Sizing up bacteria
A new theoretical framework outlined by a Harvard scientist could help solve the mystery of how bacterial cells coordinate processes that are critical to cellular division, such as DNA replication, and how bacteria know when to divide. For decades, scientists have believed that cellular division is triggered when bacterial cells reach a particular size. The new model, described by Ariel Amir, an assistant professor of applied mathematics and applied physics, in a paper recently published in Physical Review Letters, suggests that cells coordinate the replication of their DNA not through size, but by how much they grow over time. “The focus of this work is on how bacteria regulate their size — how do they know when to divide, so they all remain largely identical,” Amir said. “The question is: How do they do that, and how does that couple with other processes in the cell, such as DNA replication?” Scientists have long...