Explaining natural wonders; addendum 2 (Animals)

by David Turell @, Wednesday, September 28, 2016, 01:52 (726 days ago) @ David Turell

dhw: It is the ability to rewrite DNA to develop new ways of reaction/new organs that constitutes the inventive mechanism, and according to Shapiro that ability is conscious.


David: Understood, not accepted as conscious.


David: I accept his word cognitive as cognition, the ability to receive knowledge and learn it so as to act on it, which action I will only accept as automatic molecular reactions. The only inventive ability of cells is their mechanism to modify DNA and therefore the action if their genes. You and I agree on this last point.

Here is an article that shows the automaticity of sentient action in an amoeba:

https://www.newscientist.com/article/2107071-brain-eating-amoebas-hunt-brain-chemical-b...

Brain-eating amoebas can enter an unwary swimmer's brain via their nose, and once that happens, their chances of survival are slim. “They have these food cups on their surface, which are like giant suckers,” says Francine Cabral of Virginia Commonwealth University in Richmond. “They'll just start eating the brain.”

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The amoeba, Naegleria fowleri (shown in orange in the picture above), tends to lurk in fresh water, although infections can also result from swimming in hot springs or improperly chlorinated pools.

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After the amoeba enters the body, it bypasses the nose and related tissues and heads straight to the brain, where the first areas it destroys are the olfactory regions we use to smell, and parts of the frontal lobe, which are crucial for cognition and controlling our behaviour.

Why they specifically target the brain is a mystery. Abdul Mannan Baig at the Aga Khan University in Karachi, Pakistan, suspected the amoeba might be attracted to a chemical called acetylcholine or ACh, which is released in large amounts by cells at the front of the brain. This chemical is already known to act as a magnet for some immune cells and growing neurons.

To test this theory, Mannan looked for receptors on the amoeba that might attach to ACh. He and his colleagues started with Acanthamoeba - a similar genus that tends to infect people through skin wounds. The team isolated 126 proteins from the amoeba and ran them through a database to find other proteins with similar components or structures. One of these had a structure similar to the human receptor for Ach. The team have since repeated their search in Naegleria and found the same result.
This suggests that the amoebas have their own, ancient receptor for ACh, says Mannan. It is this attraction that probably causes the amoeba to bypass nasal tissues and head straight for the brain.

A receptor is a molecule or a series of molecules that act in a sentient way and trigger the move to the brain after sensing the ACh chemically.


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