autonomy v. automaticity: evidence for bacterial memory (Evolution)

by David Turell , Friday, April 06, 2018, 18:20 (2421 days ago) @ David Turell

Newly discovered in bacterial biofilms:

https://phys.org/news/2018-04-bacteria-memory-descendants.html

"Led by scientists at UCLA, an international team of researchers has discovered that bacteria have a "memory" that passes sensory knowledge from one generation of cells to the next, all without a central nervous system or any neurons.

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"The team studied a strain of bacteria called Pseudomonas aeruginosa that forms biofilms in the airways of people with cystic fibrosis and causes persistent infections that can be lethal. Bacterial biofilms can also form on surgical implants, like an artificial hip; when they do, they can cause the implant to fail. Bacterial biofilms are composed of genetically identical bacteria cells that can colonize nearly any surface and form communities in which single cells organize and cooperate.

"'The first step in forming a biofilm is that bacteria must sense the surface and develop the ability to attach," said Calvin Lee, a UCLA graduate student, and the study's co-first author. "For the first time, we were able to follow the behavior of entire lineages of individual cells, and we discovered that the descendants could remember the surface sensing signals of their ancestors."

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"To analyze cells that are in the process of "sensing" the surface, the scientists used a multigenerational cell tracking method that was developed by Wong's research group, along with several other data analysis methods, including one signal processing technique that is more commonly used to analyze pitch in music—the first known application of this technique for biological measurements.
"The approach revealed that two events were linked in a rhythmic pattern: the expression of cyclic AMP, a signaling molecule inside bacterial cells, and the activity level of type IV pili, the appendages on bacteria cells that are involved in the cells' movement. The study revealed that the events are separated by only a few hours.

"'Bacteria sense and remember via this rhythmic pattern, which is pivotal for their decision to suppress motility, become stationary and ultimately attach to a surface irreversibly and form a biofilm," Wong said."

Comment: the way this works is not known as yet, but my guess is newly developed epigenetic changes in the genome change the information available, so the bacteria know how to repeat the past. It is just as logical adaptation. We see builtin bacterial adaptation all the time, which is why they never disappear.