Explaining natural wonders: bacterial intelligence (Animals)

by David Turell , Tuesday, June 13, 2017, 23:31 (2718 days ago) @ David Turell

An E. coli built in mechanism just discovered:

https://www.sciencedaily.com/releases/2017/06/170613145146.htm

"In the periplasm -- the space between the inner and outer membranes of a bacteria's cell wall -- defensive proteins that detect a poison assemble like barrel staves to form a tunnel between pumps in the cell's inner and outer membranes to eject the intruders.

"By tagging a cell's proteins with fluorescent beacons, Cornell researchers have found out how E. coli bacteria defend themselves against antibiotics and other poisons. Probably not good news for the bacteria.

"When undesirable molecules show up, the bacterial cell opens a tunnel though its cell wall and "effluxes," or pumps out, the intruders.

"'Dynamic assembly of these tunnels has long been hypothesized," said Peng Chen, professor of chemistry and chemical biology. "Now we see them."

***

"Under a powerful microscope, they exposed a bacterial cell to an environment containing copper atoms and periodically zapped the cell with an infrared laser to induce fluorescence. Following the blinking lights, they had a "movie" showing where the tagged protein traveled in the cell. They further genetically engineered the various proteins to turn their metal-binding capability on and off, and observed the effects.

***

"The key protein, known as CusB, resides in the periplasm, the space between the inner and outer membranes that make up the bacteria's cell wall. When CusB binds to an intruder -- in this experiment, a copper atom -- that has passed through the porous outer membrane, it changes its shape so that it will attach itself between two related proteins in the inner and outer membranes to form a complex known as CusCBA that acts as a tunnel through the cell wall. The inner protein has a mechanism to grab the intruder and push it through.

"The tunnel locks the inner and outer membranes together, making the periplasm less flexible and interfering with its normal functions. The ability to assemble the tunnel only when needed, rather than having it permanently in place, gives the cell an advantage, the researchers point out."

Comment: this defensive mechanism must have been present in the original bacteria as a molecular machine to dump dangerous garbage. There are other dangerous substances beside copper on Earth to be defended against. It is difficult to imagine this evolved by chance evolution, finding just the right organic molecule for the built in job. The bacteria doesn't use intelligence to perform this task. It simply senses the copper danger and reacts.