing physical and chemical parameters important to all living systems," he said."

Comment: Note my bold. Of course we have biochemical commonality with bacteria. At the start of life many simple biochemical reactions were designed and evolution would carry them forward. That is how evolution works, much to dhw's surprise. Early simple steps lead to later more complex ones built on the early ones.