A putative memory system in the well-studied bacteria Escherichia coli (E. coli) has been discovered by researchers from the University of Texas and the University of Delaware. Despite the lack of a brain or nervous system, E. coli appears to be capable of remembering prior events and passing them down to future generations. Unlike conscious human memory, this bacterial memory system influences decision-making based on earlier interactions. While bacteria lack brains, they can receive and store information from their surroundings, which they can then use to their advantage, according to lead researcher Souvik Bhattacharyya.
Artificial reinforcement has the potential to restore memory in E. coli
The study’s foundation lies in over 10,000 bacterial swarming assays, examining E. coli behavior when cells collaborate for efficient exploration or form biofilms for colonization. Intriguingly, intracellular iron levels emerged as a key factor influencing swarming behavior. Low iron levels resulted in faster and more efficient swarming, whereas greater levels resulted in a more established way of life. Surprisingly, cells with low iron levels in early generations demonstrated increased swarming in later generations.
This ‘iron‘ memory lasted at least four generations, indicating a distinct type of behavioral conditioning. Daughter cells inherited the mother cell’s iron-based memory, which lasted at least four generations before naturally declining by the seventh. Artificial reinforcement has the potential to restore memory in E. coli, demonstrating a distinct intergenerational transmission of behavioral features. While the study did not identify the chemical mechanism behind this memory system, the strong relationship between intracellular iron and intergenerational behavior suggests a type of persistent conditioning. Despite the role of epigenetics in passing biological settings through generations, the short duration of heritability in this case implies a distinct mechanism.