From Newsgroup: talk.origins

https://phys.org/news/2026-06-bacteria-memories-brain.html

https://journals.aps.org/prxlife/abstract/10.1103/5zbg-8vll

Some researchers determined that bacteria that were subjected to
fluctuating high and low nutrient levels more rapidly adjusted to
changing environmental conditions than bacteria produced under
unchanging conditions. The effect could be observed several generations
after the bacteria were subjected to the fluctuating nutrient levels.

The cellular composition that adapted to the fluctuating conditions
persisted for a couple cell divisions. They proposed that one factor in
this "memory" was the differential distribution of ribosomes within the
cell under low or high nutrient conditions. This ribosomal organization
could persist through several cell divisions.

Apparently under low nutrient conditions you need fewer active ribosomes
for things like replication and cell growth, and you need to concentrate
on house keeping protein production to keep the cell functional. The distribution of ribosomes within the cell are organized to support
different cellular functions.

Beats me how ribosomes get to where they are needed within the cell, but
this system seems to persist even after the influence is no longer the
same to get them to those places. There is also the factor that the
bacteria that they used Ecoli K12 has 7 different ribosomal RNA
cistrons. The sequences are slightly different and the sequence is
related to function for structural RNAs, so there may be differences
between the ribosomes made by each cistron. The Ecoli genome is mapped
in minutes. All the ribosomal cistrons are within 30 minutes of the
position of the origin of replication (a 100 minute Ecoli genome).
Under high nutrient conditions there are multiple replication bubbles functioning so that the genes around the origin of replication are found
in multicopies. Most of the ribosomal cistrons would be multi copy
under high nutrient conditions, but under poor nutrient conditions all
of them would likely go down to single copy, so there could be a
difference in how many of each cistron is present under high and low
nutrient conditions, and it might contribute to the difference in
ribosome distribution.

Ron Okimoto

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