Bacterial growth-from physical principles to autolysins

For bacteria to increase in size, they need to enzymatically expand their cell envelopes, and more concretely their peptidoglycan cell wall. A major task of growth is to increase intracellular space for the accumulation of macromolecules, notably proteins, RNA, and DNA. Here, we review recent progress in our understanding of how cells coordinate envelope growth with biomass growth, focusing on elongation of rod-like bacteria. We first describe the recent discovery that surface area, but not cell volume, increases in proportion to mass growth. We then discuss how this relation could possibly be implemented mechanistically, reviewing the role of envelope insertion for envelope growth. Since cell-wall expansion requires the well-controlled activity of autolysins, we finally review recent progress in our understanding of autolysin regulation.

Automated summary

To increase in size, bacteria need to enzymatically expand their cell envelopes, particularly the peptidoglycan cell wall. This review focuses on how cells coordinate envelope growth with biomass growth in rod-like bacteria. It discusses the recent finding that surface area, but not cell volume, increases proportionally to mass growth, and explores the mechanistic implementation of this relation through envelope insertion. The review also highlights the recent progress in understanding the regulation of autolysins for cell-wall expansion.