Stress-mediated growth determines E. coli division site morphogenesis

Area of Science:

• Bacterial cell division
• Microbiology
• Biophysics

Background:

• Bacterial proliferation requires cell wall remodeling at the division site.
• Peptidoglycan (PG) synthases and hydrolases, along with the Z-ring, drive bacterial division.
• Regulation involves de- and re-crosslinking enzymes and the Z-ring's constrictive force.

Purpose of the Study:

• To develop a model of bacterial division in E. coli.
• To investigate the mechanochemical coupling during cell constriction and septation.
• To determine the influence of PG remodeling on cell morphology and physical properties.

Main Methods:

• Mathematical modeling using the framework of morphoelasticity.
• Simulating the constriction and septation phases of E. coli division.
• Coupling volumetric growth and PG remodeling to mechanical stress.

Main Results:

• The model accurately reproduces the shape of the bacterial division site.
• Cellular morphologies of wild-type and mutant cells were recovered by adjusting the remodeling parameter.
• A plausible range for cell stiffness and turgor pressure was determined by matching simulations to lysis data.

Conclusions:

• The model provides insights into the mechanochemical regulation of bacterial cell division.
• Peptidoglycan remodeling is a key factor influencing bacterial cell morphology.
• The study establishes a method for estimating bacterial cell stiffness and turgor pressure.