The relationship between the cellular composition and size of a species of bacteria can determine how and how well it functions. Scientists with the Life Underground team at the University of Southern California have collected data on a diverse range of bacterial cells spanning five orders of magnitude to call out the cross-species connections between cellular form and function. The paper, “Evolutionary tradeoffs in cellular composition across diverse bacteria” is published in The ISME Journal.

The team compared cell volume against the amount of DNA, ribosomes, proteins, cell membrane, tRNA, and mRNA contained within, and focused on power-law relationships—how a change in scale of one feature proportionally altered another—where some cell features followed trends more than others. How two things scaled together often suggested limitations for the cells at a given size that pointed to possible evolutionary consequences.

By using this comparative framework, the scientists show how the interconnected relationship between the cells’ energetic, physical, genomic, chemical and temporal processes help us to predict the upper and lower boundaries of bacterial size, and to also define the evolutionary flexibility and trajectory of bacteria between the boundaries.

The research was supported by the NASA Astrobiology Institute and the Gordon and Betty Moore Foundation.