In a study led by Sarah Worthan, Ph.D., a postdoctoral researcher in the Behringer Lab at Vanderbilt University, scientists have successfully evolved microbial cultures that possess the ability to sense pH changes, enabling rapid responses to environmental fluctuations.

Along with highlighting the power of lab-driven evolution, this discovery also led to finding similar mutations in nature in emerging pathogens and coral symbionts—organisms that navigate challenging pH shifts in their environments and are otherwise difficult to study.

The new paper, "Evolution of pH-sensitive transcription termination in Escherichia coli during adaptation to repeated long-term starvation," was published in the Proceedings of the National Academy of Science on September 19, 2024. The driving result from this work is the discovery of a mutation in the independently evolved populations of bacteria that occurs when the bacteria are exposed to feast and famine cycles.

According to the paper, this mutation, where an arginine amino acid is replaced with a histidine, occurred on the Rho protein, which is involved in terminating RNA transcription. Arginine to histidine mutations have also been observed in cancers and have been shown to confer an adaptive pH sensing ability to oncogenic proteins. In bacteria, these arginine to histidine mutations can sense pH and alter the activity of the Rho protein to rapidly impact how genes are expressed.

Evolved in the lab

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