Single-celled organisms without brains or nervous systems can form memories and pass those memories on to future generations, according to new research.
Bacteria are everywhere, Escherichia coli, teeth One of the most well-studied life forms Although it still exists on Earth, scientists are still discovering unexpected ways in which it survives and spreads.
Researchers at the University of Texas and the University of Delaware have discovered a potential memory system that allows you to: Escherichia coli To “remember” past experiences for hours and then for generations.
The researchers say that, to their knowledge, this type of bacterial memory has never been unearthed before.
Obviously, the memories that scientists are discussing in this case are not the same as conscious human memories.
Bacterial memory phenomenon instead I will explain How information from past experiences influences current decisions.
“Bacteria don’t have brains, but they can collect information from their environment, and if they encounter that environment frequently, they can store that information and quickly access it later to benefit the bacteria. can.” explain The lead researcher is UT molecular bioscientist Souvik Bhattacharyya.
Bhattacharyya and his team’s findings are based on strong associations from more than 10,000 bacterial “community” assays.
These experiments Escherichia coli Cells on a single plate swarm into one moving mass that moves with the same motor. Such behavior generally indicates that cells are binding to efficiently search for a suitable environment.
On the other hand, in the following cases, Escherichia coli Cells clump together into a sticky biofilm and colonize nutrient-rich surfaces.
In early experiments, researchers Escherichia coli We test cells against several different environmental factors to see which conditions cause them to swarm the fastest.
Ultimately, the researchers found that intracellular iron was the strongest predictor of whether bacteria migrated or stayed.
Lower iron levels were associated with faster and more efficient swarming, while higher iron levels led to a more sedentary lifestyle.
Among the first generation Escherichia coli Cells, this seems like an intuitive response. However, after experiencing just one swarming event, cells that experienced a decline in iron levels later in life began to swarm even faster and more efficiently than before.
Furthermore, this “iron” memory was passed on to at least four successive generations of daughter cells, which were formed when the mother cell divided into two new cells.
By the seventh generation of daughter cells, that iron memory was naturally lost, but could be regained if scientists artificially enhanced it.
Although the authors of this study have not yet identified the underlying memory system or the molecular mechanisms behind its heritability, the strong association between intracellular iron and intergenerational crowding behavior suggests some level of persistence. This suggests that some kind of conditioning is at work.
Epigenetics is known to play the following roles: Pass “remembered” biological settings for generations Escherichia coli By controlling the ‘on’ and ‘off’ settings of specific genes, the researchers say the short duration of heritability means this is not the primary mechanism here. thinking.
Iron is involved in multiple stress responses in bacteria. It makes a lot of evolutionary sense for intergenerational memory systems to form around it.
Iron-based memory systems may help Escherichia coli Adapts to poor environmental conditions and antibiotics.
Single person Escherichia coli cell can Doubles within 30 minutesTherefore, the ability to transmit such memories to daughter cells is likely beneficial even in slowly changing environments.
“Before there was oxygen in Earth’s atmosphere, early cellular life utilized iron for many cellular processes.” To tell Bhattacharya.
“Iron is important not only for the origin of life on Earth, but also for the evolution of life. It makes sense that cells would utilize iron in this way.”
‘Eventually’ Bhattacharya in conclusion, “The more we know about the behavior of bacteria, the easier it becomes to fight them.”
This study PNAS.
