Precise regulation of the relative rates of surface area and volume synthesis in bacterial cells growing in dynamic environments.

Department of Bioengineering, Stanford University, Stanford, CA, USA. Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA. Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA. Chan Zuckerberg Biohub, Stanford, CA, USA. Department of Bioengineering, Stanford University, Stanford, CA, USA. kchuang@stanford.edu. Chan Zuckerberg Biohub, Stanford, CA, USA. kchuang@stanford.edu. Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. kchuang@stanford.edu.

Nature communications. 2021;(1):1975

Abstract

The steady-state size of bacterial cells correlates with nutrient-determined growth rate. Here, we explore how rod-shaped bacterial cells regulate their morphology during rapid environmental changes. We quantify cellular dimensions throughout passage cycles of stationary-phase cells diluted into fresh medium and grown back to saturation. We find that cells exhibit characteristic dynamics in surface area to volume ratio (SA/V), which are conserved across genetic and chemical perturbations as well as across species and growth temperatures. A mathematical model with a single fitting parameter (the time delay between surface and volume synthesis) is quantitatively consistent with our SA/V experimental observations. The model supports that this time delay is due to differential expression of volume and surface-related genes, and that the first division after dilution occurs at a tightly controlled SA/V. Our minimal model thus provides insight into the connections between bacterial growth rate and cell shape in dynamic environments.