Relative Rates of Surface and Volume Synthesis Set Bacterial Cell Size.
Many studies have focused on the mechanisms underlying length and width determination in rod-shaped bacteria. Here, we focus instead on cell surface area to volume ratio (SA/V) and demonstrate that SA/V homeostasis underlies size determination. We propose a model whereby the instantaneous rates of surface and volume synthesis both scale with volume. This model predicts that these relative rates dictate SA/V and that cells approach a new steady-state SA/V exponentially, with a decay constant equal to the volume growth rate. To test this, we exposed diverse bacterial species to sublethal concentrations of a cell wall biosynthesis inhibitor and observed dose-dependent decreases in SA/V. Furthermore, this decrease was exponential and had the expected decay constant. The model also quantitatively describes SA/V alterations induced by other chemical, nutritional, and genetic perturbations. We additionally present evidence for a surface material accumulation threshold underlying division, sensitizing cell length to changes in SA/V requirements.
Biophysics Program, Department of Biochemistry and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
Leigh K
LK
Harris
Biophysics Program, Department of Biochemistry and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA. Electronic address: theriot@stanford.edu.
Julie A
JA
Theriot
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development* / Q000648:ultrastructure*; D001696:Biomechanical Phenomena; D016935:Caulobacter crescentus / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D004926:Escherichia coli / Q000254:growth & development / Q000648:ultrastructure; D005578:Fosfomycin / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000254:growth & development / Q000648:ultrastructure; D008954:Models, Biological; D010457:Peptidoglycan; D013499:Surface Properties
D000900:Anti-Bacterial Agents; D010457:Peptidoglycan; D005578:Fosfomycin